[LargeFormat] RE: lens board

[Jim Brick]

Whether or not you can use rising front has nothing to do with a flat or 
recessed lens board. A recessed lens board simply allows the front standard 
to reside farther out on the focusing track. A recessed lens board is 
usually not needed with a 90mm lens on a Technika, but might make focusing 
a little easier. When I used a 90 on my Technika, I used it on a flat lens 
board. Getting your fingers into the recessed lens to change f/stop and 
shutter speeds are really difficult. Especially if you have normal or fat 
fingers. If your fingers are skinny, you'll be OK.

A 90mm Angulon will not give you the ability to use front movements unless 
you use the smallest apertures. The circle of coverage is too small until 
you get to f/22 or smaller. This is one of the reasons they made 90mm Super 
Angulon lenses. To give a large coverage circle so you would have room to 
use rising/falling front and right/left shift. The other reason is for edge 
sharpness. The Angulon is not very sharp at the edges of the coverage 
circle. So when you rise the front, you are using the edge of the lens 
circle. The Super Angulon, not only giving a larger coverage circle, but 
making it sharp as well.

If the tiny 90/6.8 Angulon was really good, they would have not made the 
very large (by comparison) 90/8 Super Angulon. Losing almost a stop of 
focusing light as well. There is a 90/5.6 SA though, which recovers that 
lost stop.

Don't get me wrong. My 90mm Angulon is a great lens for just straight, no 
movement, photography, at f/8 - f/22. Sharp and good contrast. Smaller than 
f/22, diffraction takes it's toll.

A regular 90mm Angulon is marginal for architecture. Unless your 90mm 
Angulon is different than mine.

My 2 cents worth of experience...

Jim


At 04:24 PM 5/18/2002 +0200, fmaturana@euskalnet.net wrote:

>My Schneider 90mm Angulon arrived and as Philip cleverly thought Technika
>III lens board had different size. A friend of mine, that BTW has more than
>14 Leicas and more the 300 different cameras including various Linhof,  have
>lent to me a Technika IV flat lens board and I can use new lens in my Linhof
>but my question right now is if  I cannot use rising front element movement,
>can I? Is it usefull for that the recessed lens board?. I asked this wide
>lens for a architectural project where correcting lines is very important so
>movement is most convenient. Any help will be welcome and duly acknowledged.
>Philip please if you have this recessed lens boar for a Technika IV with a
>35mm flange hole please be so kind to let me know in a private email. I'm
>forecasting to get a 65mm Schneider for same project with the focusing
>device and then it's clear for me that no movement is possible.
>
>Kind regards
>
>Felix