First, thanks Adam. That Squaw Creek NWR can be absurd if you get the right weather setup for max geese numbers(like early spring warmth followed by snow pack just north of the refuge). Sometimes over a million can really get locked into that place and the small bodies of water. Other times they are there one day, gone the next, like a late warmth on spring return, or 0F highs in the fall as the water is shallow and freezes over pretty easy. Rented the 800mm and 600mm for eagle shots there and otherwise wasted a chunk of change for that, while better shots were had for that with my 100-400. Funny how little extra reach those really are and just how much air distortion over distance screws up images anyway. Anyway...
Re: the 24 1.4, that's a pity.
I'm looking at buying one for that reason (time lapse night shots). I've been testing a few ideas with the 35 f2 (on a 5d mk3), but that also suffers from coma. From what I've read, the 24 1.4 is supposed to be pretty sharp for such night shots. As a comparison, is it worth hiring one to verify if its an issue with your lens?
I must admit, stellar images do push the boundaries for most "terrestrial" lenses (I used to make telescopes in a previous life, so I have an understanding in what's required).
Well, I got this 24 used from lens rentals. I found that when I focused at infinity that the left side was soft and when I focused any where inside infinity the right side went to soft soft hell...to crap basically. I sent it back and they fixed it, it was decentered and the focal plane or something was tilted. I got it back yesterday morning and took it along with the sigma 50 F1.4 I replaced the canon 50 1.4 with yesterday out last night and tested the coma on stars thing again. Really little change to the 24 as far as that. It should be worlds better now for day sharpness though. But the point is it is is apparently "pimped out" now as far as tweaking it and it's still there. That and the lenstip.com 24 clearly shows the same thing. And the original site I read about it and ignored their advice and bought it anyway, well they showed it as well.
The Sigma last night didn't seem to be as bad as the Canon 50 with coma but there was plenty. It was shaped different, more like a small C instead of long wings.
Alright, I just grabbed a bunch of edge/corner crops. I tested the sigma 50 and fixed(for the other issue) canon 24L II last night same time for this. The canon 50 shots weren't testing but shooting auroras the night before. Last night's right edge/region of both the sigma and 24 seemed there was left over moisture from dissipating clouds or something over this one section of stars as they look soft in the same area. But you get the idea. I went from F1.4 through F4....but these are just at F2 as it would be nice to be able to use the lenses at that at last for night stars....http://www.extremeinstability.com/stormpics/canon24-right-f2.jpghttp://www.extremeinstability.com/stormpics/canon24-left-f2.jpg
After that 24 was fixed for decentering and focal plane tilting, doesn't seem it changed coma much anyway(again, wasn't the point of that). But that is F2 edge up to corner crops from each side. Below is the canon 50 F1.4 compared to sigma F1.4 both at F2 again.http://www.extremeinstability.com/stormpics/canon50-right-f2.jpghttp://www.extremeinstability.com/stormpics/canon50-left-f2.jpghttp://www.extremeinstability.com/stormpics/sigma50-right-f2.jpghttp://www.extremeinstability.com/stormpics/sigma50-left-f2.jpg
The right side stars being soft in one area on these last two is a little odd to me an I really think it was moisture/dissipating cloud issues in that area. It was under a cold upper low where the clouds vanish with loss of heating but there was still a haze left in the air. Otherwise the right side of my 24 just fixed would have to still be soft AND the new Sigma just bought would happen to be acting the same way in the same spot. But you can still judge the coma differences. Sigma is an improvement over the Canon 50 but still has plenty.
I can't wait to compare the sigma vs canon on regular day shots as a quick look on a cloudy yesterday showed it was big for the sigma.
Got me on what the hell fast wide lens for night stars without coma on full frame is. Maybe it is that Zeiss 21. I think the Zeiss 15 has a whole lot of vignetting at F2.8 so doubt it is that. But again, neither faster than F2.8 to start with either. Canon 14 II does it too but again F2.8 to start, but the strong purple fringing was rather annoying in the corners on stars.