not sure that, in general, RB's pick up focus errors like other mf cameras. I believe the mirror has a 'hard stop' unlike others that have a cushion of foam that can deteriorate over time. You dont show us the focusing screen - is it a standard one or 3rd party? We must presume that the camera is basically sound (ie the bellows isn't knocked out of alignment) and that the revolving adaptor/back and focus screen is seated properly. Is your eyesight OK for the viewfinder? Get a friend to try focusing it - do you get the same result? Can you try focusing at the film plane by removing the back and sustituting a piece of frosted glass?? The vf focus and fp focus must agree.Hi everyone
So I just got back my first scans, and it seems whenever I used a lower f-stop like 3.8 or 5.6, my focus lies farther in the frame than what I focused on. Or it's just blurry altogether. No problem with smaller apertures like f/11 or f/16.
Here are the worst ones:
https://ibb.co/3yx50Wd
https://ibb.co/jWYTBht
https://ibb.co/r0F8h2f
https://ibb.co/H7sqxQT
https://ibb.co/Tk6mKdP
https://ibb.co/48hgTsB
Back seems to be okay, viewfinder/glass and everything as well and I'm preeetty sure I'm focusing perfectly. Not sure about the mirror. Or perhaps I'm not looking at the right things? Anyone know what might cause this difference of DOF in VF and negative? Lens is a Sekor C 90mm.
Here are some pictures of the mirror down:
https://ibb.co/7Y995cs
https://ibb.co/kcChxgQ
https://ibb.co/qjwZ5tr
Thanks so much in advance.
not sure that, in general, RB's pick up focus errors like other mf cameras. I believe the mirror has a 'hard stop' unlike others that have a cushion of foam that can deteriorate over time. You dont show us the focusing screen - is it a standard one or 3rd party? We must presume that the camera is basically sound (ie the bellows isn't knocked out of alignment) and that the revolving adaptor/back and focus screen is seated properly. Is your eyesight OK for the viewfinder? Get a friend to try focusing it - do you get the same result? Can you try focusing at the film plane by removing the back and sustituting a piece of frosted glass?? The vf focus and fp focus must agree.
Hey Morel, merci à toi! What makes you think that, because I was under the impression it was mounted with the correct side up? On the other side, the dotted lines are foggy. Flipping it over, it cannot be seated properly in the top. So the glass itself is wrongly mounted in the fitting frame according to you? Not at home either right now, I'll be able to send more pics of the screen tonight, these were screenshots of a video I made yesterday.From the images of your focusing screen, I get the impression that the glass is mounted with the wrong side up.
Thanks for your input, Ian!1. The first thing to check on an RB67 or RZ67 is the proper seating of the focusing screen where it mounts on the top of the camera. If the screen is improperly seated, then what the viewfinder shows and what the lens projects to the film will be slightly different. This is the most likely cause of the problem.
2. Another thing to check is the correct functioning of the pressure plate in the film back. If it isn’t holding the film in the correct position, then the film might be somewhat displaced from the image plane. That would result in a fuzzy image recorded on the film.
3. If the mirror mechanism is badly worn, it might cause you to set the focus slightly off. While this might be possible, it’s not likely.
Morel, do you have the things and knowledge necessary to perform this test? And maybe other tests if need be? I could pay you a quick visit this weekend, if you were open to that... I'm from Ghent.Regarding Neil's reply: Frosted Glass -> 'Verre dépoli'. When placed against the Revolving Back adapter, in place of a film magazine, the plane of the frosted side should concide with the normal film plane. In such a setup, focus on the viewfinder an as it appears on the ground glass should match.
The problem is then likely elsewhere. IanC's points remain the best course of investigation, in the same order he presents them.
Then I'll have to develop a roll of film to test this? This isn't possible to do together then?
But the ground glass test is? Multiple people have suggested this on different platforms, shall we try that?
The one circled in blue is correct.@cramej: I was unaware of that possibility. Can you indicate precisely which screws you mean? If it helps, I have identified three candidates, circled in the various colors in the images here:
https://ibb.co/sqvpsy3
https://ibb.co/m6PnSdV
The one circled in blue is correct.
See here for more details: https://www.photrio.com/forum/posts/?post_id=1403382
By looking at your sample photos, you would need to lower the screen.
I had to do this to my RB. At that time, I did not have a loupe and now that I do, I think I need to check this adjustment on mine again.
Ok, so perhaps two pieces of stiff wire of the appropriate guage, taped firmly to a piece of wood of rectanglar section and thickness matching the hole-to-hole distance would provide more assurance?Two mechanical pencils with metal tips can work in a pinch. Insert them at an angle in opposing directions and push - very carefully. It's like trying to pick up a grain of rice with a chopstick in each hand.
By looking at your sample photos, you would need to lower the screen.
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