hmm
I'm watching this keenly
I don't have money for a new lens now but would like it...
I've found my 17-40 F4/L is good but not great:
- not fast enough for meteor shower photos at 800ISO
- not wide enough for a lot of astro stuff I want to do (used to be ok with full frame sensor)
- has distortion on the edges
- is super critical on sharp focus when doing astro stuff - very slightly off and distortions are horrible
Sure you can put the ISO up but that doesn't work well on warm nights (unless you have a 5DmkII apparently
).
I think it was the Orionids shower that I saw lots of meteors but captured few. Someone else with a F/2.8 was catching many more.
Another option is high ISO and Noise Ninja. I didn't have Noise Ninja for the Orionids but now do and it's a life saver, brilliant piece of software that enables at least another stop in ISO. Run it and you more often than not you find yourself saying "wow! amazing! it's .. .just .. perfect! and I didn't even do any tweaking!".
Wish I'd bought a 5DmkII - 7D is too noisy for my liking. .... but Noise Ninja saves me until my budget permits otherwise
(ie, several years
)
Edit: oh btw, the lens I keep my eye on is the Canon EF 14mm f/2.8 L ... looks very nice on paper (haven't used one). But then I do wonder.... for astro work how do you keep dew off such a wide lens? becomes largely unusable on dewy nights. Wrapping a dew strap around it would get tricky at best.