how to shoot with less than 800 ISO

[alexmart]

If RED MX shoot with 800 ISO can it shoot for example with 100 or 320 as minimum in sunny weather or something else? except ND filters using

and what ISO for tungsten light? less 800

 

[jimhare]

The best range for the sensor is between 320-800. The main reason to shoot 800 is to protect your highlights so as long as you are mindful of that you should be fine.

 

[Eirik Tyrihjel]

If RED MX shoot with 800 ISO can it shoot for example with 100 or 320 as minimum in sunny weather or something else? except ND filters using

and what ISO for tungsten light? less 800

Short answer = no
Iso inn red is not like in film, if there is too much light outside - and your image is burning out, setting a lower iso will not help you. In that case you have to change your shutter speed or start adding nd's.
The mx sensor is technically iso 800 native, I rate it a bit less 400-640'ish, but that's me...
The fact is that no matter what you set the iso to, you can change it later in redcine-x ( and other applications),
If you have a correctly exposed image = no burn outs (or at least no burn outs you can't live without), and yet you exposed it so to allow for the maximum latitude of the sensor. You will experience this:setting iso 2000 will make your image look very very bright, and some hot spots burned out, setting iso 100 will make it look very very dark all over, but you can change it in post in redcine-x.

So your iso setting is basically a tool to show the world what you want your image to be, and on your monitors.

It is NOT like film where you would use a 50 asa film four outdoors in fullsunlight and a 250 asa in a well lit studio.

If you need to go to iso 100, you need som ND's or a faster shutter speed.

 

[alexmart]

thanks, but as I know MX version firstly was done for 320 ISO (more 250) and then after ALEXa it was upgraded to 800. So it was done by software not hardware. Or am I wrong?

 

[David Mullen ASC]

The M-X sensor had a recommended 800 ASA rating when it first arrived, not after the Alexa arrived (it was the original M sensor that had a 250-320 ASA recommended rating). It can be rated at 400 ASA if you want, you just lose 1-stop of overexposure range and gain 1-stop of shadow information. But below 320 ASA or so, you start losing more highlight protection, which makes the image very noiseless but clippier in that classic video way. Wide dynamic range in overexposed areas is more of a film look.

Bottom line is get some ND filters and use 320-400 ASA outside if you need to, but otherwise use 500 to 800 ASA in sunlight.

You don't really need to compensate the ASA rating for tungsten with the M-X sensor, though there is a mild increase in noise in the blue channel, so you may want a slightly more conservative rating for bluescreen work or shooting blue subject matter in tungsten light, but otherwise I wouldn't worry about it.