Frank,
You're a perfect example of what I meant when I referred to the old days of two formats (mainly) with very little overlap (with due deference to all those on this list who use 35mm and MF and Speed Graphics, and perhaps now digital).
You only ever use 35mm, so focal length works fine for you.
But spare a thought for those poor saps who use several different formats, and are weighing up the pros and cons of buying a small P&S and have absolutely no idea (because the manufacturers won't help them) whether a 50mm lens on an Optio S4 is the same as a 50mm lens on a Canon G5 or an Olympus 4/3 or whatever it's called.
Bill Robb and Rob Studdert probably have focal length equivalents burned on their brains, but with older brains it's too late.
What is needed is for manufacturers to state an AOV for the lens(es) that is/are used on their particular camera model.
Welcome back, by the way.
John
On Fri, 13 Aug 2004 18:31:52 -0400 (EDT), frank theriault <[EMAIL PROTECTED]> wrote:
--- John Forbes <[EMAIL PROTECTED]> wrote:Very few people (some on this list excepted) actually know what a "focal length" is, and frankly, it's supremely unimportant. What IS important is angle of view.
When 99% of all the pictures in the world were taken with either a 35mm camera or a 6X6, and never the twain met (most of the time), the focal length was a good substitute for what was actually needed, which was a measurement of the angle of view.
With the advent of digital cameras, with their multiplicity of sensor sizes, we have to grapple with the problem of working out what angle of view will be given by a particular lens on a particular camera.
Why don't we just cut the crap, consign focal length to the dustbin of history, and just talk about AOV? At least it will avoid any more pointless threads about focal lengths being the same whatever camera the lens is used on. Whilst this may be true, it misses the point totally.
That's a very well reasoned and lucid argument, John.
However, I disagree. <vbg>
I don't know what focal length is, to be honest with you. I've seen some lengthy discussions here, with some folks that I respect disagreeing with each other as to exactly what it is. I don't care what the theory behind it is. Just like I don't care what the exact dimensions of a frame of 35mm film are.
I care that somewhere around 50 or 55mm is a "normal" focal length for 35mm, bigger numbers are like a telescope, and smaller numbers you can see a lot of stuff in the frame.
Okay, I'm being silly, but I know what to expect when I throw a lens of whichever focal length on one of my cameras. Does there need to be more?
Throwing another number at me will just make my brain hurt more than it does already.
I guess the real problem with AOV, is that it changes if you're switching a lens or lenses between 35mm film and APS size sensor slr's. Or, for that matter, between different sized sensor slr's, once they come out with a full size sensor. How will AOV be dealt with then? Will we have lenses labelled with the multiple AOV's for the various formats it might fit onto?
Focal length is simple to understand in terms of how the numbers translate into what to expect for the AOV. I'd say, just leave things as they are. Anyone who doesn't know what to expect either has a camera with a non-interchangeable lens, or has an SLR that they bought in a kit, and has no intention of ever taking that plastic consumer grade zoom of the camera anyway.
I don't mean to dismiss your idea out of hand, John. I mean, it's good to ponder such things once in a while, perhaps between sips at the pub... <vbg>
cheers, frank
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