Nikkor AF-S 50mm f/1.8 G : Review

Introduction

This time I’m bringing to you my review of the Nikkor AF 50mm f/1.8 G lens for the Nikon mount, tested with the Nikon D700 full-frame DSLR. A 50mm lens is always a useful lens on full-frame for many purposes, from candid shots in low light to street photography, closeups and portraits. It is also a popular choice for the novice DX shooter as a first buy, since normal primes are usually cheap, not only for portraiture but also to get something more from their photos than those taken with the kit lenses.
The old 50mm f/1.8 D was a very good lens, and very cheap, but users with entry-level DSLRs could not auto-focus with this lens, meaning that this update was overdue.
After having enjoyed shooting for a couple years with the Nikkor AF-S 35mm f/1.8 G when I had a DX camera, I expected at least the same performance from this new 50mm on FX. This review will show what this lens is capable of in its native format.
For starters, see how the lens looks with a D700:

The lens was introduced in 2011 as a long overdue update for users with entry-level cameras that don’t have an AF drive, giving these users a much cheaper alternative to the f/1.4 G version. It was also about time to finally put an AF-S motor in the lens, since the entire lens lineup had been updated since many years ago. This normal prime lens includes 7 elements in 6 groups, of which one is of aspherical type to take care of optical distortions. It’s an all-plastic lens, including the filter thread, except the mount which is metal, but the plastic has a good quality and is rugged like the other G lenses. Being a G lens means that it doesn’t have an aperture ring anymore.
Having a street price of about 199€, it costs, looks and feels as the 35mm f/1.8 G, which for me it was a very good lens.

Technical Specifications

Focal length 50mm
Maximum aperture f/1.8
Minimum aperture f/16
Field of view 47 degrees (on FX)
Weight 185g
Dimensions 54 x 70mm
Optical construction 7 elements in 6 groups (1 aspherical element)
Aperture blades 7, rounded
Filter diameter 58mm
Minimal focus distance 91cm (37cm from the front element)
Hood HB-47, rounded
Mount Nikon F

Mechanical Characteristics

Zoom ring n/a
Focus ring Plastic with rubber finish, no infinity stop
Focus throw 110 degrees
Focus motor Yes
Optical stabilizer No
Front element rotation while zooming n/a
Front element rotation while focusing No
Internal focusing Yes
Lens extension while focusing No
Lens extension while zooming n/a
Maximum magnification 1:6.5

Handling

The Nikkor 50mm f/1.8 G lens is larger than the previous D version due to the inclusion of an AF motor, although it’s only 30 grams heavier, but looks big on a D3100. It balances and handles nicely on any camera, though, fitting everyone’s hands better than the D version.
The Nikkor is all-plastic made, but the mount is metal. The focus ring is plastic with a rubber finish for more grip but it’s not damped, it’s not smooth and feels like it’s not continuous, but instead feels like there are many tiny bumps while turning it. It doesn’t have an hard infinity stop, therefore one has to focus manually using Live View if we’re taking the lens out for astrophotography. Contrary to other motorized lenses, the focus ring stops turning around a little past infinity, while in those other lenses the focus ring never stops turning around. Thus, the focus ring must not be forced beyond infinity or below minimum focus distance, with the risk of breaking the AF mechanism. Fortunately, I rarely use the focus ring – only in Live View in the dark. The M/A-M switch on the lens means that at the M/A setting the lens allows manual focus override, which can be very useful at times, especially when working with large apertures, to make sure than the lens is focused on the exact spot we want. The throw of about 110 degrees is good for manual focusing.
The front element doesn’t rotate while focusing, so using polarizers is fine.
Speaking about focus speed, the lens focuses fast even in low light and never hesitates. The SWM motor is silent but it’s not amongst the best AF-S motors, there are much faster versions and more silent than this one. It has a problem, though: although the lens seems to focus faster than the f/1.4 G version, the f/1.8 G misses the target like once in every 10 shots when I use apertures greater than f/2.8. And I’m talking about long distance shots. This problem happens even at noon with contrasty subjects. When I use smaller apertures I don’t get any problems. My older trusty 50mm f/1.8 D always focused fast and with precision, but noisier of course. I just played with the f/1.4 G lens for several minutes and don’t know if the misfocusing issue was there too, but the few pictures I took with it were all in focus.
I use the lens mainly on the streets, it’s a snappy shooter and my only complain is the occasional misfocus.

Resolution

For the resolution test I shot the 5 Euro bill as usual. Focus was achieved using Live View to avoid auto-focus imprecisions and to compensate for possible field curvature issues.
The first column shows a crop of the image center, the corner crop is on the second column (the expected DX border) and the third column shows a crop of the extreme FX corner. Each row represents an aperture setting, from maximum to f/16 in full stops. Here are the results:

The center resolution is already great right from the maximum aperture and only drops a little at f/16 due to diffraction. From f/1.8 to f/2, the corner and border resolution is too soft, but there is a tremendous jump in edge-to-edge quality when closing the aperture to f/2.8. By f/4 the resolution is almost on its maximum, which happens at f/5.6, and then it stays on a top level until f/16, where it drops again due to diffraction. Overall, for corner-to-corner sharpness f/2.8 can be used without any problems. This performance is pretty much in line with the Nikkor AF-S 35mm f/1.8 G that I happily owned in the past. Regarding resolution, it’s like one stop better than the previous D version. The sharpness I get with the G lens at f/2.8 is about the same I had at f/4 with the D.

Distortion

Here is the brick wall shot:

There is a small amount of barrel distortion, but less than I got with the 35mm f/1.8 G. Fortunately this small distortion has a simple characteristic and can be easily corrected in post-processing. Of course, I always expect 50mm lenses to have no distortion and this may be worrying for some. In this regard, the 50mm f/1.8 D was perfect.

Vignetting

In this test, I shot a white wall at home using tungsten white balance and set exposure manually:

Vignetting is very strong from f/1.8 to f/2 but is hardly visible by f/2.8. Using the lens wide-open will bring vignetting but the effect might be desireable after all. It can be corrected in post-processing without much effort.

Chromatic aberrations

For this test I shot a car from above on a bright sunny day early in the afternoon:

There is some blue fringing at the edges of the windows until f/2, but only a couple pixels wide. In real shooting I never worry about this, even if I’m shooting metallic objects in bright light. If the reader had played with the 35mm f/1.8 G before, I can tell you that this 50mm is worlds better. This is top performance from any lens. I can’t compare it to the 50mm f/1.8 D because I don’t remember shooting with it wide-open, as it was too soft.

Coma

Coma was tested using a LED source, at home in a dark room.
I put the light source at the center (first column), corner and extreme corner of the frame (second and third columns, respectively), at maximum aperture and stopped down.

The lens has some coma, but it isn’t worrying. I use this lens on astrophotography shots and coma is hardly noticeable. I rate the lens as simply OK regarding coma.

Flare

I shot a building in construction with the sun sneaking from a window, to see if I could see any flare traces. I started to shoot directly against the sun, then placed the sun at the corner and finally made some shots with the sun just outside the frame.

Shot directly against the sun.
Shot with the sun placed at one corner of the frame.
Shot with the sun just outside the frame.

The lens has a good resistance to flare and ghosting, keeping contrast on a high level. The worst case is when the sun is placed at one corner, where multiple reflections of light might be seen towards the other. Shooting against the sun doesn’t produce halos and don’t degrade contrast. When placing the sun just outside the frame is always a good idea to use the supplied lens hood; in this case, the flare visible on the example could easily be avoided with the hood.
In conclusion, this is a good performance which was expected for a normal prime lens.

Bokeh

The lens has 7 blades, which means that it’s almost impossible to render perfect circles. They’re rounded, so it can’t be worse than the awful bokeh that the 50mm f/1.8 D renders.
I took a defocused picture at the widest aperture of the city lights and got crops of the center, corner and extreme corners. The test was repeated for the subsequent two stops.

The lens produces a surprisingly pleasing bokeh, with out of focus highlights that are smooth on the inside and nice edges that hardly can be called distracting. The only downsides are the fact that there are only 7 blades, and the cats-eye distortion on the corners of the frame due to vignetting. This is a quantum leap compared to the bokeh of the 50mm f/1.8 D!

Macro/Close-up

The Nikkor was able to focus as close as 37 centimeters from the front element, resulting in a maximum magnification ratio of only 1:6.5. It’s exactly the same minimum distance as I had when I used the previous D version lens.
I shot an 1 Euro coin and this is what to expect at the minimum focus distance:

Summary

Build quality 5 Almost entirely plastic-made but doesn’t feel too cheap
Handling 6 Fast lens that feels nice in your hand, may misfocus for no reason, manual focusing should be much better
Resolution 9 Amazing resolution, although soft in the corners wide-open
Distortion 7 Unexpected barrel distortion for a 50mm lens, but manageable
Vignetting 8 Strong wide-open, but almost disappears stopped down
Chromatic aberrations 9 Almost invisible in most conditions
Coma 8 Far from perfect, but not problematic in practice
Flare 6 Keeps good contrast, and the hood can help in some situations
Bokeh 7 Always very smooth without accentuated edges, but gets polygonal stopped down
Overall 74% A very sharp prime lens with nice handling and a welcome update for novice users

Samples

Here are some samples of pictures I made with this lens. Settings: native JPEG, picture control set to Landscape mode, no post-processing applied except reducing to 600 pixel width.

50mm, f/1.8, 1/4000s, ISO 200
50mm, f/5.6, 1/640s, ISO 200
50mm, f/4.0, 1/1250s, ISO 200
50mm, f/5.6, 1/200s, ISO 200
50mm, f/2.0, 1/2500s, ISO 200
50mm, f/1.8, 1/4000s, ISO 200

Nikkor AF 28-105mm f/3.5-4.5 D : Review

Introduction

Here is my review of the Nikkor AF 28-105mm f/3.5-4.5 D zoom lens for the Nikon mount, tested with the Nikon D700 full-frame DSLR. This is a practical zoom lens for walking around that has a useful wide to mid telephoto coverage, which is great for street shooting, from wide scenes to portraits.
Take a look at how the lens combines with the D700:

This lens was introduced in 1999 and was sold as a kit lens or as upgrade to the kit lens supplied with the Nikon F100. The lens includes 16 elements in 12 groups, one of those elements being of aspherical type to reduce optical distortions. It’s an all-plastic made lens, at least on the outside (including the filter thread), except for the mount which is metal, but the plastic is high quality although is not rugged as the newer G lenses, being very smooth (too much) instead. The lens features an aperture ring with a lock at the f/22 position, making it compatible with the older manual SLRs.
It can be found today in the used market as a bargain; the prices range from about 90€ to 175€. I got mine as a temporary solution when I got into FX while I was waiting for other cheap lightweight options, and since then I’m having trouble finding a better affordable alternative. It has been worth every penny and much more! I’m looking forward to see how the upcoming Nikkor AF-S 24-85mm f/3.5-4.5 G does and how much it costs, because maybe this could be a good replacement.

Technical Specifications

Focal length 28 – 105mm
Maximum aperture f/3.5 – f/4.5
Minimum aperture f/22 – f/29
Field of view 74 – 23 degrees (on FX)
Weight 455g
Dimensions 84 x 72mm (120 x 72mm extended)
Optical construction 16 elements in 12 groups (1 aspherical element)
Aperture blades 9
Filter diameter 62mm
Minimal focus distance 124.5cm (4.5cm from the front element)
Hood HB-18, rounded and very enlarged up front
Mount Nikon F

Mechanical Characteristics

Zoom ring Plastic with rubber finish
Focus ring Plastic with rubber finish, with infinity stop
Focus throw 30 degrees (with focus limiter), 74 degress (without)
Focus motor No
Optical stabilizer No
Front element rotation while zooming Yes, 185 degrees
Front element rotation while focusing No
Internal focusing Yes
Lens extension while focusing No
Lens extension while zooming Yes, up to 37mm
Maximum magnification 1:2, at 105mm

Handling

The Nikkor is a small and lightweight lens for FX standards, particularly when compared with modern G lenses with internal focus motor, like the Nikkor AF-S 24-120mm f/3.5-5.6 G zoom lens. The lens looks nice, except when the ugly hood is attached – it’s an absurdly huge hood, rounded and very enlarged up front, like a funnel. I never use the hood, but if I needed one I’d look for other third-party alternatives.
Using the lens may be disappointing at times, especially when trying to frame the subject with precision. The Nikkor is all-plastic made at least on the outside, including the filter thread (except the mount which is metal), and both the zoom and focus rings have a rubber finish for enhanced grip. The problem is that the zoom ring isn’t damped, in fact it’s the worst zoom lens I ever used (I thought the Nikkor AF 28-80mm f/3.3-5.6 G was the worst). Zooming is all but smooth and feels like rubbing plastic on plastic, and the ring gets stuck all the time, making precise framing very hard. Also, zooming is very non-linear; the change in magnification seen in the viewfinder doesn’t act linearly as the zoom ring is turned around. To make things even worse, the front element rotates a lot while zooming, being an absolute nightmare when shooting with a polarizer.
On the other hand, the focus ring is much smoother and never gets stuck, but it’s pretty much useless for manual focusing due to the very short throw. There’s a switch on the lens that limits the minimal focus distance to 0.5 meters, which makes focusing quick (but not lightning quick) on the D700 when the limiter is activated. To turn off the limiter, one has to zoom in at least to 50mm, but once the switch is moved there’s no way back to wider focal lengths, unless the user focuses some object between 0.5 meters and infinity. It’s a bit cumbersome at first but one gets used to it.
The 28-105mm has a very good close focus capability, reaching a maximum magnification ratio of 1:2 at 105mm. Mind you, this feature isn’t perfect though; the center resolution is very good, but the corners never reach the same level because of the huge field curvature at that setting.
So, regarding handling, this lens feels very cheap but it’s not that bad for a walkaround lens. I prefer to use a lightweight lens like this on the streets instead of a 24-120mm f/4 VR, for example. Besides, you may be positively surprised with the image quality if you manage to find a good copy.

Resolution

For the resolution test I shot the 5 Euro bill as usual. Focus was achieved using Live View to avoid auto-focus imprecisions and to compensate for possible field curvature issues.
The first column shows a crop of the image center, the corner crop is on the second column and the third column shows a crop of the extreme corner. Each row represents an aperture setting, from maximum to f/22 in full stops. Here are the results:

28mm

At 28mm the center resolution is already excellent right from f/3.5 and only starts to get worse at f/16 due to diffraction. The corner and border resolution never reach the same level, but is more than acceptable and stays constant until f/22 where resolution drops significantly. The edge-to-edge resolution is good but could be better especially when stopped down, as happens with most lenses, but instead remains constant trough the aperture range.

70mm

By 70mm the resolution in the center remains on an excellent level and corners follow very closely. Only the extreme corner performance is noticeably worse, being a little soft until f/8, but at f/11 there’s a sudden jump in quality. This isn’t very noticeable outside the studio, but if you need excellent resolution in the entire frame then f/11 is the aperture to choose here.

105mm

At 105mm the lens continues to deliver great resolution figures straight from the maximum aperture of f/4.5, and only the extreme corners are visibly softer. The resolution characteristic here is identical to the one at 70mm. Some owners of this lens say that the lens is very good at all focal lengths except at 105mm. Au contraire, my copy is worse at the wider end; for my type of shooting I wish it had better resolution here than at 105mm.
Like I said before, at the macro setting at 105mm, the center resolution is great (like as seen above at 105mm), but the corners are always much worse and don’t improve much, even when closing the diafragm to the minimum of f/29. But it’s nice when your subject fills the center of the frame, anyway.

Regarding resolution, this Nikkor is a solid performer and produces stunning pictures on the D700. It could be a little better at 28mm at the edges, of course, but that’s about it.

Distortion

Here are the brick wall shots:

28mm

70mm

105mm

At the widest focal length, the lens produces a considerable amount of barrel distortion. This can be almost entirely corrected in post-processing, and I say “almost” because even then the pictures still have a residual mustache distortion. It’s not problematic though, unless you need perfectly distortion-free images. At the other focal lengths there’s nothing to complain about because distortion disappears completely.

Vignetting

In this test, I shot a white wall at home using tungsten white balance and set exposure manually:

28mm

At 28mm, vignetting is strong wide-open and down to f/4. By f/5.6 the light losses are average but improve greatly afterwards.

70mm

At 70mm, there is just a bit of vignetting at f/4.5 but vanishes stopping down, resulting in very uniform light distribution across the frame.

105mm

At 105mm, the lens vignettes wide-open down to f/5.6, but from f/8 there aren’t traces of it anymore.

The lens suffers from vignetting more at 28mm, at the f/3.5 and f/4 settings. Nothing that can’t be solved in post-processing, though. At other apertures and focal lengths this isn’t an issue.

Chromatic aberrations

For this test I shot a car from above on a bright sunny day early in the afternoon:

28mm

105mm

As happens with older lenses without special low dispersion elements, there’s a noticeable amount of purple friging in high contrast areas at the maximum aperture at all focal lengths. It’s not visible when looking at the entire image on my monitor, but viewing at 100% may reveal fringing reaching several pixels wide. Stopping down brings the problem to a negligible effect, which may still be noticeable in careful pixel-peeping. Overall it’s still a good performance from any lens.

Coma

Coma was tested using a LED source, at home in a dark room.
I put the light source at the center (first column), corner and extreme corner of the frame (second and third columns, respectively), at maximum aperture and stopped down.

28mm

105mm

The lens suffers from heavy coma, putting it on par with other old lenses, especially at the wider end. Obviously it’s not a good candidate to take out for astrophotography.

Flare

I shot a building in construction with the sun sneaking from a window, to see if I could see any flare vestiges. I started to shoot directly against the sun, then placed the sun at the corner and finally made some shots with the sun just outside the frame.

Shot directly against the sun.
Shot with the sun placed at one corner of the frame.
Shot with the sun just outside the frame.

The lens has a weak resistance to flare and ghosting that interferes on the overall image contrast. When shooting against the sun there’s a huge halo around it that occupies almost the entire image. Placing the sun at one corner reveals the multiple internal reflections, which are very visible in the entire frame towards the opposite corner. Even when the sun is already outside the frame, there’s almost a 100% probability of still having problems. Unfortunately, since the supplied lens hood is so large at the front, it only reduces the problem a bit when the sun is just outside the frame, and that’s another reason I don’t use it at all (besides the ugly look).
In conclusion, this is the worst case I’ve dealed with so far. But since normally people never shoot against the sun or at the proximity, in practice this isn’t an issue.

Bokeh

The lens has 9 aperture blades, thus it’s expected to get circular out of focus highlights. I took a defocused picture at the widest aperture of the city lights and got crops of the center, corner and extreme corners. The test was repeated for the subsequent two stops.

28mm

105mm

The bokeh from this lens is almost perfectly circular in the entire frame, in fact so far it’s the most constant characteristic I’ve seen. There’s only a little distortion in the extreme corners, but there’s no cats-eye distortion or any worse drastic effects. On the down side, the bokeh is never smooth on the inside and the edges are very pronuntiated, especially at the widest focus length.
Overall, the lens has a better than average bokeh characteristic, and produces very nice out of focus renderings in all situations without interfering negatively with the subject.

Macro/Close-up

With the focus limiter activated, the Nikkor was capable to focus as close as 44 centimeters from the sensor plane, or 32 centimeters from the front element, resulting in a maximum magnification ratio of 1:5.2 at 105mm. When the focus limiter is switched off, the focus distance drops down to 16.5 centimeters from the sensor plane or 4.5 centimeters from the front element, to a maximum magnification ratio of 1:2 at 105mm.
I shot an 1 Euro coin and this is what to expect at the minimum focus distance:

28mm

105mm

105mm, focus limiter off

Summary

Build quality 4 Almost entirely plastic-made and feels cheap
Handling 5 An useful zoom lens with decent AF speed and features, but zooming is disappointing in many aspects
Resolution 8 Great resolution overall, but could be improved a little at 28mm
Distortion 8 Noticeable barrel distortion at 28mm, but disappears afterwards
Vignetting 8 A little strong at biggest apertures, but good looking otherwise
Chromatic aberrations 8 Only visible at maximum aperture at all focal lengths while pixel-peeping
Coma 5 A lot of coma especially at 28mm, but always present at other focal lengths
Flare 3 Very weak resistance against flare, and the hood doesn’t help here
Bokeh 7 Circular but very nervous with accentuated edges at 28mm, but improves at 105mm
Overall 67% A very sharp and handy lens in FX that bears other good optical characteristics, but there’s an equal number of downsides too

A final remark

On a very subjective opinion, the final score doesn’t reflect how great and handy this lens can be on the street if one takes some basic precautions. As long as you shoot with the lens stopped down on sunny days and never shoot against the sun, the lens can produce fantastic images with good color (a bit on the conservative way), good bokeh and relatively low distortion.
Thus, for anyone starting with FX with limited funds, this lens is the one to start with. There are many other alternatives with similar focal range, but the 28-105mm is hard to beat in resolution, regardless of price. In fact, I’ve seen much worse from third-party lenses with constant f/2.8 aperture.
In few words, this is a cheap lens that produces fantastic results, as long as you take the precautions refered above and can live with the many mechanical limitations.

Samples

Here are some samples of pictures I made with this lens. Settings: native JPEG, picture control set to Landscape mode, no post-processing applied except reducing to 600 pixel width.

105mm, f/4.5, 1/160s, ISO 200
105mm, f/4.5, 1/125s, ISO 200
28mm, f/5.6, 1/1000s, ISO 200
38mm, f/8.0, 1/500s, ISO 200
28mm, f/11, 1/320s, ISO 200
90mm, f/8.0, 1/500s, ISO 200

Tamron SP 70-300mm f/4-5.6 Di VC USD : Review

Introduction

This is a review of the Tamron SP 70-300mm f/4-5.6 Di VC USD telephoto lens for the Nikon mount. The test was once again made using a D700 full-frame DSLR. This is a well-built lens, very solid without any wobbling parts, and competes directly with the Nikkor AF-S 70-300mm f/4.5-5.6 VR lens which has been very successful among amateurs and enthusiasts. Here’s how the D700 combines with the Tamron lens:

This has been a very welcome addition to the market, because the Nikkor had been alone price-wise, and third-party options were not up to the standards. Fortunately, the Tamron is a very viable alternative and it even has some characteristics that surpass its direct rival, as we will see. The Tamron belongs to the SP (Super Performance) line, the same line that has, among others, the highly praised 17-50mm f/2.8 (DX) and 28-75mm f/2.8 (FX) lenses. This 70-300mm is the first Tamron lens having the new USD (Ultrasonic Silent Drive) auto-focus motor for fast and silent focusing, and also the first including their innovative optical stabilizer mechanism, VC (Vibration Compensation). Indeed, the lens is very silent and rather quick focusing, but may hunt at times in areas with low contrast, the same happening in low light situations, otherwise the lens focuses quickly. The lens also has special glass elements, LD (Low Dispersion) and XLD (Extra Low Dispersion), which are employed to take care of chromatic aberrations. One thing that’s always good to have is IF (Internal Focusing) and this lens got it, and because of that the front element never rotates when focusing, therefore using a polarizer is no problem.
At a retail price of €389 right now, at a first sight and looking at the specifications, the lens seems to have a great price/perfomance ratio, but that’s the thing we’ll find out later in this review. On the D300 I had before, this lens was stellar for the price, having very good sharpness corner to corner at every aperture and only with a slight drop at 300mm, being a terrific combination for quick operation speed and optical performance in all focal lengths for users who don’t normally shoot in low light situations.

Technical Specifications

Focal length 70 – 300mm
Maximum aperture f/4 – f/5.6
Minimum aperture f/32 – f/45
Field of vision 34 – 8 degrees (on FX)
Weight 765 g
Dimensions 144 x 80mm (194 x 80mm extended)
Optical construction 17 elements in 12 groups (1 LD element, 1 XLD element)
Aperture blades 9
Filter diameter 62mm
Minimal focus distance 144cm (125cm from the front element)
Hood HA005, petal-shaped
Mount Nikon F

Mechanical Characteristics

Zoom ring Plastic with rubber finish
Focus ring Plastic with rubber finish, no infinity stop
Focus throw 160 degrees
Focus motor Ultrasonic Silent Drive, allows full-time manual focus override
Optical stabilizer Vibration Compensation, up to 4 stops capability
Front element rotation while zooming No
Front element rotation while focusing No
Internal focusing Yes
Lens extension while focusing No
Lens extension while zooming Yes, up to 51mm

Handling

The Tamron is a big fat lens and even with the D700 is a little front-heavy, but not overly so. Playing with the zoom ring feels like plastic against plastic, but nevertheless it’s not only smooth enough for quick operation, but also acceptable enough for the times when you need precise framing. Some people complain that the zoom ring is a little stuck on their copy, but that might be true when the lens is brand new; I don’t remember mine having a stuck zoom ring. The focus ring feel is similar, but since it’s lighter it’s easier to turn around.
The lens allows full-time manual focusing without the need to turn the lens or camera to manual focus. Common with other built-in auto-focus motor lenses, the focus ring never stops rotating and is capable to focus past infinity. The Tamron focuses as near as 144cm from the focus plane (125cm from the front element) at 300mm, resulting in a maximum magnification ratio of 1:4, which is less magnification than the previous Tamron 70-300mm was capable of (1:2).
The lens has a long petal-shaped hood and the caps are of good quality. The front cap is similar to Nikon’s, allowing you to take it off and put it on without the need to take the hood off. The lens has a metal mount, which is a must-have for such weight, but doesn’t have a tripod collar, so be sure to have the camera well attached to the tripod socket when using the combo for long exposures.

Resolution

For the resolution test I shot the 5 Euro bill in the studio. Focus whas achieved using Live View to avoid auto-focus imprecisions and to compensate for an hypothetical field curvature.
The first column shows a crop of the image center, the corner crop is on the second column and the third column shows a crop of the extreme corner. Each row represents an aperture setting, from maximum to f/22 in full stops. Here are the results:

70mm

At 70mm the center resolution is already excellent right from f/4 and only deteriorates at f/22 due to diffraction. The corner resolution is on a very good level until f/11 and drops noticeably at f/16. The borders are on a much lower level; by f/4 the sharpness is only acceptable and improves slightly at f/5.6, but reaches a good level from f/8 to f/11 before dropping again at smaller apertures. All in all, a very good performance at this focal length (not that, from now on, if you’re considering using this lens on DX, use the first and second columns only as reference, since the second column shows crops of the same area as the extreme corners on DX).
Moving on to other focus lengths now…

100mm

At 100mm the resolution at the center and corners is excellent already wide-open and only drops by f/22. The extreme corners are good wide-open at reach very good figures by f/5.6 and the resolution drops a bit at f/16. From 100mm to 135mm seems to be the lens’ sweet spot.

200mm

At 200mm the center resolution is always on an excellent level but the corners start to show some limitations. Wide-open and until f/8 the resolution figures are only on an acceptable level and the extreme corners follow closely. At f/11 there’s a sudden increase in quality in the entire frame and that continues at f/16. By f/22 the resolution drops a little but not by much as in previous focal lengths.

300mm

At 300mm, resolution drops noticeably in the entire frame but remains good to very good at the center. On the downside, the corners are never on the same level, and for good edge-to-edge sharpness one has to stop down to f/16 or even f/22. This is not noticeable in the real world, trust me, because at 300mm you tend to put the subject at the center anyway.

Overall, the Tamron shows a strong performance, producing sharp and contrasty images at all focal lengths, and its strongest selling point is the resolution and contrast at 300mm. This is much better than the Sigma 70-300mm f/4-5.6 APO Macro I had before and better than its direct rival, the Nikkor AF-S 70-300mm f/4.5-5.6 G ED VR I had played with.

The only thing that changed my opinion about the Tamron now, compared to the performance delivered with my previous D300, is the noticeable variation in exposure. It is very visible, at all focal lengths, that the lens underexposes a lot at the maximum aperture and less so stopped down, exposes well at f/8 and overexposes at f/11, before underexposing again by f/16. The weird thing is that it wasn’t noticeable at all with the D300, when only I had some minor overexposures in bright sunny days which were corrected simply dialing to -0.3 or -0.7 EV, independently of the aperture I was using. Now I can’t say that my lens doesn’t underexpose or overexposes, but instead a combination of the two that is dependent on the aperture. I can’t really say if this is because of heavy vignetting, but if so it affects the entire pictures and not only the borders, but also there’s a bit of overexposure at f/11 that is visible in the camera histogram. This will be more visibly explained below in the vignetting test.

Distortion

For the distortion test I shot a brick wall, again:

70mm

135mm

300mm

The lens distortion is practically absent at 70mm but starts producing a certain amount of pincushion at 135mm which stays constant until 300mm. On the field this is practically invisible and can be easily corrected in post-processing if needed.

Vignetting

In this test I shot a white wall at home using tungsten white balance and setting exposure manually. The exposures were judged by the camera histogram and are considered to be spot on when it’s centered.

70mm

At 70mm, vignetting is strong wide-open and less so at f/5.6, before improving considerably at f/8. At smaller apertures it disappears completely.

135mm

At 135mm, the same behaviour happens exactly as before.

300mm

At 300mm, only the widest aperture is affected by vignetting but in a very strong way. At other apertures there isn’t any noticeable light losses towards the edges.
As said above, the lens is affected by exposure differences that affect the entire image, as opposed by vignetting which only affects the borders of an image by any degree. I also could not find an explanation for the overexposure seen at f/11 from 70mm to 135mm. This is the first time I had a problem like this one and I’m not sure if the problem is related to this particular copy or any other sample. There are many people who complained about their copy producing under- or overexposed pictures, but mine gives exposures that were unpredictable at first, but can be corrected dialing exposure compensation accordingly depending on the aperture used. This phenomenon is more visible in Matrix metering mode and less so in Center-Weighted mode. I found no differences between aperture and shutter priority, or manual exposure modes. I will try to repeat the test if I have the chance of getting another copy.

Chromatic aberrations

For this test I shot a car roof from above, on a very sunny day early in the afternoon.

70mm

300mm

The Tamron employs low dispersion glass elements to reduce chromatic aberrations and it’s clearly visible that the lens performs as advertised. Aberrations are negligible at almost every aperture, except at its maximum where minor vestiges can be found on extremely high contrast situations, but only at the widest focal length. That’s a very good performance for a lens in this price point.

Coma

Coma is an important requirement in astrophotography and usually affects the corners of most lenses. Lenses that are affected by coma produce comas (hence the name) instead of bright light points in dark backgrounds. One way to test coma is using a LED source of light at home in a dark room.
I put the light source at the center (first column), corner and extreme corner of the frame (second and third columns, respectively), at maximum aperture and stopped down.

70mm

300mm

The lens isn’t much affected by coma and the only distortions visible are in the halos around the center, where they stretch the more the points are closed to the borders, but the points themselves remain perfectly circular. This is not uncommon for lenses with such moderate maximum apertures.

Flare

I shot a building in construction in front of me, with the sun sneaking from a window, to see if I could see any flare vestiges. I started to shoot directly against the sun, then placed the sun at the corner and finally made some shots with the sun just outside the frame.

Shot directly against the sun.
Shot with the sun placed at one corner of the frame.
Shot with the sun just outside the frame.

The images are not much affected in all situations, which shows that the lens has good resistance to flare keeping contrast on a high level. The worst case is when the sun is placed at one corner, where the multiple internal reflections of light may be noticeable in the opposite corner.

Bokeh

Thanks to the 9 aperture blades, we can expect circular out of focus highlights from this lens. I took a defocused picture at the widest aperture of the city lights and got crops of the center, corner and extreme corners. The test was repeated for the subsequent two stops.

70mm

300mm

The bokeh from this lens is perfectly circular at the center and suffers from the cats eye distortion due to vignetting in the corners and more so in the extremes. The out of focus highlights are rather nervous on the inside at 70mm but get perfectly smooth at 300mm, and the edges aren’t much accentuated, resulting in smooth transitions and backgrounds that are soft and not distracting at the longest focal length. All in all, the lens has good bokeh characteristics which are amongst the best in its class, especially when we take the moderate apertures involved into account.

Macro/Close-up

The Tamron was capable to focus as close as 144 centimeters from the sensor plane, which means 125 centimeters from the front element, resulting in a maximum magnification raio of only 1:4 at 300mm. I shot an 1 Euro coin and this is what to expect at the minimum focus distance:

70mm

300mm

Image stabilization

This lens introduced Tamron’s new image stabilization technology, VC (Vibration Compensation), to compensate for unwanted small movements, and it’s advertised as giving an advantage of 4 stops. This means that at 300mm, one can shoot with speeds as slow as 1/20 seconds.
To test it, I shot the back of a street lamp from my window. The first column shows crops of the subject shot with VC off, and the second column shows them with VC on for comparison. Here are the results at 300mm:

It shows to me clearly that the VC works as advertised, resulting in sharp images at 1/20 seconds. Of course, one has to build some technique to hold the camera and lens steady, so that the benefits of this technology can be applied. The image taken at 1/20 is a little softer but due to diffraction (an aperture of f/32 was used).
Contrary to Nikon’s VR mechanism where 2 axis (up and down) are used, VC used 3 axis: up, down and yaw (up-left, down-right) to compensate for diagonal shakes. One more difference to VR is that VC appears to work with full power right from the moment you press the shutter button halfway, and stays there moments after the picture is taken. VR works with less power and only commutes to full power when you press the shutter button down to take the picture. This is the reason why the images in the viewfinder are almost static with VC, when compared to what is visible with VR. This doesn’t mean that VR is much worse, because it’s not, but I found VC to give me more keepers. And it works as advertised, which is amazing.

Summary

Build quality 7 Mostly high quality plastic but all parts are tight together
Handling 7 Nice feel overall with silent and fast AF in most situations, the zoom ring could be damped for smoother operation
Resolution 7 Very good center sharpness, good corners and acceptable extreme corners in most apertures, amongst the best in class
Distortion 9 A little pincushion distortion but not noticeable in everyday shots
Vignetting 8 Strong at biggest apertures, negligible afterwards (not considering the variations in exposure)
Chromatic aberrations 9 Rarely visible, if any only at 70mm at the widest apertures
Coma 9 Not perfect, but the lens almost doesn’t have issues here
Flare 8 May produce some flare in harsh conditions, but contrast stays always on a high level
Bokeh 7 Circular but very nervous with accentuated edges at 70mm, but gets pleasantly smooth at 300mm
Overall 79% Very good lens on DX and FX, a valuable lens if you need stabilization and can’t afford any of the 70-200mm offerings

Samples

Here are some samples of pictures I made with this lens. Settings: native JPEG, picture control set to Landscape mode, no post-processing applied except reducing to 600 pixel width.

300mm, f/5.6, 1/125s, ISO 200
300mm, f/11, 1/160s, ISO 200
70mm, f/4.0, 1/1600s, ISO 200
70mm, f/4.0, 1/2000s, ISO 200, -0.7 EV
270mm, f/5.6, 1/1250s, ISO 200
70mm, f/11, 1/320s, ISO 200
100mm, f/4.2, 1/1250s, ISO 200

Voigtländer Color-Skopar 20mm f/3.5 SL II Aspherical : Review

Introduction

I present you my first review, of the Voigtländer Color-Skopar 20mm f/3.5 SL II Aspherical lens for the Nikon mount. The test was made on a D700 full-frame DSLR. The lens has a very compact design, which is commonly referred as “pancake”, and if you’re like me you’ll appreciate the size and weight of this lens, making a relatively lightweight kit with the D700 for walking around the streets. Watch the funny combo below:

Its retail price of €449 seems fair for a pancake lens. Having a maximum aperture of only f/3.5 it’s not the fastest prime lens out there, but this aperture limitation is common for such design. In fact, there are not many pancake lenses as cheap as this one, and particularly on Nikon land these pancake lenses are a rarity. The lens includes an aspherical element to reduce aberrations and distortions. As a manual focus lens, it can be a bit limiting for you depending on your shooting style, but that’s also true for every manual focus lens such as Nikkor AI or Zeiss ZF lenses. The fact that the lens has a wide focal length eases this limitation a bit, being very easy to focus anywhere you want.
I didn’t write a review of this lens when I had my previous D300, but from the tests I did and all the real world shootings I made, I found this lens to be a very good performer on DX stopped down. I even went on a trip to Holland only with this lens and didn’t need anything else on the streets. On DX, the focal length is just perfect and it was very handy for taking pictures of churches and other tall buildings, street scenes and urban landscapes. This time I’m showing you the results of a much more demanding test (on FX), so let’s find out if the Voigtländer is worth your consideration if you’re searching for a wide angle lens.

Technical Specifications

Focal length 20 mm
Biggest aperture f/3.5
Smallest aperture f/22
Field of vision 94 degrees (on FX)
Weight 205 g
Dimensions 29 x 63 mm
Optical construction 9 elements in 6 groups, 1 aspherical element
Aperture blades 9
Filter diameter 52 mm
Minimal focus distance 20 cm
Hood LH-20N (optional)
Mount AI-S, CPU integrated

Mechanical Characteristics

Zoom ring n/a
Focus ring All-metal with rubber finish, no infinity stop
Focus throw 170 degrees
Focus motor n/a
Optical stabilizer n/a
Front element rotation while zooming n/a
Front element rotation while focusing No
Lens extension while zooming n/a
Lens extension while focusing Yes, 3 mm
Internal focusing No

Handling

The Voigtländer is a very compact lens as you can see above in the pictures, and being all-metal it’s very well built and surprisingly heavy for such size. Being a manual focus lens, probably the most important aspect is how the focus ring feels on your fingers, and it does indeed feel great. The focus ring is perfectly damped and focusing is very smooth. I had been shooting with some manual focus lenses (AI-S and Samyang) but focusing with this lens feels even better than those. It feels smooth and has a long throw of about 170 degrees for precise focusing. This is mostly useful in near distance, of course, because from about 10 meters to infinity there’s almost no need to move the focus ring again. Beware, though, that the lens is capable to focus past infinity which isn’t good news for astrophotographers. Fortunately most cameras today have Live View, which is of precious help if you want precise infinity focus. The focus ring has a rubber finish for a perfect grip.
The less positive things about this lens is that it doesn’t have a lock on the aperture ring, therefore watch out and keep the aperture ring on f/22, otherwise you’ll get a fEE error on your LCD display. Because the lens is so tiny and there’s almost no space between the focus and aperture rings, attaching and dettaching the lens from the camera can be a bit difficult, but with a firm grip on both focus and aperture ring, along with the fixed 3mm spacer in between, it can be done but be warned that the lens gets almost glued to the camera.
Anyway, my only thumbs down goes to the front cap which gets off so easily with just a small touch. There were many times that I had my camera and lens on my shoulder pack and the cap was off. Just throw it out and get a Nikon one.

Resolution

For the resolution test I shot a near distance object and a far away building to find out if there were any visible differences in image quality. I focused using Live View and focused again using this method when moving the target to the corners. Turns out that the lens performs very similarly and all distances, regarding resolution and vignetting, therefore I’m not showing the far distance results this time.
The first column shows a crop of the image center, the corner crop is on the second column and the third column shows a crop of the extreme corner. Each row represents an aperture setting, from maximum to minimum in full stops. For the near distance test I used a 5 Euro bill as target. Here are the results:

You can see that the center resolution is already very high and the images have very good color and contrast. This is always true until f/16, from which diffraction starts making effect. The corner resolution is very weak at f/3.5 and gets acceptable only by f/8, where I mainly use the lens on landscape photography (or f/11 for that matter if there’s enough light). The extreme corners are dismal – this is the effect of putting a pancake lens on a full-frame camera – resolution practically doesn’t exist wide open, and coupled with heavy vignetting this makes an awful combination for available light photography. The extreme corners get much better only by f/16.
If you want corner-to-corner sharpness this lens has to be stopped down to f/16 at least, or f/11 if you can tolerate some mushy corners. Depending on your subject even f/8 can be used, as long as the corners don’t have fine details.
In conclusion, this is a lens to be used on sunny days or with the help of your tripod. This is a huge disappointment to me because the lens is great on DX!

Distortion

For the distortion test I shot a brick wall, of course:

The lens distortion is well controlled. Vertical lines are always straight and there’s no signs of barrel distortion, which is great for taking pictures of buildings. The problem resides on horizontal lines, and this mustache distortion can be very noticeable if the target has many horizontal lines. This type of distortion is very difficult to correct in post-processing, so it is best to avoid placing horizontal lines on the top or the bottom of the frame, where distortion is mostly visible.
As an example, here’s a “real world” photo of an interior. You can see that vertical lines remain straight as long as you hold the camera parallel to the ground. Because there weren’t any horizontal lines due to the framing angle I used, this shot seems perfectly balanced:

Vignetting

In this test I shot a white wall at home using manual white balance.

As detected previously on the resolution test, vignetting is very heavy wide open and things start to get even only by f/8. Notice that this is mostly visible on shots of white walls like this. As a matter of fact I can make a nice use of the vignetting wide open on shots of flowers and other small stuff like that. Fortunately most or all vignetting can be removed in post-processing.

Chromatic aberrations

It was a clear bright sunny day with the sunlight reflecting on my brother’s car and I searched for a spot where to make the shots. I shot the FIAT logo at all apertures because it was so shiny:

The use of an aspherical element is an important feature on any lens, and it’s pretty clear that Cosina made an excellent job to maintain the CA levels negligible. From all the shots I made with this lens there wasn’t a single day I noticed any fringing issues. The lens earns the maximum score here.

Coma

Coma is an important requirement in astrophotography and usually affects the corners of most lenses. This can be tested on the field, on a starry night, to check for weird distortions on the stars. Basically, lenses that are affected by coma produce stars that are no longer light points but comas instead (hence the name). One other way to test it is using a LED source of light at home in a dark room.
I put the light source at the center (first column), corner and extreme corner of the frame (second and third columns, respectively), at f/3.5 and f/5 (one stop down).

You can see that at f/3.5 the lens produces high amounts of coma at the extreme corners, although it gets better by stopping down. This is no big deal since the moderate maximum aperture is not very attractive for astrophotographers anyway, but if you’re taking this lens to the field be sure to use at least f/5 to avoid coma. Other than shooting stars and LEDs, there aren’t any more real world examples I can remember that may produce this coma aberration, so this shouldn’t scare you away.

Flare

I walked around my backyard doing many shots trying to get any flare vestiges. I started to shoot directly against the sun, then placed the sun at the corner and finally made some shots with the sun just outside the frame.

Shot directly against the sun.
Shot with the sun placed at one corner of the frame.
Shot with the sun just outside the frame.

I took many more pictures and tried hard to produce flare but without success. That demonstrates that the Voigtländer has top quality coatings inside and the results put it along with the best lenses I used, with terrific flare resistance, and all of this without the need of the LH-20N hood available separately.

Bokeh

The Voigtländer has a moderate maximum aperture and a very wide angle, so the defocused quality of an image doesn’t get the same importance as with the fastest professional grade lenses. The lens has 9 aperture blades so we can expect pretty circular out of focus highlights.
For this test I took a defocused picture at f/3.5 of the city lights and got crops of the center, corner and extreme corners. The test was repeated for f/4 and f/5.6.

The bokeh from this lens is pretty circular at f/3.5 thanks to the 9 aperture blades, as expected, except at the extreme corners where weird distortions are visible. The bokeh is very nervous internally and the edges are a bit pronounced which of course isn’t attractive at all. Stopping down to f/5.6 starts producing polygonal highlights. Generally, with this lens it’s better to shoot close-up subjects with the maximum aperture, where the center sharpness is already very good, to get the best out of focus renderings.

Macro/Close-up

The Voigtländer was capable to focus as close as 20 centimeters from the sensor plane, that is 12 centimeters from the front element. I shot an 1 Euro coin and this is what to expect at the minimum focus distance:

Summary

Build quality 9 The front cap gets off too easily, otherwise the lens is a jewel
Handling 10 Superb feel of a very solid lens, very easy to focus manually, with exposure being controlled automatically by the camera
Resolution 6 Very good center sharpness, poor corners and horrible extreme corners even at moderate apertures
Distortion 7 Some mustache distortion to be aware of, especially when placing horizontal lines at the top and bottom of the frame
Vignetting 6 May work on your favor or against you, depending on the subject, but it’s easy to correct
Chromatic aberrations 10 None, this is probably the best lens I have with such resistance
Coma 7 Wide open there’s coma at the extreme corners, but stopping down minimizes the problem
Flare 10 Top notch, no vestiges found whatever I have tried
Bokeh 5 Circular only at f/3.5 but very nervous with accentuated edges, and gets polygonal at smaller apertures
Overall 75% Excellent lens on DX, but look elsewhere if you need good edge to edge resolution and low vignetting on FX

Samples

Here are some samples of pictures I made in my backyard. Settings: native JPEG, picture control set to Landscape mode, no post-processing applied except reducing to 600 pixel width.

f/3.5, 1/200s, ISO 200
f/3.5, 1/160s, ISO 200
f/3.5, 1/320s, ISO 200
f/3.5, 1/200s, ISO 200
f/11, 1/15s, ISO 200, -0.7 EV
f/8, 1/400s, ISO 200
f/3.5, 1/320s, ISO 200
f/4, 1/50s, ISO 800