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Metering with a Sekonic L-398A - what exposure compensation for an REX 4?

Jack Wormell

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Simple question (I think): I have a Bolex REX 4. I have a Sekonic L-398A light metre. I use the Cine numbers on the light metre for the reading. But I'm still unsure as to what exposure compensation I should be making from the light reading to the aperture on the camera. Half a stop open? A stop?

Thanks for any guidance


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Page 13 of the manual always works for me. 

"Real" speeds are how fast the shutter stops action

"Adapted" speeds are the ones you would use with your meter. 

Just use the "Adapted" speeds from the table; there is no other  'compensation' needed. 

Edited by Don H Marks
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Here's a copy of the original manual for a Rex 4:


There are a few ways you can meter.

Either use the "adapted" exposure times listed in the manual - ie 1/80 sec for 24fps. This takes into account both the 133 degree shutter angle and the 1/3 stop light loss to the viewfinder.

Or if using cine mode on a light meter (which assumes a 180 degree shutter) then you need to compensate an extra 2/3 of a stop (1/3 for the prism light loss and 1/3 for the difference between 180 and 133 degrees). The easiest method is to set your meter ISO at 2/3 stop slower, so for instance if using 100 ISO film you would set your meter to 64, or if using 250 ISO set your meter to 160 etc. 




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