hamradio
Well-known
So, I picked up a J9 on a whim in LTM. Beautiful shape, chrome, made in '56. I threw it on my Bessa R, fully not expecting it to focus properly. Put the shutter in B with a cable release, opened the back, placed an old SLR focusing screen in the film gate.
Lo-and-behold, it works almost perfectly. Infinity is dead on, 2m is dead on. At its closest, 1.15m and f/2, it's just a hair off--maybe an inch or two. Its barely a difference, and in practice, I think user error with the RF would make more of a difference...it's one thing to focus at a black cross on paper as a target, but when I focus at random things around the house, my own focusing has a little error. Any discrepancy is gone by f/4.
I put the lens on my known-good Fed 2, and it seems as if the error might be greater.
This brings up the question:
This makes me wonder,
Is the close-focusing error due to the lens itself being spec'd to a different RF standard, or is it due to the focus-shift with Sonnars? For those who've tried J9s on normal LTM bodies, how far off was the focus? It's not like I can really adjust anything with this lens...there's one shim for the whole optical unit to adjust infinity focus, and no shims for the rear cell. I'd have to manually lap down the metal on the cell.
Lo-and-behold, it works almost perfectly. Infinity is dead on, 2m is dead on. At its closest, 1.15m and f/2, it's just a hair off--maybe an inch or two. Its barely a difference, and in practice, I think user error with the RF would make more of a difference...it's one thing to focus at a black cross on paper as a target, but when I focus at random things around the house, my own focusing has a little error. Any discrepancy is gone by f/4.
I put the lens on my known-good Fed 2, and it seems as if the error might be greater.
This brings up the question:
This makes me wonder,
Is the close-focusing error due to the lens itself being spec'd to a different RF standard, or is it due to the focus-shift with Sonnars? For those who've tried J9s on normal LTM bodies, how far off was the focus? It's not like I can really adjust anything with this lens...there's one shim for the whole optical unit to adjust infinity focus, and no shims for the rear cell. I'd have to manually lap down the metal on the cell.