Dust spec inside lens??

[masdog]

Hey everyone. I have a quick question. When I took out my 70-200mm to shoot a hockey game this evening, I noticed a black spec off in one corner of the viewfinder. At first, I thought something had attached itself to the viewfinder lens or the mirror, but it was clean. Then I looked through the lens (without it being attached to the camera, and I noticed the black spec sitting on one of the internal elements.

I took a few images hoping that this spec would show up, but it doesn't appear in any of them. Nor was the spec there when I used the lens this morning to shoot some images at a Veterans Day/Bring the troops home rally.

I think it might be dust, but I can't be sure. Its not showing up in my images, but I see it when I look through the viewfinder. Am I crazy? Or is it just a piece of dust?

[JSPhoto]

No your not crazy this happens often, but shouldn't show up in photos unless you have a light background and aperature above f8, and then it may not show up.
I have even heard of two cases where dust mites were actually in lenses! but they didn't appear in photos. One guy did get a photo of one of the lil devils though. He ayte some dust and vanished after that.

JS

[masdog]

Well, I was going to post that I figured it out. It ended up being an object on the focusing screen.

[JSPhoto]

Good to know it was there and not elsewhere....easier to clean too!

JS

[mjs1973]

Ya beat me to it. A very common problem, and one that's pretty easy to fix with a little puff of air.

[another view]

I have that happen every once in awhile. The thing to remember is that if you can see it in the viewfinder but it's not in the pictures then it's not going to be on the lens. The viewfinder is still looking thru the same lens that the image will be made with, so if you see something in the viewfinder then it will be in the image. This is one of the huge advantages of SLR cameras.

I suppose on close inspection most, if not all, of my lenses have some dust inside of them. I've never seen it in the viewfinder and it's never shown up in images either. It's pretty normal, but then there shouldn't be too much, either.

[livin4lax09]

I have that happen every once in awhile. The thing to remember is that if you can see it in the viewfinder but it's not in the pictures then it's not going to be on the lens. The viewfinder is still looking thru the same lens that the image will be made with, so if you see something in the viewfinder then it will be in the image. This is one of the huge advantages of SLR cameras.

I suppose on close inspection most, if not all, of my lenses have some dust inside of them. I've never seen it in the viewfinder and it's never shown up in images either. It's pretty normal, but then there shouldn't be too much, either.

except it you have dust on your mirror. In that case, it won't show up in the photo.

[another view]

except it you have dust on your mirror. In that case, it won't show up in the photo.

That's what I was saying - or at least trying to! Dust on the mirror or focusing screen will show up when looking thru the viewfinder but since the mirror and focusing screen are "out of the picture" (pun intended) when the shutter opens, there's no problem.

Even dust on the front element of the lens won't show up too often. What might make this happen would be a short focal length lens and/or a small aperture. This is because the front element of the lens is closer to being in the DOF in these cases than, say a 200mm at f2.8 and focused at 30' - the DOF is a long distance from the front element so it won't show up. Same deal with sensor dust on DSLR's too. Stuff on the front element can also show up more when shooting into a light source (sunset, backlit, etc). Internal lens dust may be a problem in this case but I think it would have to be pretty bad to show up.