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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

High refresh rate Monitor for critical focus of very fast moving objects, wildlife ??

E

Ernest Kovacs

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I am doing a lot of 4K 120FPS filming of weasels that move very quickly. Even when their body is still their head darts around at amazing speeds.

I'm finding perfect focus is very difficult. I'm thinking the animals fast motions are creating a soft appearance in the monitor even when in focus??? I'm using a 7" Liliput Q7 monitor with SDI out from Red Dragon. I've heard about fast refresh monitors used in Video Gaming. Would they help in my critical focus of fast moving wildlife? Do they exist in a 7" size?

I have been trying different amounts of peaking, but still seems like focus is challenging even when I'm weraing reading glasses and very close to monitor.

Thanks for any suggestions.

Ernie
 
It's the most difficult focus to do when, on a long lens, your object is moving in your direction and you are doing slow motion. Still camera have taken a long time before getting to the point that every picture is sharp. So I suppose it's even more difficult for a human hand to do it on slow motion. If your animal is in the center of your frame you could try punch in. Depth of field, practice and luck are your best friends.
 
Thanks Patrick. Yeah, depth of field is thin on my 600mm lens. Sometimes a wisker is in focus, but the eye is still a bit soft. None would ever notice at normal speed, but in slow motion and when filling the frame with a headshot it's got to be perfect.

I imagine some auto focus video cameras with eye recognition must be getting good enough to accomplish to do this?
 
Do the Weapons' output 4k Video? Maybe with a DSMC2? ...for some reason I believe it's limited to 1080p60
 
DSMC2 cameras do not output a 4k signal, but the DXL does.

And I would highly recommend using the EDGE focus mode, as it is LEAPS AND BOUNDS better than any other focus peaking I've ever used.
 
Ernest Kovacs said:
Thanks Patrick. Yeah, depth of field is thin on my 600mm lens. Sometimes a wisker is in focus, but the eye is still a bit soft. None would ever notice at normal speed, but in slow motion and when filling the frame with a headshot it's got to be perfect.

I imagine some auto focus video cameras with eye recognition must be getting good enough to accomplish to do this?
Click to expand...

A reasonable solution would be to find a way to increase your depth of field.

There is nothing available commercially that will solve this problem.

Most modern camera autofocus systems use edge/contrast so it will focus on the eye or the whisker or a bug that flies into frame; whatever give it a a better contrast target, and it will still need to "Hunt" back and forth to fixate focus

Phase detect systems are better in that they can estimate the distance and focus the lens without the "hunting", but they still can't make the decision on the focus target

A monitor with faster refresh won't help because of basic human physiology; it will take at about 1/10 of a second for you to recognize a change in the picture, however much time it take for you to figure out how far your target moved, and another 1/10 of a second to move your hand accordingly. so you are talking about minimum of 1/3, and up to 1/2 seconds, to refocus. At 120fps, that would be anywhere from 2 to 6 seconds of time at playback.

There are many great, talented 1st ACs who are incredible at pulling focus on fast moving action, but that usually requires rehearsal and muscle memory. The weasels are moving unpredictably, which is much more difficult to track and respond to.
 
Thanks very much for replies!

Even though my hand reactions will never react to the "individual frames??" of a fast refresh rate, would it decrease the "Ghosting blur". Would it help give their fur a crisp appearance on my filming monitor when properly in focus. It's remarkably hard to tell if the subject is in perfect focus or not when they are moving quickly, even as I adjust the focus back and forth a bit, nothing in the image seems totally crisp when they are bouncing around at their spaztic speeds, until I play the footage back in slow motion, then of course it is maddeningly obvious. I am shooting 180 degree shutter 120 FPS.

I've started thinking of having someone looking at a big (20 inch) monitor do the focus wirelessly, but I'm not sure it would help that much .

My eyes are good. I've become pretty good at making this all work, but trying to make results even better. Somehow??????????
 
I haven't used the edge focus much. One of my difficulties I've experience, even with peaking, is it will show something like a wisker as an in focus edge, even when it's not in perfect focus. The wisker just has such a pefect edge that almost in focus fool the peaking into showing it as in focus. Do you think edge focus will avoid this?

Thanks,

Ernie
 
If they are moving quickly then motion blur will always occur, especially at 180 degrees, for most RED frame rates.
 
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