Hello, i just got this used lightmeter from someone. I have a question about the aperture. It's currently on shutter priority mode right now, when i measure, theres a smaller number that shows up next to the aperture. the manual says its the 1/10 F Stop. But im a little confused, whats the point of that?
any help would be great. Thanks
They are there for accuracy, i.e., for picky people like me, who use fractions of f-stops.
For example, let's say I'm out shooting flowers on a roll of Ilford Delta 100 and so is my friend, Bob. Bob rates his Ilford Delta 100 normally, at E.I. 100. However, I prefer to rate mine at E.I. 160 which is 2/3 of a stop higher than E.I. 100 (or approximately 6/10 of a stop higher, which is the way the meter understands it).
With the L-358 set at ISO 100, Bob meters the light falling upon a flower, and the meter provides an incident reading of 1/125th @ F/5.6. But because I rate my film at E.I. 160, I could not use that reading because the meter is set for ISO/E.I. 100. Instead of using F/5.6, I would "close down" the aperture 2/3 of a stop to F/7.1.
If I move the meter's "ISO 1" dial from 100 to 160, the meter will read
"F/5.6 & (6/10)" (because we have added 6/10 of a stop to F/5.6) which is F/7.1.
Let's say that another friend, Carol, joins us. And let's say she rates her film at E.I. 125. In relationship, she rates her film 1/3 higher than Bob but 1/3 lower than me. If we set the meter's "ISO 1" dial to 125, the aperture reading will change to
"F/5.6 & (3/10)" which is F/6.3.
From memory, here are some approximate equivalents:
F-STOP = SEKONIC READING
F/2.0 = F/2.0
F/2.2 = F/2.0 & (3/10)
F/2.5 = F/2.0 & (6/10)
F/2.8 = F/2.8
F/3.2 = F/2.8 & (3/10)
F/3.5 = F/2.8 & (6/10)
F/4.0 = F/4.0
F/4.5 = F/4.0 & (3/10)
F/5.0 = F/4.0 & (6/10)
F/5.6 = F/5.6
F/6.3 = F/5.6 & (3/10)
F/7.1 = F/5.6 & (6/10)
F/8.0 = F/8.0
F/9.0 = F/8.0 & (3/10)
F/10.0 = F/8.0 & (6/10)
F/11.0 = F/11.0
F/13.0 = F/11.0 & (3/10)
F/14.0 = F/11.0 & (6/10)
F/16.0 = F/16.0
F/18.0 = F/16.0 & (3/10)
F/20.0 = F/16.0 & (6/10)
... and so on!