Exposure with a Pan Cinor f 3.4, 25 to 100 mm Zoom
Posted 21 October 2006 - 07:31 PM
My question was:
The recent discusion on the pan Cinor lenes spurred me to buy one myself:
It arrived Oct 12, and the focus is more than a bit rough, in fact I think the ring is not engaged, but assuming I can get over that little bump, I am wondering what happens with exposure on these guys.
The lens front says it is a "Pan CINOR 1:3.4 F=25 a 100" (a four to one zoom) the diaphram is labeled 2.4, 2.8, 4, 5.6,8,11,16,22 - So I am guessing that the 3.4 is the "effective" f-stop?
Looking from the back of the lens their is a small black dot in the center, if you remove the back section which rotates to let the c-mount turn there seems to be some prisims on each side of the diaphram, which I assume is where the light is syphoned off for the finder? So should there be an allowance for the lost light, juts like you would need for a bolex.
The dogleg finder did show an image, so I am at least partway to geting my 60 bucks us worth out of it.
Posted 21 October 2006 - 08:12 PM
I don't know for sure, but I agree with you that the effective f-stop is 3.4 when set at 2.4. As you know, this is a one stop difference, which seems to account for the light loss for the finder and reflections(transmission).
Posted 21 October 2006 - 08:18 PM
Edited by Herb Montes, 21 October 2006 - 08:18 PM.