Thanks all. It’s fun to make these! So the shots were all taken with a Ricoh GR. Some of the shots had the Ricoh wide angle adapter on the camera, and some not. I used a Trailpix tripod for all shots.
As for stacking images, I do that every time. I usually shoot 25 seconds at ISO 100, f/2.8. But I don’t hesitate to stop down and use higher ISOs if I need more depth of field. I’ve found ways to correct for that noise (see below). Make sure if you’re not shooting in RAW that your white balance is set
Now things get really technical, and once I have a bit more experience I’d like to write a tutorial for this (and maybe some scripts for windows users?). But basically I do the stars/sky and the foreground separately, but using the same original exposures.
For the stars I stack the shots with StarStax, as I’ve found it to be the fastest program out there. If necessary I’ll remove planes or meteors from the source images by painting over them in black (the black will never show up in the StarStax output).
Some of my shots I’ve done this and gotten good results as-is, but I find the foreground quality is generally lacking, so I try to improve upon it, generally with median filtering. Boosting a single source image and trying to get good color out of it is generally a loosing proposition, but the average of several images yields much better results. This is a good demonstration of the power of the median average for noise reduction.
I like to use the moon as my light source. So I go through and find where I think the moonlight is at its best, and take a bunch of images from that time (say, 9). It’s important that the number is odd rather than even. Then I subtract dark frames from the shots and average them together with a median filter. I use imagemagick, a command-line program. I don’t know of any easier-to-use apps to do this, unless I get around to writing a script for it (maybe try Deep Sky Stacker?). Sometimes I add pairs of images together to get brighter ones before I take the median.
Anyway, once you have a good foreground and good stars, you have to create a mask to separate the two. Sometimes this is easy, and sometimes it’s hard. For the first shot I posted I just used a gradient and that worked fine. For the joshua tree I used the blue/yellow channel (in LAB mode) of the foreground shot, which has better separation of the sky than anything else I found. I played around with levels until I had the outline nice and sharp.
Hope that’s not too much detail! I’ll have to write a lengthier blog post about this stuff, once I get my process dialed down a bit more.
