Mamiya 7 RF alignment with different lenses
Sorry I know this topic has been addressed a lot here, but I still can't figure out what is going wrong with my Mamiya7.
I sent it for a repair at a specialized shop, and this shop also performed a RF calibration.
However when I checked the infinity alignment, I saw it was off and thought it could result from the transport from the shop.
I then performed an calibration with the small crew, based on infinity alignment.
But then, I noticed some of my pictures where out-of-focus.
I then checked the alignment again, by placing an object precisely 1 meter away form the Mam7 (80mm lens), and checking the alignment in the RF, which was OK.
I then performed the same test with my 65mm lens, and noticed there was a 3cm out-of-focusing with this lens. However, the infinity alignment with this lens is OK (as with the 80mm).
My question is then : is it possible that a lens is decalibrated, and would it be possible to re-calibrate it ? Or do I have to take this decalibration into account while focusing, and adapt the alignment in the RF when taking photos ?
Do someone has the same problem and how do you deal with it ?
Thanks for your help !
Using film or did you put a little ground glass on the film rails?
However when I checked the infinity alignment, I saw it was off
Well I mean I turned the focus ring to the infinite stop, and then checked that a far away standing object (several kilometers) was aligned in the RF.
This test didn't didn't involved film nor ground glass, for my tests I'm supposing (mistakenly perhaps) that the only things I can trust is :
- when the ring is focusing at infinity, the lens is actually focusing on infinity
- when the ring is focusing at the most close, the lens is actually focusing on 1 meter
I've also done empirical tests with film, with the 80mm lens, with closed objects (2 or 3 meters), and it seems to be more or less in focus. I did't performed films tests with the 65mm yet.
Which repair shop did you send it in to?
I had this problem with my Mamiya6 and the 150mm lens;all other lenses were fine.it only worked after lens and body calibration at Mamiya in Germany(Munich).That was 10 yearsago and it worked ever since.
Originally Posted by clasbou
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I sent it to the only repair shop in my country. But that repair shop is trusted by the whole french photo community, so I think the job was well done.
I performed new tests with another Mam7 body, and the result are the same :
Focus on infinity :
80mm aligned, 65mm are well aligned
Focusing on an object with focus ring is at the closest position :
- the distance between the object and the 80mm is 1m
- the distance between the object and the 65mm is 93cm
So I conclude the 65mm focus mechanism is not linear...
I'd like to perform tests with a ground glass placed on the film plane, and checking the focus on it, but it seems the Mam7 won't fire while the back is opened, do you know if it is possible to force the shutter firing ?
My mistake, the shutter is well firing.
The above statement could be false. The collimation (infinity stop setting) could be incorrect on the affected lens. The camera body could be fine. You don't know until you check.
Originally Posted by clasbou
Yes. It's possible for the ring to not be accurate.
Originally Posted by ic-racer
If you do not have a ground glass to check with,, use frosted tape over the film gate and check your focus there. Then verify where the index is.
One of those cases where it's "Pay me for what I know, not what I do." It's pretty simple when you know what to look for.
Heavily sedated for your protection.