20D Long Exposure Noise Reduction ??

[photofinish]

Does anyone have any thoughts on enabling custom function 02 for long exposures? Is it really worth it? I have NIK Define 1.0 which also does noise reduction for me...

[roanjohn]

..........give it a try..........take the same scene with it ON and OFF.

........see if its worth it.

ro1

[Reminisce]

Its really mostly useful for 5 second and more shots. I know hot pixels arent much of a problem for DSLRs as they are P&Ss, but they can still show. I dont take many long exposures, but the couple I have taken came out smooth as a baby's bottom with CF2 on.

[drisley]

Pretty much what Reminisce said...
The LENR doesn't really reduce noise in the tests I've done since the noise is already so low.
However, it does help eliminate hot pixels.
It would be more accurately named "Long Exposure Hot Pixel Reduction" imho.

[photofinish]

Thanks, guys, for the help. Now that the nights will be longer, I want to try my hand at some night shots, especially with Christmas lights. :)

[Deckyon]

There is another way to do noise reduction, one that is generally quicker at the shot end, but a little more work on the post-processing end.

Bassically, the NR built-in the camera subtracts a dark-frame taken after the shutter closes. That is why, when NR is turned on, the camera takes the extra time to "process" the image before taking another photo. Bassically - most basically - you take a 30 second image where the shutter is open exposing the chip to light, then the camera closes the shutter, but re-exposes the chip to the darkness for the same amount of time (30 secs.) and then the DIGIC subtracts the dark-frame from the "light-frame" leading to a very good StN ratio.

There is a way of working this out, speeding up the time at the camera taking the shot. If you are going to be working with the same shutter speeds, you can leave the lens cap on the lens, and then take a shot at the working shutter speed - lets use 30 seconds, again. You now have a dark-frame showing all the noise on the chip that would appear after 30 seconds for that ambient temperature. Now you can take all the 30 second shots without the in-camera processing taking another 30 seconds. One thing to think of, if your room temperature or ambient temp around the camera changes drastically, you need to take another dark frame, as the noise pattern will change.

Now, when you get home, you open the dark-frame and one of the light-frames. Select all the dark frame and then make sure the light frame has focus. You will then want to apply an adjustment layer allowing you to subtract the dark frame from the light one, virtually eliminating noise.

I use this method for taking pictures of the stars and other astro-images. Most of the shutter speeds are at 30 second to 90 seonds. At ISO 800, and subtracting the dark frame, I have noticed images every bit as good, if not better, as ISO 200-400.

It just depends on where you want to spend your processing time, at the camera or at the computer.