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Saturday, March 11, 2006

Make that mm-e

I've made a small emendation to my earlier suggestion about digital terminology, based on a number of conversations. Several people have come up with the same idea, and I think it's a good one. It's that "mme" is too close visually to "mm" and should instead be written "mm-e." Spelled out, it would of course be mm-equivalent.

Also, I'd like to jettison my own suggestion of an approximate version (using a tilde). I agree with those who've said that approximation is assumed.

For those who have objected to the idea for various reasons: I'm not trying to create a new standard. I'm just proposing a shorthand way of saying, "...which would be equivalent to an XXmm lens in 35mm," which photo-writers already do all the time—heck, there are even digicams that have zoom rings marked with these equivalents rather than actual focal lengths. And what, after all, is a "magnification factor" or "field of view crop"? It's just a way of translating digital camera lens field angles into equivalent 35mm focal lengths!



Anonymous Josiah Davidson said...

Field of view is more universally applicable and appropriate. “35mm equivalent” will eventually become more abstract as its frame of reference becomes obsolete.
But the main point is to pick something that works, go with it, and never look back. Then it will establish its own relevance. Let's not repeat the mistake we made in this country with our feeble attempt to convert to metric. Learn to think in the new standard. Don’t be always making conversions to the old.
Just do it.
Everybody uses it.
Thanks Mike.

11:22 AM  
Anonymous Anonymous said...

Why create a new unit of measurement "mm-e"? The focal length of a film lens is only that and nothing more, it's not a measurement of image zoom. People just got used to what a "210" mm lens would provide, and attached a new meaning to the numbers that's only valid on some cameras.
So lenses on cameras with sensors other than 35mm should still be measured in their true focal length.
But some new scale for field of view would actually be more useful.

12:08 PM  
Anonymous Anonymous said...

What about all of us who have learnt photography pretty much from the start with a 1.6 or 1.5 sensor, and know what each focal length means perfectly well in terms of our own cameras? ;)

5:03 PM  
Anonymous Anonymous said...

Mike, the whole idea of referring to lenses by their focal length is a bit silly (and more so when you start referring to them in "fake milimeters"). Why not just use angle of covereage (say at the diagonal)? The specific focal length will change with format but the angle is what we really want to know when we seek these "equivalents".

7:51 PM  
Anonymous Anonymous said...

I wonder why lens aren't just marked with their field of view in degrees since what we want to know is the coverage of the scene. This would work for all lenses and formats

1:51 AM  

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