Actually a lot of the newer lenses don't get much in the way of extra coverage as they are stopped down wheras some of the older designs get a huge amount. The difficulty is defining coverage, since a lot of the older lenses get very soft at the edges. In some cases older examples of the same design will have more coverage than newer ones since the manufacturers have tweaked them to reduce the image circle so that the edges don't get too soft. If you are contact printing from an ULF neg, say 12x20, then you really don't need much resolution but if you are doing mural prints from 4x5 the you will want it to be bleedingly sharp across the entire neg. The 8x10 and ULF guys will often distinguish between the area that is illuminated and the area that is covered, with coverage being a subjective measurement based on the photographer's own requirements for sharpness. The phrase YMMV gets used a lot in discussions of LF lenses.
Paul Ewins Melbourne, Australia 27/12/2011, at 3:14 PM, William Robb wrote: > On 26/12/2011 10:04 PM, Darren Addy wrote: >> I'm mostly view-camera illiterate, so I'm sure a more informed voice >> could chime in here, but I'm seeing that "maximum coverage" is >> achieved on some lenses only when stopped down significantly. On a >> camera with rise, swing and tilt capability, I'm guessing that >> "maximum coverage" could only be achieved with the lens and film back >> parallel (I'm sure someone will correct me if that is inaccurate). >> > > I think all lenses do get an increased image circle as it is stooped down. > Generally this is only important to the large format user who depends on a > large image circle to allow the use of camera movements. > Often, in order to cover the entire format when using significant tilt of the > lens or shifting of the lens or film, the lens also needs to be stopped down > to secure coverage of the corners of the film > > > -- > > William Robb > > -- > 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.
