Exposure Adjusting

[oriecat]

I know I should know this, or how to figure it out, but its one of the areas where I get all confused...

Say I'm bulk loading film... I buy a roll of 1600 ISO. Now the canisters I have have the code for 400, or if I used a non-coded canister, then my Nikon defaults to 100. I don't want to pull the film, so how can I adjust the exposure so that it is actually exposed properly at 1600?

 

[mrsid99]

Now let's see....if it's 1600 film in 400 cans then we'll need four of them...but if the camera is defaulting to 100 then maybe it should be 16?
But it could be only four again if it's 100 in 400 cans but then again.....?

 

[voodoocat]

400 is 2 stops, 100 is another 2 stops, so 4 in all.

 

[ksmattfish]

If you have ISO 1600 film and you want to shoot it at 1600:

camera set to ISO 400: under expose by 2 stops

camera set to ISO 100: under expose by 4 stops

 

[oriecat]

Thanks guys!!

 

[Jeff Canes]

No way to set the ISO manually:?:

 

[oriecat]

Nope. It reads the code or it defaults to 100...

 

[havoc]

Lame ass Nikon's My sheep are trained to stampede any Nikon camera's they come in contact with..... Now if only i can train them to leave the owner alone....

 

[zio]

i was playing with my canon today and i can change the ISO if i want...so what does that do?

 

[voodoocat]

It's so the meter in the camera knows how to expose the film propely. If you want to change how the film is rated. Say you are shooting with Velvia rated at ISO50. Most people like to overexpose by a 1/3 of a stop and shoot at ISO40. You would then manually set this on the camera.

The cheaper SLR's leave that option off for some stupid reason. I don't know about Canon, but with Nikon you cannot change it manually unless it is an N90 and higher.

 

[Josh]

to keep from getting confused, f-stops go by dubbling and film speeds tend to fallow.


50, 100, 200, 400, 800, 1600, 3200

count the stops and shoot like mad baby!

 

[ksmattfish]

Shutter speeds and film speed go by doubling or halfing for each stop, but there is a different pattern for f/stops:

1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32, 45, 64....

Each of the f/stops above are 1 stop, but notice every other one is doubled.

 

[Josh]

You are thinking of your appature setting (witch is not the same thing as an f-stop). And yes they doubble too. They double the amount of light let through (or cut in half dippending on witch way youre going)

An f-stop is not a setting at all but a measurement of light. One f-stop is twice the amount of light as the previous stop. And all three things that we us to control the exposure work in f-stops (film speed, shutter speed, and appature settings). That is why most ppl call the appature an f-stop, because it is designed to cut out half the light or doubble it.

You can stop down or up with any of the three methods:

f-8.0 to f-11.0= one f-stop
1/125 sc to 1/60 sc= one f-stop
200 asa to 400 asa= one stop

Or you can switch them up =):

f-11 to f-8 and a half, and 1/125 sc to 1/90 sc = one f-stop

 

[ksmattfish]

Shutter speed and film speed are never refered to as f/1/125th or f/iso 100 as far as I've ever seen, while aperture is regularly refered to as f/2, f/8, f/64 etc....

Ansel Adams considers f/stop to refer to aperture, and that's good enough for me. If you look up "f/stop" in the index of "The Camera", it says "see aperture". In the section on shutter speed he consistantly refers to aperture as f/stops and never refers to shutter speed as f/stop. I was taught in school that f/stop specifically refers to aperture, and differences in shutter speeds and film speed were always described by the term "stop" (with no f/).

 

[motcon]

Shutter speed and film speed are never refered to as f/1/125th or f/iso 100 as far as I've ever seen, while aperture is regularly refered to as f/2, f/8, f/64 etc....

correcto. 'f' refers to focal length. it's a function of the inverse square law of light. for practical purposes, just remember the 'stops'.