# How to keep ISO consistent?



## Davephoto (Oct 21, 2012)

Hi all,

I need some help on how to keep the ISO as consistent as possible when shooting a short film with the 5d mark III. How to do this?

Does it mean I set and lock the ISO at let's say: 160 ISO throughout the whole shooting? And change the aperture to match the ISO (and locked shutter speed at 1/50)?

Thanks, have a nice day,

Dave


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## Viggo (Oct 21, 2012)

Set the camera to Tv , set the shutter to your 1/50 and iso to 160 and the only thing that will change is aperture.

Personally I set my camera to M and the desired aperture and 1/30s and set auto iso , as I would rather have a little more or less noise than the depth changing.


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## Axilrod (Oct 21, 2012)

If you're looking for consistency I'd try and stick with manual settings, you definitely don't want to use auto ISO while shooting video. Your shutter speed is fixed, so that stays at 1/50. You want to keep ISO as low as possible of course, and set a limit for how high you're willing to go. On the 5D3 my limit is ISO1600 for professional work, maybe 3200 but it's never come to that. 

If everything is maxed out then add more lighting. On a sunny day even at ISO100 you're going to have to stop down quite a bit, so I'd really only be concerned about low-light situations. Either way, I wouldn't try to shoot an entire short with no lighting, it can make all the difference in the world (regardless of how well these things do in low-light).


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## Mt Spokane Photography (Oct 21, 2012)

Something has to change if the lighting changes. Can't be shutter speed, so aperture or ISO. Which do you value mosy? The aperture will vary the depth of field and might look obvious, so its either lock everything down, or let something change. Take your choice.
Using external lighting that does not vary is obviously the best, but not always possible.


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## LetTheRightLensIn (Oct 25, 2012)

Davephoto said:


> Hi all,
> 
> I need some help on how to keep the ISO as consistent as possible when shooting a short film with the 5d mark III. How to do this?
> 
> ...



I'd use M mode, lock the 1/50th (for most scenes), set the aperture to DOF you desire and then adjust lighting, ND filters and ISO as needed yourself (sometimes you might keep ISO more similar and just use a different DOF if you are afraid the scenes might not quite match in 'grain' and they really need to and things would be too extreme otherwise).


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## Viggo (Oct 25, 2012)

Axilrod said:


> If you're looking for consistency I'd try and stick with manual settings, you definitely don't want to use auto ISO while shooting video. Your shutter speed is fixed, so that stays at 1/50. You want to keep ISO as low as possible of course, and set a limit for how high you're willing to go. On the 5D3 my limit is ISO1600 for professional work, maybe 3200 but it's never come to that.
> 
> If everything is maxed out then add more lighting. On a sunny day even at ISO100 you're going to have to stop down quite a bit, so I'd really only be concerned about low-light situations. Either way, I wouldn't try to shoot an entire short with no lighting, it can make all the difference in the world (regardless of how well these things do in low-light).



So auto iso is a bad idea, yet you wrote you have your limit set to 1600?


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## Davephoto (Oct 28, 2012)

Thanks guys!
My set-up: M, 1/50, aperture to desired DOF, and max 1600 ISO for pro work,


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## Chris_prophotographic (Nov 2, 2012)

I have been on manual since about 10 years.


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