Schneider 47mm XL centre filter exposure correction?

[Ronan]

Hello Kind people of LFP! I am shooting a new project tomorrow with a 47mm xl on my ebony SV45TE. I have a centre filter IIIc 4x. Can you tell me how many stops to compensate using this with 160 Portra and im using a flash. THANK YOU!

[Michael R]

Schneider’s indication for the IIIc is 2 stops. Incidentally that’s what 4x means.

[Ronan]

Schneider’s indication for the IIIc is 2 stops. Incidentally that’s what 4x means.

THANK YOU!!!

So I rate 160 film at 50iso?

[Corran]

40, or perhaps 25-32 as many rate Portra more like 100-125 EI.

[Ronan]

40, or perhaps 25-32 as many rate Portra more like 100-125 EI.

Thanks! yes i usually rate it about 100!

gent!

[phdgent]

Here are some technical publications by Schneider:

SCHNEIDER CENTER FILTER DATABASE.pdf
SCHNEIDER CENTER FILTER PROGRAM.pdf

[Ronan]

40, or perhaps 25-32 as many rate Portra more like 100-125 EI.

just double checking, I did a test on my digital camera, 100iso it lowest it goes. I have to fire my flash 1200w twice to get the right exposure at F22. So if i want to expose at 25iso to compensate for my filter I pop the flash 8 times? Thank you

[Corran]

That should be correct. No reciprocity issues like film.

[Ronan]

That should be correct. No reciprocity issues like film.

Well i am shooting film but i dont think you get reciprocity with flash as I am filling it with short bursts of light?

Thanks all again, the stress shooting sheets that cost almost 20 euro each now!

[Kiwi7475]

Well i am shooting film but i dont think you get reciprocity with flash as I am filling it with short bursts of light?

Thanks all again, the stress shooting sheets that cost almost 20 euro each now!

Actually reciprocity failure happens both on long and on very short exposures. However modern films only exhibit issues on the short end when the exposure is below ~1/5000 second, most even less than that, so you should be fine with a flash unless you’re using really exotic, very high speed flashes.