The strange light leak of hasselblad 500cm

Hello,

There is a strange light leak happening in my hasselblad 500cm recently. The leak is not from the edge of the film, but in the center of it. The leak emerges in similar position of the film, but not exactly the same.

I sent it to the local repair center(I don't live in USA). They changed the light seal of the megazine and adjusted the rear curtain. However, the problem continues, and the repair center doesn't know what else could cause this.

Does anyone know how to solve this problem or have any idea?

The attached files are the pictures with the leak problem.

Thanks for all you help.

 

 

The location and shape/pattern are, to my eye, consistent with a problem with the auxiliary shutter-aka the "barn doors" at the back of the body that pop open when the shutter button is pressed and then close when it is released.

 

My inclination would to first of all observe them and make sure they're opening and closing correctly. You should be able to push them open with your finger and have them spring back closed. If you operate the camera with the back removed, there again they should open as soon as the shutter button is pressed and close when it is released.

 

To check for light leakage through these curtains, you can remove the back and then go into a dark room and shine a light through the front of the camera. Ideally, I'd suggest pre-firing the mirror, but I don't actually recall whether or not this opens the auxiliary shutter(and I don't feel like walking out to the car to get mine, which is where it's sitting now). In any case, with your eyes well acclimated to the darkness you should see a thin strip of light at the door "seam" if in fact this is where the light leak is.

 

IIRC, there aren't any actual seals on these doors, but rather they just rely on fitting together tightly and overlapping. If the shop did in fact adjust them, I'd suggest that either they need to try again or you need to try a different shop.

The location and shape/pattern are, to my eye, consistent with a problem with the auxiliary shutter-aka the "barn doors" at the back of the body that pop open when the shutter button is pressed and then close when it is released.

To check for light leakage through these curtains, you can remove the back and then go into a dark room and shine a light through the front of the camera. Ideally, I'd suggest pre-firing the mirror, but I don't actually recall whether or not this opens the auxiliary shutter(and I don't feel like walking out to the car to get mine, which is where it's sitting now). In any case, with your eyes well acclimated to the darkness you should see a thin strip of light at the door "seam" if in fact this is where the light leak is.

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Thanks for the reply.

I just check it in the darkroom with a flashlight from different angles. I don't see the light from the auxiliary shutter. Also, the pre-lock of mirror will open the auxiliary shutter.

However, if I set the flashlight above the body and remove the waist-level viewfinder, then push the shutter button, I can see light in the upper part of body while the auxiliary is opening and the mirror is not fully up.

I discuss this with the repair center on the phone, but they think it's not the reason of the leak because the light is moving out of the body, besides, if the auxiliary shutter opens later, the expose of the film could be interfered.

I can not tell the opinion of the repair center is right or wrong.

Edited November 27, 2018 by filmlover

I was certain ben_hutcherson had the correct answer, but if you don't see light thru the closed doors then the leak may be elsewhere.Sometimes a Hasselblad light leak enters thru misaligned body mount and back mount surfaces.This can happen if either or both become warped thru impact damage, or the raised ridges become too worn. This possibility can also be tested via flashlight.

 

Wind the camera, attach the back, then remove the lens and dark slide. Press and hold the shutter release, and lock the rear doors open by moving the shutter button switch to T position. While looking closely thru the lens mount, slowly move your flashlight all around the seams between body and back. If you see light seeping in from any edge or corner, you have a bent or warped plate in the back or camera body mount (or misaligned hooks on the camera).. You can narrow it down further by trying other backs: if other backs have the same leak in the same place, the body mount needs to be serviced or replaced. If the leak only occurs with the one back, that back's plate needs to be aligned or replaced.

 

Note the rear shutter doors can be an extremely tricky part of the camera to service. They can give the appearance of working perfectly, but still leak when the camera is loaded with film and used outdoors in bright daylight. I've seen many a 500cm with random rear door issues: intermittent failure of doors to fully close, intermittent failure of doors to overlap in proper order, slightly warped doors that intermittently leak, intermittent coordination with mirror timing, etc, etc. The Hasselblad 500cm is one of the most brilliant camera mechanisms of the 20th century, but its also overly-complicated and fussy. When it works, its great, when it doesn't, it can be a huge headache. If the leak persists, you will need to either try a dedicated technician who specializes only in Hasselblad repairs, or sell the problem body and/or back and replace them with better examples.

Edited November 27, 2018 by orsetto

Could be an internal reflection during exposure. Check for any loss of black paint inside the camera body, especially on sharp edges or the tops of baffles.

Thanks for all the replies and help.

The back is not attached to the body very tightly although I can not see direct light leak.

Both body and back have some small spots of paint loss inside.

So I use tapes to seal seams between body and back except the slide side, then close the viewfinder before press the shutter button every time to reduce light from outside.

To my comfort , the light leak disappeared though I still don't know the exact cause of it.

So I use tapes to seal seams between body and back except the slide side, then close the viewfinder before press the shutter button every time to reduce light from outside. To my comfort , the light leak disappeared though I still don't know the exact cause of it.

 

Well, the good news is you have verified your repair shop fixed the dark slide seal properly, and it is definitely not the source of the leak. Now you just need to isolate either the viewfinder area or the back seam as the problem. You can do this by shooting a couple of frames with the viewfinder opened. If the leak returns with the viewfinder open (but the back seals still taped over), you probably have an issue with the mirror not fully covering the viewfinder during exposure: if it sags a little, a gap remains open between viewscreen and mirror. Light leaks thru the gap, bounces off a reflective surface in the front part of the camera (lens mount?) and strikes the film while the rear doors are open. The cure is to adjust the mirror spring and brake so that the mirror fully caps the focus screen during exposure.

 

If you do NOT experience the leak with the viewfinder open (but the back seams still taped), the problem is almost certainly caused by the back mount issue I mentioned in an earlier post. If you don't mind keeping the camera taped, then I suppose you could just keep using it that way ( a surprising number of Hasselblad users have posted that they do this routinely). But I think it would be a good idea to at least borrow another film back, and check if it also leaks without being taped. If it does, then you know you'll eventually want to replace the body (this is often cheaper than the repair cost). If the problem turns out to be localized in your film back, that is much less expensive to replace, and once replaced would give you a fully normal camera.

That is weird. I'd contact the factory and send them the photo with the leak and see what they say.

If you find that the gap between the film back and the body are the cause, you might check to make sure the back release button is returning completely when released. If not, your back will fit loosely.

Have you now identified where your light leak is coming from? As I have the same issue which you can view here:

Light leaks - Naomi Goddard Photography

And similarly to yourself after sending it off for repair I had no positive results, so would love to know if your camera is now working correctly (without having to close the mirror and tape the camera up when taking an image).

The fact that the long sides of leak is almost perfectly sharp means that the limiting 'frame' of light is very close to film. If it was 'barn dors' the light line would be at the middle of frame that is not the case. I have suspicion that film was exposed to leak when it is on releasing or receiving spool -outside of the film back frame.

It would be helpful for one of the two folks who have the problem to continue with the testing and posting of results. Since the OP of this thread saw good results with tape wrapped around the joint between back and body, then it would be a step forward to take a couple of test frames with the tape ONLY on the bottom of the back, then a few frames after adding tape to the sides of the back, and then finally another few frames with tape on the bottom and sides and now ADDED to the top joint. Try not to use the dark slide at all during the testing and definitely do not remove the back between the time when the film has been loaded and when it was fully taken up at the end of the roll.

On second viewing, my guess is that it's a light leak between magazine back and camera body, or within the A12 back itself.

 

The fact that it's a horizontal streak would seem to eliminate a leak from the sides of the camera. However, a small pinhole can produce strange effects when aligned with the sun and at an acute angle to the film. So I wouldn't rule anything out.

 

The camera itself may have been serviced, but what about the magazine back? It might be instructive to watch

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It could be a timing problem between the mirror, lens and auxiliary shutter (barn doors). The auxiliary shutter should be completely closed before the mirror drops and the lens re-opens. Hardened lubrication or weak (hairpin) springs which close the doors, is a common problem with older cameras. The lowered mirror does not completely block light at the bottom of the camera, which is where the fogging seems to occur in the example.

 

The solution is to have the camera serviced and lubricated. It is not particularly expensive ($250 or so, plus parts). and your camera will work like new for many more years.

 

The auxiliary shutter should have no noticeable delay. While they may eventually close completely, you may see a flash of light if you look with the back removed. You should hear the flaps close before the mirror drops.

I believe a properly operating 500 mirror and auxiliary shutter will act in the following sequence:

- depressing the shutter releases the mirror

- the mirror reaching its fully retracted position (parallel to the focusing screen) releases the auxiliary shutter (flaps at the rear of the body)

- the auxiliary shutter remains open until the the shutter button is released

 

The mirror does not return to its original position until the film advance knob has completed its full rotation.

You're correct about the sequence of operation. I rarely use the 500 c/m, but it has worked perfectly since getting a CLA in 2004. The mirror returns instantly in a 200 or 555 body

 

The barn doors in a camera in need of service can be sluggish, and may not close completely. Winding the camera can jostle the barn doors, causing them to close completely, but perhaps not quick enough to prevent fogging. They should snap closed without any noticeable hesitation, but that's hard to know without a visual reference.

 

Reflections from degraded anti-reflective coating can cause fogging of the sort noted.

 

Light leaks through the darkslide seal appear to start in the middle of the frame. An improperly installed seal can have wrinkles which might produce a pinhole leak with the results shown. Such leaks tend to have a distinct edge facing the light seal, due to the shadow cast by the opening in the back. The leak in the examples is symmetrical from side to side, making the light seal an unlikely candidate. It's easy to verify if a second back does not show the leak. You can examine the condition of the seal by removing the faceplate of the back, and carefully replacing it as to not damage the seal.

Sorry for replying so late. I have been busy these days.

 

After tape test I know that the leak is not from back mount .

 

Then I went to the repair center to borrow another pair of body and back to test interchangeably.

 

The result is that my body works fine with their back, but my back still has light leak with their body.

 

So I know that the leak must be from the film magazine.

 

I discussed this with the repair center, and they guessed the reason is that some part of the film magazine deteriorate through age or use. Actually one of the mechanics recalled that he saw a old leica m3 with similar leak. But they still fail to find the questionable part.

 

In the end the repair center sold a little used film magazine to me at decent price.

 

I hope that this reply can provide some thoughts to solve this unusual problem. And thanks to everyone again for enthusiastic replying.

This is a great thread, showing how helpful people can be.

I am having the same issue. I have replaced the light seal, but still have the horizontal light streak. When I use another film back I do not experience the same thing...

Has anyone confirmed why this type of leak is happening? What is the best way to fix it (other than buying a different film back)?

 

Thanks!

B

I have exactly the same issue with one of my backs - the most old one.

It seems to me the reason of the leak is that this back seats a little bit loose on a body because of worn locking mechanism.

 

^ if it is localized to one particular back of yours, that is an interesting clue. Bear in mind, the image is upside down on the film.

Yes, this leak never appeared on two my other backs.

At least I'm sure that it is not a light seal damage.

I had once one light seal broken and I know how it looks like.

The light is obviously coming from the direction of the sharpest edge, which would be the top of the camera. Looks like it's time for a new back, or a refurb of the defective one. Or a tape-up job.