Quote Originally Posted by fstr View Post
I decided to take the plunge and see for myself which lens I like most. I picked up the 40mm locally and placed an order for the 85mm (should show up next week). Whichever I like least will go back.

I do have one additional pondering: 40mm versus Tamron 17-50mm. The Tamron runs about twice the price of the 40mm currently with rebate. That to me spells good value. Both are 2.8. So in theory if IQ is the same the Tamron should be a better option with the only negative the fact that it is bigger.
If I like the 40mm I may just order the Tamron to see how the two compare
I once did something similar and ended up with two lenses. Be ready to like both of them for different reasons!

I have had two copies of the Tamron 17-50 (non VC). The first (which is actually property of the school I run) is a fantastic lens. Sharp wide open with IQ that rivals my L lenses. Focuses fast (albeit noisily) except in very low light. When I had to give it up to the school, however, I decided to buy my own and got a TERRIBLE copy that I returned. Quality control tends to be an issue for Tamron and Sigma. So if you get a good copy, and you don't mind that it's not that cute, tiny little pancake lens, IMO the 17-50 is fully worth the extra $. But those could be big ifs.

FWIW, I wouldn't replace the 50 f/1.8 with the f/1.4 solely for AF speed. The bokeh on the f/1.4 is significantly better though.

I love the 85 f/1.8 for head and shoulder portraits. Even though it's less useful indoors, I like it MUCH more than the 50 f/1.4. And even though it's my least used lens, it's the lens that has taken the most shots that I have actually printed in larger format.

Finally, if you are getting OOF shots of kids running towards you, and you're not using AI Servo, that might be the explanation.