Originally posted by ChristianRock You can't go wrong with the 77, but if I may make a suggestion, how about looking at the FA 135 2.8? I find the jump from 50 to 135 isn't as big as it seems on paper, meaning that I can cover the in-between with my feet. Last week I went to the zoo with the family and all I used was a 50mm and my A 135mm (I have the A version... it's what my budget allows). One on the camera and the other in my pocket. The only time I missed a shot was when the 135 wasn't long enough. Everything else, the combo handed fine. I also have ventured into the local parks and woods several times with nothing but a 28mm and the 135mm.
Once you have one, it's far more useful than you think. One of my favorite things is to take pictures of my wife when I'm about 20 feet away or more. A lot of times she doesn't even know I took the picture, and I have some candid shots I'm very happy with. I do the same with my kids.
Funny, I was about to say the same thing - FA77 or FA (or F) 135/2.8.
You can't get much more discreet than these two lenses. The FA135 is so intimidatingly small that people treat you like you're pointing a 35mm or something at them.
And the FA77 is even a little better. You'll think it's fantastic if you haven't had something like it before. But it costs more and isn't as long (really, you might want longer).
I have no affiliation with the potential sale, but I noticed KEH still has a BGN FA135 for a very reasonable price. I'm not planning on selling mine, so you'll have to go elsewhere!
In fact, at this point you should probably take the money that an FA77 costs and get the FA135 plus a Tamron 17-50 (or 28-75, if you insist).