Strange things on my CCD!!!

Recently learned about adjusting levels in Adobe Photoshop, in order to maximise the tonal contrast for a particluar image, and thought I'd try something.

I took an out of focus shot of a piece of plain white paper subject to natual light. This obviously gave me a very tight tonal range.

I then used Adobe to spread this across the full available range.

To my surprise, in every shot I took, I noticed some "blobs" of darkness. Always in the same exact place on the picture, regardless of the piece of paper I used.

This morning I repeated the process and to my horror, there's MORE blobs appearing!!

What is this? Is it mold or something? I've only had the camera for a couple of weeks. At this rate my CCD is going to be covered in dark blobs in a few days time!

Now that I know where the blobs are also, I can notice them showing up in the un-edited images. Only very faintly I admit, but I'm a bit of a perfectionist so they're really bugging me.

Is this normal? Or a job for Canon?

Here's some blobs so you can see what I mean (this is at ISO 100, focused to infinity and purposeful camera shake (so that what you see is NOT from the source of the image, it MUST be from the CCD right?):

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MY GOD, thats iso 100??!!!
there is ore noise than picture...
Do those blobs appear on evey lens?
They seems like specs of dust, you might not be able to see them with you nakes eye.
Get a blower/cleaning kit, DO NOT BLOW AIR FROM YOUR MOUHT, you have water particles in your breath, and cameras are allergic to water!
If that doesnt solve it, then its job for canon...
What camera is it anyway?!
K

Your sensor is coverd with dust,just give it a good clean.Try a rocket blower first if that dont work then you need some digi pads or something.i used digi pads.

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Sure, its dust, but that noise i cant get over, i dont get that at 1600 iso!!!
If you are scared about the sensor being fauly....take a pic with the lens cap on and check the histogram in PS to see if you have any dead pixels.they are white. some are inevitable.
K

That's some major dust.

My sensor was ok till i got my EF100-400

Read his post again - he used Photoshop to spread the very tight tonal range in a pic of a pure white background over the entire available range. That's where the chroma noise you see comes from.

I'm sure there's no (visible) trace of it in the original shot.

It's a 350D. And yes, there's no visible noise without performing the level adjustment. But I can make out the "blobs" without level adjustment if I take a shot of something with very low tonal range or contrast.

the blobs and noise are easier than ever to take out with PS CS2. Are you using that version?

Right - more investigations.

I took a few shots with NO lens on at all and there's zero blobs.

I removed my daylight filter (HAMA PRO), cleaned the front element (light dusting), and took another shot... the blobs return.

So its something to do with the lens. I find it interesting that ALL of the blobs are the same size. I reckon there's some dust somewhere that's the cause of this. But I can't see it anywhere.

I've only got the one lens at the moment (Canon EF-S 17-85mm), so I can't try it with another one.

Ya reckon it's dust on the innermost (nearest the sensor) element?

I dont know if shooting without a lens on would show sensor dust?If you hold the lens up to the light can you see any dust inside?

The blobs (technically called "goobers") will only show up with small apertures, generally f/22 or higher.

If you try the same lens at different apertures you'll see the difference.

It's sensor dust. No doubt about it.

It is on the surface above the sensor, so you've got to get in there with a broom and sweep it out. Not really.

---Bob Gross---

use some pec pads/eclipse/and a rubbermade frosting spatula to get rid of them... works great every time...


you reminded me that its about time I clean my sensor again, so I think im gonna do it right now

I disagree. If you have dust/dirt on your sensor, it'll show up from f12 and higher, even when not using auto-level, if you're shooting blue sky.