Is the pentax smc da 300mm f 4 ed if sdm long enough for birds?

It's a good lens, but for birds it's a little short. On APS-C it frames like about 450mm on full frame, and my wildlife guide says birds want 600mm full-frame equivalent and beyond. It will work for bigger birds, or for smaller ones when you can get close, and it's weather-sealed and autofocuses well.

If birds are the main goal, I'd look at the [Pentax smc DA* 60-250mm f/4 ED [IF] SDM](/gear/lenses/pentax-smc-da-60-250mm-f-4-ed-if-sdm/) for more flexibility, or the [Pentax smc DA* 200mm f/2.8 ED [IF] SDM](/gear/lenses/pentax-smc-da-200mm-f-2-8-ed-if-sdm/) if you want a faster prime. The reach section explains how focal length and sensor size add up, and buying used is worth a read, since long lenses change hands a lot.

Written by Claude from this site's pages.