PDA

View Full Version : Stupid question: Sensor dust or other?



WestCoast
08-17-2008, 03:16 PM
So, I've noticed artifacts in my recent (over the past month or so) photographs. There are four dark, circular smudges near the top center of some of my photos in an approximate diamond pattern, an example of which can be seen here...

http://farm4.static.flickr.com/3132/2772057448_a05d29feae_b.jpg

These appear with both my 18-55 mm and 70-300 mm lenses and tend to be seen more at lower focal lengths, so I'm pretty sure that it has something to do with the sensor. I looked back at some of my older photos with light-colored backgrounds in this region and either see just one of the splotches or none at all.

Sensor dust is the first thing that comes to mind, although I find it odd that these artifacts are so circular. One would think that dust would be more irregularly-shaped, although I'm not an expert in this. I was thinking that it could be from dried salts left over from condensation but, again, I don't know much about this.

DownByFive
08-17-2008, 03:33 PM
looks like sensor dust to me...my guess is that this photo was taken at a fairly small aperture. As the aperture gets smaller, the dust will grow more pronounced and it's shape will be more well-defined. At larger apertures, say up to f/5.6, it's generally unnoticeable.

WestCoast
08-17-2008, 03:46 PM
Yeah it's at f/8. I didn't know about that relationship, but it makes sense. Thanks.

K1W1
08-17-2008, 04:21 PM
+2 on sensor dust.
Take the lens off open the mirror and give it a blow of fresh clean air and all will be well again.

imagesbyjudd
08-20-2008, 11:10 PM
Be sure not to use the compressed air in the can, first there are contaminates that can cause problems, not to mention moisture is also occasionaly present that can actually weld dust to the sensor. I've had to clean my d200 sensor twice in the roughly 18 months that I've had it. It was easier than I expected. Tried a repair shop at first as I didn't want to touch it. But they were almost 2 weeks out for service. I couldn't wait, so bought bottle of eclipse e2 and sensor wands. Worked like a champ. If you do a google search, there are a couple of web sites that will walk you through the process. Dust is always going to be with us so if your going to take a lot pics with a dslr you might as well learn how to clean it.