Mystery spots

<p>This was shot with a d300 and and 18 200 VR lens. I've noticed these spots on occasion and it is a mystery to me as to why they show up and then disappear on there own. Sometimes when I shoot a series burst it will appear in all the frames. In this case looking at the EXIF data these frames where taken 17 seconds apart. The prior frames have the weird marks. If it was some sort of dirt or shmutz on the lens wouldn't the spots show up almost all the time (depending on the way light hits the sensor). There does not seem to be a pattern of when they show up as far as I can tell. It doesn't happen enough to annoy me an require oodles of spotting but I'd be interested on your theory/solutions or ways to try to get these spots to show up all the time.</p>

<p>I haven't checked definitely but I think they show up mostly with the 18-200VR. I'll have to check to see if it shows up with any of my other lenses.</p><div></div>

<p>If you want to find the pattern, check the aperture you shot at.</p>

<p>As a lay expansion ...<br>

Sensor dirt shows markedly at smaller F stops (F16, F22, etc.) as the shadow is distinct.<br>

Jeff suggests you look at exif data for the spotty pics. Most likely you'll see that they occur when the lens is stopped down as above. Those shots at F3.5, 4, 5.6 etc. will most likely look clean.<br>

This is a classic way to determine if something is sensor dirt. Most anything on most lens elements will never leave distinct spots this way, as the cause of them is too far from the sensor plane and way out of focus.<br>

Jim.</p>

<p>Could be dirt on the sensor. </p>

<p>Don't think it's something on the lens - it would be blurry. </p>

<p>Also doesn't look like any hot or stuck pixels I've ever seen. </p>

<p>Dave</p>

 

<p>That's the typical look of sensor dust, and yes, they show more at smaller apertures. It is not the look of e.g. a drop of water on the front lens element, which would make for a blurry area (again, more obvious at smaller apertures). On the my D300 I set (in the menus) the camera to clean sensor at each power-up, and I haven't had these spots show up since.\Chris</p>

<p>Bingo guys. I looked at the pattern in the exif data and af f - 27 those spots are super sharp and annoying. The last frame with no spots was shot at f-4. </p>

<p>I'm going to try it by shooting at a blank wall at various f-stops to verify and then trying the sensor clean mode although I suspect those critters are really firmly attached to the sensor. Thanks!</p>

<p>Set your camera to clean when you turn it off and turn it on. When I did that they virtually disappeared for me.</p>

<p>I doubt whether they will be that firmly attached; they look rather big and bigger ones usually do come off with the rocket air.<br>

And what Richard says, on the D300 you can set the camera cleaning action on powering on, off or on and off. Make sure it's enabled for either one at least.<br>

(Shooting at f/27, by the way - why?? It will only give you a very soft image thanks to diffraction)</p>