EXPOSURE CALULATION

Doyle Thomas

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Oct 28, 2006

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VANCOUVER, W

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• Apr 14, 2007

• #1

Assume an aperture of f/166 and an ISO 100 then

f/128 at 64 is the same (2/3 stop)
f/90 at 120 is the same
f/64 at 250 is the same
f/32 at 500 is the same

So if I set the meter at ISO 500 take a reading and set the stop at 32
it should tell me exposure time - reciprocity at f/166?

 

tpersin

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• Apr 14, 2007

• #2

i believe the simplest way is to set your meter for f16 and iso 100, multiply the resulting exposure value by 100, and then adjust for reciprocity...

good luck!

-tom

 

Last edited by a moderator: Apr 14, 2007

OP

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Doyle Thomas

Member

Joined

Oct 28, 2006

Messages

276

Location

VANCOUVER, W

Format

8x10 Format

• Apr 16, 2007

• #3

Assume an aperture of f/166 and an ISO 100 then

f/128 at 64 is the same (2/3 stop)
f/90 at 120 is the same
f/64 at 250 is the same
f/32 at 500 is the same

So if I set the meter at ISO 500 take a reading and set the stop at 32
it should tell me exposure time - reciprocity at f/166?

ok, now I have my Mind right. its:

Assume an aperture of f/166 and an ISO 100 then

f/128 at 64 is the same (2/3 stop)
f/90 at 32 is the same
f/64 at 16 is the same
f/32 at 8 is the same

So if I set the meter at ISO 8 take a reading and set the stop at 32
it should tell me exposure time - reciprocity at f/166.

 

Jim Noel

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Mar 6, 2005

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• Apr 20, 2007

• #4

If the camera uses 35mm, 120 or 5x4 film, use Fuji Acros and forget about reciprocity calculations. That is the only film I use in pinholes of these sizes.

 

Helen B

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Jul 1, 2004

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Hell's Kitch

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• Apr 20, 2007

• #5

You missed out f/45:

f/128 at 64 is the same (2/3 stop)
f/90 at 32 is the same
f/64 at 16 is the same
f/45 at 8 is the same


Best,
Helen

 

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Doyle Thomas

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Joined

Oct 28, 2006

Messages

276

Location

VANCOUVER, W

Format

8x10 Format

• Apr 21, 2007

• #6

Thanks!

Assume an aperture of f/166 and an ISO 100 then

f/128 at 64 is the same (2/3 stop)
f/90 at 32 is the same
f/64 at 16 is the same
f/45 at 8 is the same
f/32 at 4 is the same

So if I set the meter at ISO 4 take a reading and set the stop at 32
it should tell me exposure time - reciprocity at f/166.

 

tpersin

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Pittsburgh,

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• Apr 23, 2007

• #7

or, another way, would be to set your meter for f16 and iso 100, multiply the resulting exposure value by 100, and then adjust for reciprocity...