Re: Weird finding about 14in Kodak Commercial Ektar~
Quote:
Originally Posted by
Jim Graves
Kevin ... if you're asking about the 14" CE in the Ilex No. 5 Universal ... my aperture measures at 52mm when set @ f-6.3 ... as does OP's ... but it opens to 57mm when moved beyond the f-6.3 setting to the end of it's range.
Interesting thing is ... if you divide 14" by 57mm you get 6.3 ?!?!?! But, of course, optics are not that simple ... with nodal points, etc., etc., etc. More thinking than I want to do ... I just put the pointer on 6.3, set the meter for 6.3, and forget about the caliper measurements. I'm just going to assume they knew what they were doing when they made the lens. As for OP's friend and his barrel lens ... I have no idea what happened.
Try this, measure with your calipers the iris opening with the glass on, then off. You will have different measurements.
Re: Weird finding about 14in Kodak Commercial Ektar~
From the front or the back?
Re: Weird finding about 14in Kodak Commercial Ektar~
I took off the rear groups to measure the actual size.
Re: Weird finding about 14in Kodak Commercial Ektar~
Measured from front and back with the lenses in ... with the aperture set at f-6.3 ... measures out at 52mm on both ... exactly the same measurements as with the glass removed.
Am I missing something??
Re: Weird finding about 14in Kodak Commercial Ektar~
I suggest everyone read about the Entrance Pupil. "The entrance pupil is the image of the aperture stop formed by all optical elements anterior to the stop."
There is a good diagram here, Fig 67: http://www.oculist.net/downaton502/p...1c030.html#ape
Re: Weird finding about 14in Kodak Commercial Ektar~