Hasselblad 500C focus adjustment

[ProdigalSun]

Hello folks, I have been posting here asking some questions on my 500C that I've been working on. I had to replace the frame that holds the screen assembly as one of the screws was snapped off in the frame. I got a new (used) identical screen frame assembly from a tech in Europe and got it installed but can't get the camera to focus to infinity.

I know that you are supposed to put the spring in, then the fresnel (in this case a beattie bright screen), then the ground glass, then the little hold down frame and screws, using the screws to adjust the screen height.

I have found that I can't get it to focus at infinity. I can't get the screen low enough. I tried removing the spring which gets the screen lower, but still not quite enough to get it to focus at infinity. I suspect the previous owner may have had the same issue as after the screw got snapped off he used just the fresnel with no spring or glass (and apparently used it for years this way).

Any ideas? Is it something else in the camera that's out of wack? Thanks for the help!

 

[4season]

Would inverting the screen help?

 

[cowanw]

Does not the Beattie bright screen replace the fresnel and the GG. Your first post suggests you are using both the bright screen and the original GG

 

[ProdigalSun]

4season - I did and either way it won't focus at infinity. It is currently oriented with the rough side of the fresnel down.

Cowanw - This may infact be the case but the issue seems to persist glass in or out. I assume removing the ground glass might make it a bit brighter but I don't think it would have an effect on the focus issue as the issue seems to be that the screen can't be adjusted low enough, so removing the glass wouldn't lower the fresnel at all.

 

[4season]

I forgot to mention the small foam pads behind the mirror: If those are rotted, you won't be able to focus accurately.

 

[OAPOli]

Normally you would have the Fresnel facing up towards the ground glass side. The Beattie screen should be used alone. Are you sure it a proper Beattie screen?

You should check if the lens itself is focusing properly. Unfortunately it is hard to do so with the Hasselblad bodies. You either need the focusing attachment or the older C12 with the peep hole.

 

[ProdigalSun]

4season, Yes, I have a feeling I might have a foam pad issue.

Oapoli, I went ahead and flipped the fresnel but it's too dark out to check infinity. Will check in the AM. And I don't know if it is a proper Beattie. The previous owner just told me the screw in the frame snapped when his tech went to put in the Beattie screen and he seemed to think that was the screen in the camera. The screen seems pretty thin, just a bit thinner than the ground glass. I attached a picture. Seems like it might warp when adjusting screen focus but maybe I'm wrong. Does this look like the real deal?

Unfortunately I have neither the focusing back or the old style back to check the lens.

 

[OAPOli]

To me it looks like a plain Fresnel. A standalone focus screen should have some frosting. Does it catch an image on its own?

You can check the lens with another camera. Place a piece of glass, sharpie a mark on the centre, place it on the back's rollers and hold it there. Take a second camera with a longer lens than the Hassie and carefully focus it to infinity. Then look through the Hassie lens with the 2nd camera. The mark on the glass will appear sharp only when the Hassie lens is at infinity.

 

[ProdigalSun]

Ok! Thanks! I was wondering because the image looked terrible without the ground glass! The image is also darker than the factory screen on my Mamiya C330 which seemed wrong for a Beattie screen from what I've read. I went ahead and flipped the fresnel but it didn't make much of a difference.

I also checked with another lens that I have (I would say of mildly dubious reliability) and it reads exactly the same amount off focus as my other lens. I then tried putting a few layers of masking tape on the peg the mirror rests on to lift it just a touch and I get focus at infinity in the middle of the screen, so with the spring removed and the tape on the peg I can hit focus in the middle of the screen.

I have a strong feeling this means the foam under the mirror is degraded and needs to be replaced. I'll take on moderate repairs, but I think that one is a bit beyond my comfort level. I'll use the camera for now for deep depth of field shots, then send it off to a tech to evaluate it once I've beefed up the camera fund a bit.