question about peak grain focusergreenspun.com : LUSENET : Large format photography : One Thread
I feel kind of dumb asking this..... My buddy just bought a new peak focuser for a photo class. He asked me what was the pourpose of the eyepiece being movable (you can adjust it by screwing it in or out) .. I did not know as it seems to me that having to focus the focuser by moving the eyepiece would not make sense...... Oh and if you do the eyepiece, how do you get back the correct focus...yes he moved it. ok so did I.
-- mike kwiatkowski (firstname.lastname@example.org), August 23, 2001
I believe its to accomodate your individual focussing distance. There should be a reticle (a hairline or a circle on the mirror). Move the focusser till your eye is able to comfortably bring the reticle into sharp focus. This way, your eye is not straining to bring something into focus. Its the same principle as a diopter correction. Cheers, DJ.
-- N Dhananjay (email@example.com), August 23, 2001.
Mike: "N" is correct. Focus the eyepiece on the recticle or hairline. That sets the focusing device up so that the aerial image of the grain is focused at the correct distance and the eyepiece is sharply focused. The movable eyepiece adjusts focus to the individual using it. If the grain making up the negative is in focus, the enlarger is in focus.
-- Doug Paramore (firstname.lastname@example.org), August 23, 2001.