Stan, The Physics escapes me right now, but maybe Mark Cassino will chime in. He really drove home the point some time ago when he talked about using a tiny sensor P&S for bugs. Regards, Bob S.
On Sat, Mar 7, 2015 at 9:32 AM, Stanley Halpin <[email protected]> wrote: > Bulent’s recent question about a possible foray into large-format film > photography, primarily for macro shots, yielded several comments about how > one gets a shallower depth of field with Large Format (LF). I seen that, > heard that before. One or more of the 645z reviews I’ve seen made a big deal > about how the medium format (MF) niche was crippled if not doomed by the > inherently shallow depth of field. I remember in the early days of APS-C and > smaller sensors, some were moaning about the difficulty of getting shallow > enough depth of field. > > OK, so it seems that the general consensus is that moving from LF to MF to FF > to APS-C to smaller sensor carries with it a corresponding increase in depth > of field. > > But what does this mean? Really? > > I understand that lenses with longer focal lengths have shallower depths of > field. So a 75mm lens will have shallower depth of field than a 50mm. > And I understand that a 75mm lens on a 645 format will have the same > effective field of view as a 50mm on a FF 35mm format. Is this why the larger > formats are considered to have shallower depth of field? Because I need to > use a longer lens to achieve the same field of view? > > What if I had a 100mm macro lens that could be adapted to fit on the 645z and > a K-mount FF and a K-mount APS-C. Since the lens and its focal length are > constant, does the depth of field remain constant, with only the effective > field of view changing? Or does the depth of field also change? > > In short, I think my question is whether the accepted relationship [LF & MF = > shallower depth of field] really has anything to do with the sensor format. I > am guessing that people are talking about a practical issue (need to use > longer lenses to get the same field of view on a LF) rather than a physical > issue of the interaction between sensor size and lens. But I can’t tell... > > stan > -- > 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.
