aperture scale

claudius · May 6, 2014

hi, i need a scale for my Compound shutter fitted with a Symmar 300 mm f5,6 ( 500mm f12)
anyone that has one and are are willing to screw it off and send me a scan or photo copy ??
or even better has one original in surplus ??
klaus
denmark

ps how on earth do you place an add in Wanted and for Sale list ?

MattKing · May 6, 2014

You need to be a paid subscriber to place ads in the Wanted or For Sale sections.

I'm sure that no one will mind this thread though.

Good luck!

AgX · May 6, 2014

Only subscribers can start a thread in the classifieds section. As member you can post in such threads though.

Sirius Glass · May 6, 2014

I sent my lens off the SK Grimes and he produced a custom scale for me. Worth everything I paid for it!

claudius · May 7, 2014

thanks everybody.
one problem solved, i am now subscribing, thank you for the advice.

next is the aperture scale.
i know to send shutter/lens into repair, that costs 50 dollars. the problem is postage forth and back, that will run up to additional 50 bucks.
hence my looking for a copy to transfer onto the empty scale.

klaus
denmark

Jim Jones · May 7, 2014

If you will be satisfied with an aperture scale that is much more functional than elegant, you can make one. The f/number is the focal length of the lens divided by the apparent diameter of the lens as viewed from the front of the lens. Allow for parallax when viewing that diameter. The numbers can be written on white tape placed over the original scale, and perhaps protected by clear tape.

removed account4 · May 7, 2014

hi klaus

i have had a 210-370 with 1 aperture scale
i was told by the friend that sold it to me
that 5.6 was 12 and everything else was about 2.25 slower
5.6=12, 8=16.25ish, 11=22.25ish, 22=32.25ish ( roughly )
here's a scale i found years later for the 210/370

yours is a plasmat convertible like mine so the apertures are probably similar
you can do the measurements and math as jim suggests, that's usually the best way to verify...

you probably know this already, but you remove the front cell to convert it, but if you remove the rear cell instead
its not the same FL so your aperture scale will be off. ( and converted it will take a big bit more than the labeled FL to focus at infinity )

nice lens!

john

binglebugbob · May 8, 2014

OK, you're looking at the front of the lens. Say that the aperture blades form a hexagon....so how do you figure the "apparent aperture"?

If the blades formed a perfect circle, it'd be easy to determine the diameter. But that isn't often the case.

Do you split the difference and average the opening formed by the hexagon?
bob.

Steve Goldstein · May 8, 2014

Bob, I just mentally imagine a "best" circle that coincides with the blade edges. In some areas the blade edges will be inside the circle, in some areas outside it, but on average it's close enough. Remember, 1/3 of a stop is 25%.

To Klaus' original question, I emailed a photo of the requested scale to him this morning.

claudius · May 9, 2014

hi steve,
thank you very much for the photos, great help.
thank all of you for your nice answers, i play safe and use steves photo to make a paper scale to stick on.
that is of course if noone has a spare scale for me to buy?
klaus

aperture scale

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