Black Spots In Center Of Phtot - I Don't Think Are Dust

[MattMurph]

Whenever I push the f-stop up to f/14 or above, or whenever I do closeup bokeh photos, my images have hundred of tiny black dots. In the bokeh, they are all over the circles of color, and whenever I take a standard photo with a high f-stop, they are all over the center, with a width approximately 1/3 of the image.

On the bottom image, you can clearly see the standard dust, but in the center are these other dots.

What in gods name is it and where is it?

http://www.flickr.com/photos/mattmurphy3141592/6567639825/in/photostream

http://www.flickr.com/photos/mattmurphy3141592/6577305291/sizes/l/in/photostream/

 

[Colweb]

On the bottom image, you can clearly see the standard dust, but in the center are these other dots.

What in gods name is it and where is it?

To me it looks pretty similar to what I have seem with my camera ones. Still don't know what it really was, but a wet cleaning of the sensor cleared all of it.

 

[mosswings]

They're oil or some other liquid substance - they look like rings, not dots, as dry dust does. Your sensor needs a good wet cleaning. You haven't said what camera body you're using, but if its the D7000 it's possible that your camera body suffers from oil spatter coming from the mechanisms inside the camera box. This manufacturing problem has surfaced on a few D7000s mostly from earlier production runs. Clean it off well and watch to see if the spots reappear. If they do, send a picture to Nikon Service and ask them if it looks like the mirror box needs a thorough cleaning...on them.

 

[MattMurph]

My camera is a Nikon D40X.

 

[mosswings]

My camera is a Nikon D40X.

Nevertheless, you clearly have gotten something liquid on the sensor surface. This can happen if some moisture gets into the mirror chamber and "glues" existing dust to the surface, or if some aerosol contaminants are encountered.
When was the last time you cleaned your sensor?

Your D40x does not have any sensor cleaning features, so will require the occasional wet cleaning with PecPads or some of the other products out there. I use the Dust-Aid Dust Wand wet cleaning kit. It's compact, well priced, and doesn't use rotating brushes or other fancy stuff to do a good job. Since the D40X doesn't have a mirror-lock-up, it's a bit trickier to do than on those bodies that have MLU, so it might be worth taking it down to your trusty local camera repair store for a professional cleaning.

 

[MattMurph]

I was thinking about getting the supplies for the Copper Hill Method, and a bottle of pure methanol.

And the D40X does have a mirror lock-up function.

 

[mosswings]

I was thinking about getting the supplies for the Copper Hill Method, and a bottle of pure methanol.

And the D40X does have a mirror lock-up function.

My bad. Make sure that you start with a fresh battery, though. I believe that the MLU feature takes battery power to keep the mirror up, and you've only got about 2 minutes before the battery is discharged to the point where the camera releases the mirror.

Copper Hill is of course the original good method. Pure methanol is overkill; modern sensor cleaning products have moved on to non-flammable liquids - partly so that you can carry them with you on airplanes, but also to avoid toxic vapors and potential sensor damage. I found it was easier to go with the Dust-Wand kit and know that I was getting the right pads, wands, and solution. Whichever brand of wet cleaning kit you choose, it'll cost about $25 to start but gets cheaper quickly.

 

[MattMurph]

Also, does anyone see anything wrong with the shape of the red / orange circles? Is that normal or is there something wrong with my aperture?

 

[mosswings]

Also, does anyone see anything wrong with the shape of the red / orange circles? Is that normal or is there something wrong with my aperture?

Completely normal. What you're seeing is the actual shape of your lens' iris, out of the plane of focus. Look closely and you will see 7 curved sides corresponding to the 7 curved blades that move in and out to close down and open up the iris.

 

[SteveL54]

It may not be just on your sensor. You may have that stuff splattered on the backside of your lens rear element as well.

This is what stuff on the rear lens surface can do to OOF point light sources.



I think the small well defined spots are probably on your sensor, but the larger and less distinct rings are likely on the back of your lens.

Notice how each of the bokeh circles has the same large circular pattern in it, but a different set of small rings. This is because any debris on the backside of the lens is copied within every bokeh circle whereas, of course, sensor debris is not.

Also, does anyone see anything wrong with the shape of the red / orange circles? Is that normal or is there something wrong with my aperture?

The overall shape of the bokeh circles looks OK to me.

Steve