ISO 400 with ISO 50 film?


TPF Noob!
May 23, 2006
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OK, so i splashed out and got myself some B&W film. One of the films has is 50 ISO. Does that mean that the film can only be used at 50 ISO or what? Thanks
I wouldn't recommend pushing iso 50 film. it's fine grain film, that's what it's for. if you want ISO 400 film why not get ISO 400 film? you can push ISO 100 film to 400, but pushing ISO 50 film seems silly...
Yeah, but what happens if you are in a situation when you have to?

What i mean is if you buy 36 exposures, you cant be sure that for the whole time you are taking pics you will need ISO 50.
Good point... but you can't change horses mid stream. Once it's been used at 50 it has to stay that way. And I agree 50 ISO film does not push process well.

You're better off having specific films for specific purposes and if you want to change then rewind the film carefully after making a note of what exposure it was on and loading the desired film. When you're finsihed with that one unload as before and reload the previous one and wind on a couple past where it was before. You do that with leaving the lens cap on setting the camera to manual exposure and manual focus and click away.

There you go ...clear as mud.

It's a very bad idea to take different parts of a roll at different ISOs. You'll end up with part of the roll exposed properly and part of the roll either overexposed or underexposed. And with a 3-stop difference like the that between 50 and 400, the improperly-exposed part will produce pretty disappointing results. It is possible to push a whole roll of film from 50 to 400; that is, you expose the film as if it were 400 film and then develop it for longer than normal so that the final negative is of proper density. However, this does come at the cost of quality (you'll have larger grain and higher contrast, for example). Like Daniel said, pushing from 50 to 400 isn't recommended. If I had a partly-exposed roll of ISO 50 film in my camera and ended up in a situation where I absolutely had to expose at 400, I would rewind the roll of film and put a roll of 400 in (if you remember what frame you were at, you can always put the film back in your camera and expose the rest of the roll at a later date).

edit: looks like poppicker hit the submit button while I was still writing my post ;)
i hate it when that happens.

Yeah, ok, so if i rewind the roll of film all the way back to exposure 1 i can take it out without risk of damage?
no, if you rewind it back to exposure 1 you'll risk damaging exposure 1 (and perhaps 2 and 3 as well). What you want to do is rewind it so that the film leader is sticking out (as it was when you first bought the roll of film), rather than rewinding the film all the way into the canister. If you have a manual-wind camera, you can do this by feel (you can feel when the film breaks free of the right spool and becomes loose, then it's safe to open the camera). If you have an automatic-winding camera, it may have a setting to leave the film leader out, which you will want to turn on. If you accidentally end up winding the leader back into the canister, there are devices you can get or make to fish it back out (a google search should produce good results).

edit: lol, poppicker beat me again!
no, if you rewind it back to exposure 1 you'll risk damaging exposure 1 (and perhaps 2 and 3 as well). What you want to do is rewind it so that the film leader is sticking out (as it was when you first bought the roll of film),
Yeah, sorry, that's what i meant. But...what do i do when i want to start using that one again? How do i go about getting it back to say....exp. 23?

PP, my camera is a currently a Canon A-1 but will soon be an EOS 3000.
What I would do is set the shutter speed at its fastest setting and the aperture at its smallest setting, and with the lens cap on advance enough frames until you were back at 23 (you might want to advance for good measure to 24 just to make sure you're not overlapping on any previous exposures)
And Aperture is used when shooting what exactly? thanks

PP, it is all manual. Not sure about the EOS 3000, though.
OK with the manual one, you just need to wind back carefully, you'll feel it pull slightly when it's almost fully rewound. STOP.

If you have an old film that you can play with, you'll soon get to know the feel and sound of the film rewinding.


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