[LargeFormat] Elgeet Update
Les Newcomer
largeformat@f32.net
Tue Mar 4 06:20:10 2003
On Tuesday, March 4, 2003, at 02:31 AM, Clive Warren wrote:
> Alan,
>
> Richard may have mentioned this earlier, but in1962 the Elgeet 'firm=20=
> acquired ownership of the ancient establishment of Steinheil in =
Munich'=20
> (from Kingslake).
> The only mention of large format lenses I can find is the Elgeet=20
> Anastigmat f4.5 250mm which is of course your lens. Be wary that the=20=
> circle of illumination is probably larger than the useful image =
circle.
>
> Cheers,
> Clive
>
>
Looking up Steinheil in my '39 ed of "Handbook of Photography" I find=20=
they made a 250mm f4.5 Unofocal lens. This was similar to the Celor and=20=
Aviar, and later the Artar. It has 4 symetrical air spaced elements =
with=20
an angle of view of 60=B0, and is the basis of most process lenses.
If we let a=3D the radius of the coverage angle, then 2a=3D 2[focal =
length x=20
Tan (half the angle of view)] will give us the circle of coverage. =
Thus
2a=3D2(10 x Tan 30=B0)
2a=3D 2 x 5.7735"
2a=3D11.54"