Unusual problem - 10D outdoor images

[TBoyd]

Although I haven't been an active poster in this forum, I browse through it regularly & appreciate the wealth of knowledgeable input found here.

For several weeks I have noticed what appears to be lens flare on images taken outdoors in sunlight with my 10D. I finally took some time this morning to experiment & found it is NOT lens flare. The problem occurs with all 3 of my lenses on the 10D. I took the shot with the same lenses on my D30 backup, and there was no problem.

I have cleaned the sensor & mirror, but the problem is still there. Here is a sample image to illustrate:

Any ideas, suggestions are appreciated.

---TBoyd

http://www.ns2.s4avahost.net/~harmonys/problem.jpg

[RichardtheSane]

It looks like more light is hitting the sensor in the area of defect than should be.

I'm not sure exactly what could cause it, maybe something inside the body (behind the mirror?) os possibly even the shutter. I don't know for sure, but I do recommend takin git to Canon.

btw. does it happen on both raw and jpeg?

[TBoyd]

Thanks for your interest, Richard.

I get the same results regardless of whether I'm shooting jpeg or raw.

I agree, there must be something going on with the shutter. I forgot to mention that I also tried shooting using mirror lockup, but still get the same arc of light on the image.

Something must be refracting - or reflecting - that arc of light to the CMOS. I'm afraid to do anything more than cleaning the sensor & mirror.

I forgot to mention that I don't have the problem shooting indoors - with or without flash (550EX).

TBoyd

[RichardtheSane]

Are there any scratches or defects in the body?
Or on the back of the mirror?

Long shot, but possible...

What formware do you have? I cn't imagine this being a firmware problem but it pays to have the latest version when troubleshooting!

Also, do you have any warranty?

[Steven M. Anthony]

I think Canon just sends all their defective product to the Virgin Islands to kind of "balance" the lives of the photographers who live there (compared to ours...)!

[George]

It looks like you might have a scratch on the glass that covers your sensor. Does it get worse at higher f-stops?

[sjprg]

Just an off chance. Try putting the viewer eyepiece cover on and see if light is coming in the eyepiece.
Do you wear glasses? Maybe reflection from them in the eyepiece????

[TBoyd]

Thanks - Richard, Steven & George.

The camera body is intact. I did some research on dates of past photos & realized this problem began after my first sensor cleaning. I used the tools, Eclipse solution, and cleaning method from the Copper Hill Images site: http://www.pbase.com/copperhill/ccd_cleaning

I don't blame Nicholas at Copper Hill for my problem. The cleaning method removed several spots that were on my CMOS. I have recleaned the CMOS several times since my last post, but the arc still appears on most outdoor pictures.

George brought up an interesting idea. I did some test shots at different apertures, and found that the arc across the image was more pronounced at larger apertures. I shot pics of blue sky in apertures ranging from f2.8 in steps to f22. The arc is very pronounced at f2.8, and gradually diminishes as the aperture size decreases. It is not visible when approaching f11 & higher. Any thoughts on this?


Hey Steve - there are actually problems in paradise without Canon trying to create them! :wink:


TBoyd

[George]

If it's more pronounced at higher apertures, then it's most likely on the sensor. (Higher apertures also show dust more.)

The fact it's at the same place on all pics and lenses would seem to rule out much anything else. The reason it probably shows up more outside is because of it being brigher.

[TBoyd]

Thanks, George.

It is most pronounced at f2.8, which is just the reverse situation where dust on the sensor is most visible at f22 or higher.

BTW - I just experimented with indoor shots of a blank wall using the 550EX flash - at different apertures & there is no problem there!

TBoyd

[Jim_T]

Have you tried a dark frame ?

Take an ISO 400 shot with the lens cover on and the eyepiece covered.

Adjust the levels and see if you can bring out the line.. If so, I'd say there is an internal problem with the sensor or associated circuitry..

[TBoyd]

Jim:

I just performed your suggested test & adjusted levels. The crescent does not appear at all.

I'm thinking that somehow - when the shutter opens - light is somehow reflecting off of something inside & on to the sensor that creates the crescent on the image. As the aperture is opened wider, it lets in more light, and more light is refected to the sensor. This would explain why it is worst at f2.8.

I've looked carefully into the sensor area with the camera in the "clean sensor" mode, but don't see anything unusual. Whatever is causing this is staying put, regardless of how many times I've cleaned the sensor, because the crescent is always in the same spot on the image.

TBoyd

[TBoyd]

jsprg:

I somehow missed your post earlier. You had me going for a minute, since I shoot with my glasses on. I tried covering the eyepiece, but it didn't solve the problem.

TBoyd

[George]

Are you shooting raw or jpeg? Whichever one, do you see the same problem with both?

[TBoyd]

George:

The problem is the same - RAW & JPEG.

TBoyd

[slin100]

I read somewhere that the shutter curtains travel in an arc. The artifact in your image could suggest that one of the curtains is leaking light.

[Andy_T]

Have you examined the flocking (if there is any) on the inside of the camera (the housing of the sensor)?

Maybe you should try an alternative cleaner once....

Best regards,
Andy

[George]

Does the artifact move at all... or it it exactly the same place every time? I'm thinking you might have a hair caught in your shutter mechanism. (If it got worse at a lower aperture, it should mean that it's not on the sensor, but something further away.)

[TBoyd]

George:

The arc of light is always in the same place. If the problem was caused by a tiny hair, I would think the shutter action would cause it to move, and the arc would occur in different places.

TBoyd

[TBoyd]

Thanks to all of you for your input. After contacting Canon Tech Support, the only solution is to send the 10D in for repair. I'm very curious as to what is causing this strange problem. :arrow: :arrow: ???

At least the repair should cost less than a 20D :roll:

It would be a good excuse to the wife to get one :lol:

But NO - My next camera has got to be the 1Ds :twisted:

TBoyd

[George]

George:

The arc of light is always in the same place. If the problem was caused by a tiny hair, I would think the shutter action would cause it to move, and the arc would occur in different places.

TBoyd

Yep... that's why I asked if it stayed in the same place.