Hasselblad PM90 prism way out of focus

[Ai Print]

Hi,

I just added a Hassy PM90 prism to my kit for use with a CFV50c back and it is out of focus something serious. I got it from KEH and it looks virtually brand new, has the standard neutral diopter ( OD/90 ). I tried it on three bodies, my wife looked through it ( I now use a -1.5 ) and it is completely back focused meaning the point is behind the surface of the prism that faces the screen. I took the diopter off and in no way did that help, part of the optical path although all I saw was the back of the prism, no optics.

Besides the obvious of returning it hassle free to KEH, any suggestions on trouble shooting this? In looking at the photos, does this look right or is it missing something?

 

[Sirius Glass]

Since you tried it on three bodies, the problem is not from a body being out of alignment. Return it to KEH and have them fix or adjust it, replace it or refund it.

 

[cowanw]

You are using your glasses to look through?

 

[Ai Print]

No, not wearing glasses. To be honest I think someone pulled a fast one on KEH when they sold the prism to them and swapped the glass around in the eyepiece in order to make a sale.

Oherwise this makes no sense at all.

 

[bdial]

It's a possibility that someone installed a custom diopter.
Another could be that yours is in backward.
Is the convex side facing the prism?

 

[Ai Print]

Yep, convex in, flat side out. I bet that is what it is, KEH seems to not even inspect their gear anymore, this has become a recurring theme with them in the past few years.

 

[bdial]

If it helps, I just did an experiment with the eyepiece of my PM45. With it off the camera and held at my eye it produces a sharp image at about 2 inches, roughly.