measuring focus with HVX with tape measure

S

shenwppd

Member
When measuring focus distance from the subject to the HVX, what landmark on the camera should be use to get the most accurate focus ditance. Think it may be near the front or rear of the hinge of the LCD screen, but am not sure. Can anyone speak with aurthority on this?

thanks, Steve
 
The front of the lens.

But the markings aren't going to be terribly accurate at the very closest distances anyway. Once you get to four or five feet away they're pretty good.
 
landmarks

landmarks

Interesting. I called Panasonic about a month ago and to my surprise the technician said it was near the hinge of the LCD. I put in another call and am awaiting a reply. Will let you know what they say today. Was he misinformed?

Thanks, Steve
 
Broadcast camera lenses are typically measured from the front of the glass. Did you ask him where the chip block was, or where to focus from? The chip block is probably around where the LCD hinge is, yes, but the focus calibration should be from the front of the lens.
 
If you're using cinema primes like DigiPrimes, that's what they'd be calibrated for and how you'd use it. But for typical ENG/broadcast, those lenses are calibrated from the front of the lens.

Here's what Bill Turner of Schneider Optics said about it:
Video lenses that do have markings denote the distance from the front of the lens not the image plane (the object distance) - except for a few very pricey film style lenses made for film-style video production that have witness marks measured from the image plane .
Click to expand...
(taken from this post)
 
Barry, if I were to buy a lens, how would I tell if it's calibrated for measurements from the glass, or the image block? Is there some specification that will tell me? Or do I just judge this on whether or not it's called an ENG lens?

I'm assuming that just about all primes, which are generally intended for film-style production as you mentioned, will be set for the "film plane". But when using a zoom?
 
If the lens has witness marks for the focus points, that's usually a good indicator that it's designed for film-style work. But if there are just general focus numbers and no direct witness mark, that's probably indicative of a more video-style system. The film-style lenses that employ film-style focus would be things like the Zeiss DigiPrimes or their Fuji counterparts.
 
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