fast prime for night photography

Hi, I'm getting into nocturnal photography here in Costa Rica and am considering picking up a fast wide angle prime for two reasons -- 1) to get a brighter viewfinder for composing in dim conditions and 2) for occasional short exposures (e.g., 30 seconds) where a fast aperture would be a benefit in allowing me to use lower ISOs. Of course, I'm also counting on a bit of a sharpness boost from the prime, particularly at the wide apertures, compared to my 17-40 mm f4. I can't break the bank, and I also do not need another heavy lens, so I'm considering these two alternatives:

The Canon 28 mm f1.8 (<!-- m -->http://www.bhphotovideo.com/c/product/1 ... _28mm.html<!-- m -->)

The Canon 35 mm f2 (<!-- m -->http://www.bhphotovideo.com/c/product/1 ... _35mm.html<!-- m -->)

I would be using these on a 5D body and don't care about noisy/slow AF. I'm interested basically in sharpness from the widest aperture through to f16. I will be using this lens for moonlit landscapes and stars (as points and trails).

Can anyone help me with impressions of these lenses and/or suggest possible alternatives in a similar price range?

Thanks!
Greg Basco

Hey Greg,
Can't comment on the 2 lenses but will offer......most people recommend around 20 mm for night/star photography.....not sure why....just my research. I use the 17-40 that you have for my night stuff and like it......but I use a big flashlight to aid composition. I am looking at the 16-35 f2.8L ll USM AF as a replacement but it is much more expensive pricewise. According to pop photo it offers significant improvements over the 17-40 but I will continue to do some more research on it.

Not to hijack this thread, but if Roman could post a tutorial on how to do, lets say, lighthouse photography with stars and catching the beam, I'd be really interested it that. I too want a better and sharper lens. I use the 5D and the 28-135 for night work, mostly at lighthouses.