Best (reasonably priced) telephoto portrait prime?

If it were me and I was looking for a long portrait prime I would look no further than the 135L. I currently use the 70-200 mkII and rarely go to 200mm. I cant see how people can justify the 200 2.0L for portraits it cost 5K more and weighs 4lbs more than the 135L. There is also the 200 2.8 for cheap. Who has clients that can tell the difference when the lenses are used properly for background blur.

From your list, I have only the 300mm f/4L IS. I didn't buy it as a portrait lens, but I've found that it does a great job. It works best when you're outside and the light is good. Since I started using it for people photos, it has become the lens of choice. I use it mostly to photograph my 2 year old son. He's concentrating on playing ball with me in this photo:

IMAGE LINK: http://flic.kr/p/ee2Vz​A

Dillan_K wrote in post #16597364
From your list, I have only the 300mm f/4L IS. I didn't buy it as a portrait lens, but I've found that it does a great job. It works best when you're outside and the light is good. Since I started using it for people photos, it has become the lens of choice. I use it mostly to photograph my 2 year old son. He's concentrating on playing ball with me in this photo:

IMAGE LINK: http://flic.kr/p/ee2Vz​A

This was shot at f/5.6. The long focal length makes blurring the background easy, especially if you have some room between the subject and the background. This only works for outdoor shots. The composition isn't great, but this is the shot that made me realise the potential of the lens.

The colors, separation and subject everything perfect!

I should say, despite what I just posted, if I were looking for a portrait lens, I'd probably get a 135mm f/2 rather than a 300mm f/4L IS. It would be more useful in a greater variety of situations.

davidfarina wrote in post #16597714
The colors, separation and subject everything perfect!

Thanks David! I appreciate the complement! I really like the photo too. He's concentrating so hard!

Great photo Dillan! I'd like all the folks who say you should never take portraits with a lens longer than 100mm to explain everything that's wrong with your photo. To me, it's right on. I love taking portraits with longer lenses. I also have the 300mm f4 and have used it from time to time for this very purpose. My favorite "longer" lens for portraits is the 200mm 2.8 L.

I completely agree with what you are saying, nightcat. I mistakenly believed, when I first bought the lens, that the 300mm f/4L IS was not a good choice for portraits because it was too long and too slow. I just needed more room, that's all. It's certainly not too slow. It isn't as sharp as a 200mm f/2L IS, nor does it have as shallow a depth of field, but it is capable of achieving a somewhat similar look:

IMAGE LINK: http://flic.kr/p/edWq5​R

Nice photos. That 300mm must need an awful lot of room to do a full body contextual portrait though which is what I am hoping to do!

Draculr, that is why I said the 135mm f/2 would be a better choice. The 300mm focal length does require a lot of room (it's not bad for head shots, but full body would be pushing it). It's completely impractical indoors. It's really my wildlife lens, but it takes nice portraits too. If you want full body portraits, use a 50mm or an 85mm lens.

Dillan_K wrote in post #16598473
Draculr, that is why I said the 135mm f/2 would be a better choice. The 300mm focal length does require a lot of room (it's not bad for head shots, but full body would be pushing it). It's completely impractical indoors. It's really my wildlife lens, but it takes nice portraits too. If you want full body portraits, use a 50mm or an 85mm lens.

It's definitely the safest choice. Maybe I should just use the brenizer method to get closer to (and surpass) that magic 200mm f2 look

The 200 2.8 ii has been a great portrait lens for me, even on my crop body. It does require some space, but it was actually bought to shoot field sports with. For just over $500 I bought mine in like-new condition.

It's not that I don't like my 100/2 for portraits, it's just that I love the colors I get from the 200 2.8 II. That said, the 135/2 appears to have very similar (odentical?) colors. Great AF on the 200, and I assume the 135 is at least as good.

I'm thinking you will love either one, it is just a matter of picking your favored length.

Out of respect of all suggestions given thus far, if the 200/2 is out of the question, the 135L is the way to go.

You should have the 70-200 f/2.8L IS II in your bag. Image quality is great and the versatility offsets the size and weight.
Anyone without modern/quality zoom lenses is neglecting some valuable tools.
Granted there are terrific primes. I just don't like changing lenses much.

Only other lens to consider is sigma 150 2.8 OS macro. Extremely sharp, reasonably sized and with IS.
dont use the 200 f2 IS as reference its and F2, and includes much less of background for the same framing of your subject. the better isolation of your subject, and less distracting shrubs in the background is primarily the results of the above two.
I think you are overhinking this a little actually. If you want IS, and not zoom, and small, the sigma is your only choice. If you can live without IS, 135L is excellent, as is 200 2.8

+1 to the 135L or Sigma 150 OS macro, or possibly the Sigma 180 OS macro. The Sigma also doubles as a macro for shots of the rings etc.

The distance you'll be putting between yourself and the subject for a full body 135mm+ shot will typically mean you'll have no trouble blurring the background.

The more I think about it, the more I think the Sigma 180 OS Macro is the one you're looking for.