Sinar fresnel lens question?

[Dave Dawson]

Hi All, Please excuse this what might seem to some a very basic question but all the LF cameras I have used in the past have had their fresnel lens inside the camera with the grooves in contact with the ground surface of the focusing screen. However it appears that with the Sinar F,C,P range the fresnel fits on the outside of the camera behind the gg screen.

My question is....Doesn't that give TWO focusing points?:confused:

Please put me out of my misery gently

Cheers Dave in London

 

[Ian Grant]

No, the focus is always on the ground glass, the fresnel is only altering the direction of the light in these screens not offering magnification. It does matter which way the particular back is designed to take the fresnel as that can afect focus if you place the combination the wrong way around.

Ian

 

[Dave Dawson]

Ahhhhh, So the concentric rings of the fresnel are in contact with the smooth side of the gg screen...Correct ?

 

[archphoto]

Yes, that should be right.
I have had it this way for 20 years on my Sinar P2.
Having it the other way around would mean that you damage the fresnel when focussing with a magnifier.

Peter

 

[Dave Dawson]

Now I understand....Thanks Ian and Peter........Job done.

Cheers Dave