Is the in-camera Long Exposure Noise Reduction necessary when using a camera in cold weather? This is a question I have wondered about for a long time so I finally did a more specific test.
First of all, what is Long Exposure Noise Reduction? Here is the scoop: When LENR is turned on, the camera makes the exposure and then re-energizes the sensor again, for the same amount of time, basically taking a second picture with the shutter closed. The camera then compares the two and performs a noise reduction algorithm before writing the file to the card. Supposedly, long exposures can increase heat on the sensor, resulting in possible noise. While this is a good feature, should potential noise be a problem, it creates a delay when shooting since you have to wait for the same amount of time as your exposure before you can preview the file. The only time I have used it is when shooting the northern lights, but the delay is annoying.
The following comments is based on my experiment with the Canon 5D Mark III camera, so if you have a different model, I suggest testing it.
At -30 degrees (F) below zero, I shot hundreds of consecutive frames of 30 second exposures at ISO 1000 with LENR turned off. There was no sign of noise or hot pixels in any of the images. Now that is a pretty cold temperature, but my other less specific tests at +20 degrees (F) showed similar results, but I will need to do a more aggressive, repeated exposure test to be sure. In the future, when it is below zero at least, I will no longer turn on LENR!
Great article, excellent Blog.
Condensation: How do you manage condensation with a cold camera when you take it indoors? I normally zip it into a cold plastic bag that’s been in an outside pocket, take it inside and wait for it to thaw before touching it (if I’m in a hurry for pictures, I first remove the card). But doing that with your frosty camera above would introduce a lot of moisture. Is wiping it off with a cold rag before going in the bag, good enough?
More great and useful information Patrick! I’m still hoping you’ll do something for us your computer system/backup. I really appreciate what you do.
Thus has been my experience as well. Truth be told, I’ve always shot with the LENR off, software-based noise reduction works so well. Not to mention that I’d be missing another exposure of activity while the camera would be running its black frame:) Can’t have that now, can we?
Great! Such an informative blog indeed.
Patrick, I stopped using the in camera noise reduction a couple years ago when software got better at noise reduction. It drives me crazy to wait.
My question is does the LENR work on the RAW file or does it only affect the jpg it sends to your review screen. I have not done any tests because I don’t use it anymore.
Mike, High ISO NR is preformed only on the jpeg. LENR is applied to the raw file before it is written to the media card, thus the wait, since it takes a duplicate shot with the shutter closed and analyses for hot pixels. My understanding is that LENR is different than chroma and paragraph (LENR) noise reduction and is based on a sensor getting hot. It is also my understanding that post production noise control, i.e., luminance and color NR in Lightroom is different than hot pixel noise.
Karen,
I put my cold camera in a down parka or in my camera bag before bringing it inside, and let is warm up slowly. That works just fine.