ISO Settings on Film and Camera

[SteveEllis]

Hi Guys,

I'm trying to understand all the effects of ISO and have a few questions.

1 - What happens if I set my cameras ISO speed to be different from the ISO speed of the film?

2 - My cameras ISO setting goes up to 6500, what would you use such sensitive film for?

Thanks
Steve.

 

[Rob]

1. Then the exposure will be under/over by as many ISO levels as you mis-set it for. Setting the camera to ISO 200 with ISO 100 film will underexpose it one stop (-1EV) which probably won't have too much effect on normal neg film. There's a good sticky at the top, but I've just noticed it doesn't seem to mention ISO!

2. Very low lighting conditions. Typically you can "push" or "pull" i.e. under or over expose using the above mentined method to a few stops, especially with films like Kodak T-Max 3200. Rating that at 6400 will still work and will possibly allow hand-holding in conditions where even the human eye cannot see properly (without flash). It's used a lot in gigs, museums etc. where flash is undesirable or not permitted. Generally the image is sooo grainy it's only good for arty shots.

Hope this helps, and hope I got #1 the right way around (I'm always getting confused!)

Rob

 

[SteveEllis]

So you never really want to set the ISO of the camera to be different from that of the film.

Thanks Rob, that clears some stuff up for me

 

[Rob]

Not really as some cameras have a +/- EV dial which does the same thing for when you may want to disagree with the internal automatic modes and with others you adjust the aperture or speed (in opposite directions) to cause the same effect.

There won't be a film person here with a manual ISO setting who hasn't at some point stuck a roll of 100 through as 400 or vice versa. I have several times and always got away with it, with the notable exception of Velvia which doesn't take that kind of treatment!

Rob

 

[SteveEllis]

What is +/- EV?
Is there any particular reason you would want to override the film ISO with the Cameras ISO setting?

Also, what is Velvia?

 

[Hertz van Rental]

EV stands for Exposure Value and is a way of measuring exposure.
When you adjust EV you are basically adjusting the exposure your camera meter is giving you.
For example:
At ISO100 you could get an exposure reading of 1/60th @ f4 which corresponds to EV10 for that ISO. Changing the EV is just another way of over or under exposing.
So at 1/60th @ f4, +1/2EV would underexpose the scene by 1/2 stop.

And you will find out about Velvia from here
http://www.fujifilm.com/JSP/fuji/ep...p;jsessionid=258E9FAFB8BF0712751BFD7E7620D28E

 

[myopia]

with the notable exception of Velvia which doesn't take that kind of treatment!

meanwhile, the Fuji website advertises Velvia as having "Excellent Push/Pull Characteristics"
:er:

 

[JonK]

You can push film if you want to accentuate grain and contrast in your images. Just make sure you tell the processors you pushed 200 to 400 or whatever the case may be.
If they say a film has excellent push/pull characteristics they usually mean that the differences will be negligible.

Velvia is Fuji slide film that gives highly saturated images, can be quite contrasty I think. . Rated at ISO 50 I believe. Lots of pros rate it at ISO 40.

 

[Danc]

EV stands for Exposure Value and is a way of measuring exposure.
When you adjust EV you are basically adjusting the exposure your camera meter is giving you.
For example:
At ISO100 you could get an exposure reading of 1/60th @ f4 which corresponds to EV10 for that ISO. Changing the EV is just another way of over or under exposing.
So at 1/60th @ f4, +1/2EV would underexpose the scene by 1/2 stop.

And you will find out about Velvia from here
http://www.fujifilm.com/JSP/fuji/epartners/proPhotoProductVelvia.jsp;jsessionid=258E9FAFB8BF0712751BFD7E7620D28E

Are you sure +1/2EV would underexpose the scene by 1/2 stop? I thought is OVERexpose?? Seem confusing enough.

 

[Hertz van Rental]

Are you sure +1/2EV would underexpose the scene by 1/2 stop? I thought is OVERexpose?? Seem confusing enough.

Yes. You're right. My bad.
-1/2EV would overexpose - +1/2EV would be under.
I was tired... I hit the wrong key... I don't use EV very often... I'm getting old and forgetful...
Pick an excuse

 

[Marctwo]

You did it again Hertz. Concentrate. :hertz:

You're right, Danc. -EV will underexpose, +EV wil overexpose.

 

[SteveEllis]

Cheers guys, that all helps a lot, still a little out of my depth but getting there