I was out with my grandson a week ago for T-ball practice. I thought, what a fine time to finish a roll of film I'd started in my old 'F' and a fine time to take out the old 50-300 f4.5 AI zoom, all 20 pounds of it, or so it seems.
When the negatives and CD came back I was a bit surprised to see this shadow on all the images.
At first I thought the old 'F' was screwing up, until I got to the first shots, with a 20mm prime, and the shadow was not there. So, I concluded, it must be the 50-300 zoom. I'll refer to it as a lazy aperture, someone may have a better term, if so is there a simple remedy? A CLA on a lens? Who and is it worth it? Or is this something else?
Looks more like vignetting. A lazy aperture would cause an overexposure situation. Were you using a lens hood? If so, is it completely round?
The other possibility is that the negatives weren't sitting right in the machine when they made the CD. I've had that before, where I have to crop an image to get rid of a black border that's not supposed to be there. Usually have them redo the CD when that happens.
Vignetting?.. I suppose it's possible, the hood that came with the lens is what I used, maybe I didn't have it seated properly. It shows no damage or lack of being round.
On the roll of 36 every shot taken with the 50-300 has this issue, about 12 were taken with a 20mm prime and have no problem. So I'm thinking it would have to be quite a coincidence for the negatives to be mounted improperly in the machine... but stranger things have happened.
I guess what I need to do is to reproduce the problem, time to shoot another roll.
Maybe I chose a bad term "lazy aperture" may indicate the whole aperture is the problem. What if it was just one blade? Is that possible??
We're going down to the coast Sunday to test it a bit more. Although the D200 test is simple I'll try it as well, even though the 50-300 would act like a 70-400?? The D200 may reach beyond the dark spot, but digital film is cheap.. It's worth a test.
I have tried that thru the lens at the light exam. The shadow occurs at the bottom of the image so the blade I'd be interested in, as I look thru it, would be at the top. It seems a bit low but by and large hard to tell, hand holding with the old naked eye (very old, bi-focaled, naked eye).
I did the D200 test tonight, a couple of quick shots out my window at 50mm and 300mm, the shadow is gone. The D200 may reach beyond it. As I mentioned, we're headed to the coast Sunday a film test with this is on the agenda. Who knows, I may find it just needed some work.
I can see a greater amount of shadow on the left bottom of the image but a small amount to the right bottom as well. I also feel that there is an out of focus spidery feel to the shadow. I might be wrong but I wonder if there is some evidence of fungus or some other physical disturbance, e.g. fibres. I would have expected a slightly more 'round' with a more consistent 'feathering' effect from a lagging aperture blade. Richard
I think there it could be one of two possibilities, maybe three. I shot another roll with it, here's one of many acceptable shots. No shadows to be found.
So my possibilities: 1) This time it was an F2 not the F, maybe something wrong with the body?? Since the F worked just fine with a prime lens, I doubt this.
2) I didn't use the lens hood this time, was it vignetting?? For it to vignette just across the bottom I would think the lens hood would show a dent somewhere, which it does not. It looks as round as it ought to be. Doesn't vignetting usually appear on all 4 corners?
3) Maybe the old lens just needed some work? It had been sitting for a while, maybe it was just stiff. After some attention and more use it functioned better.
I tend to like option 3, in time I'll put the lens hood back on and see if the problem comes back.
Meanwhile, thanks to all that responded, keep shooting!
Will the F let you fire the shutter with the back open or off? No film, of course! If it will, put it on B or some slow shutter speed and take a shot while looking through the back of the camera. That might let you see what is going on.
The F seem sto work just fine, although I've not had it CLA's in a while. The aberration appears on the bottom of the image, which would mean to me that where ever the problem is/was it was on the top of the item. The F's shutter moves from the right to the left, not down and up, so I don't think it would be the problem. At this point it's just a matter of keeping an eye on it the next time I use the lens.