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B4 lens Iris calibration?

PostPosted: Fri Feb 15, 2019 1:33 pm
by Kim Janson
We have plenty of used B4 lenses with analogue control. viewtopic.php?f=2&t=86117

We will test that the Zoom and Iris works smoothly and have build a simple test system for that, to step the f-stops and make a smooth run trough the hole scale.



Testing the different lenses we have, it is clear that Iris acts very differently on them, corresponding differently to the input voltage levels. We could offer also Iris calibration, but what are the voltage levels that correspond to certain f-stop?

There is 3 easy to access potentiometers. It seems to adjust f-stop min and max, and the speed Iris follows on Auto mode.

IMG_3774.jpg
IMG_3774.jpg (82.53 KiB) Viewed 479 times


Could someone help on this, or how fo you normally calibrate the Iris on such lens? With the camera?

Re: B4 lens Iris calibration?

PostPosted: Mon Feb 18, 2019 8:25 am
by Kim Janson
Anyone? I just would need the voltage levels that correspond to f-stops:

f1.7 = x.xx V
f2.8 = x.xx V
f4 = x.xx V
f5.6 = x.xx V
f8 = x.xx V
f11 = x.xx V
f16 = x.xx V

Can not get it from the lenses as they seems to be all a bit different voltage levels and do not have camera that would have this connection. Anyway would be nice to find some official document, maintenance manual etc. providing this information. I guess it must be somehow standardised? or do the lenses always need to be tuned for the camera?

Re: B4 lens Iris calibration?

PostPosted: Mon Feb 18, 2019 1:18 pm
by Robert Betzner
This is what I found in the manual from our Panasonic HPX3100 (see attachment).


Cheers

Robert

Re: B4 lens Iris calibration?

PostPosted: Mon Feb 18, 2019 2:40 pm
by Kim Janson
Thanks Robert.