K-01: Samyang 85mm f/1.4 or Tamron Adaptall-2 90mm f/2.5?

Started Feb 12, 2013 | Discussions thread
JNR
JNR Senior Member • Posts: 2,809
Re: K-01: Samyang 85mm f/1.4 or Tamron Adaptall-2 90mm f/2.5?

KentG wrote:

So what you really want is family photos, not "portraits" in the real sense. The original use of 75-90mm lenses as portrait lenses was for studio work to get the correct aspect for head and neck shots where the nose and other facial features would not be outsize due to FOV issues. And fast F ratios to control the focus points and keep the background out of focus. But that was with FF film cameras. That requires the subject not to move so the focus does not shift. In your case I guess you won't be able to control the "subject" that well. You will have to open up the DOF to account for that and that will not isolate the subject as well. For that I would use a fast focusing AF setup because if the subject moves as much as 1-3 inches forward or back you are going to have trouble getting the shot in focus with a manual setup. This is a problem most baby photographers have. And one reason why I won't do it either. If it was me doing it, I hate to say it, but I would switch to my Canon system to do that and use something like the EF-S 17-55/2.8. That will lock focus about 2x as fast as my Pentax cameras (*ist D, K10D, K20D, K-01).

Other way is to use catch-in-focus with a fast manual lens, set the aperture as open as you can, then move yourself forward or back to hit the focus point. If you put it on a tripod it will be hard to get the shots with a manual lens. I shot with manual lenses for 17 years before I bought my first AF camera (Canon EOS 620). I shot everything from wildlife to motorsports. For moving subjects you had to pick a spot to focus on that the subject had to go thru, because unless they stopped you could not get focus manually most of the time before they moved. Unless you set a very large DOF, which would not be what you want. I still have a lot of manual lenses even though I have sold most of my Tamron AD-2 lenses within the last year or two, because I find they are really only good for static subjects most of the time. Takes some real practice to be able to move the focus ring on a manual lens just enough to catch something that is moving on you.

You can always shoot an AF lens manually but there is no way to get a manual lens to AF when you can't follow fast enough. That is just my perspective at 65 YO with 45+ years of photo experience (and a brother who is a pro).

Kent Gittings

These are very good points in the context of the goals of the OP. I would pull out my old Canon, and shoot with the Tamron 28-75/2.8. Of course, if you have to go with the Pentax system, the same Tamron is a good, economical choice available in PK; best when stopped down just a bit.

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JNR
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