I recently picked up a C220, and I really like it, but I seem to be having focusing issues. I have three lenses (55mm, 80mm, and 180mm). None of them are perfect; the 55mm has internal spotting (not a haze), the 80mm has the beginnings of separation in the rear group along the edge, and the 180mm has haze on a number of elements in the both lenses. I use the 55mm and 80mm, but haven't used the 180mm for anything other then a focus test.
The 55mm is what got my attention with a focus issue, with this photo:
It looks to be front focusing quite badly. The fort is what I focused on, but the grass in the foreground is the only thing that comes close to being in focus.
I decided to do a focus test with all 3 lenses to figure out if it was the lens, camera, or me. Took 3 shots with each at different distances; 30ft, 10ft, 5ft in the backyard just as a quick and dirty test.
These are from the 5 foot test, cropped to 100%, all were focused on the "World's Greatest Boss" mug. (Ironically, the 180mm lens which has the worst haze (and a potentially flipped element), gave me the best center focus.)
The C220 doesn't have an interchangeable ground glass, but I'm not sure if it has the same foam deteriorating issue at the GG that the C330 has. The GG is installed with the correct side (smooth) up. It's my understanding that the GG screws are on so tight from the factory that it is highly unlikely that they have loosened.
I use the magnifier always, and I even used a loupe to confirm my focus on the GG.
None of the lenses wobble when mounted.
The focus issue is there with both 120 and 220 film (the fort is on 220, the mug on 120).
The lens seat on the body is smooth and parallel, and the lens clip is tight when closed.
My next step would be to put a ground glass from an RB67 on the film rails (wax paper or similar I have trouble getting flat on the rails), and evaluating from there. If there is a mismatch between the viewing GG and the film rail GG, how would I adjust it?
With the 180mm pretty much spot on with the focus, my only other thought is that both the 55mm and the 80mm aren't shimmed properly internally, or something. But how likely would that me?
Any thoughts or suggestions?
The 55mm is what got my attention with a focus issue, with this photo:
It looks to be front focusing quite badly. The fort is what I focused on, but the grass in the foreground is the only thing that comes close to being in focus.
I decided to do a focus test with all 3 lenses to figure out if it was the lens, camera, or me. Took 3 shots with each at different distances; 30ft, 10ft, 5ft in the backyard just as a quick and dirty test.
These are from the 5 foot test, cropped to 100%, all were focused on the "World's Greatest Boss" mug. (Ironically, the 180mm lens which has the worst haze (and a potentially flipped element), gave me the best center focus.)
The C220 doesn't have an interchangeable ground glass, but I'm not sure if it has the same foam deteriorating issue at the GG that the C330 has. The GG is installed with the correct side (smooth) up. It's my understanding that the GG screws are on so tight from the factory that it is highly unlikely that they have loosened.
I use the magnifier always, and I even used a loupe to confirm my focus on the GG.
None of the lenses wobble when mounted.
The focus issue is there with both 120 and 220 film (the fort is on 220, the mug on 120).
The lens seat on the body is smooth and parallel, and the lens clip is tight when closed.
My next step would be to put a ground glass from an RB67 on the film rails (wax paper or similar I have trouble getting flat on the rails), and evaluating from there. If there is a mismatch between the viewing GG and the film rail GG, how would I adjust it?
With the 180mm pretty much spot on with the focus, my only other thought is that both the 55mm and the 80mm aren't shimmed properly internally, or something. But how likely would that me?
Any thoughts or suggestions?
