Recently I tested two Fujifilm lenses on the GFX 100S. Since I can't afford a full fleet of native glass my plan is to use my modest collection of fine vintage (manual focus) glass. I have been happy to use a selection of these on the full-frame (135 format) Panasonic S5. But not all of these lenses will support the larger sensor size. I expect some vignetting, especially wide open. Or the borders could simply be too weak (e.g. blurry with aberrations).
So... bring on the testing! I lined up a selection of Contax-Yashica mount Carl Zeiss lenses, namely:
- Carl Zeiss Distagon T* 2,8/28
- Carl Zeiss Planar T* 1,4/50
- Carl Zeiss Makro Planar T* 2,8/60 C
- Carl Zeiss Sonnar T* 2,8/85
- Carl Zeiss Planar T* 2/100
And a few M42 screw mount lenses:
- Carl Zeiss Jena DDR Pancolar auto 1,8/50 MC
- Meyer-Optik Gorlitz Domiplan 2.8/50
- Pentacon 2.8/135
Pentax will have to wait since the adapter I purchased is apparently on a world tour.
Test method
I shoot my bookshelf at about 110 cm distance. This subject has a variety of colours and textures while maintaining consistent diffused sunlight. This test won't tell us anything about flare, bokeh, etc. but is useful for acuity and (most important) the behaviour across the frame. Here's the setup:
- Tripod mounted with image stabilisation off.
- Timed shutter release used.
- Manual focus using magnification feature.
- ISO constant at 1000.
- File format is lossless compressed 14-bit RAW.
- Developed in Affinity 2 with default settings.
This test provides a baseline but not optimal images. Any real-world development would produce better photographs in terms of desired colours, contrast, sharpness, etc.
I stacked the 11662 x 8746 pixel images and then reduced the overall size by 50%. Then I cropped to a 1000 pixel square in the areas of interest. Unlike previously, this test was not made to compare lenses but rather to evaluate each lens on its own terms.
I shot each lens series twice: first with focus in the centre (on the "Mc" in "McInnes") then with focus at the extreme left side (on the "c" in "Uncommon"). This varied a bit with the different focal lengths.
Click on each image below to expand to full size. View on a computer, not a mobile screen.
Test results
1. Carl Zeiss Planar T* 1,4/50
The lens is sharp and contrasty in the centre of the frame by f/2. It has noticeable light falloff at the sides but nowhere vignettes. The quality is excellent by f/4. If you wish to isolate your subject without compromise in the image, choose this lens and set it to f/2.
2. Carl Zeiss Makro Planar T* 2,8/60 C
Usable wide and excellent at f/4. For some reason it's hazy already at f/8 even though diffraction shouldn't matter until about f/16. This is consistent at the centre and side of the frame. I always considered this an under-rated lens since the 1:2 macro is darned useful. I might need to try it again to see why the images are deficient. It can't be the need for a hood since the front element is deeply recessed.
3. Carl Zeiss Sonnar T* 2,8/85
I've reviewed this lens in detail as it's absolutely my favourite at this focal length. It is one of the most compact 85mm ever made and somehow also manages to be an excellent performer. It is sharp all the time while giving that special Sonnar contrast. No it is not an f/1.4 but I prefer my subjects to be in focus. I must say that I am so surprised that this wonder maintains performance even on the larger sensor. Wow. Just, wow.
4. Carl Zeiss Planar T* 2/100
While usable wide open I have always known that this lens benefits from stopping down once. Overall I prefer the rendering to the Sonnar but this is a big heavy lens that I rarely take out. Looking at this performance on the larger sensor it's clear that it prefers the 135 format sensor. Sonnar wins all the way. This was quite unexpected.
5. Carl Zeiss Jena DDR Pancolar auto 1,8/50 MC
There's so much hype over M42 lenses especially those made in the DDR. People seek swirly bokeh or special degraded looks. But not me. Every time I have tried one of these lenses I am repelled by the bad build quality, poor ergonomics, and naff rendering. Of course you can still make excellent photos with this type of lens but why be hampered by your tools?
This fast 50 is centre sharp at f/4 but its Western counterpart achieves that two stops earlier. The edges are only just OK at f/8.
6. Meyer-Optik Gorlitz Domiplan 2.8/50
I paid 50 clams for this which is too much. It's just hazy rubbish all the time. Of course there might be better copies out there, but other manufacturers have a much higher hit rate.
7. Pentacon 2.8/135
I forgot I owned this lens because I rarely need this focal length and when I do I've better options. Like the previous lenses it was even difficult to get focus since the subject was so indistinct. The one upside is that the lens is rather cool looking.
0. Carl Zeiss Distagon T* 2,8/28
I noticed immediately that this lens has hard vignetting so I did not proceed with the test. I have better 28mm lenses under the name Pentax. Time will tell whether those cover the larger sensor.
Conclusion
I trust that this little exercise makes a useful contribution to the available compatibility data. We shouldn't expect a lens made for a smaller image circle to perform at all well on the GFX. Those that did were definitely over-engineered for their time. There are definite winners here:
- The CZ Sonnar 85mm has a home in my bag.
- The CZ Planar 50mm will need to compete with some amazing Pentax lenses next time I perform this exercise.
If I find two lenses to be similar after this simple test, then I will commit to evaluating bokeh and other characteristics.
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