HVX and the Brevis. . . how far do you stop down your HVX?

Stephen Pruitt

Stephen Pruitt

Member
Hi all you HVX/Brevis users. . .

On my HVX/Brevis set-up, I find that I am getting much better edge-to-edge sharpness with my HVX stopped down to about 6.8 than when it is wide open. Is this normal? Or am I doing something wrong? That's giving up a lot of light!

Stephen
 
You are not focused on the screen correctly I think.
I get pretty good focus wide open.

How bad does it look wide open and what are the Zoom and focus numbers your lens is set to.(set your display to number)
How are you focusing?

Lenny Levy
 
Thought that HVX at anything other than wide-open was good. Remember reading that 4-5.6 if possible.
 
You can get improved edge to edge sharpness by using the spacer ring that Cinevate sells. This will put the ground glass a little further away from the camera.
 
Seems to me I'm usually somewhere close to that. Last time I looked it was Zoom 71 or so and Focus 9- 10 closer to 10.
I'm going for full frame though, not Academy aperture.

I don't use a spacer ring. Is that recommended for the HVX?

How do you focus it? You should always find you focus at wide open HVX Iris by the way. If you want to close it later fine but set-it wide open always. I usually want to err a teensy bit toward the far end of perfect center focus because that's where the corners are.
My suggestion is to get a file for a resolution chart which you can find around these pages or on say the Brtevis or Redrock sites as I recall.
Go to Kinko's and blow them up to 3 or 4 feet.
Mount it on a board and double check your focus that way. Go back and forth between the 35mm lens and the HVX focus then tape of the HVX.
I prefer this because I know I'm focusing on the image not the front or back of a dirty screen.

It may not be absolutely perfect at wide open HVX but it should be damn close.

I find it hard to set-up the Brevis with auto focus on the screen like you can say with an SGPro.
 
If I recall correctly the HVX is at it's best at f4 to f5.6. What has been very hard to assess is how much the lens-centricity variations in these cams affect sharp corner to corner focus. What is clear is there is significant number of HVX's with an image being captured over 5% skewed to the left or right of the physical lens center. One wonders if there are spherical aberration issues as the cams deviate from the lens center.
 
No doubt it will get better as you stop down, but I find that its acceptable wide open for me though I try to stop down both the adapter and the 35mm lens when I can.
You shouldn't need to be at 6.8 for it look pretty good though.

Lenny
 
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