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What is the iso of the HPX170?
- Thread starter vic777
- Start date
Barry_Green
Moderator
There's a whole chapter in The HPX&HVX Book on why trying to do this with a light meter is a risky proposition.
The "effective" ISO of an HPX170 ranges from about 125 to about 1000, depending on what gamma curve you're using and what iris setting you're at. I know it sounds crazy, but I researched it thoroughly, and my recommendation is: you cannot cannot cannot just set a light meter to a fixed ISO and expect it to deliver accurate results with one of these video cameras.
For those who want to do it anyway, try 500. The camera responds at about 500 ISO over much of the exposure curve, but not all of it. As long as you're lighting to an f/4 to f/5.6, 500 will be about accurate (again, depending on the gamma curve).
The "effective" ISO of an HPX170 ranges from about 125 to about 1000, depending on what gamma curve you're using and what iris setting you're at. I know it sounds crazy, but I researched it thoroughly, and my recommendation is: you cannot cannot cannot just set a light meter to a fixed ISO and expect it to deliver accurate results with one of these video cameras.
For those who want to do it anyway, try 500. The camera responds at about 500 ISO over much of the exposure curve, but not all of it. As long as you're lighting to an f/4 to f/5.6, 500 will be about accurate (again, depending on the gamma curve).
Carlos Corral
Well-known member
That's interesting. I currently use 6 of scene files you provided in your HPX book Barry. I use the Film Look Scene file the most. Does each scene file you in your book use a different ISO setting in the camera?
Barry_Green
Moderator
It doesn't work that way. It depends on the overall light level; the lower the light level, the slower the camera's response, and the higher the light level the "faster" the perceived response. I don't know what causes that -- it could be that the aperture isn't accurately marked on the lens, or ... who knows. I don't know. All I know about it is that the "perceived" ISO changes based on what level of light you're subjecting the camera to, and it doesn't change in a linear fashion.