Noise!

D

DinoS

Hmmmmm.......Paste!
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Hi

recently after going on a trip to the Icehotel in sweden and looking at some of the photos i have noticed that there is still quite a bit of noise on some of the images although i took it at ISO 100.

why is this?

also a couple of shots i took were in raw at iso 200 at 1/60 but were underexposed so i lifted them is PSE and they look quite noisey WHY?

thank

Mark
 
were underexposed so i lifted them is PSE
Click to expand...

That is your answer. Hopefully someone will be able to explain the mechanics of why that happens.
 
ok, i will wait with intrest
 
my only thing is though why the noise with the long shutter speed of 30 seconds?
 
noise at long exposures happens due to exactly the same reasons as high ISO noise, whereas the current through the sensor is high at high iso to allow data to be recorded, the lower current running through the sensor for a long period causes heat to build up on the sensor which leads to noise in the data.


pulling an image in post production will also lead to noise
 
Have you turned Noise reduction on for the longer exposures?
Failing that, some programs such as Noise Ninja or Neatimage can help a great deal but it's always best to try to get the best result in camera first.
Raising brightness/levels/exposure, etc of a dark image will always highlight the noise & is therefor a less than ideal solution - sometimes unavoidable due to the conditions we are forced to shoot in though.
Do you use a flash? May be an idea to read up on what is possible with them if you don't already know (not for your long exposures though unless going for creative shots) :thumbs:
 
can you get noise reduction on the 400d, i didn't think you could?
 
thanks, i wish i new that before going on holiday
 
You can just blur the image ever so slightly to help with noise reduction.

I mean like a tiny amount, so that it still looks sharp but all the noise particles blur together.
 
could you clond the really obvious ones out,

how do you blur it?
 
400duser said:
but were underexposed so i lifted them is PSE and they look quite noisey WHY?
Click to expand...

If you just increased the brightness the relative difference between pixels would remain the same and you would notice the noise. But increasing the exposure isn't linear so you get bigger steps between the brightness of adjoining pixels and the noise becomes more obvious. The more you compensate for under exposure the more obvious the effects of the non-linear adjustment.
 
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