tom hudson

Thanks for the responses, everyone. I'm taking a look at some of the scanners you mentioned; The Scan Dual IV's price is certainly right and it looks like it'll do what I want -- I was shooting for around 3000DPI, and the reviews I've found for it are pretty positive.

I appreciate the input!

I have a D100 and a bunch of old 35mm slides I want to digitize. I

found an inexpensive slide duplicater from Bower ("Digital

Duplicator") which is a piece of crap. The optics are terrible and

you cannot get a decent focus to save your life.

Can anyone tell me if there is a good quality attachment for the D100

that will allow quality slide duplication? There has to be something

out there. Thanks!

OK, I went out and shot some 10-second exposures of the night sky, with and without the filter, and with the lens at 28mm and a bit higher, to test the theory that the optics were touching at 28mm or something else was out of whack. I downloaded the images and cranked up the contrast to see if there was evidence of the artifacts. There was none on any of the exposures.

Soooo.... I'm going to keep my eye out for northern lights and the next time they show up, I'll have the filter off the lens. In fact, I've taken it off and will leave it off. I was told years ago with my first SLR to get a Sky-1A filter, put it on and leave it on to protect the lens. I wish I hadn't been told that.

When I get more photos, I'll report back and post them. I _REALLY_ appreciate the quick responses from all of you. I just found this forum today but will be joining up.

@Will: Go to http://astronomy.klanky.com, I've slapped a few images up there for your amusement. I have to go dig through my archives for more, and when I get some free time I'll add them with some more descriptions. You'll see the circular artifact on the two aurora images.

Good heavens! You guys answer so quickly I had three more responses by the time I finished composing my response!

I think Darren has nailed it -- the ONLY time I've seen these rings is on aurora photos, and I have the Sky-1A filter on all the time to protect the lens (D'OH!!!) Too bad there's no aurora activity tonight; I'd love to get out and test the theory. I will do some general long exposures and see if anything turns up with no aurora in the scene.

@Will: I have a Tiffen Sky-1A on there. I'll try a shot or two with that off and see what I get.

@Frank: I would have thought so, but the same thing showed up on a film exposure on my 6006. At least, on the Photo CD version of it. I'll see if I can dig up the negative on that and verify that it's actually on the film.

@Tristan: I've only seen it in low-light, long exposure images (two different aurora borealis shots, by coincidence). Both were at the 28mm end of the operational range.

@Les: I took the filter off and looked through the lens at a bright light, there was nothing obvious visible. However, looking at some photos on the Web regarding Newton's rings, which I hadn't heard of before, it sure does look like that may be what's going on. I wonder if two of the elements are touching at the wide-angle end of the lens's range, causing the rings. I will run some tests ASAP.

THANK YOU for all the responses; I'll report back after making some test exposures.

I have an AF Nikkor 28-85, f/3.5-4.5 lens that I've had for a while. I

took some photos of the aurora borealis a couple of days ago with my

D100 and the images all have a strange circular artifact at the

center. Looks like some sort of light interference pattern (see image

at http://klanky.com/images/LensArtifact.jpg).

The first time I saw this, coincidentally, was an aurora image I shot

with this same lens, but on a 6006 body shooting film. I had the image

put on a Photo CD and when I looked at it, I figured the Photo CD guys

had screwed it up. Apparently not!

Anybody seen anything like this before? Any ideas what the cause might

be? Suggestions appreciated!<div></div>