On Tue, Apr 13, 2010 at 09:26:43AM +1000, Tanya Love wrote: > I thought that "equivalents" were only if you were using FA lenses? I > thought that the Das removed this need to "convert"? > > Tan.
Not so. This is why thinking of it as a "focal length conversion" is bad. A DA 50mm lens is a 50mm lens, and acts just the same as an FA 50mm lens. Both will cover the same angle of view whe mounted to a particular body. The "focal length multiplier", "conversion factor", "equivalent focal length", or whatever comes when you try and use two different cameras with different sized sensors (where a frame of film is also a sensor). Using a 50mm focal length lens on a camera with a 24x16mm sensor (such as the Pentax DSLRs) will not cover the same angle of view as when using the same lens on a camera with a 36x24mm sensor - it will be exactly the same as creating an image from the central 24x16mm portion of the larger sensor (because that is, in fact, what you are doing). This is basically what you would get if you used a 75mm lens with that larger sensor (at least as far as angle of view is concerned). -- 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.
