Phase One back focus plane misalignment

[jazzy]

Good evening Lula,

My first time here (and what a difficult signing up process, harder than my high school exam if I remember correctly).

I have recently upgraded to IQ160 from P25+ (private sale). What I notice is every photos now have an ever slight front focus in AF mode. It seems that the sensor plane of my IQ back is a little bit further back than where it's supposed to be.

Could you please advise me if this is something that is calibrate-able by Phase One? Another solution is recalibrate the in-camera AF, but as it has been working well with P25+ back I rather keep it as it is.

Thank you kindly,

[synn]

If you have a 645 DF+, you can use the AF fine tune feature to take care of this:

AF Fine Tune [20]
3. Use the front dial to scroll to Custom function 20
4. Using the rear dial to fine-tune the focus point on subject closer or further away from the camera.
50 = Neutral factory calibration
Minus = Move AF point closer
Plus = Move AF point further away

[synn]

Ah, ok.

I would recommend getting in touch with the nearest P1 dealer to see what they suggest.

[Bo Dez]

I had this problem once with a P1 back. It was a catastrophic failure on a shoot that was very difficult (ie impossible) to troubleshoot in the middle of a fast paced shoot. It turned out it was the sensor mount screws were loose and it was creating a tilt shift effect with the sensor wobbling around. The shoot was a near disaster so beware to all - When people say "there are no moving parts nothing can go wrong with a back" don't listen!

[Miyata610]

I have a similar problem with my Phase One back on a Hasselblad V.

I ended up shimming the mirror, because I could work out a way to do that. Now it won't focus properly on film.

I tried the Phase One support blog with no luck. They expect me to take it to a dealer. There's no chance of that given that the likely cost will exceed the value of the back. I wish they'd just release some service manuals for the long discontinued backs.

[jng]

Without some sort of independent measurement, it's hard to know which of the components - camera body, P25+ back, IQ160 back - is out of spec. With that said, I would consider the alignment within the camera body's focus path as a starting point for troubleshooting. As a case in point, I experienced significant front focus when using my newly purchased IQ160 on my Hassy 501CM (and slight back focus on my older 500C - talk about frustration!). At least with the Hasselblad V system bodies, the mirror falls out of alignment with use and with age. Even though I purchased my Hasselblad equipment elsewhere, my Phase One dealer shipped the body for me to Hasselblad-Bron for service, which took care of the problem. Note also that the 60 Mp back is less than forgiving of focus errors, which makes using it on a vintage contraption a bit of a challenge (but a rewarding one when it works).

[eronald]

Mine is unfortunately Contax 645, which I dont think have that feature. Thank you

What you need is a Contax repair specialist. The camera can doubtless be adjusted - if the sensor plane is orthogonal. If not you need Phase service.

Edmund