John Francis wrote: >On Sat, Sep 16, 2006 at 01:28:26PM -0400, Mark Roberts wrote: >> Ryan Brooks wrote: >> >> >Adam Maas wrote: >> >> At f2.4, the 70 is about perfect for me. Essentially the same length and >> >> speed as the legendary Nikon 105 f2.5, which is a superb portrait lens. >> >> >> >You are getting more DOF with the 70mm though. >> >> Not true. Not at the same subject magnification, anyway. (And that's >> what you'll be doing if you compare both lenses as portrait lenses.) > >Actually, Mark, Ryan is right. > >A portrait taken with a 105mm lens at f2.8 on a full-frame camera will >have a shallower depth of field than the same portrait (taken from the >same spot and enlarged to the same size)
Right. But I specified "same subject magnification", not "taken from the same spot". And "same subject magnification" is pretty much how everyone does portraits: You frame as a head shot, waist-up, 3/4 or full length and compare two lenses with this view. I've never heard anyone saying. "Well this Lens 1 has shallower depth of field with a head shot than Lens 2 does with a 3/4 shot": It's not a meaningful or useful comparison. -- Mark Roberts Photography & Multimedia www.robertstech.com 412-687-2835 -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
