On Dec 19, 2010, at 9:42 AM, Thibouille wrote: > Of courses some are (imagine if not...). > Yep as for vignetting, maybe distortion as well, FF lenses used on > APS-C suffer less, proportionally than an APS lens on APS body. > But those lens will sometimes (often?) offer CA for free as well and > often less sharp as well, simply because they didn't need to be in the > first place. But this is really hard to generalize. A cheap APS lens > is usually ... not great at all and and older FF lense maybe a lot > better (or not). Individual testing needed, really. > > Just remember some lenses are not APS lenses though they have DA name. > 55 is FF, 60-250 is FF, 200 and 300 as well, 40ltd is FF and 70 is > debatable.
The 60-250 covers 24 x 36, but it's optimized for APS. I suspect that true of the other DA lenses as well. None of the DA* lenses display appreciable vignetting on APS frames, so that's a straw dog. Paul > > 2010/12/19 Boris Liberman <[email protected]>: >> On 12/19/2010 2:11 PM, paul stenquist wrote: >>> >>> Then why worry about the lens frame? A lens designed for APS-C will >>> outperform one designed for 24 x 36. (They're both full frame. Just >>> different frames.) Paul >> >> I opine (may be wrong, but that's my right) that some 24x36 designed lenses >> outperform some 18x24 ones. In particular, some Sigma EX 24x36 lenses show >> impressive degree of correction of geometric distortions. For my kind of >> shooting it makes them particularly attractive given their price tag. >> >> You're however absolutely right that there are no "partial" frame lenses >> here. Unless of course, we're speaking of circular fish eyes /grin/. >> >> Boris >> >> -- >> PDML Pentax-Discuss Mail List >> [email protected] >> http://pdml.net/mailman/listinfo/pdml_pdml.net >> to UNSUBSCRIBE from the PDML, please visit the link directly above and >> follow the directions. >> > > > > -- > Thibault Massart aka Thibouille/Thibs > ---------------------- > Photo: K-7, Sigma 28/1.8 macro, FA50/1.4, DA40Ltd, K30/2.8, DA16-45, > DA50-135, DA50-200, 360FGZ ... > Laptop: Macbook 13" Unibody SnowLeo/Win7 > Programing: Delphi 2009 > > -- > PDML Pentax-Discuss Mail List > [email protected] > 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 [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
