7D user manual: IQ "can degrade" during long rec session?

Peter J. DeCrescenzo

Peter J. DeCrescenzo

Veteran
I'm generally impressed with what I've read about the 7D and some of its "prototype" example videos, but the following paragraph at the top of page 159 in the 7D user manual gives me pause:

"Camera's internal temperature increase and image degradation:
- If you continue to shoot movies for a prolonged period, the camera's internal temperature will increase. This can degrade the image quality. While not shooting, turn off the power. ..."

Obviously we'll have to wait until final release versions of the camera are shipping to see whether or not it actually has this issue, or if the doc is mistaken.

My concern is that if the 7D does lose IQ as it warms-up that this might be more of a pain in the *ss than some of its (few) other limitations.

Aside: Does anyone know if other "popular" DSLR cams such as the 5DM2, GH1, etc. have this issue?
 
Every digital camera has this issue. The warmer electronics get the less efficient they usually are. They liquid cool high powered telescope imagers for this very reason.

It's not really that quality degrades as much as noise is introduced more and more. Don't let this enter into a camera purchase, as every camera will have this "feature" :-p
 
I wonder how much this accounts for the noise and banding issues some people seem to have with the 5D and GH1 and not others, and I wonder how the GH1's CMOS copes with 4 hour continuos recording on a 32GB SD card?
 
Luis Caffesse said:
Would be easy enough to find out.
What sort of shot do you think would be the best of to demonstrate this?
Evenly lit shot of a macbeth chart perhaps?

I could see if I can line that up.
Click to expand...

One where fixed pattern noise, i.e. the noise generated from the CMOS circuitry is most visible. So white sheets or lightly coloured sofa, in a dimly lit room would probably be best.

Then again, any dimly lit pale coloured surface would be a good background for heat generated noise.

I may try it with my GH1 but I don't want to fry it. I am pretty convinced there is a heat issue with CMOS. It's the same reason CCD technology is kinda abandoned for high speed VDLSRs... it gets too hot. CMOS is better but not immune.

I haven't noticed the issue with the GH1, shooting for sometimes hours at a time but only recording for small on / off portions of that and never in particularly hot conditions.
 
Would be easy enough to find out.
What sort of shot do you think would be the best of to demonstrate this?
Evenly lit shot of a macbeth chart perhaps?

I could see if I can line that up.
Click to expand...

LOL! 4 hours continuous recording? Ok.
 
That is a pretty serious detractor along with the limited run times.... Again, we are getting a lot of peformance in a yugo sized box... I too have heard of Red owners having to pack their camera in ice her in FL to keep it running smoothly... Maybe they should make the next one with an optional cooler bag...
 
well, i don't know if this applies necessarily to the gh1 because it's in live view all the time whereas canon and nikon aren't. and you would think that the gh1 is designed to work without the sensor overheating. the d90 would overheat, in fla weather, in about 30mins. i'll have to wait and see what the gh1 does.
 
Since there is a 4GB limit on MOV file size, at 8MB per sec, that works out to about 8 minutes max per take.

I'm curious what their definition of a long take is.
 
it is an issue.

my 5dII get quite upset if its on for a long period of time...

just shot a documentary, and by the end of the day the footage gets more and more vertical gridded banding/noise/crappylookingstuff. camera wason for practically 12 hours straight. i shot 5,000 stills and about 3 hours of footage.

i thought the camera was broken. but i was using it at 500-3200 iso. high iso's also make it heat up faster it seems. she was hot to the touch by the end of the dy...
 
Justyn said:
I too have heard of Red owners having to pack their camera in ice her in FL to keep it running smoothly... Maybe they should make the next one with an optional cooler bag...
Click to expand...

Actually they are way ahead of that all ready. This was spotted outside IBC. Might be why Scarlet is delayed, this is pretty F-ing serious technology!

 
Then again keep in mind Red is 8.6 MP at 2.33:1 while 1080p is only 2.07 MP at 16:9. That is over 400% more data, it is like comparing these:

calculator.jpg
calculator.gif


:)

Chips have become WAY more efficient so the new generation of Red cameras should run several times cooler. Jannard said that they will.

TimurCivan said:
it is an issue.

my 5dII get quite upset if its on for a long period of time...

just shot a documentary, and by the end of the day the footage gets more and more vertical gridded banding/noise/crappylookingstuff. camera wason for practically 12 hours straight. i shot 5,000 stills and about 3 hours of footage.

i thought the camera was broken. but i was using it at 500-3200 iso. high iso's also make it heat up faster it seems. she was hot to the touch by the end of the dy...
Click to expand...

Timur, you can always be trusted to deliver the goods. Thanks for the info!

I think I'ma gunna drill me some holes and slap a CPU cooler on the bottom of mine. http://www.frozencpu.com/products/9...LGA1366_based_Xeon_5500_Nehalem_EP.html#blank

Then maybe I can overclock me a little higher ISO out of it!

MUAHAHAH!!!

:)
 
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you mean 25,600 isnt high enough for you?

jeez.... i mean its basically just images of sand after that point....
 
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