Issues w/ streaking

[yoichi_nagano]

<p>I brought a Mamiya 645 1000s and a PD prism finder with me on a trip to California recently. Before the trip, I shot a test roll without the pd prism finder to be sure the camera was functioning properly. The camera seemed to function well and the processed images looked great.</p>

<p>However, during the trip the mirror started to stick in the up position after the shutter was triggered. At first I thought the issue was the communication between the pd prism finder and the camera body, and worried this meant that the shutter was also malfunctioning. But after bringing the 645 to a camera store in California and giving it an admittedly too quick film-less test in the shop, it seemed the issue was just the mirror--the shutter seemed to open and close in accordance with the shutter speed settings, regardless of how the mirror behaved. I continued to shoot, albeit nervously, for the rest of my trip.</p>

<p>Fast forward to my return to New York. I had my film processed and scanned at a reputable lab. I was depressed to find that nearly 50% of my images were either un-exposed (i.e. blank) or blemished by streaks (see an example below). On the streaked images, the streaks occur in roughly the same section of the frame to roughly the same degree. I shot only with available light, no flashes (which anyway, to my knowledge and experience, would be a sync issue and result in the opposite: an under-exposed section)</p>

<p>I am a new medium formate user, so the issue could certainly be me, not the camera, but I am confident that I read and followed instructions carefully.</p>

<p>I am assuming this is a shutter issue, but I'd really appreciate some input from those of you who have had similar experiences or who might have an idea of what's wrong. </p>

 

<p>Thank you, all,<br>

-Yoichi<br>

<img src="http://i1288.photobucket.com/albums/b488/Yoichi_Michael/93640004_zps9sfig4cq.jpg" alt="" width="749" height="1024" /></p>

[dave_wilson1]

It seems to look like shutter curtain bounce, but I could be wrong because I no longer remember the shutter direction. I

never owned one of these but several colleagues used them and I remember such a problem one had.

[russ_britt3]

<p>The streak looks like a light leak.......the Finder is not really connected to the shutter in any way on that camera.<br />Sounds like you have several problems all at once going on?<br />Not sure who would service those now........good luck.<br />I had that combo back in 1975....switched to Hasselblad in 1980.</p>

[tom_chow]

<p>Looks like a light leak from the top or bottom of the camera/film back, depending on which way you held the camera. Are all of them the same intensity, or are some stronger?<br>

<br />Although it runs the same direction as the shutter curtain (short edge) shutter stalls/unevenness doesn't usully look like that (ie, the exposure doesn't usually recover after the shutter stall). But it still might be, you can check that if you have an old tube television or CRT as you can watch the scan line progress as the shutter moves across the film plane. Shutter stalls are usually the same intensity, where as light leaks depend on how long the film rested in the film gate.</p>

[stephen t]

<p>I would remove the lens and the back, make whatever adjustments you need to so you can fire the body (multiple exposure switch perhaps - not familiar with that particular model). Watch what happens with the mirror operation. Using the waist level finder for now.<br>

If the mirror mechanism is sticking, you CAN lube it sparingly with, and I do mean ONLY with, NYOIL. A web search will take you to the subsidiary that sells it in small quantities. It is used by watch and camera repairmen....oops, repairpeople. NOT the synthetic blend, but only the refined mineral oil one. Apply it with a TOOTHPICK, not a dropper. Put the smallest amount on a toothpick, and touch the pick to the spot. The toothpick should look almost dry.<br>

Has worked for me. Best to gather up several more opinions before delving into the project - a lot of very knowledgeable folks on this forum.</p>

<p> </p>

[ondebanks]

<p>That's definitely a light leak from a degraded light seal in the door-frame of the film chamber. Been there, fixed that. Just scrape out what's left of the old mushy foam with a toothpick [second time in this thread that the humble toothpick is the tool of choice!], and apply replacement self-adhesive black foam strips, available from online merchants. IIRC I cut the narrow strips myself from a bigger piece of self-adhesive black foam.</p>

<p>Tip: if your photos seem to show light leaks, check whether the leak extends past the image area onto the film rebate. If it does (and I will bet that in this case it does), the light is entering from the rear of the camera/back. If not, it's coming from the front. This is true of pretty much any camera.</p>

[yoichi_nagano]

<p>Thank you all very much for your input!</p>

<p>Below are a couple more examples, both taken from separate rolls. I believe the issue might actually be shutter bounce/stall, as mentioned by Dave and Tom. To support my opinion, I should explain that while this issue occurred frequently, it did not occur consistently, meaning it did not happen on every frame--I did get a number of clear shots on rolls that included streaked shots. If it were a light leak, wouldn't every frame on an affected roll be more or less affected?</p>

<p>Also, as you can see from my additional examples the streaks are fairly consistent in location, intensity, and gradient, which suggests to me a mechanical, i.e. curtain, malfunction.</p>

<p>Finally, given that, as I mentioned in my original post, there were seemingly completely un-exposed frames on certain rolls, the shutter not firing seems the cause. </p>

<p>Is my reasoning sound? It seems I'm going to have to repair the shutter AND mirror mechanisms. Thank you all again.<br>

<img src="http://i1288.photobucket.com/albums/b488/Yoichi_Michael/93610002_zpsoorev5lj.jpg" alt="" width="749" height="1024" /><img src="http://i1288.photobucket.com/albums/b488/Yoichi_Michael/93620004_zpserbhi3t0.jpg" alt="" width="749" height="1024" /></p>

[ondebanks]

<blockquote>

<p>I believe the issue might actually be shutter bounce/stall, as mentioned by Dave and Tom. To support my opinion, I should explain that while this issue occurred frequently, it did not occur consistently, meaning it did not happen on every frame--I did get a number of clear shots on rolls that included streaked shots. If it were a light leak, wouldn't every frame on an affected roll be more or less affected?</p>

</blockquote>

<p>No, believe me, it is a light leak. Why doesn't it affect every frame? Because it depends on (a) how long a piece of film spent sitting on the roller at the top of the film insert, facing the leaky door seal, waiting to be wound on; and (b) how bright the external ambient light conditions were while it was sitting there. It could take many minutes or hours of leak-exposure to register what you see on the film, so taking shots in relatively quick succession made those shots come out ok.</p>

<blockquote>

<p>Also, as you can see from my additional examples the streaks are fairly consistent in location, intensity, and gradient, which suggests to me a mechanical, i.e. curtain, malfunction.</p>

</blockquote>

<p>The consistency is also a hallmark of a light leak from the upper rear. The affected area of film must be sitting on a particular roller to be illuminated by the leak. If frames are regularly spaced at the film gate, they are also regularly spaced at the light leak position.</p>

<blockquote>

<p>Finally, given that, as I mentioned in my original post, there were seemingly completely un-exposed frames on certain rolls, the shutter not firing seems the cause.</p>

</blockquote>

<p>Now that could be a shutter problem alright. But first, can you rule out with certainty that you didn't just grossly underexpose those frames? One thing to watch with the PD prism is that when you mount or change the lens, you must ensure that the pin under the front of the prism engages in the lug on the aperture ring of the lens. If it doesn't, and you stop down the lens aperture, the PD prism doesn't know that and it will happily tell you that your exposure is fine when it's going to be very underexposed.</p>

[tom_chow]

<p>I agree with Ray, I still think is looks like a light leak. Shutter bounces rarely recover (ie: exposure is good on either side of the streak) and shutter bounce streaks are uniform for the whole length.<br>

<br />Light leaks from the dark slide slit often start part way into the frame due to the film gate offset. I'm guessing the streaks do not continue past the frame (into the rebate?). If they do, then the leak is from the film back door seal.</p>

[yoichi_nagano]

<p>Ray, thank you for that exhaustive response. I guess I've got a light leak--but thanks to you a solution as well.</p>

<p>Regarding the un-exposed frames, I was generally very careful to ensure the pd prism pin was engaged in the lens' aperature lug, having learned that lesson the hard way, but I did change lenses fairly frequently and therefore it is possible I simply forgot to check the engagement.</p>

<p>I'm sure this won't be the last time I'm heartbroken by a ruined roll or frame of film. C'est la vie de film photography. </p>

<p> </p>

[ondebanks]

<p>Yoichi, you're very welcome. Always glad to help a fellow MFer and Pdotnetter!</p>

<p>I remembered a roll I shot 9 years ago where I diagnosed this problem on an old M645 1000s body I had just acquired. The photo below is from this roll - artistically it's "nothing", just a test photo taken across the road from my house, where I pointed the rear of the camera towards the bright sky for a while and then wound on and shot a couple of handheld frames.</p>

<p>My light leak is obvious and resembles your one closely. Notice how another sign of this type of rear light leak is that, in both our cases, the leaked light is not the same colour as the scene being photographed. </p>

<p>4 of the 15 shots on that roll showed a leak to some extent...the ones without leaks were taken following shorter intervals and/or in more subdued ambient light inside woodland.</p><div></div>