What else is in your kit? Based on your options as presented, and with no knowledge of your other gear except the 300mm, I would suggest the 15-85, especially if you are not planning on going full frame in the near future. That would give you good IQ, and a very useful walk-around range.


If you are into macro, though, the 100mm non-IS is a great lens, and is also good for portraits, etc. Very sharp. I'd pick that over the 85 just because it is more versatile. Of course, your 300 has a short enough MFD that you can kind of do macro work with it, so if that is your main goal, I'd choose something else.


I have the 28-135. It seems to be designed to work better on a FF body than my 1.6x crop.It does well enough, but I'll sell you mine if you want it. [] Very clean example, low mileage. I am trying to get to a 24-70 f/2.8 ASAP.


The 50 f/1.8 is so cheap, it shouldn't even be in this list, unless you want it AND another one on the list. As a matter of fact, that and my lens, new, are only about $400 or so total. Together.


The 50mm f/1.4 is very nice, but if all you had was that and the 300, I would think you'd miss some shots.


A great deal depends on what kind of shots you want to take. Personally, I would like to have nothing shorter than a 300 in my kit, if it were just for fun. In that case, none of your choices would work for me.


I love to shoot wildlife and flowers, etc. I have used my current 400mm Sigma to do macro work, and it's really neat. It also is a pretty decent length for birds and other critters.


For my hopefully soon startup photo "business", I will need shorter stuff, like the 24-70. Eventually a 70-200 f/2.8 IS II, as well. So that's a whole other ball of wax.