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I had the opportunity this weekend to try out long exposures with the 30D, after a 10 minute exposure I noticed a really horrible looking blue gradient on the bottom edge of the frame. Thinking it was the lens I tried the 50mm F1.4 with the lens cap on and an exposure of 135 Secs @ F3.5 I noticed the same phenomenon. I took the camera back to the reseller today, and they had no clue. (The camera has since been sent back to Canon in Johannesburg.) Was wondering if anyone could shed some light on my dilemma?
I have attached a resized test image here:
And a 100% crop of the image here:
Exposure was 120 Secs @ F3.5 using an ISO of 1600. (Seems to happen on all ISO's)
I've heard of heat induced noise or "amplifier glow", but surely not after 120 secs and so severe?
Thanks in advance.
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Was the camera hot Bruce?
Astronomical cameras are cooled to reduce noise.
However, this looks like it may be a faulty sensor.
It certainly isn't pretty.
Camera was out in the cold Doug, I was wearing nearly 3 layers of clothing.
Strange thing is regular exposures (1 - 30 secs) are not affected. If the sensor is faulty, what is Canon's policy? The camera is still under guarantee.
I would not have thought that long exposures and high ISO's go that well together, I'm not surprised you got some interesting results.
If you read my post above I clearly state that it happens on all ISO's.
Sorry tiger I missed that, just tried it on my 1D Mk2, iso 1600 130sec, with noise reduction on and off. Some hot pixcels with NR off but nothing like you are getting, does sound like a dodgy sensor you have there.
This happens on the bottom of the image, that means the top of the sensor.
Have you used the included rubber-thingy to block any stray light from entering the viewfinder? It seems like you get some stray light coming trough the viewfinder and fogging your images.
The blue tint may be due to some optical merits of the pentaprism.
Hi, I used the eyepiece cover that's on the neck strap. My previous camera was a 300D. I managed to do a 40 minute exposure without the eyepiece cover, and didn't have the problem mentioned above.
I do 10 minute exposures all the time
Try 10 minutes at 5.6 and a low iso!!
I use iso 50 on the 5d and no noise reduction on..
Make sure the camera is adjusted to the cold and you should have no problem..
Have a quick look at my night stuff and see for yourself
Very strange Bruce - sending back to Canon sounds about right.
All Canon's Sensor Calibration did was waste a couple days. 2 weeks now without the camera, and they have finally decided to replace the sensor? Should I be worried?
Quote: Should I be worried?
Not realy, because if they change it correctly your camera will either be fixed or they will have to get you another. These things are normaly done at sub assembly level so the risk of change is probably low. There will be new ones where sensors will be changes as part of normal manufacturing rectification. Also because they know of your concern they should test it to make certain it is ok.
Mind you 10 min, that is a very long exposure, it could be long enough for in-camera thermal effects to show up.
Thanks for the reassurance. I suppose It's either gonna work, or they will have to replace. It's just knowing that a 5 month old camera, has already had open heart surgery
Surely 10 minutes is not that long in terms of Digital SLR exposures? I remember on my 300D I managed an exposure of about 40 minutes. A bit of noise, but nothing near the likes of the image I posted above.
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