Phase One 645 back focus issues

Discussions regarding Phase One 645 AF and Mamiya 645AFDIII Camera

Phase One 645 back focus issues

Postby mpetrick » Sat Jul 11, 2009 3:40 am

We've just started using a Phase One 645 with the P65+ back with Phase One 45mm, 80mm and 120mm Makro. We are having back focus issues that first became apparent with the 120mm. Performed a focus test at about 12 ft. and found the recorded focus point to be 6 - 8 inches behind the point that was focused on. Phase One says this could be the body or the back. Have others run into this problem?
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Re: Phase One 645 back focus issues

Postby Jari 3 » Sat Jul 11, 2009 10:00 pm

I own the same setup of camera and lenses only with the P30+ and could not get the focus right on the 120. I then exchanged the screen to a micro prism screen focussed carefully but still I have a back focus.
So far I thought it were my mistakes and I did not run a dedicated focus test.
I even thought of exchanging the 120 for the new 150/2,8 as I assumed AF would do a better job then I could.
In the next days I will run a focus test and post the results.

Jari
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Re: Phase One 645 back focus issues

Postby Jari 3 » Sun Jul 12, 2009 1:22 pm

After running some test shots I have to confirm your findings.
My 120 has a back focus of about 10-15cm from 5m distance. On Monday I will contact my local Phase dealer for support.
I tested the 80 and 45 as well, both have a correct focus.
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Re: Phase One 645 back focus issues

Postby Peter9 » Tue Jul 14, 2009 9:28 am

Hi Jari and Mpetrick

I’m sorry to hear about your experience, and I agree that you should contact your local dealer as they will be able to help you sort out the problem.

I’m a little puzzled by the scenario you are describing Jari as I would expect the problem to be present on all lenses and not just one, please send me a message when you find out where the problem is located.

All the best

Peter Tirsgaard
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Re: Phase One 645 back focus issues

Postby Jari 3 » Wed Jul 15, 2009 8:41 pm

Mea Culpa.......

I had the microprism screen and the film with the cropping frame mounted in the wrong order. This caused somehow the wrong focussing.
My dealer found the mistake and changed it for me.

I am still considering changing the 120 for a 150AF as the AF is a big help when shooting portraits wide open, each milimeter counts here and it seems that I am not so good in using the MF.

Jari
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Re: Phase One 645 back focus issues

Postby Peter9 » Thu Jul 16, 2009 8:42 pm

Hi Jari

I’m glad to hear that you found the reason for the problem, it had me puzzled that only one of the lenses was out of focus, but that explains it as the 120 is a MF lens.
I do most of my portraits using the 80mm and the 150mm as I do enjoy shooting with a very shallow DoF, and even though it’s easier to do manual focus on a medium format system than on a DSLR it makes you able to concentrate more on the rest of the scene.

I did some macro shots in the studio with the 150mm and an extension tube and that worked out quite well.

All the best

Peter Tirsgaard
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Re: Phase One 645 back focus issues

Postby Nick361 » Tue Jul 28, 2009 4:02 pm

I experienced focus issues with my new Phase One camera as well. There are several variables that have to be taken into consideration when evaluating this problem and the best discussion of this problem is on Joseph Holmes website. Rather than go through it all here it is best to just check out the site.

http://www.josephholmes.com/news-sharpmediumformat.html

In my case the autofocus was accurate and manual was not. After much back and forth the problem was finally resolved with a new camera body. One must carefully evaluate every body for proper focus and every back for chip planarity before putting them into service. The Mamiya service center in the US is currently not equipped to properly evaluate focus issues so you must do this testing yourself and work with a dealer who will properly support you. Best to evaluate all this before purchase.
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Re: Phase One 645 back focus issues

Postby NN8918912 » Tue Jul 28, 2009 9:55 pm

Nick36 wrote:I experienced focus issues with my new Phase One camera as well. There are several variables that have to be taken into consideration when evaluating this problem and the best discussion of this problem is on Joseph Holmes website. Rather than go through it all here it is best to just check out the site.

http://www.josephholmes.com/news-sharpmediumformat.html

In my case the autofocus was accurate and manual was not. After much back and forth the problem was finally resolved with a new camera body. One must carefully evaluate every body for proper focus and every back for chip planarity before putting them into service. The Mamiya service center in the US is currently not equipped to properly evaluate focus issues so you must do this testing yourself and work with a dealer who will properly support you. Best to evaluate all this before purchase.




The problem that usually occurs when you can properly auto focus but manual focus does not work is the diopter setting on the eyepiece. I get this support call many times and I have see this happen in many demos. You hand photographer a camera and they start using auto focus and then decide they want to use manual focus but never test their eye piece and set the diopter. The best way to do this in my opinion is to look through camera against a white wall, turn the diopter setting to the - side. Slowly bring it into focus and you will see the focus screen outline come into focus. SOmetimes I like to average these to insure your eye is just not drifting. Then I would test with newpaper of something flat with copy. Works every time for me on any camera, P1, Contax, Mamiya, or Hasselblad.

Give it a try. Now this will not work if you have the mask in the wrong place because at this point you have taken the camera out of factory spec as far as the viewing system.


Chris Snipes
Image Production, Inc

Authorized Phase One Dealer

http://www.imageproduction.com
chris@imageproduction.com
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Re: Phase One 645 back focus issues

Postby Henry1 » Wed Nov 11, 2009 5:58 pm

Chris,

What about the focus confirmation indicator (the green dot). If AF on a particular lens is accurate, will I get the same result if I switched to MF and shoot only when the confirmation light shows up?

My own take is NO, it does not always yield accurate focus.

Can anyone share his own experience? Thanks.

What I feel is really needed is to have a Micro-adjustment feature on the body just like the one found on Canon's IDs MKIII. That way we can calibrate focus and store data for each lens we use.
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