?? re Image Spots and Cause

*geezer52* · 11-04-2009, 12:10 PM

Not sure if this is the right place to pose my question, Plz be lenient if it isn't.

I shoot a lot of pictures towards a clear blue sky (skydivers in fact) from the ground. I use a K2000 with a DA 55-300 and in the course of a day I might take 300 pictures, never removing the lens from the camera. But over time I notice small round dots start appearing in the images. This happens fairly often and I clean the sensor to fix the problem. These dots are easy enough to fix in PP and they are pretty much un-noticeable in pictures that aren't mostly blue sky. These are two sample shots to illustrate the problem (15 images apart in the camera). The first shot is clean while the second has the spots (highlighted). From outing to outing the spots appear in different locations. I'm wondering if some small drops of oil or other lubricant is coming off the lens mechanism or perhaps the mirror as the problem shows up after pointing the camera nearly straight up. Thanks in advance for any comments (FWIW taking a shot of the clear blue sky does seem to be an excellent way of seeing if your sensor has any crap on it)

Lowell Goudge · 11-04-2009, 12:12 PM

dust on sensor

*geezer52* · 11-04-2009, 12:17 PM

Originally Posted by Lowell Goudge

dust on sensor

These spots I get are consistently round not just in this sample. Wouldn't dust "spots" be more irregular in shape?

Lowell Goudge · 11-04-2009, 12:29 PM

Originally Posted by geezer52

These spots I get are consistently round not just in this sample. Wouldn't dust "spots" be more irregular in shape?

Nope.

it is dust, if you can stop down they will change shape slightly,

look at the sensor, by selecting sensor cleaning and having the lens off, you can actually see them and hopefully blow them off.

otherwise you may need to be more aggressive about cleaning them with a specifically designed sensor cleaner.

*wildlifephotog* · 11-04-2009, 01:00 PM

Yep, those are dust bunnies alright.

jnorth · 11-04-2009, 02:09 PM

This caused a wonder moment, at least based on my interpretation of what I heard when I read the post. If one just uses the camera's sensor cleaning function where is that dust going? Isn't the potential there for it to just reappear? I've only used my cleaning function a couple times and both times ended up pulling out my sensor cleaning kit anyhow.

A nice function to go with the preview where it flashes the highlights would be one where it flashes dust on the sensor. It's a drag after a day of shooting to find that very early on you got dusted, and don't pick it out on the lcd.

Lowell Goudge · 11-04-2009, 02:22 PM

Originally Posted by jnorth

This caused a wonder moment, at least based on my interpretation of what I heard when I read the post. If one just uses the camera's sensor cleaning function where is that dust going? Isn't the potential there for it to just reappear? I've only used my cleaning function a couple times and both times ended up pulling out my sensor cleaning kit anyhow.

A nice function to go with the preview where it flashes the highlights would be one where it flashes dust on the sensor. It's a drag after a day of shooting to find that very early on you got dusted, and don't pick it out on the lcd.

no, there is supposed to be a perminantly sticky place where it collects. but eventually it will be all full.

**Damn Brit** · 11-04-2009, 02:31 PM

Originally Posted by geezer52

Not sure if this is the right place to pose my question, Plz be lenient if it isn't.

If you're not sure where to post, please don't guess, post in Everything Else and a moderator will move it if necessary.

*geezer52* · 11-04-2009, 04:11 PM

Originally Posted by Damn Brit

If you're not sure where to post, please don't guess, post in Everything Else and a moderator will move it if necessary.

Understood, but just so I know, was this the right forum?

*LeoTaylor* · 11-04-2009, 08:36 PM

They look like dust spots to me. The dust is so far out of focus it comes out as an almost round somewhat transparent dot, like you have. You can see blue in your spot even though the dust is opaque. Aiming straight up aggravates the problem.

As you mentioned they usually show in the sky. They are easy to clone out afterward. My K100Ds lacks any sensor vibrator so I depend on a Giotto Rocket Blower. Only once each on two cameras have I resorted to a wet cleaning. Best solution is blow out the chamber well and never change the lens. istDs and K1x0Ds are so cheap you can have a camera per function. Works for me.