Hello Stanley!
SS>Hi Hap,
SS>You wrote in a message to Matthew Kiwala:
SS> HN> I thought a 127 or 135mm lens was normal for 4X5. Are you sure on
SS> HN> the 210mm? I've been told that is a short tele for 4X5.
SS> HN> chat with you soon!
SS> HN> hap
SS>Well going by the formula Ed put on here recently that
SS>standard focal lenght is equal to the digonal I get 162mm
SS>but as I have not seen a lens of that size I would guess
SS>the 135mm or 200mm would be the nearest.
I'm set then as I have a 165mm lens 
SS>4" * 25.4 = 101.6mm
SS>5" * 25.4 = 127mm
SS>Square root of ( 101^2 * 127^2 ) = 162.64mm
SS>Standard angle of view = 53deg =360/PI*ATAN(0.5*Diag / Focal Length)
SS>The reverse of this formula (Diag/2)/TAN(Radian(Angle/2))
SS>                                          ^Only needed if you use 
Spreadshee
SS>Will give you the focal lenght for any given angle of view
SS>eg 50deg Standard, 25deg Slight telephoto (100mm on 36mm
SS>film) Wide angle 90deg (around 22mm)
SS>Regards,
SS>Stan
AAAAAAARrrrrrrrggggggggggggggghhhhh! Now I remember why I hated
calculus!
chat with you soon!
hap
 * SLMR 2.1a * DOS: Tells a computer what to do with itself!
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