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Incompatible focusing screens

Hi Marc,

Amen to your suggestion. Lets put this to rest.

You are the digiback guru here, I learned a lot of that part of the system from your posts.

Hm....... that makes me wonder, maybe we should go back to figuring out our mystery guest called "Tilt sensor"? ;-)

Maybe you know: do the Hasselblad digibacks have a 'service menu', or in other words, can a service person run diagnostics on it using the menu? I was just wondering if the problematic CFV was maybe left in some kind of diagnostic mode after its trip to Sweden.

Does not explain the temperature sensitivity I think, but still.

Wilko
 
I second Jürgen's recommendation.

David Knapman, however, is not just a "trained Hasselblad man". He in fact is the man who trained the trained Hasselblad men.
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It will be very hard to find anyone more knowledgable and skilled than he.
His services are very sought after, mostly by people wanting their pre-1957 cameras repaired, since he is the only one who really knows how to do it, and has the necessary tools. So there may be a long waiting list.

Changing the screen isn't a really difficult thing, and other people will be able to do that too.
In the 500 C, the correct screen position is determined by a frame spring below the screen, together with the screws that hold the corners of the screen. They have to be adjusted in turn, and it takes a bit of time.
Because of how the screen position is adjusted, the thickness of the screen in use is not important, and you can change the original for almost every other screen.

But like Wilko said: the Acute Matte screen has to be taken out of the double frame it sits in, and the very thin glass cover breaks very easily. The glass of a regular screen is very much thicker, and comes out of the frame without a problem. That will be why Paepke rather replaces the broken original with a non-Acute Matte screen.
So it may be no more than a matter of willing to take a risk, and of who exactly is taking the risk.
 
Yes Wilko

Thats him . I do hope that he is still doing well and is in good health . I have a hand written letter from him here , with two wonderful drawings , showing details of a film magazine for the 1600F/1000F . He is one of the last geniuses of the early HASSELBLAD times .

Jürgen
 
Hi Austin,

Difficult to explain this huh? ;)

Well, actually the foam is critical for making sure that mirror is pushed against the metal frame that houses the mirror. It is the position of the metal frame that is adjusted by the repair people, so the combination of the foam and frame must be correct.

If I remember correctly there are 3 small foam parts behind the mirror that perform this task. So yes, the foam is behind the mirror, so inbetween the metal plate that is the back of the mirror frame and the actual mirror itself. Exactly like you note, the trick is the mirror needs to be pushed nicely against the frame for the whole system to be of sound adjustment.

You really want to grab your 500C, the movement of the mirror on its way down is a fascinating one. Normally you do not notice until you pay special attention. It is not a simple move up/down operation like you see in a 35mm SLR for ex&le. It is much more interesting.

I'm tempted to ask the repair person to make some digi-pics of the disassembled mirror, 1 picture = 1000 words.

Wilko
 
Hi Jurgen,

I recently had my hands on a very nice 1600F camera. These are really handsome cameras. Think about it: 1/1600, purely mechanical, with a shutter this size, and all that in the 50-ies!

I sofar resisted the urge to start a Hasselblad collection :)

Wilko
 
Let us all hope with Jurgen and QG that David will live long and prosper.

Think about it: we are rapidly loosing the people capable of repairing mechanical cameras (not only Hasselblads). We move towards a "1. Remove the electronical module that you think is faulty. If it was not the culprit, repeat step 1.

Before someone thinks I'm a Luddite: I am a computer geek by training and trade. Still I marvel at the mechical cameras.

Wilko
 
Wilko

I have two 1600F in excellent condition (all functions fine and shutter in very good condition)
I must confess , i could not resist to start a HASSELBLAD "collection" . All my "collection gear" is fully functional and in very good technical and also optical condition . What i am still looking for , is a very good EKTAR 80mm or 135mm lens . I know where to get one , but the price is rather high , and I do not feel save to give my credit card number .
Of all my gear , i have , there is only one which does not work . Its the CFV BACK .
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Hi Wilco,

> Well, actually the foam is critical for making sure that mirror is > pushed against the metal frame that houses the mirror.

Yes, but it is not a critical tolerance. The foam just has to do its job. If it does more than its job, that's nice. It's like a pressure plate. The pressure has to just push the plate against the film rails...and the rails are the locating device, not the springs. If the springs are a bit strong, so what...no problem. But if they are insufficient, then there is a potential problem.

> It is the > position of the metal frame that is adjusted by the repair people, so > the combination of the foam and frame must be correct.

Understood.

Yes, I'll take a look at the 500C I have.

Regards,

Austin
 
Hi Jurgen,

You fell for the collectors temptation.. ;-)

Actually, the same ex-Hasselblad repair guy showed me a short tele (135mm? I don't recall) for the 1000F/1600F on the camera fair last Sunday. It was for sale but I do not know what he wanted for it. Probably not too cheap I'm afraid.

Shall I try to find out for you?

Wilko
 
Thanks for your help and suggestions! I'll definitely give David Knapman a ring if this doesn't work out - I still hope it will get back a) soon and b) in better condition than it left here.

Man, this has been a stretch... I called them before sending the camera in and was told it should take one week. Of course, my fault, I hadn't thought about the carnival issue in the Rheinland. Or rather, I didn't expect they'd not get it done before closing for carnival.
I don't know, this really has been a strange experience. They have been recommended by a fellow MF shooter, and I was pretty confident. When nothing happened, no calls, no emails, I called them and was advised that I probably hadn't sent the fax confirmation back. Sure I had and had the fax protocol to prove it. The guy looked for it while I was on the phone instead of taking my word for it.
And then breaking my screen, telling me that the AM wouldn't fit - I would have understood if they had explained that they don't want to risk the screen.

Wilko, I'd really like to check if they replaced the foam. Is it possible to see that without disassembling the camera?

I should have sent it in before becoming attached to it. Unfortunately I shot with it for some weeks and love it. Actually, it worked just fine, I just felt I should be proactive and give it a well-earned cleaning. Yeah, sure...
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Antje
 
Hi Austin,

Critical is a bit a matter of semantics I guess. I was shown a body were the mirror, once gently pushed, basically stuck to the back of the mirror frame. Of course you do not normally push the mirror. But on the same camera a sequence of cock/release operations showed the mirror sometimes not being pushed back fully against the mirror frame. This could cause inconsistent mirror positioning. Not good.

All in all it really depends how bad your foam has become, you are right that "good is good enough". Unfortunately I think this is difficult to judge until the repair person seperates the mirror from the foam. And by then you might as well replace it while you are there.

For the pressure plate: yes, the distance and alignment (plan-parallel to the camera's back please) of the rails are what is crucial.

It really is as simple as that. One of the things I need to ask on a next occasion is about the folklore(?) of the matching inserts. Given that the rails are in the right location, why would another insert matter (assuming the pressure plate spring is 'springy' enough of course)? Any idea?

Again the Hasselblad factory has built a special rigg for testing the back's rail alignment. The service docs have drawings of this kind of tool.

When I'm not mistaken people whom the factory trained got a set of alignment tools (well, they had to pay for it I assume) to perform these tasks.

Wilko
 
Hi Antje,

I hope I have not contributed to the problem, at least that was definitely not the intention.

I just checked the service documentation and there are indeed 3 small foam patches. I was not sure of the 3, now I am. One in the top center of the mirror, close to the hinge. The 2 other ones are each in a bottom corner of the mirror.

The partnumber of them according to my docs is 13141, they are called "Foam plastic strip" which is not very descriptive.

The way I look at it, I do not think there is any way to find out if they were replaced apart from the 'push the mirror trick". Or maybe the repair folks will give you a detailed list of parts they used. If they do, look for the foam part numbers.

As for breaking the screen: their mistake -> they pay for a replacement one. That they do not want to try to do the AM installation, well.. I can imagine that, given the price of an AM. I would myself not feel comfortable. But that said, calling the AM installation impossible is simply not true.

All in all it does not make me feel very comfortable to be honest.

Wilko
 
The matching insert thing is about the position of the rollers in the film gate relative to that of the rollers of the insert and the pressure plate, and how that improves film flatness.
To put it simply: the rollers in the gate 'pull' the film flat (the film gate edges, against which the pressure plate is pushing the film, only do that at, well... the edges), and to be able to do that best, the position of these small rollers must be adjusted to that of the bits on the insert so to form an optimum angle (about 8 degrees) between film plane and film feed.

It's not folklore, but it does not make a huge difference.
 
Hi Antje:

Welcome, I hope your first experience here has been rewarding and you will continue to participate. I also hope the repair to your camera is swift and accurate.


Marc:

Maybe consider a kinder way of challenging what you may disagree with ?>

I agree. I think we all need to remember that posts are very short and sometimes the brevity, choice of words used to describe something should be given a little more latitude so as to prevent ill comments. And I think we should ignore the temptation to attack a specific word in a post and try consider the overall meaning of the post.

Perhaps offering a different idea, or suggestion, or asking for more information could also be a preventive measure.

Also, not taking something out of context. Perhaps the words in a post are correct as to the discussion of the specific thread, but not in another context. After all during nearly 4 years we have some very long threads. This one today had 35 posts when I opened my email this evening.

Regards:

Gilbert
 
Wilko

Thanks for offering the "1600F/1000F 135mm" contact . I have the 60mm Distagon , the 80mm Tessar and the 135mm Sonnar . All in excellent condition . I also have the 250mm Sonnar , which needs CLA . This can be done by David Knapman .

There is also a 135mm Ektar . Available from Kevin Cameras , but very expensive . But it is allowed to dream .

Paul

Nothing new from the CFV front , no answer yet . It's not only the tilt sensor , but also , the back does not work at temperatures below +15 Celsius .
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Gilbert James (Gjames52) wrote on February 22:

' 2007 - 5:51 am,I agree. I think we all need to remember that posts are very short and sometimes the brevity, choice of words used to describe something should be given a little more latitude so as to prevent ill comments. And I think we should ignore the temptation to attack a specific word in a post and try consider the overall meaning of the post'
Click to expand...

I support this 100%.
It is a pity some posters think their opinion counts as an absolute law that should be respected by others.
It is not only this "attitude" but quite often the way they express themselves that is irritating and induces a less pleasant response.

Thanks Gilbert for your clear analysis.
 
Hi Jurgen,

As for the Ektar 135mm: life would be so dull without dreams. We all know that we in reality can use only a limited number of cameras/lenses. But does that stop us from collecting more? Of course not ;-)

Sweet dreams of your Ektar ;-)

Wilko
 
Good, let's get off the arguments.

Please tell me about the Ektar lens one should dream of. I know nothing of it. I love good lens stories.
 
You can only use both of them (80 and 135 mm) on 1000 F or 1600 F. cameras. They are quite good.

The "dream" part is in the joy using these old machines brings to people succeptible to that sort of thing.
I am.
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And in the excitement of the "hunt" for these lenses. While the 80 mm is relatively common, the 135 mm is really hard to find.
Collecting pre-1957 Hasselblad equipment is fun, not just because you can still use these machines and the bits that go with them, and get great results that rival those of 'modern' Hasselblads, but partly also because the pre-1957 system is quite small, and it is not difficult to gather a rather complete collection in a short amount of time.
So you get to that stage where you only need one or two bits more pretty soon. Simply buying readily available bits is nice, but hunting down those final missing bits is where a collector's adrenalin rush really begins.
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That's about all there is to it.
 
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