Hot Pixels On Long Exposures

[adox66]

I know of no "automatic fix" in Lightroom for noise, and I wouldn't expect or want it as I'd want to be able to adjust for noise on a photo by photo basis. They do have both Color and Luminance Noise adjustment sliders.

According to the EXIF data this is a 923 second exposure. That's a LONG time - over 15 minutes. That's plenty of time for the sensor to heat up and produce hot pixels and general sensor noise. What you can do is produce a similar black image by covering both the lens and the eyepiece and shoot a 923 second black exposure, which should theoretically produce the same level of sensor noise in the same areas. You can then use that image with the original RAW file to subtract out the noise. This is the same methodology that the camera uses with Long Exposure NR without having to wait out in the field for a second 15 minute period while the camera produces the black image and then does the subtraction in-camera.

There's a difference between hot sensor noise and hot pixels. As @hark stated, a hot pixel is always hot, regardless of exposure times. What you have is evidence of an overheated sensor. And a lovely shot, btw. If you wanted, you can desaturate your reds, magentas and purples in LR without impacting the overall color of the photo - at least not to my eyes. The spots are still there, but they're white instead of hot pink. Or, if you prefer, after doing basic adjustments in LR you can send it to Photoshop and use color-specific noise reduction. I did 100% NR on the red and green channels, reducing details to 0%. This took out a ton of noise, and was very effective given that you're image is almost all shades of blue (i.e. this may not have worked as well on a more color-full image). From there it was just a matter of using the spot healing brush to take out the white flecks that were left. Harder to see on a 1000px upload, but I can shoot you the full size image if you'd like. You definitely loose some sharpness on the rocks, but again this was done quickly and on a JPEG and not the RAW file.

Lots of options available to you.

View attachment 61380

Wow what a fantastic and detailed response. Really appreciated, as are everyone's replies here.

Id love a copy of the full image you edited. Can you email it to me? [email protected]

i don't have photoshop so can't use that for pp but have Lightroom so some really nice tips there.
I have used the healing brush on some other images, takes a lot of time though if there are lots to clone out. In fact I'm becoming a little obsessed with it and how zoomed in to 200% on some images to clean them!

its really from 30 second exposures and higher than I'm having issues. I should have maybe picked a less extreme image to post here for opinion.

Because I am so relatively new to photography, a lot of the noise(or whatever we will call it) could be largely down to me, certainly in my earlier shots which were done without grad filters and were most likely under exposed in large parts.

My my main concern is to make sure it's not an issue with my sensor not being right.

I have a be a few photography friends who I shoot with, who are much more experienced than me, so I can get their input too. Problem is they are all, to a man and a woman, Canon users so none will be familiar with my specific camera.

Thanks again for the replies. They really are appreciated.

 

[BackdoorArts]

Large copy is on its way through the ether. There's likely still some stuff to be cleaned in there, but it was a quick and dirty attempt.

The healing brush in LR5 is better, but the tools required to handle this level of noise may be beyond LR's power to deal with. I suspect that were you to use in-camera Long exposure NR you'd eliminate most of this - and also wind up waiting around a long time for it to work. As I mentioned, there may be a way to do it in LR with the black photo, but I'd have to Google it the same as you. If not in LR then perhaps in PS Elements? You can find older versions of that fairly cheap.

What I saw definitely didn't look like hot pixels, and if it's not consistent from image to image all in the same spot then it's likely not that.