I personally know by memory for the prime lenses I used the most, and out of personal experimentation in real world shooting -just because I like to know- although P mode with MTF program will get you there easily. For the non-chip lenses I guess a couple of clicks from wide open.
The ones for me that I found is worth knowing (partly because I used them often) are the 43/1.9 (some magic happens at f4 and 5.6), 31/1.8 (f5.6), 21/3.2 (f8) and 15/4 (f8 or f11). In some cases finding those sweet spots rekindled some lens love. And I also know that I get slightly sharper images with the 35/2 than the 31/1.8 @f2, that the DA40/2.8 is slightly sharper at 2.8 than the 43/1.9 at f2.8 and that the 50/1.4 gets ok at f2; for the rest I don't care that much/don't know/don't shoot with them that often Photozone.de has charts that I found pretty accurate for the lenses I have; and I used them just to answer questions like is the 16-45 better @ 16 than the 12-24 @ 16? without having to test myself (which I won't do anyway) On Mon, Jun 4, 2012 at 6:22 PM, Larry Colen <l...@red4est.com> wrote: > I was thinking about my quest for sharpness, and was considering trying to do > some research into what the aperture "sweet spot" is for each lens, and was > wondering if anyone had already made a chart of them. > > Then I wondered how much it really matters. I've heard "a couple of stops > down from wide open", "anywhere between f/8 and f/16", and a couple other > rules of thumb. I do know that on some lenses, particularly the FA50/1.4, > that stopping it down a couple of stops from wide open, makes a huge > difference. And I suspect that if you look on an MTF chart, you might be > able to easily see the difference between f/4 and f/8, but is there a > practical noticeable difference? > > There is also the question of sharpness at the critical focus distance, and > overall sharpness. That a lens might be sharper at f/4 than f/16 at the > focal distance, but with a lot more depth of field, more of the photo will be > sharper at f/16, than at f/64. > > I'm primarily interested in answers based on personal, practical experience, > rather than theory. My hunch is that as long as I'm not too close to wide > open, or pushing diffraction limits, optimizing aperture for sharpness is not > the most productive place to spend my time and energy. That I'm generally > best optimizing the aperture for the picture, and not trying to optimize the > aperture for MTF. > > -- > Larry Colen l...@red4est.com sent from i4est > > > > > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. -- http://www.flickr.com/photos/ferand/ -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
