Exposure with a Pan Cinor f 3.4, 25 to 100 mm Zoom

[Charles MacDonald]

I accidenly posted this question in the wrong forum before and don't know how to delete it there. http://www.cinematography.com/forum2004/in...showtopic=17828

 

My question was:

 

The recent discusion on the pan Cinor lenes spurred me to buy one myself:

 

http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewIt...em=250029075558

 

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. :blink:

 

any advice?

[Mike Rizos]

Hi Charles

 

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).

[Herb Montes]

The focusing ring on my Pan Cinor came loose once. I simply used a jeweler screwdriver to tighten the very tiny screws on the ring.

Edited October 22, 2006 by Herb Montes