1. I've come to like my M 120/2.8 because it gives me enough reach to take nice shots of the kids without them noticing they're being photographed. Manual shooting is still my favourite, but when I want to do some AF shooting I prefer the Sigma 70-200/2.8, as it's focal length suits both portraits and (to some degree) wildlife/sports.
2. Sometimes I wish I had a DA 50-135/2.8, or an A/M 200/2.8 or K 200/2.5. Sometimes the 70-200 is a bit too big and heavy - and too professional looking, so people want me to take photos for the sports club or community home page. A more "candid" lens with some reach and a fairly big aperture would be nice to have on those occasions.
Edit: Bugger! I see now that I flunked on the second question. I forgot it should be a lens that I have. I can't think of any particular lens that I wish I'd brought with me. If I've made the wrong choice for a shooting, I regret don't taking *that* lens with me instead. It depends on the situation.
Last edited by deus ursus; 06-21-2016 at 01:10 AM.