Pentax K10D RAW noise reduction
I shoot a lot of long exposure shots with my Pentax K10D. One of my pet peeves is waiting for the built-in noise reduction to take a 1:1 dark frame subtraction exposure. This ends up doubling the length of time for each shot. Not that big of a deal if you are shooting 1 second exposures but a bit of a PITA if you’re shooting 5 minute bulb shots.
In-camera noise reduction is pretty critical for shooting JPEGs. Sure, you can always shoot your own series of dark frames at different ISOs and use them with 3rd party software to remove hot spots, etc. but this seems a bit extreme. So, I have just left the in-camera NR on and lived with the dark frame subtraction double exposure.
Many times I’ve noticed that there are hot spots in the initial Adobe Lightroom previews of my long exposure RAW files that disappear the first time I zoom in to 100%. This got me to thinking that maybe Lightroom could take care of long exposure noise on its own without the camera’s help. After searching Google in vain for a definitive answer, I decided a quick test was in order. I was pleased to learn that, now that I am shooting exclusively in RAW, I can turn off the in-camera noise reduction on my K10D and eliminate the wait between long exposure shots. (In-camera NR is still recommended for JPEG shooting).
Here’s what I found in the test. All shots are 30 seconds at f/16 and ISO 400 using my 50mm f/1.7 SMC-A lens with only LR’s default processing applied. Sorry for the crude composition…
From what I could tell from this test, there is virtually no difference in noise between the RAW images with and without in-camera noise reduction. In fact, to me the images without the NR has slightly better contrast and more shadow detail. Keep in mind that these are unprocessed RAW files so I could easily get similar contrast and saturation as the JPEG image while maintaining the greater detail and dynamic range of the RAW images.