I've started to dive into the rabbit hole of getting a good milky way "Hydrogen Highway" wide angle mosaic shot, preferably something maybe 1/4 this size https://app.astrobin.com/i/td1tki. I'm looking for a camera lens that would be sufficient for my camera. I have an ASI 6200mm with 4.5nm Edge filters SHO and LRGB V Pro that can shoot safely down to F2.7, and some say even faster. I am thinking about combining data from my Redcat 71 with a much wider scope. Perhaps minicat 51 or standard f2.7-f2.8 camera lens. Can anyone point me in the right direction as far as what lens I should consider? I've heard about bad field curvature on the minicat 51 but isn't that how all small/wide angle lens are with FF camera? TBH I don't care as much about mild field curvature as some folks...Just blurx it out and if you're zoomed out enough it doesn't bother me.
Wide angle lens recommendations for Milky Way? (Full frame camera)
Samyang/Rokinon 135mm F/2. Test here: Samyang 135mm F/2 @ F/2 with Full Frame Sensor Test (OSC) - AstroBin
andrea tasselli · Jul 5, 2026, 05:13 PM
Samyang/Rokinon 135mm F/2. Test here: Samyang 135mm F/2 @ F/2 with Full Frame Sensor Test (OSC) - AstroBin
how hard was it to get the proper backfocus?
No effort at all. Standard 46.5 mm.
I use an asi2600mc Air on my Rokinon 135mm, you just have to hope you get a good copy, if you do it’s tough to beat that value. You can also buy the Astro Essentials M48 adapter which gives you all 44mm of backfocus and then you don’t have to rely on the cheap/lousy bayonet adapters, you just have to get a Canon EF version of the lens. There’s also lots of third party options for brackets and accessory holders, I ended up designing and printing my own version which puts the EAF below the lens. I use a CAA with my 2600mc Air as well and have no problem getting plenty of guide stars. This is the most recent image I captured with my setup: