Where I find 100mm too long is shooting something like a wedding reception, which I've done 3 times now. Inside, there is a significant chance that some guest will pop into the foreground. Outside, the 100 works well. I just shot a wedding this weekend, and slapped on the A35-70mm f4 because the M100 f2.8 was giving me this problem. The tradeoff was that the A zoom was much harder to focus. So, of course, I "need" a fast 85mm lens.
Fred wrote:
Hi, Carlos.
Probably the M 85 mm. f:2 is an excellent choice for portraits.
The M 85/2 is a pretty good portrait lens, despite its unpretentious seeming design, and is the most economical Pentax K-mount 85.
The lens I use the most for portraits is a K 85 mm. 1.8 and I love it. [and] The only problem about the K 85 mm. 1.8 is that it's scarce nowadays and consequently somewhat expensive, if you happen to find one in good condition.
The K 85/1.8 is a really fine lens for portraits, but has gotten ~very~ expensive to obtain. In the field of expensive 85's, it's a "best buy"...
I also have a K 105 mm. 2.8, but I also think it is a bit long for that kind of work.
The K 105/2.8 is fine, if it's not too long for the situation, and if you watch out for its bokeh. Actually, I usually wouldn't find 105mm too long, and I often use a 135mm lens for portraits. (The limiting factor is often the available space - the 135mm FL gets might long feeling if the room is small.
Fred has a comparison test in his web page about several 85 mm. Pentax lenses. I found it very useful when I was trying to decide which 85 I should buy.
http://www.cetussoft.com/pentax/85compar/
My favorite 85's are the A* and the FA* 85/1.4's. (I also like suing the Tokina AT-X 60-120/2.8 when a zoom fits the situation...)
Fred
