And still it is true that a 35mm on an APS sized sensor is not a 50mm but the same 35mm with a too narrow lens shade on. All this is very true - no need to proove it again - but it is of not much help to anybody. It is the field of view that is of primary interest to most people when chosing a lens. "What frame do I get?" is the question that is asked. And the correct answer (in the case of an APS sized sensor) is "You will get what you expect from a 50mm lens on a 35mm film camera". As it is a fact that we usually 'think' in focal lengths (and not in format/FOV values) the '35mm equivalent' can serve wonderfully as a rule of thumb with all the various sensor sizes. I don't see any other way and the industry has more or less agreed on this. I also have a small digital P&S and I don't even KNOW the exact focal length off hand, but it yields frames at around a 35-70mm equivalent...
If we want to be of any help to people asking, then we should point out WHAT differences there are (in real world terms) that make the 35 on the *ist D act differently from a 50 on the ME Super. As for Depth of field it would be worth pointing out that you loose about one stop compared to what is printed on the lens (engraved ... on some lenses). Or, in other words, you get one stop wider DOF compared to using a 50mm on a ME super. But that's about all, isn't it? Sven -----Ursprungliche Nachricht----- Von: Stan Halpin [mailto:[EMAIL PROTECTED] Gesendet: Donnerstag, 25. Dezember 2003 06:25 An: [EMAIL PROTECTED] Betreff: Re: Coming to terms with *ist D lens mag factor? on 12/24/03 9:18 AM, graywolf at [EMAIL PROTECTED] wrote: > Hum? I figure that 127 is the equivalent of a 31mm on 135 camera. And the 105 > is > the equivalent of a 46mm. I have always found it strange that people do this > stuff, because one works differently in different formats, one tends to use > much > closer points of view with a large format camera and thus shorter relative > focal > length lenses. Furthermore prior to the 70's when there was a 35mm explosion > and > it became the norm no one hardly thought in those terms. As Shel says it seems > to be a dumbing down factor (I am ignorant of anything but 35mm make it > understandable to me without my having to think)... Has anyone here ever had to learn a new language? You can do it two ways (to simplify the analogy); full immersion within a setting where nobody speaks your current language(s), or, a setting where you learn the new vocabulary and rules of grammer by reference to your current language(s). Dumbness nor smartness have anything to do with it, they are both perfectly good approaches to learning languages. The second approach is better for most people most of the time, though it depends on how thoroughly you need to become fluently how soon. Anyone here ever try to switch from one camera format to another? Same deal. You can go total immersion with no reference to what you know or you can work from what you know already. The latter approach will work best for most people most of the time. I am pleased that manufacturers are recognizing this point, they too seldom ignore the way real people learn new things. In other words, Shel is wrong, as is Cotty and graywolf, when asserting that there is something "wrong" about saying a 20mm is "like a 35mm 30mm lens" or saying that a 75mm 645 lens is "like a 35mm 50mm lens." Using a common point of reference which the vast majority of photographers know does no harm to any but those with feet problem or other problems that I won't go into on Christmas Eve... Happy holidays! A fresh snowfall here in central Michigan today, a beautiful cardinal obligingly posing in a nearby bush, my 300mm lens giving me the FOV of a 450mm when taking a picture of said cardinal with my ist-D, all is good in the world. Stan
