Carina at Low ISO

[avandonk]

This image is the result of combining thirty two three minute exposures at an ISO of two hundred. THe odd and even images were median combined and then the resulting two images were summed. This is the equivalent of median combining sixteen six minute exposures. This also has the added advantage of almost completely eliminating any sensor noise.

Large version 2MB here
http://members.optusnet.com.au/~avandonk1/CARsmal.jpg

Details Canon 5DH, Canon 300mm f2.8L at f/2.8, 32x3min at ISO 200, Hutech LPR filter,in camera noise reduction on. All images processed with IP and stacked with RStar, adjusted levels with PS.

Bert

[RB]

That is stunning Bert !

:eyepop:

[h0ughy]

fantastic Bert! i hope too to eliminate most of the sensor noise when I get my little 350 back from its trip to korea! if I can get a 10th of what you have I will be beaming!!

[tornado33]

Gee, amazing. Youre right, even on the hi res version there is so little noise, very smooth. Its amazing how much more area the full sized sensor covers with the 300mm lens too.
I must see about imaging Carina with your lens here this weekend :)
Houghys modded camera would go well on the lens too!
Scott

[avandonk]

Thanks all. I purposely offset the mount alignment by moving it slightly in both RA and DEC. I then established that a three minute exposure was good for drift and rotation. A ten mininute exposure showed slight rotation and slight drift. Even though autoguided. This then has the effect that all exposures are slightly offset and when median stacked the residual noise (even after in cam noise reduction) the 'holes' simply dissapear. The in camera noise reduction helps as while the 'dark' frame is being taken the camera sensor is moving to a 'new' slightly offset position.

I am looking forward to houghy's camera with tHe lens. Saves me doing the experiment!

No one image is final. All are a mere reflection of reality. The more of us that image the closer we come to this relisation. All images are equally valid.

We should all just enjoy what we can achieve and just try to do better.

Bert

[RB]

Bert, while the in-cam NR is doing it's thing, would this mean the sensor is cooling down or is the sensor directly in use thru this NR cycle too ?
I know it's recommended that the LCD is to be switched off to minimize heat build up too.
Just wondering if this is true for the sensor too.

[avandonk]

I think you are worrying about amp glow? The later model Canons 20D up have the amp turned off during long exposures.
Bert

[avandonk]

I have also found that NOTHING beats the in camera noise reduction in the Canon 5DH. I can assure you I have tried everything. ImagesPlus comes close but not as good. If the temperature changes over the image collection, the correction turns to crap. The drivel about taking twice as long is a lie as I have never had good noise reduction using a set of dark frames collected before or during or even after. The only consistent results was you guessed it ICNR. Canon do something very cunning the noise in their chips is subtracted at the sensor individual pixel level (ie every green green blue and red) we cannot beat this with software after interpolation.

I am working on putting my 5D into a peltier fridge maybe then if the temperature remains constant which I highly doubt.

Bert

[RB]

Thanks for the info Bert.
Yes it was amp glow I was thinking of.
I was shocked recently when I viewed an old image of mine taken on the 300D.
The amp glow was very noticeable.

The 5D is an amazing piece of kit indeed.

[avandonk]

Yep even the 5D has amp glow and it dissapears with ICNR.

Bert

[skeltz]

not bad bert,not bad at all..i like it.

[ving]

not bad at all bert :)