Hasselblad 500C/M & 80mm

I have recently returned to film and resurrected my 500 c/m. It seems I have a back focus issue. 3 images here f4.0 – f8.0 – f 22.0 view at 100%
Tripod, mirror lock-up, cable release, camera scanned the neg Z7 + Sigma 105Macro
Any ideas before I send it off for a tech assessment?

Make sure the focus screen is properly seated

If it's not something obvious such as a focusing screen which isn't seated properly, I'm guessing that the foam behind the mirror has deteriorated, and that will affect focusing accuracy. Replacing it is kind of a pain, so you might as well get a complete CLA done on the camera body and any film backs which have been sitting idle.

I bought a new CFV-50C screen and tested both the original and the latter. The camera is in pristine condition and was little used from when I bought it 1989. The screen seating for both (screens) as far as I can see is perfect. The mirror is also pristine. I have two finders, a PM and and waist-level, both were tested, the images are a summation of the latter.

I am also thinking it may be the mirror seating. As I remarked the mechanical condition is pristine, however time may have done its job on some of the lesser robust parts like – as you say – foam, seal etc.

My Hasselblad 503 CX got slightly out of kilter before I bought it. The store I brought it from had their Hasselblad repairman check it out. He showed me how it put the body in a jig, showed me the misalignment, adjusted the camera body back into specification and I have not had a problem with the camera.

It is likely the 3 foam pads behind the mirror, they push the mirror up against the top frame. You can usually tell when the foam has deteriorated because the mirror becomes a bit loose inside the carrier.

Replacing the pads is relatively strait forward, but not if you’ve never worked on a camera before.

I once purchased a 500CM from KEH with that problem. Thankfully I had a ground glass back to compare focus to verify that the mirror was out of adjustment.

itsdoable said:

Replacing the pads is relatively strait forward, but not if you’ve never worked on a camera before.

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Were you able to do that without removing the entire rear casting of the camera (mirror, barn doors, etc)? I would have loved to simply pry open the mirror assembly from the front of the camera, but feared that it would require excessive force. And in any event, one of the barn doors on my camera was damaged, so the rear casting needed to come out anyhow.

Does anyone know why there's foam behind the mirror in the first place? I wonder if I should have replaced it with some non-deteriorating substance. But granted, there's a bunch of other foam throughout the camera, like the barn door dampener cushions.

Sirius Glass said:

Welcome to APUG Photrio!!​

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4season said:

Does anyone know why there's foam behind the mirror in the first place? I wonder if I should have replaced it with some non-deteriorating substance. But granted, there's a bunch of other foam throughout the camera, like the barn door dampener cushions.

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I will get some advice from a specialist. I don't intend to go replacing anything, I simply don't have the knowledge or tools.

The foam pads can be replaces without removing the outer casting. The mirror carriage is opened by un-bending the 2 tabs at front of the carriage to separate the 2 pieces. There are several parts in both the body and shutter that are dismantled and adjusted by bending a tab, that is they way they made them back then. If you are uncomfortable with that, get a service technician to do it. You can only bend the tabs so many times.

The foam behind the mirror is essential as the mirror carriage bends (torques) when the mechanism lowers. The left side of the mirror cage hits the hard stop in the body, the right side is forced to lower a bit more so the latch can grab it, bending the mirror cage. When you wind the body you can observe the mirror cage bend. The metal cage can bend infinitely, but the glass mirror cannot, so it's supported inside the cage with foam pads.

They could have used metal springs behind the mirror, but that adds weight. So does using screws to hold close the mirror cage. And the original foam pads last 40 years, and the metal tabs last the life, if you are careful. The Bronica S2 uses metal springs and screws, but is heavier, and although you never have to replace foam pads, the mirror cage cracks with use.

The later Hasselblads with the gliding mirror system (GMS), both the 500 version and the 2000 versions, do not have mirror foam pads as the up/down mechanism does not require the carriage to twist.

4season said:

If it's not something obvious such as a focusing screen which isn't seated properly, I'm guessing that the foam behind the mirror has deteriorated, and that will affect focusing accuracy. Replacing it is kind of a pain, so you might as well get a complete CLA done on the camera body and any film backs which have been sitting idle.

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Very few Hasselblad users realise how important this 'foam issue' is.

BTW, how can one mount a screen the wrong way in a 500C/M?

4season said:

Does anyone know why there's foam behind the mirror in the first place? I wonder if I should have replaced it with some non-deteriorating substance. But granted, there's a bunch of other foam throughout the camera, like the barn door dampener cushions.

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The foam is there to protect the mirror against what happens during 'the slam'.
An experienced repairman wil use a more 'modern' and yet correct kind of foam, and have the needed tools to properly calibrate the camera/mirror box.

You wouldn't want to know what foam deterioration does with other camera's, remember the Pentax LX's sticky mirror syndrome?

Today I had a conversation with the Hasselblad UK service technician. He confirmed the common consensus in this thread; i.e its 99% certain it's the mirror foam/seating furthermore its a common issue with cameras of this vintage. It's now gone off for a full service, not cheap, but it's got to be worth doing. herewith a link to the company FYI: https://www.classicv.co.uk/faqs.html

Loovic said:

Today I had a conversation with the Hasselblad UK service technician. He confirmed the common consensus in this thread; i.e its 99% certain it's the mirror foam/seating furthermore its a common issue with cameras of this vintage. It's now gone off for a full service, not cheap, but it's got to be worth doing. herewith a link to the company FYI: https://www.classicv.co.uk/faqs.html

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A very wise decision and worth the money!

I sent my 500 to the same place and it was worth each penny. Did a great job of servicing, including sorting out my own focussing issues, similar to yours

Loovic said:

Today I had a conversation with the Hasselblad UK service technician. He confirmed the common consensus in this thread; i.e its 99% certain it's the mirror foam/seating furthermore its a common issue with cameras of this vintage. It's now gone off for a full service, not cheap, but it's got to be worth doing. herewith a link to the company FYI: https://www.classicv.co.uk/faqs.html

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I take my Hasselblad to Samy's on Fairfax and have Mike the Hasselblad repairman look it over and adjust it. On rare occasion I leave it there for special personal time.

If you take care of your Hasselblad, it will take care of you, and might outlive you.

Each 5 years, I brought mine (bought new in 1981) systematically in at the repair shop for a thorough checkup and a full re-lubricating.
That camera system was the bread and butter for our family during almost 40 years, and never failed!

I once used it for a series for a B to B brochure in a brand new huge deep freezing warehouse (-40°) at the Antwerp seaport.
All the traditional lubricants had to be replaced by a graphite based lubricant that didn't stiff up in the cold, the shutters needed a special treatment too, a rather costly affaire!
The gear, light meters, film and tripod, had to be acclimatised, in a dry environment, for 2 days before going in and 2 days when coming out, humans only got less than a hour... The Wratten filters got so brittle that they tore while sliding in to the holder.
The Hasselblad held perfectly for the full 5 days of shooting, but, at the end, I felt unwell for a few days...

I'm sure i've made the right decision, after all it was stored unused for almost 25 years. I opted for the full service which is a complete strip down, inspection of all parts (replacement if needed) and lubrication. He told me it should be good for another 20 years no problem.

Philippe-Georges said:

BTW, how can one mount a screen the wrong way in a 500C/M?

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It can be installed upside-down, resulting in the ground glass being 1 or 2mm out of position.

Axelwik said:

It can be installed upside-down, resulting in the ground glass being 1 or 2mm out of position.

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The little feet go down, not up.

Sirius Glass said:

The little feet go down, not up.

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I always known that, but can hardly imagine that been done, the shiny side down and the matt surface up on which the projected image is formed, and the finder shaft will not that easily slide in due to the little feet being up (I tried it out before writing this comment)...

I got my 500cm back from Classic V a couple of weeks ago after a full service. The camera is now perfect; after some comprehensive testing the focus is now spot on everytime (resting done on a tripod with MLU)