For me the most important issue in deciding what focal length to use is whether I want to expand the relationship between fore ground and back ground objects, (as in with a wide angle) compress them (with a long lens) or render them neutral (with a normal lens.) With this in mind, even with a zoom lens on the camera , all zooming is done with one's feet. When the stars are aligned It's never about getting closer to a subject with a long lens, or getting more stuff in the frame with a wide.
When I started using a 40mm lens (dead neutral, assuming cropping for standard size enlargements) on 35mm it took a while to adjust to seeing subjects without any compression or expansion between elements. But it was very helpful insofar as it made me more aware of the effect of compression and expansion when using other focal lengths.
Any way-- If you've already got a 50 I'd concur with the above suggestion of 24mm. It gives a more dramatic perspective expansion effect than a 28 mm and is wide enough that it's really easy to set up leading lines that take the eye right into the picture, yet it isn't as hard to handle as a 21mm or wider lens which really demands careful positioning to avoid converging parallel lines etc. It's also the widest you can get for shooting people without doing weird things to their heads if they end up at the edge of the frame. A 24 35 50 combo is overkill-- good to own, but I'd never take all three of those out with me unless I wanted to spend all my time dickering about which lens to use rather than shoot. Id go 24+50 or 35, but that's just me.
Last edited by jpberger; 05-27-2010 at 03:32 PM. Click to view previous post history.