Lens makers used to give this number. My Zeiss lenses generally claimed to be best at 5.6, and this is now my default setting even though I no longer have any Zeiss lenses.
The theory was you set the lens on 5.6, or whatever, and used the hyperfocal distance to get the sharpest photo with the most depth-of-field. Some of the Pentax cameras had a setting which automatically set the lens at its best aperture, which was coded into the chip, I suppose, when it might have been cheaper just to paint that aperture mark a different colour. B > -----Original Message----- > From: pdml-boun...@pdml.net [mailto:pdml-boun...@pdml.net] On Behalf Of > Larry Colen > Sent: 04 June 2012 23:22 > To: Pentax-Discuss Mail List > Subject: How much difference does optimizing the aperture make? > > 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. -- 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.
