Does this look like a camera fault?

growse · 15 Nov 2006 at 03:47

Hi all. Went up the empire state for a bit of night-photo-ness. Forgot the tripod but they had handy walls there. Anyways, I'm just looking at the shots now, and I'm noticing some strange things. All these were taken with:

Canon 350d
Canon 10-22
ISO 100
No Hood
Hoya UV filter

These are straight from RAW conversions. Processing tends to show up these effects more.

Here goes:

First up, there's a big curved vertical line across the sky. Subtle, but the arrow points at where it is:

Second problem - 100% crop of the sky of the previous image. This isn't on every image, but is noticeable on some of them. Where it's present, it's on the whole image:

Finally, here's a different image that shows up what looks like fingerprints and that line again:

Now, I think the fingerprints are fingerprints. I have a suspicion that the line is some sort of internal reflection, from the filter? Solved by a better quality filter? The weird diagonal lines I have no idea about. CCD fault?

Does anyone have any ideas about how I can avoid these issues in the future? There are no perceptable fingermarks on the filter, but it's not been properly cleaned in a while.

Raymond Lin · 15 Nov 2006 at 03:56

I don't see anything.

binaryknight · 15 Nov 2006 at 04:38

i only see it if i look very very hard or the polorised? third picture.

not noticable in normal viewing wouldnt worry too much

have you run a swab across the sensor or rear element of the lens?
does it only happen on long exposures?

growse · 15 Nov 2006 at 04:43

Hmmm weird. The second image shows very clear diagonal lines to me, and the third image has a huge circular shadow on it. I'll go recalibrate my monitor just in case it's fallen way out, but I doubt it......

Zip · 15 Nov 2006 at 05:50

They all stick out like dogs balls to me and can see them intantly.

Im not sure what it would be though because i dont know much about cameras

Irish_Tom · 15 Nov 2006 at 10:30

The last one looks like dust or a hair on the sensor (looks exactly like what I had). I can't see anything wrong with the first picture, all I can see in the second one is the diagonal lines...

My advice would be to clean the sensor! I was lucky in that I could see the offending hair and was able to lift it off the sensor with a swab. If it's more serious than that then you might need to get a sensor cleaning kit. They can be had for about £35...

Panzer

rpstewart · 15 Nov 2006 at 10:38

Panzerbjorn said:
My advice would be to clean the sensor!

It's quite possible that there is something on the sensor but I'd check first before going probing around in the mirror box. Find yourself a well lit blank, light wall or a good sized patch of blue sky and take a photo of it at the smallest aperture you can (f/22+ if possible), don't worry about camera shake or focussing. If you take a look at the resulting image it should be fairly obvious is there's something on the sensor. A hair should be shiftable with a decent air blower (not canned!) which is a little less scary than swabbing.

Raymond Lin · 15 Nov 2006 at 13:28

binaryknight · 15 Nov 2006 at 14:59

i actually see the diagonal lines in the second easily thought it was moirre / interference on my monitor (amp is reasonably close and the monitor is slowly dying)

is quite odd

growse · 15 Nov 2006 at 15:17

Ok, I'll do some testing tonight to see if there is anything on the sensor. I'll try both the lenses I have.

As for the diagonal lines, :confused:

Johnny|lucidcomposure · 15 Nov 2006 at 15:28

That dark curve. isn't that a slight of light leakage?

Mohain · 15 Nov 2006 at 16:04

Fstop11 said:
That dark curve. isn't that a slight of light leakage?

Wouldn't light leakage be white, not dark?

Johnny|lucidcomposure · 15 Nov 2006 at 16:37

Mohain said:
Wouldn't light leakage be white, not dark?

Yeah thats true I suppose. Its just in the common place and same curve that I have seen other people suffer from.

gandhi · 15 Nov 2006 at 17:45

ok, the spots on the last image are most likely to be dust, either on filter or lens elements (front or rear), without the lens hood, the light is causing them to show up more obviously.

The dark stripe could just be due to internal reflections or a mahoosive piece of gunk on the sensor. It would have to be massive to show up at f5.6. Most probably the former.

The stripes are a result of long exposures and little light available as far as I can guess and are a 'feature' of the sensor itself.

All the above are very subjective, if the faults occur in every exposure you take then it is some sort of problem with the sensor/lens/filter etc. If they only occurred in these shots then it is more likely to be 'ambient' problems.

The joys of emperical knowledge eh?

growse · 15 Nov 2006 at 18:09

gandhi said:
ok, the spots on the last image are most likely to be dust, either on filter or lens elements (front or rear), without the lens hood, the light is causing them to show up more obviously.

I will go home and give everything a good clean. Does anyone have any general guidelines? I got a "popular high street shop" cleaning pack with my lens a while back, and that has a yellow cloth, some weird papery things and what seems to be alcohol. I've generally been using just the cloth to rub dust off - any advice on how to do a really good filter/lens clean would be appreciated

The dark stripe could just be due to internal reflections or a mahoosive piece of gunk on the sensor. It would have to be massive to show up at f5.6. Most probably the former.

A good point - given the aperture it *does* seem more likely to be a reflection. I don't know what this would be from though - is it more likely to be the lens (I always thought the 10-22 was a good one) or the filter/lens combination?

The stripes are a result of long exposures and little light available as far as I can guess and are a 'feature' of the sensor itself.

Does every CCD do this? or just the 350D? I'll have to look carefully at what the images that has the stripes have in common. It could be that the only images with stripes were taken with AEB, but that's a wild guess in the dark. It seems a bit silly that a DSLR can't cope with long exposure shots without putting annoying stripes on the image.

All the above are very subjective, if the faults occur in every exposure you take then it is some sort of problem with the sensor/lens/filter etc. If they only occurred in these shots then it is more likely to be 'ambient' problems.

The joys of emperical knowledge eh?

Indeed. It's frustrating (the stripeyness) because I don't know if:

a) It's caused by bad technique
b) It's caused by not-pro-level equipment (should I buy a 30D?)
c) It's just one of those things that happens to all DSLRs.

Even if I knew which of these it was, I'd be able to do something more about it.

gandhi · 15 Nov 2006 at 18:40

most lenses will suffer from internal reflections unless they are very fancy pro level ones, and even those get it some times without the use of a lens hood.

I don't know if the canon 10-22 is designed for digital, I use nikon and the digital lenses are coded 'DX' those that are ortiginaly designed for film cameras can suffer from light being reflected back into the lens from inside the mirror box and off the sensor itself sometimes, so that could be the answer to your dark smudge.

Lens cleaning......I use a brush and nothing else for fear of scratching the lens coating. If there is an abrasive bit of grime and you try to wipe it away with a cloth you can scratch the coating of the lens, no matter how much alkyhol you use!

Sensors....the crop you showed us was only exposed for 2 seconds and negative compensated by 1.3 stops, so the correct expsoure should've been around 5seconds. did you 'push' the exposure in raw conversion? That can show up things like this too, have a bit of a google for sensor noise, exposure etc and see what comes up. Your camera should also have a setting for long exposure noise reduction, you should use this for exposures over about a second, again google sensor noise and black-frame noise reduction.

Hope this helps? It's unlikely that your camera is borked and a little refinement of your technique should solve your problems.

And no, buying a better camera wont help!

ElDude · 15 Nov 2006 at 18:44

I must be blind. My monitor is calibrated properly and I can't see anything

{edit} Oh, actually after seeing the third image, I can see it now I know where to look. I was looking for a slightly different kind of line

gandhi · 15 Nov 2006 at 19:25

ElDude said:
I was looking for a slightly different kind of line

*sniff*

growse · 15 Nov 2006 at 19:54

gandhi said:
most lenses will suffer from internal reflections unless they are very fancy pro level ones, and even those get it some times without the use of a lens hood.

I don't know if the canon 10-22 is designed for digital, I use nikon and the digital lenses are coded 'DX' those that are ortiginaly designed for film cameras can suffer from light being reflected back into the lens from inside the mirror box and off the sensor itself sometimes, so that could be the answer to your dark smudge.

Lens cleaning......I use a brush and nothing else for fear of scratching the lens coating. If there is an abrasive bit of grime and you try to wipe it away with a cloth you can scratch the coating of the lens, no matter how much alkyhol you use!

Sensors....the crop you showed us was only exposed for 2 seconds and negative compensated by 1.3 stops, so the correct expsoure should've been around 5seconds. did you 'push' the exposure in raw conversion? That can show up things like this too, have a bit of a google for sensor noise, exposure etc and see what comes up. Your camera should also have a setting for long exposure noise reduction, you should use this for exposures over about a second, again google sensor noise and black-frame noise reduction.

Hope this helps? It's unlikely that your camera is borked and a little refinement of your technique should solve your problems.

And no, buying a better camera wont help!

Thanks for the advice.

The 10-22 is an EF-S, so is designed for 1.6x crop DSLRs.

As for using a brush - there's a brush on the end of my air-blower, but what if it's grease or something that won't shift?

Sensor - I think I keep it in long exposure noise reduction mode all the time. Will have to double check. Correct, it's 1.3 stops down, but that's because I was using AEB and the camera didn't meter the light correctly. This is straight from RAW - no fiddling.

it's good to know that it's nothing that's broken. I'll have to go up there again and work on my technique

Will take a tripod this time as well.

woodsy2k · 16 Nov 2006 at 10:19

Are you shooting through a glass window? because if so i believe that is what causes the dark line on image three that can be seen quite clearly (this will also be the cause of all the other flare on that image as well).

As for the diagonal lines on image 2 i dont have a clue im afraid.