I'm still quite fond of the EOS30 and that's the camera I use 99% of the time when shooting 35mm. Some time ago I got a 2nd hand Canon EF100 f/2 which I've been using off and on. But I've got a focus problem: this combination of body + lens seems to exhibit a significant front focus issue. In other words, if I focus on something on the horizon (effectively infinity) the negative shows the focus to be some distance closer than the actual point of focus. This happens with autofocus as well as careful manual focusing.
I have so far not noticed anything like this on this camera with other lenses - but I have to say I always use a 50mm or even shorter lenses, and nothing longer than that.
So I did the (in my mind) logical thing, which was to put the camera with lens mounted on a tripod, focus on a point on the horizon, open the back, put a piece of ground glass exactly in the film plane and flip up the mirror (which is awkward with an EOS 30, but it can be done). Well, what do you think? The image on the film-plane ground glass matches perfectly with the image in the viewfinder. Mind you, I've used this approach successfully to calibrate the rangefinder on some 35mm cameras as well as the mirror on a medium format Mamiya, so I'm not taking a stab in the dark.
The obvious cause could be a problem with film flatness, but the camera is pretty much like new from the inside, the pressure plate is firm and presses like a motherf*** (it does its job just fine it seems). I never noticed a problem with other lenses, but like I said, they're shorter and shorter lenses tend to be somewhat less iffy when it comes to precise focus - or put differently, focus problems with shorter lenses are just a little less obvious most of the time. Still, haven't had any. Just with this EF100/2.
I'm stumped. Can anyone enlighten me on the focusing system of the EOS 30 and any possible wear of mirror catchers etc? Has anyone ever experienced this same issue by any chance?
Obviously I tried googling several times, but the results are horribly diluted by the masses of digital pixel peepers worrying about focus issues with their digital gear (not saying those aren't legitimate, but it does make finding information on film bodies specifically harder).
I have so far not noticed anything like this on this camera with other lenses - but I have to say I always use a 50mm or even shorter lenses, and nothing longer than that.
So I did the (in my mind) logical thing, which was to put the camera with lens mounted on a tripod, focus on a point on the horizon, open the back, put a piece of ground glass exactly in the film plane and flip up the mirror (which is awkward with an EOS 30, but it can be done). Well, what do you think? The image on the film-plane ground glass matches perfectly with the image in the viewfinder. Mind you, I've used this approach successfully to calibrate the rangefinder on some 35mm cameras as well as the mirror on a medium format Mamiya, so I'm not taking a stab in the dark.
The obvious cause could be a problem with film flatness, but the camera is pretty much like new from the inside, the pressure plate is firm and presses like a motherf*** (it does its job just fine it seems). I never noticed a problem with other lenses, but like I said, they're shorter and shorter lenses tend to be somewhat less iffy when it comes to precise focus - or put differently, focus problems with shorter lenses are just a little less obvious most of the time. Still, haven't had any. Just with this EF100/2.
I'm stumped. Can anyone enlighten me on the focusing system of the EOS 30 and any possible wear of mirror catchers etc? Has anyone ever experienced this same issue by any chance?
Obviously I tried googling several times, but the results are horribly diluted by the masses of digital pixel peepers worrying about focus issues with their digital gear (not saying those aren't legitimate, but it does make finding information on film bodies specifically harder).