Rear focusing issues with Hasselblad 503CX

[Duceman]

Yesterday I shot a roll of Acros II for some portraits. My setup was a Hassy 503CX with a 150mm Sonnar. First time using this lens since having it CLA'd a year or so ago. I don't recall the last time I used this Hassy body. All shots were taken with strobe flash and camera on tripod. I developed the roll in XTOL 1:2 for 13 minutes @ 68F. Development seemed alright. However, when I scanned the images, in each of them, the subject was slightly out of focus, but everything about six inches and further behind the subject was in focus. I took great care in focusing on the eyes of the individual whom I was photographing. And I don't recall having had this issue before.

Based upon what I've been able to come up with through internet searching, seems the issue is one of two things: (1) the mirror is out of alignment, which will require a CLA; or (2) my focusing screen may have been upside down. Regarding the second point, this camera has a split image Brightscreen Proscreen 20/20. I had it installed with the identification sticker showing up. (see below stock image) I'm trying to think if maybe since the last time I used this if I had taken the screen out and may have put it back in upside down. But it doesn't seem, based upon the screen's construction, that that should make any difference. Nor have I been able to find any online instructions on how to properly install.

Before sending the camera body off, I was going to put a test roll through this camera again, as well as another Hassy I have, just to see if that's the issue. But before doing so, I thought I'd ask here if there's anything else I should consider as part of the problem.

 

[Duceman]

I have owned many 500 series bodies (retiring commercial photographer), but never had a mirror go out of alignment, although I hear it is possible.

Thanks. And I tend to agree with the above, and am doubtful that the mirror is in fact out of alignment; though I do not use this body all that often, it was in alignment the last time I used it and nothing has happened to the body since. That's why I'm thinking that it *might* be a focusing screen issue. Or.... my eyes have drastically changed since the last I was using my Hassys!

 

[ic-racer]

The best camera manufacturers have been plagued with 120 film’s tendencies to rise above the pressure plate, since the film is only held to the pressure plate at the perimeter.
It is the lens designers who suffer. I even recall reading complaints about it in a Zeiss catalog.

 

[itsdoable]

I bought the exact same Brightscreen Proscreen 20/20 with the brass frame, and it back focused on my 203fe, especially noticeable with the 2/110. I replaced it with an Hasselblad Acute Matte screen, which was fine. I think the Brightscreens were not manufactured to spec, or they required a screen calibration during installation (which is what the BOSscreens needed).

The Brightscreens are nice and contrasty, so if you like them, it maybe worth while to get it calibrated. But the Acute Mattes are also good, and no calibration is needed.

 

[Eff64]

The Hasselblad screens are mounted in an aluminum frame. It is pretty hard to have one upside down without noticing.

You should try switching screens for your test, and keep detailed notes of what is what.

 

[Duceman]

The Hasselblad screens are mounted in an aluminum frame.

Wasn't using a Hasselblad screen, but a Brightscreen Proscreen, like the brass colored one shown above, which looks identical from frontside to backside.

Finished with the test results.... will be posting shortly.

 

[Duceman]

Ran a test today. Used the same equipment as before, but also added another 500c/m Hassy body and 80mm Planar lens. I took shots after turning screens, swapping screens and swapping lenses on both bodies. Also, being that I didn't want to waste my "good" Acros film, I used an expired roll of Tri-X 400. This meant that instead of shooting at f/8 or f/11, I was shooting at f/16 and/or f/22, under the same conditions.

So, the results? Well I'll be a monkey's uncles, but EVERY shot was now in focus! Could it really be that operator error was responsible for 12 out-of-focus shots? I suppose, but it would have been the first time that's happened. I really can't explain it, other than something had to have been misaligned yesterday. And I took shots with the Brightscreen in both positions, which didn't seem to make any difference. I did learn, though, that my Brightscreen for the 503cx would not fit into the 500c/m; the Brightscreen is ever so slightly taller and the two little prongs on each side will not go over the screen to lock it into place. I wasn't about to force them, so I did not use the Brightscreen with the 500c/m.

 

[BrianShaw]

Could it have been a misload, with the film not under the tab?

And don’t feel alone being a monkey’s uncle… I could take that as a nickname some days!!

 

[btaylor]

Ran a test today. Used the same equipment as before, but also added another 500c/m Hassy body and 80mm Planar lens. I took shots after turning screens, swapping screens and swapping lenses on both bodies. Also, being that I didn't want to waste my "good" Acros film, I used an expired roll of Tri-X 400. This meant that instead of shooting at f/8 or f/11, I was shooting at f/16 and/or f/22, under the same conditions.

So, the results? Well I'll be a monkey's uncles, but EVERY shot was now in focus! Could it really be that operator error was responsible for 12 out-of-focus shots? I suppose, but it would have been the first time that's happened. I really can't explain it, other than something had to have been misaligned yesterday. And I took shots with the Brightscreen in both positions, which didn't seem to make any difference. I did learn, though, that my Brightscreen for the 503cx would not fit into the 500c/m; the Brightscreen is ever so slightly taller and the two little prongs on each side will not go over the screen to lock it into place. I wasn't about to force them, so I did not use the Brightscreen with the 500c/m.

When you changed the aperture 2 stops it also changed the depth of field at the subject. So not really an apples to apples test. If it were me I would be shooting any focus tests wide open to minimize DOF.

 

[itsdoable]

<snip>...I used an expired roll of Tri-X 400. This meant that instead of shooting at f/8 or f/11, I was shooting at f/16 and/or f/22, under the same conditions...<snip>

f/8 is only good for focus calibration tests if you are using a ~500mm lens. Do the focus test with the lens with the largest aperture diameter, and use it wide open. Stopping down hides all sort of focus errors.

You can also do a quick test with a lens that you know has a good infinity stop. Focus on the moon (or a high contrast object near infinity) and see if the screen agrees with the infinity stop. That will often tell you if the screen is not correctly calibrated.

My BrightScreen Proscreen 20/20 only showed the back focus when I was shooting the 2/110 wide open, and looking back at the earlier photos, I could see that there was a consistent back focus with that screen.

 

[Duceman]

f/8 is only good for focus calibration tests if you are using a ~500mm lens. Do the focus test with the lens with the largest aperture diameter, and use it wide open. Stopping down hides all sort of focus errors.

You can also do a quick test with a lens that you know has a good infinity stop. Focus on the moon (or a high contrast object near infinity) and see if the screen agrees with the infinity stop. That will often tell you if the screen is not correctly calibrated.

My BrightScreen Proscreen 20/20 only showed the back focus when I was shooting the 2/110 wide open, and looking back at the earlier photos, I could see that there was a consistent back focus with that screen.

When you changed the aperture 2 stops it also changed the depth of field at the subject. So not really an apples to apples test. If it were me I would be shooting any focus tests wide open to minimize DOF.

I agree that I should run another test. I just wanted to replicate what I did yesterday; I already had everything all set up and it was a holiday.... so... that's what I did. Hopefully sometime in the next week or so I'll have some time to do a much better test under better conditions.

 

[Eff64]

I agree with the comments posted about not using a small aperture for this. It seems like you are already on board with that anyway. The thing about the one screen being slightly taller is a tough thing to factor.
It is my understanding that when you focus on a screen (in the correct position) the image is forming on the bottom surface. It doesn’t make sense that the Brightscreen results were not affected by which side was up.