freaklikeme
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Lupin 3rd wrote:
I'm not an expert, so take this with caution. For what I know film reciprocity failure would be the main caveat. It applies to all emulsions once you go beyond 1-ish seconds.
I can't find the link to the blog where I read this, but this person tested Rollei Infrared 400 and found that the long exposure times were close to those of SFX 200.
For times in seconds if 'm' is the number of seconds your camera meters with the ND filter on then the number of seconds you need to expose 'e' is equal to m to the power of 'p'. For SFX (and apparently Rollei Infrared), 'p' is 1.43.
So if you meter:
4 sec -> expose 7.2 sec
8 sec -> expose 19.5 sec
15 sec -> expose 48 sec
30 sec -> expose 129.5 sec
60 sec -> expose 349 sec
Hope I make sense and this helps....Show more →
It does and good safety tip. I haven't hit a second or slower yet. I've shot a couple rolls of Rollei IR 400 with a Coklin 720 filter, but it's all been sunny day, so I think the closest I've come is 1/15. I haven't even metered with the filter on, since it appears to be very close if not right at its advertised six stops, which it makes the math easy. So I've had it easy so far (the Nikon 35-70/2.8's IR markings are spot on at 35 and 70, so even focusing has been a breeze). Now I want to take off the training wheels, so I appreciate any and all advice.
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