I recently bought a Wista 8x10 field camera (it will be the subject of another review). It was a package deal that included a Komura 210mm, f/6.3 lens, that is supposed to cover 8x10 without much movement (I haven't tested that yet).
Didn't think much about it since I already had a really nice Rodenstock 210 mm, f/5.6. The Rodenstock has been one of my favorite lenses for a long time, so I figured I'd dump the Komura on a popular auction site and be done with it.
Then I opened the package. I confess that I was a bit surprised. Wow. Sure it's a third of a stop slower but it's also a third the size (well close, 50mm vs 68 mm thick)! For many photographers, how much it weighs is the important number: Rodenstock - 450 grams; the Komura just over 300 grams.
Frankly, I had never heard of Komura until this one showed up. A quick search returned rather positive comments. Yeah, I was going to have to test it for myself.
The plan was simple and rather pragmatic: shoot the same scene with both lenses and see if there was a noticeable difference. I've uploaded the photos to Flickr:
Komura vs Rodenstock
Notes: Shot on Ilford FP4 at ISO 80, processed in SP-76EC in the SP-8x10 tray for 8 minutes at 68F. (Frankly, the negatives are just a little bit dense.) Both shutters where calibrated before testing. Tripod was not moved between shots; the only adjustment was to refocus. Negatives scanned on a Epson 850 using the default settings. No post processing.
I think the Rodenstock might have a slight edge regarding sharpness but my ability to focus properly is probably a bigger factor.
The actual focal length of the Komura is probably just a bit longer than the Rodenstock.
The difference in brightness during focusing was noticeable but not really significant.
I won't make any statements regarding contrast since I haven't tried optimizing for it.
The shot of the bridge was taken into the sun on an overcast day and the Rodenstock seems to have less flare. In all fairness, the sun was maybe a bit brighter during the Komura shot.
Again, this wasn't designed as a highly contrived laboratory grade test and it would take a lot more than a dozen test shots before I'd get too dogmatic about either lens.
Summary: For me, the weight/size savings and the option to use the Komura on my 8x10 means that I'm selling the Rodenstock.