Olympus 80mm bellows lens at 1:1 on GFX 50R

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Navman Contributing Member • Posts: 510
Olympus 80mm bellows lens at 1:1 on GFX 50R

Having advocated so much for this lens as a good performer at 1:1 on my GFX, I thought I should put up some results. These below were shot at F/8 with the camera mounted vertically over a very solid work bench and with the camera levelled with a spirit level in both x and y directions. I found what appeared to be the optimal focus in magnified view using a linear stage equipped with a styret micrometer to control the distance to the target. I then took seven images at 0.2mm steps bracketed around this 'optimal' focus point. I imported the images into LR, increased the contrast (+40), and selected the sharpest image. I then exported both the full image at 50% reduction, and then 1000x1000 pixel crops in the centre and each of the corners. No output sharpening was applied.

For those interested in this lens, mounting it presented a few challenges, given the age of the OM mount and a scarcity of suitable adapters. Initially I used it on an Olympus bellows but found that it vignetted unless I put my 45G extension tube between the camera and the bellows. I then tried an Olympus 65-116mm variable extension tube, which also requires the 45G between the camera and the OM adapter - but in this configuration it covers the full GFX sensor with no vignetting at all, and with good resolution right into the corners.

It also appears to be delivering a very flat plane of focus, with the image with the sharpest centre performance also delivering the sharpest corner performance. A similar image at F/5.6 had marginally sharper resolution in the centre of the image, but greater falloff in illumination in the corners - corner sharpness was similar to this shown below.

I'll be very happy to use this as a process lens for copying negatives and old contact prints. I also have the 135 bellows lens, but it is more difficult to take to 1:1 - it provides similar performance to this at 0.5x.

Finally, I had no USA notes, so used a local (NZ) $20 bill - I hope that is an acceptable currency of test!

-John

Entire frame @ 50%

Centre at 100%

Bottom left at 100%

Top left at 100%

Bottom right at 100%

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Fujifilm GFX 50R
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