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 p.25 #1 · Adapting Lenses to the Fuji GFX | |
rdeloe wrote:
I do love those OM lenses! I built a whole tilt-shift system using Olympus OM lenses on a Fuji X-T2. I've since moved on to a tilt-shift setup I built for the GFX 50R, but I still have most of the OM lenses I used.
In building out my system, I tried one copy of OM 28/2, but found it to be totally unacceptable as a shift lens. So I'm surprised (and pleased for you) that your copy works well. I actually thought there might be something wrong with the OM 28/2 I tried; it has a very good reputation and should have done better. Your test supports the conclusion that I had a dud....Show more →
It's not too strange since the demands on the lens will be higher with a small APS-C sensor since you magnify any aberration more. And if you shift, you'll probably use the whole ~43 mm image circle. On the GFX my corners are at an image circle of ~51 mm at 16:9, but with much lower magnification.
I do think that the OM 28/2 has floating elements, so check if your hit infinity at the mark or close to it. If not, shimming the adapter (or lens) might make the results better.
Your post inspired me to quickly try some of my OM lenses on my GFX 50R, using my Toyo VX23D outfit, to see where they vignette. I tested at f/11 at just over 1 metre to the subject.
* OM 24/2.8 vignettes hard, but using a 4:3 crop leaves you with a usable image of roughly 5,200 x 6,931 pixels.
* OM 35/2.8 is interesting. It doesn't vignette hard over the sensor area (just a bit of darkening in the corners). However, the usable area isn't bigger than OM 24/2.8. Outside of the roughly 5,200 x 6,931 pixel area the image is a blurry mess.
* OM 50/2 is a really nice and well regarded lens in the Olympus lineup. It vignettes hard, but not as far in the frame as OM 24/2.8. A 4:3 crop of 7,400 x 5,550 pixels looked to have even illumination. From my testing of OM 50/1.4, I know that the faster 50 has a slightly larger image circle and will give a larger usable area.
* OM 90/2 is another star in the Olympus OM lineup. It covers the whole GFX 50R sensor with no vignetting at all that I could see.
I have to be careful about offering conclusions about image quality because my test setup wasn't ideal. However, just judging by the centre of each image, where I'm more confident that the lenses were at their best, I wouldn't run out and buy an OM to GFX adapter to use these lenses (with the possible exception of OM 90/2, but I have good choices at that focal length already). I have better alternatives for everything up to 35mm. After that I don't have any lenses that work (but I find 35mm on the GFX sensor is almost wide enough for me, so I can live with this gap).
...Show more →
I actually find the OM 35/2.8 quite useful at 33x44 mm. Yes, the corners will be smeared, but there is virtually no vignetting at all and at f/11-16 it's pretty sharp over the entire area except for the extreme corners.
The 50/1.8 requires a slight crop and I find the Nikkor 50/2 a better lens. It vignettes less, is sharper and has nicer character. Stopped down or reasonably close, there's no need to crop at all.
I'll keep an eye open for the 90, but it's a bit too expensive for just playing around, I think. 
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