Problem with F3 or lens or ???

<p>I am wondering whether these black marks are caused by lens apertures or Nikon F3 shutter, or perhaps something else. These photos were all taken with a nonAI Nikkor 24mm f2.8 and Nikon F3.</p>

 

<p>I think we need to see them. Otherwise the only black marks I see are from your keyboard. Maybe the picture linking button didn't work ?</p>

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<p>Too hard to tell ;))</p>

<p><img src="http://thegrantfoundation.org/untitled.jpg" alt="" /><img src="http://thegrantfoundation.org/1111.jpg" alt="" /></p>

<p>OK, here they are. I don't when they changed the upload system, but it is finicky with Chrome. :p</p>

<p>Looks like something in front of the lens if you are referring to the big black blobs in the lower part of the photos.</p>

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<p>But there wasn't anything, almost every image on the roll was like this... i would have known if there was</p>

<p>OK we can guess away but that won't help. This could be a loose aperture blade. Take the lens off stop it to about f8 or 11 and work the lever on the back, see if it's opening and closing properly. Open the camera back and fire the shutter on manual 90, I don't remember anymore if others will work with back open. If so fire on any setting especially slowere ones and see if something in body is hanging down or mirror is dragging something along. Anyway, you need to check more. Maybe at worst a piece of anti reflection black paint junk floating around in lens, just gotta check better and report back.</p>

<p>Well set the shutter speed on bulb, open the back and push the button. Then you might be able to see something if it's hiding behind the mirror. Shutter curtains are too close to the film to cause something that blurry and curved.</p>

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<p>Do you have any other lens at hand so that you can at least find out if is the lens or the camera that is causing those shadows?</p>

<p>I think it's the lens.</p>

<p>Everything seems to be in order. The shutter runs vertically and seemingly has no problems. The lens aperture blades seem to be in order. Could it possibly be related to my depressing the DoF button while shooting? Anyways, I will run another roll of film through and see if it does this again. Could it just be the film?</p>

<p>With great difficulty I mounted the lens on a D200. No problems (though it is a DX sensor).<br>

Thanks for the feedback, since I can't see any objects between the shutter and the element, and the shutter seems to be ruled out, I will assume the film had some sort of issue.<br>

Thanks.</p>

<p>From many years of shooting 35mm, fingers are one cause, front halves of ever ready cases, children's heads. Whatever it is it has to be close to the lens. I don't think the dof preview button will do it. Lock up the mirror and see if anything hangs down from it.</p>

 

<p>The F3 shutter doesn't run vertically- it's a horizontal shutter. w you look at the film, does the "blob" bleed out into the blank regions between the frames? If so, this would suggest the film itself is at fault. If not, back to the drawing board.</p>

<p>The mirror function appears normal. I have to rule out anything in front of the lens. Nearly 30 images is far too many for me to be making such a mistake. For a rangefinder, perhaps. But I surely would have noticed...</p>

<p>When you inspect the negs, what does the trouble seem to show across all the frames. Can you stick the negs on a flat scanner or copy printer machine so we can see a few negs. Thanks</p>

<p>Does not bleed off of negative, frame number still visible. These issues are consistently at bottom of frames, on both left and right.</p>

<p>Another sample:</p><div></div>

<p>Really odd. I can see no discernible pattern in the marks. On one slide the lower numbers are darker, but for most of them they are normal. I have not dismounted all of the slides. They are Ilford FP4 Plus processed as positives by dr5. I lack the technology to scan the whole slide.</p>

<p>Just run a roll of colour neg film thru and have it processed at the local 1hr shop.</p>

<p>I don't know if DR5 use a chemical or optical second exposure, that could be a cause of strange problems, or some other error in processing like accidental fogging.</p>

<p>Another thing to look for is a piece of film stuck in the shutter, examine things carefully as you advance the film with the back open and the mirror locked up without a lens mounted.</p>

 

<p>It's a roughly semi-circular shape of approximately the same size on all three photos, but not in precisely the same place on each frame. My first guess would be something physically blocking the lens during the exposure, such as the top half of an ever-ready case flopped downward but not completely out of the way of the lens. I've seen this same thing dozens of times in photos taken with non-SLR cameras, but never with an SLR since that type of physical blockage would be visible through the lens.</p>

<p>It would help if you could provide a contact print of the film (you say these are positives, not negatives), or place the film against a backlit surface and photograph the film strips. Otherwise we're just guessing. I suppose it's possible that something was physically blocking the light path during the positive conversion process, but it seems unlikely that it would be placed so similarly in each frame.</p>

<p>Probably not the case, but remotely possible: Wet film will stick to itself, damaging the emulsion erratically. The culprit: very high humidity. The only time it happened to me was in Florida.</p>

<p>I think film sticking to itself due to high humidity would leave more sharply defined blemishes, rather than these blurry marks. The blobs are all occurring at the lower side of the pics, which would mean that any obstruction would be at the upper side of the film in the camera. IIRC, the F3 has a small secondary mirror behind the main mirror, that reflects light down to the photocell on the floor of the mirror box. Is there any chance that this small mirror is not flipping up out of the way? I take it that this isn't a newly acquired F3, and that it was working fine up to this?</p>

<p>Yes it was working fine. In fact, the first few frames of the roll are blemish free. At no point did I drop it, but who knows what could have happened.</p>

<p>Here are the images, forgive the quality. The top is frame 9, here the numbers are darker than the ticker at the top of the frame. The other 3 frames are 14,15,16. You can see that the obstruction doesn't go between frames. I don't understand how some of the frames only have the lower right corners blackened. That doesn't seem to support the secondary mirror hypothesis, which I was also thinking earlier...</p><div></div>

<p>You seem to have checked everything else so...<br>

If one of the edges of the shutter curtains is not truly vertical then partial underexposure at high shutter speeds (narrower slit) can occur. A damaged curtain can also drag and cause the underexposure to be uneven across the frame.<br>

Common enough problem with cloth-curtain shutters and with results just like yours.<br>

I have to admit that I've never seen this happen with an F3 because the curtains are titanium, not cloth, and significant damage to a curtain has usually in my experience caused catastrophic shutter failure. So I'm far from sure that this is even a possibility, but it is at least easy to check!<br>

Inadvertent pressure on a rubber lens hood was my first thought though... done it myself.</p>

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