Can I change the ISO on my film camera?

Question

I have a Canon Rebel G and recently took a photography (film) class at my college, I asked my professor if I can change the ISO at any time during my roll of film, he replied back to me by saying "Don't change your ISO if you are using a 200 ISO or whatever film leave it at that" so then I asked why? and he said "just because" So my question is if I have a roll of film in my camera (whatever the speed) am I able to change it if I find myself in different lighting conditions? If no, please explain why. And yes I know, why don't I stick to digital? Well for the time being I actually love shooting film.

Answer 1

The usual procedure is to set the ISO on the camera for the film you have loaded (the film ISO will be printed somewhere on the box and on the film canister).



It is possible to shoot a roll of film at a different ISO to that which it is rated at, and then 'push' or 'pull' process the film (or ask the lab to do it - a proper photo lab that is!).



What you CANNOT do is to change the ISO in the middle of the film - because it all has to be processed at the same time, the ISO needs to be consistent for ALL the frames shot.



To adjust for different lighting conditions during shooting, you ONLY alter the aperture & shutter speed.



Good for you for shooting film - I shoot (and enjoy) both!

Answer 2

Iso Film

Answer 3

You can change the ISO setting on the camera, but the film's ISO is a fixed property of the film. By changing the camera setting, all you will be doing is under or over exposing the film.





It is possible to shoot an entire roll at a different ISO and then push or pull process the film accordingly. However, if that last sentence didn't make any sense, then listen to your professor, and don't change the setting.

Answer 4

Film is rated at a specific ISO to give the best results using standard processing. If you shoot at a different ISO then the film needs different processing to develop the images correctly. If you do this you must tell the processing lab that the film has been exposed at ISO "whatever". If you take it to the local store then you will be met with a "Durrrrrrr!" and it wil lget standard processing cos they won't have a clue what you are taling about. So you will need specialist (= expensive) processing via a proper photo dealer.



Because the whole film can only be processed as a single piece the whole film has to be exposed at the same ISO.



The only time you would change ISO mid roll would be to "fool" the camera's auto system into under or overexposing. But most SLRs will have exposure compensation so this would rarely be used.

Answer 5

Unlike digital photography, in which you can change the sensitivity for each shot if you want to, the ISO of a film is fixed by the manufacturer, so when you buy a 200 ISO film that is what you get. If you think the light is poor so change the film camera setting to 400 ot 800 ISO then the film is underexposed and you get feeble or almost non existent prints. Just a fact of life that we all had to live with in the days before digital! We learned to use slower shutter speeds if the light suddenly became poor.

Answer 6

The ISO "speed" of film is just a method of properly calibrating your camera's metering system. If you dialed in ISO 400 on your camera and used ISO 200 film, your camera would just underexpose everything by -1EV.



In reality, this is no different than if you left the setting at ISO 200 and just changed your aperture/shutter speed until the metering system showed -1EV on your camera. The results would be the same.



There is a technique called "pushing" whereby you can use your film at a different ISO.



This used to be done to get better low-light performance when films of the day were not that fast.



Say you had ISO 200 film, but used ISO 400 on the meter (or just mentally calculated -1EV).



Then, when you took the film to the processor, you would tell them you pushed the film by -1EV, and they would over process it by the same amount to get film correctly exposed.



But this could not be done on an individual photo - it had to be the whole roll.



I doubt anyone is around at the film processor anymore that would know how to do this.



One problem with pushing though. You can go 1EV, and perhaps 2EV, but any more and the limits of the film are such that you get to the point where you reach "reciprocity failure", where the inverse-square-law no longer works. That is, doubling or halving the shutter speed or f-stop relationship no longer works.



In short, reciprocity failure means that if you go say -3EV, the lab cannot recover the proper exposure (and all of the detail of the photo), by using +3EV.

Answer 7

The ISO of the film is set at manufacture. Since every frame has the same ISO you develop the film based on that. If you're using ISO 200 and shoot 12 frames and then change the ISO to 400 and shoot 12 frames and then change the ISO to 800 and shoot 12 frames and then push-process the film during development to develop for ISO 400 your exposures made at 200 will be 1 stop overdeveloped and the ones made at 800 will be 1 stop underdeveloped.



Being able to change the ISO at any time is the one advantage I concede to digital. If I know there's a possibility that I'll be indoors where there isn't great lighting I usually carry a second body loaded with ISO 400 and fitted with my 58mm f1.2 prime.

Answer 8

Yes. It will change the exposure of the film, and with some cameras limit what other manual settings you can use. MANY of the later "film" cameras, with electronics, don't have an ISO setting available. They read the information on the film holder, (35 mm primarily;) which works fine as long as you only use commercial film and don't reload. Personally, I wouldn't have one I couldn't set for specific uses. In order to get these pictures to come out good, if taken with the wrong ISO setting, you can forget the "1 hour photo" places.

Answer 9

The film is set to a specific speed.

If you change speed then this has to be accounted for in processing and a film can only be processed once at one specific setting so if you change speed back and forth then process "normally" some frames will not come out properly.





So the answer is NO, once you have started the roll at one speed you should keep to that speed.



Tell your instructor he is a dick if he could not be bothered to explain properly.

Answer 10

Since film cameras can only have one speed (ISO) of film in them at a time, the ISO must be set for that particular film or the camera settings won't work properly. If you put 100 ISO film in the camera and set the camera for say 800 ISO you could end up with under exposed or blurry shots.

Answer 11

The speed of the film is built into it, the only way you can change ISO with film is to to change the film.



Chris

Answer 12

Don't change your ISO if you are using a 200 ISO