graywolf wrote: >He asked about which lens would match his other eye when he looked through the viewfinder. That is different than a normal 50mm (normal on 135 cameras because that is what the Leica came with), and normal rule-of-thumb ( = diagonal of the negative ) 43mm on 135. So, yes it is confusing.
>Compared to a 50mm on 135 film it would be about 33mm. >Compaired to rule-of-thumb it would be about 29mm. >But to give a life size image in the viewfinder he would need about 82mm. >Does that make it any clearer? Okay, ignoring some input that did somehat confuse me, I think get this now. (I did need to think about it more.) For the *istD to emulate the field of view (hope that is the correct term) that a 50mm lens has on a film camera -- because the center of the image is essentially cropped by the APS sensor and "magnified" -- it would have to use a 33mm lens. In other words, a 33mm on the *istD would give the same field of view as a 50mm on a film camera (approx). Not sure about the rule of thumb thing, but for mathematical figuring, I guess you mean, it is 29mm. But for him to look through the view finder and have the image match his other eye, the lens would actually have to be 82mm. This is because with a DSLR, the APS sensor crops the center of the image. So on a DSLR the *normal vision* lens is a 82, where on a film camera the *normal vision* lens is a 50mm. In other words, because of the cropping, what is the normal vision lens on a film camera, a 50mm, would 82mm on a DSLR. But to emulate what we are used to as the normal vision lens on a film, camera, the 50mm, the lens would be 33mm. In other other words, the normal vision lens for a DSLR is actually not the same as on a film camera. Not sure I put that the clearest way I could. It was very hard figuring out how to word those sentences. :-) But do I have it now? Marnie aka Doe
