Voigtländer Color-Skopar 28mm f/2.8 SL II Aspherical : Review

Introduction

I’m back again with my newest lens review, this time of the Voigtländer Color-Skopar 28mm f/2.8 SL II Aspherical lens for the Nikon mount, tested as usual on a Nikon D700 full-frame DSLR. Just like its twin sister lens, the Voigtländer Color-Skopar 20mm f/3.5 SL II Aspherical, this is a pancake lens with a slim, elegant design, and makes a very portable and lightweight combo with the D700 as shown below:

Just like its twin, the retail price of €449 doesn’t seem cheap at first, but besides being an all-metal lens it has a relatively fast maximum aperture, especially for a pancake design. Pancake lenses are particulary rare in Nikon mount, and this lens may be like a God’s send for those who appreciate shooting with this type of lenses. This lens looks so similar to the 20mm f/3.5 that I will base my description of the 28mm on that review I wrote some time ago.
The lens includes an aspherical element to reduce aberrations and distortions. Being 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 reduces this limitation a bit, being very easy to focus anywhere you want.
I’ve been shooting with this lens for some months now and I have better feelings with it than those I had with the 20mm which performed badly on the full-frame sensor, and now I trust this lens for every occasion where I need to travel light. The 20mm was a sweet lens on DX, it had the perfect focal length to cover a great range of scenarios, and I used it mainly to shoot street scenes, landscapes, monuments, inside museums and churches, cafés, pretty much everything I wanted. But when I migrated to FX I wasn’t that enthusiastic with the focal length, and worse, it performed badly in the corners. So I looked forward to Cosina to release a new pancake lens with a equivalent focal length on FX, and voilà, it seemed that Cosina was listening to me and didn’t took much time for this 28mm to arrive. I was also thrilled that they increased the maximum aperture to f/2.8.
Last time I used this lens was on my summer vacations in southern Spain and I loved it, it performed so much better than the 20mm, that I was shooting at f/4 all the time in churches and museums with no regrets. The maximum aperture was also excellent when I needed to do a close up or a quick portrait, since the quality at the center of the frame is very high. It looked like I was shooting again with the 20mm on my old D300, but seemed even better! This lens was also good to shoot unnoticed among the multitude of tourists that visited the region at that time of the year, but also got a few smiles from other photographers that were curious about its diminute size. But I will describe its performance in detail below.

Technical Specifications

Focal length 28 mm
Biggest aperture f/2.8
Smallest aperture f/22
Field of vision 74.8 degrees (on FX)
Weight 180 g
Dimensions 25 x 62 mm
Optical construction 7 elements in 6 groups, 1 aspherical element
Aperture blades 9, straight
Filter diameter 52 mm
Minimal focus distance 22 cm
Hood LH-28N (optional)
Mount AI-S, CPU integrated

Mechanical Characteristics

Zoom ring n/a
Focus ring All-metal, with infinity stop
Focus throw 160 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, 6 mm
Internal focusing No

Handling

Handling this lens is every bit the same as handling the 20mm, so I will basically copy-paste the same description.
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 have 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 160 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. The lens stops focusing on infinity which is great news for astrophotographers.
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 at 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 (once again) to the front cap which gets off so easily with just a small touch. I instantly replaced that cap with a (heresy!) Canon 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 between those distances. As usual, I focused with Live View and re-focused when moving the target to the corners.
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. Here are the results:

The resolution at the center is already excellent straight from the maximum aperture, showing high contrast and clarity. This is always true until f/16, from which diffraction starts affecting the image and there’s a loss of contrast. The DX corner resolution is not so good wide open but is more than acceptable at f/4 and peaks at f/5.6, and keeps on high values until f/16. The extreme corners are a bit weaker at f/2.8 and appear affected greatly by vignetting, but after quick correction in post-processing it is visible that the problem is not that much the lack of sharpness. If DX corner sharpness improves greatly at f/4, the extreme corners will take one more stop to reach similar levels. But still, for very good sharpness across the frame it’s better to stop down to f/8, or f/11 if critical sharpness is needed on the extreme corners of FX.
This is great performance on very close targets, but what about “real world” where most of the time the target is at at least several meters away?

Although this target seems a bit flat in contrast, careful examination shows that there are no meaningful differences in resolution, being already excellent at f/2.8 in the center and very good in the DX corner, but not so good in the FX corner and still affected by heavy vignetting. The aperture of f/8 delivers very good resolution across the frame, just like we saw in the previous test.
In conclusion, this is a much more versatile lens than the 20mm with a broader range of useful apertures, which was to be expected from the start since 20mm is more difficult to produce than a 28mm lens, especially when we’re talking about pancake lenses, and also because the maximum aperture is higher.

Distortion

For the distortion test I shot some tiles:

The lens distortion is well controlled. There’s a mild amount of barrel distortion but generally it’s not noticeable on most shots, and it’s easy to correct in post on architecture photos if needed.

Vignetting

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

Just like it was detected previously on the resolution test, vignetting is very heavy wide open and improves significantly by f/4. From f/8 and down it generally doesn’t show up in images. Notice that this is mostly visible on shots of white walls like this. As a matter of fact, f/5.6 is already pretty much free from vignetting.

Chromatic aberrations

It was a clear bright sunny day with the sunlight reflecting on my car, and I took pictures of a area of high contrast:

The use of an aspherical element is an important feature in this lens for taking care of distortions and aberrations, and once again Cosina made an excellent job to keep aberration levels at negligible levels. From all the shots I made with this lens there wasn’t a single day I noticed any fringing issues. The lens deserves the maximum score here.

Coma

Coma is an important requirement in astrophotography and usually affects the corners of most lenses, especially wide-angle lenses and particularly old designs. I tested coma using a LED source of light 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/2.8 and f/4 (one stop down).

At f/2.8 the lens produces high amounts of coma even in the DX corner and much more so at the extreme corners, and doesn’t really get much better by stopping down. This is very unnattractive for astrophotographers, and if you are thinking of going out shoot the stars wide open, you better think twice or you might not like the results. This lens is awful in this regard, just like the 20mm was.

Flare

I shot several pictures on my backyard trying to get flare vestiges, and the result is as follows. I started to shoot directly against the sun, then placed the sun at one corner and then shot 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 Voigtländer has very good quality coatings inside and the results put it along with the best lenses I’ve used, with great flare resistance and keeping the overall contrast on high levels. There’s just a bit of veiling flare around the sun but no ghosting was detected on other parts of the frame. You just need to be a little cautious when shooting with the sun just outside the frame, and for this it might be a good idea to use the LH-28N lens hood available separately. Overall this is a very good result.

Bokeh

This is a wide angle lens and therefore the quality of the out of focus area of an image is not a primary aspect to consider, but still, since the lens has a relatively fast maximum aperture and 9 diafragm blades, one might expect acceptable renderings of out of focus highlighs. So lets see how the lens fares in this matter.
For this test I took a defocused picture at f/2.8 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 out of focus highlights are pretty circular at f/2.8 thanks to the 9 aperture blades, as expected, although the corners reveal the cats-eye distortion due to vignetting. Although circular, the highlights show pronounced edges and nervous interiors, but nevertheless it’s not distracting at this aperture when looking at the entire picture on my monitor. Closing down to f/4 reveals the outcome of the straight aperture blades and stays like this when closing down further. 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 22 centimeters from the sensor plane, or about 15 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 A beautifully well crafted lens, but the front cap is rubbish
Handling 10 Buttery smooth focus ring and very solid, compact lens, with CPU contacts for the automated exposure modes
Resolution 8 Excellent center sharpness, very good corners and fairly good extreme corners at moderate apertures
Distortion 8 Well controlled barrel distortion for a wide-angle lens and easily correctable if needed
Vignetting 7 Very strong wide open but improves greatly stopped down
Chromatic aberrations 10 A winner just like its 20mm sister lens
Coma 6 Very strong in the corners wide open, gets just a little better by stopping down
Flare 9 Great performance, but be most careful when the sun is just outside the frame
Bokeh 5 Circular only at f/2.8 but very nervous and pronounced edges, and gets polygonal at smaller apertures
Overall 79% A good pancake lens with very much expanded range of useful apertures for FX

Samples

Here are a few pictures I took during my past holidays and in my backyard. Settings: native JPEG, picture control set to Landscape mode, no post-processing applied except reducing to 600 pixel width.

f/4, 1/25s, ISO 800
f/8, 1/400s, ISO 200
f/5.6, 1/160s, ISO 200
f/8, 1/80s, ISO 400
f/4, 1/640s, ISO 200
f/8, 1/320s, ISO 200
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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