Originally posted by Ron_Man What exactly compells you to require 2.8?
At a wide angle, f4 is relatively fast at 12mm.
Specifically for my needs, anyway, a wide angle angle is really good for landscapes and hardly ever shoot my 12-24 higher than f8.
In the few times I've needed it indoors with "adequate" lighting, f4 and 1600 ISO isn't by any means "fast" but certainly not slow (K-5).
Just curious as to why you require 2.8.
That's a good question.
I shoot a lot of trail runners in the early morning. So, there's not a lot of light, they're moving (obviously), and I want to capture them with an ISO that isn't crazy high. Also want to get as much of the mountain landscape in the background as possible. Examples:
https://www.flickr.com/photos/28805392@N02/
Most of those shots I took with my Sigma 10 20. A great lens. I'm basically just wishing it was a bit faster, or for a prime like the 15 DA in a slightly faster offering.
---------- Post added 04-11-15 at 09:46 AM ----------
Originally posted by MPrince Does it have to be a name brand Pentax lens? A lot of people seem to think highly of the Samyang/Rokinon/Bower 14mm 2.8 lens, according to reviews here and at B&H Photo.
The Samyang would be a good option except for the fact that it doesn't have AF. In the early morning light, I need AF to capture moving runners.