In the epistle "Re: Mard Gras (Larry B)" scribed 04-12-98 14:36,
Hap Newsom did thus proclaim to Larry Bolch:
Hap 
HN> LB>HN> I thought a 127 or 135mm lens was normal for 4X5. Are you sure on
HN> the LB>HN> 210mm? I've been told that is a short tele for 4X5.
HN> 
HN> LB>A 127mm - 135mm would be the rough equivalent to a 35mm lens on a
HN> LB>35mm camera - wide normal. A 210 would be a slightly long normal
HN> LB>like a 55mm lens on a 35mm camera. The actual normal lens would
HN> LB>be about 160mm or about 6.4".
HN> 
HN> LB>A 43mm lens is actually the mathematical "normal" focal length on
HN> LB>a 35. If I remember correctly, going to 50mm lenses made it cheaper
HN> 
HN> Arrrrgh! I'm not getting the answers I wanna get ! my guesses are all
HN> coming up wrong!
As a rough estimate of equivalent focal lengths, divide the focal
length of a 4x5 lens by 3.8 to get the equivalent for a 35mm camera.
Thus a 135 on a 4x5 (135/3.8=35.526315) is about the equivalent of
a 35mm wide angle. 
For:
645 use 1.75. 
2-1/4 Sq. use a factor of 2,
6x7 use 2.1 - 2.2,
6x9 use 2.5
5x7 use 5
and 8x10 use 7.6.
Of course round-off to the nearest focal length that is
actually in existence. Focal lengths tend to vary from
lens to lens, and batch to batch so there is no point in
being more precise. Also while a 35mm shooter may have a
dozen or more lenses, large format shooters may get along
fine with two or three. An 8x10 negative does not crumble
into indistinct globs of grain if cropped somewhat! Even
with fine contemporary films, it is well to compose to fill
the frame as much as possible with 35mm.
HN> LB>... I'm too sexy for my Nikon, too sexy for my Linhof...
HN> 
HN> Well I'm not, so send 'em down to me...and the widelux, and the hassy
HN>   too while you're at it!
Sorry, never had a Hasselflex. The only 2-1/4 sq. at the 
moment is a classic Zeiss SuperIkonta BX and I think I have
a square back someplace for a 6x9 Graphic. Neither could be
confused with Uncle Victor's fancy box camera.
larry!
... We don't believe in miracles here,
    but we do rely on them.
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