The Math of Multiple Lenses

A

adrian Vanderbosch

New member
Hey All,

New to the forum. I have a question that I'm hoping you can help me with. I need to know what exposure I'm actually shooting at. I'm a creative type and math is something that readily makes my brain melt anyway, and when you pair that with the complexities of shooting with an HVX200 and Redrock combo, I'm totally lost.

I guess I'll just give an example of a particular 35mm lens/HVX aperture config and someone can tell me what my true fstop is:

Let's say I'm shooting with my 35mm lens at 2.8 and my HVX is set at 3.4, 1/24 shutter at 24 fps. Accounting for the light loss of the Redrock and the Micro X, what is my actual fstop? Making matters even more confusing, I'm working with the new Cinecreen II which reduces the amount of light loss previously seen in the Redrock. HELP ME! A light meter is useless to me unless I can figure out where I am on stops with all of these variables.
 
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I can't answer that one. But you're gonna get some pretty yucky footage with your shutter at 1/24. It'll be on the smeary side. Unless of course you're going for that effect. The general rule is 1/(2xframerate) or more so 1/48 or more for 24fps.
 
The 1/24 was a random example. What I'm really interested in is some kind of equation in which I can plug in the different variable numbers and find an exposure.
 
I'm trying to figure out the same thing, I think you have to just run a test with a light meter and a 18% gray card with the redrock on and the HVX set to the settings you want to use.
 
I think what you are really asking is what is the ISO/ASA rating of the camera + adaptor. I don't know what it is for the setup you use, but the original HVX is around 320, add the LetusEx and I believe its around 200.

Once you know the rating, you can adjust exposure based on f-stop of either the cam and/or the 35mm lens.


Hopefully someone else can confirm the answer, because I use Zebra Stripes to adjust exposure, not a meter.


Jason
 
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