[LargeFormat] 14" Dagor Coverage?

[Les Newcomer]

Some more non-emprical data.

Kingslake says the angle of view on a Dagor is 70°

Imagine a triangle with the lens at the top corner, the bottom side
being the ground glass, the sides being the sides of the image circle.

The distance from the lens to the ground glass is 14"  If we draw a
perpendular line bisecting both the top angle and the ground glass we've
got the makings of your typical High School nightmare--Trig.

We know the top angle(A) is 35° side b is 14" we want side a

a=(b•TanA)
a= (14•.7002)
a=9.8028"

But that's only half the ground glass so double it to 19.6056"

again this may increase as you stop down, but it'll be tight.

les

(This actually works out to 1.4 times its focal length)
 

Clive Warren wrote:
> 
> Just back after another weekend away - left most of my gear at home as it
> was pouring with rain and forecast for the same all weekend.  As you may
> expect there was a morning of great clouds and some blue sky - should have
> just popped the gear in the boot of the car...... typical of English
> weather and I should have known better.
> 
> The list was very quiet again over the weekend so the little palm top
> wasn't really needed.... Anyway, thought I would break the silence and pass
> on a request for info. from someone in the f32 Forum - does anyone know the
> coverage of a 14" Dagor f7.7 and its performance?
> 
> The poster seemed to think that it may cover 16 x20.
> 
> Cheers,
>             Clive
> 
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