On Tue, Jun 27, 2006 at 12:13:14PM +0200, Martin Trautmann wrote: > On 2006-06-26 19:29, John Francis wrote: > > Put an MX and a *ist-D up, side by side, one to each eye (you'll > > have to do that with the cameras in portrait position), each with > > a 50mm lens fitted, and objects seen through the two viewfinders > > *will* appear to be the same size (and will appear just a little > > smaller than you would see with the naked eye). It's just that > > the MX will crop to one rectangualr portion of the total field > > of view, while the *ist-D will crop to a somewhat smaller one. > > > > Most viewfinders, in fact, try to present their image at an > > apparent distance of around 1m from the eye. So if you imagine > > a wall about 1m in front of you the MX viewfinder (with a 50mm > > lens) is just about like looking through a rectangular 30" x 20" > > window in that wall, while the *ist-D viewfinder (with the same > > 50mm lens) is like looking through a 20" x 13.3" window. But > > in each case the objects, as seen through those windows, are the > > same apparent size. > > Thanks for the clarification. I now understand better what magnification > means. I did not expect that what you see in the viewfinder of a DSLR is > that much smaller than the image of a full frame.
Note that I'm comparing an MX (an early, minimal-automation camera) with the *ist-D. The later Pentax bodies, with more information to be shown in the viewfinder, dedicate less of the total area to the image - they have to leave room for electronic readouts for aperture, shutter speed, focus point selection, focus confirmation, over/under exposure, etc. The MX had minimal additional information; the shutter speed was superimposed on the image area, and the aperture was visible through a small window that let you see the aperture ring on the lens. The only extra information was the five coloured LEDs for exposure (an electronic form of the old match needle metering). By the time you get to the auto focus bodies, though, the magnification has been cut back to somewhere between 0.7x and 0.8x. For bodies such as the MZ-6 (aka the ZX-L) or MZ-7 (ZX-7) the total image area, at 90% coverage and 0.7x magnification, is only a little larger than the *ist-D (95% coverage and 95% magnification of a rectangle only 67% of full frame). -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
