what do you think about the 135mm 2f prime lens?

[Skirball]

I think it’s a great lens.

It’s hard to offer more than that without more info.  Intended uses, what size sensor you’re using, etc.

 It’s a reasonably fast prime at a decent telephoto distance.  It’s popular for sports shooters or those wanting more reach than your typical primes (35, 50, 85, 100).  Performance wise it’s quite good, but you have to weigh in the focal length – most people like fast primes for low light use, but at 135mm you need a faster shutter speed (rule of thumb: shutter speed = 1 / focal length) to get sharp photos.  If you try to treat it like a fast 50 and handhold at 1/30 in a dark room you’re going to be disappointed.

Also, if you use (fill) flash there’s a narrow band in-between fast enough shutter speed and max sync speed.

People often decide between a 85mm and a 135mm.  There’s many good discussions online about the two, you should be able to learn a lot about the pros/cons of each.

[TCampbell]

I own one of these -- I use it for low-light event photography (usually concerts) but I've also used it for portraits. 

It's f/2 focal length is great for low-light situations but it also creates a gorgeous background blur so while I don't shoot a lot of portraits, I have used it for portraits and it can really pump out the "bokeh" if you're into that.

[anitaw2]

what about gerneral photography...outside, sports, kids, etc?

[TCampbell]

For "outdoor" daytime photography, light collection isn't usually an issue... but you can still use the lens because of it's somewhat long focal length and the beautifully de-focused backgroudn blur quality that it provides.

For outdoor sports, it's probably not long enough... most outdoor sports would want at least a 70-200mm zoom and up to a 400mm prime for athletes out on the field.  

A 70-200 f/2.8 is great for indoor sports because the range is nice and the f/2.8 focal ratio deals with the poor lighting so often found in indoor venues.  The 135 is a great prime for these indoor locations ... roughly halfway between 70 and 200mm so you're basically splitting the difference BUT you're getting f/2.

For small rooms it's not practical because you can't get far enough away from your subject... the lens presumes you'll be able to put some distance between the camera and the subject -- meaning if you use it indoors you're probably in a large room.  

Otherwise you're shots are going to be primarily head-shots and you'll really be "filling the frame".

[ebiggs1]

"what about gerneral photography...outside, sports, kids, etc?"

I have an older version of the 135mm f2 but not the current version. As a "general" photography lens, it is probably not a good choice. If you have a crop body this really is not a good choice.

On a FF camera it makes a great portrait lens. But it is better described as a specific lens than a general all around lens.

As a compromise, and why I don't have the current version, is the 85mm f1.4 Sigma. Give it a look see.