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-   -   JVC 4k cams for basketball games (https://www.dvinfo.net/forum/jvc-connected-cam-series-4k-camera-systems/537768-jvc-4k-cams-basketball-games.html)

Jerel Peterson January 13th, 2021 02:27 PM

JVC 4k cams for basketball games
 
I am strictly an amateur, point-and-shoot videographer. I am webcasting basketball games for a local high school using these cameras:
JVC GY-HM 250SP
JVC GY-HM 170OUA
JVC GY-HC 500 USPCU

For now, I am usually using the 500 as the only 'manned' camera--the other two are at opposite ends of the floor pointing at their end of the court. Lately I have noticed that my webcasts aren't looking as sharp as I think they should be.

I have always left auto-focus on. I am zooming in with the main camera quite a bit sometimes, but usually keep it at approximately the same zoom amount.

Should auto-focus be able to handle fast-moving sports? When I quickly zoom in tight on a player, it gets quite blurry for a couple of seconds -- is that normal? Since the action can change so quickly, I can't see using the focus ring as a viable alternative.

Also, last night I was using the 250 as the 'manned' camera, and I couldn't figure out why the picture looked so poor. I messed with the focus ring and got it back in to focus. But I never turned manual focus on -- it's always been set for auto-focus (unless I could have mistakenly turned it off). So, now that I've messed with the focus ring, will auto-focus be screwed up -- do I have to re-set something? I won't be able to go in to the school until the next game, so I can't check it out in my working conditions ahead of time.

As you can see, I buy cameras that are well beyond my level of comprehension, but I'm embarrassed when I see other webcasts with much clearer video even though they are using much cheaper cameras. I will be upping my Mbps rating in Wirecast to see if that helps, but I just have a feeling I am not using the camera correctly.

Paul R Johnson January 14th, 2021 07:18 AM

Re: JVC 4k cams for basketball games
 
Remember that in sport, auto focus is nowhere near foolproof. It works by looking constantly for the hard edges, and often needs to go out of focus to check and then back in again. If while it does this somebody moves closer to the camera, it gets confused and can then remember this position as important. Or, they just don't detect something is wrong. They're better than they used to be, but sharpness of picture is the camermans job to check. So frame the picture on the lock off cameras and zoom in on an object about half way between the furthest distance you need and the closest, adjust on manual focus to be sharp - zoom out again and leave it. Or do that, then engage autofocus and kind of hope? It works most of the time. The cameras that you need to zoom in closer are the ones more likely to go soft.

Autofocus is terrible at sport when things come close to the camera. You know that person in the left of the frame is unimportant, but the camera doesn't so might focus on them instead. I've heard people say autofocus is better now and it's like a car auot gearbox, theyre much better nowadays, but I look at autofocus like automatic braking that my wife has in her car. The car slams the brakes on because something is spotted like a car safely moving sideways - but the car yells warning and slows down unnecessarily. It's safe, but frequently wrong because it's brain cannot make the decision properly - and this is like focusing. Your eyes and brain connected to your hand.

It will get it right most of the time. You won't see autofocus in use on broadcast basket ball, or any other faster moving sport. In a one man band, you may have little choice, but it will go wrong, it works by guessing!

Jerel Peterson January 14th, 2021 06:59 PM

Re: JVC 4k cams for basketball games
 
Thanks for the reply. It's kind of what I was expecting to hear. I think I'll just leave it on autofocus and accept whatever it gives me.

Paul R Johnson January 15th, 2021 02:37 AM

Re: JVC 4k cams for basketball games
 
Why? With a static camera, you have a near foolproof method of getting sharp focus that trending there, even if somebody does something. Letís say your camera is on autofocus and is sharp before the match, but then a ball goes out of play near the camera. Somebody picks it up and throws it back. The camera tries to focus on the ball, but settles on somebody closer, or an object. It wont know it has got it wrong and spoils the shot for the rest of the game. Manual setting would solve that problem and be something that would take twenty secs when you lock it off? I donít understand? Posting for advice takes more effort? What kind of answer were you hoping for?

Roger Van Duyn January 15th, 2021 08:35 AM

Re: JVC 4k cams for basketball games
 
Quote:

Originally Posted by Jerel Peterson (Post 1963368)
Thanks for the reply. It's kind of what I was expecting to hear. I think I'll just leave it on autofocus and accept whatever it gives me.

Jerel, I don't shoot sports very much any more, but when I did, I always left the unattended cameras when doing a multicam shoot on manual focus, but turned the focus ring until the infinity symbol appeared. Don't know if you've seen it before, but it looks sort of like the number 8 laying on it's side.

When set to infinity, that means that everything beyond the minimum focal distance of the camera is supposed to be in focus. It's not perfect, but works a lot better than leaving the camera in auto focus. At least you won't have big changes when the camera is trying to hunt for focus if you leave it set on infinity. Realize, you probably won't have super sharp focus at times, but it will be sharp enough with all the motion you have in sports that people viewing your recording won't notice.

Jerel Peterson January 20th, 2021 08:48 PM

Re: JVC 4k cams for basketball games
 
Quote:

Originally Posted by Paul R Johnson (Post 1963370)
Why? With a static camera, you have a near foolproof method of getting sharp focus that trending there, even if somebody does something. Letís say your camera is on autofocus and is sharp before the match, but then a ball goes out of play near the camera. Somebody picks it up and throws it back. The camera tries to focus on the ball, but settles on somebody closer, or an object. It wont know it has got it wrong and spoils the shot for the rest of the game. Manual setting would solve that problem and be something that would take twenty secs when you lock it off? I donít understand? Posting for advice takes more effort? What kind of answer were you hoping for?

Maybe I'm not understanding the difference between auto and manual focus. If on auto, and then it tries to focus on a ball coming near the camera, wouldn't it auto-focus back to the players once the ball is out of the picture?

I'll try the manual focus next game with the 2 stationery cameras. They are up on a shelf in the corner of the gym, I have to climb up on a ladder and can't actually get behind the camera. It's a bit precarious, but flipping the lcd around should let me see it decently enough. So I would set the manual focus on the free throw lane area? That's where most of the action occurs. I just assumed it would get out of focus if players were down in the corners

Paul R Johnson January 21st, 2021 06:45 AM

Re: JVC 4k cams for basketball games
 
You look at the viewfinder/screen and look at how much DoF you have, then you pick a distance that lets the action be in the acceptable focus zone. Autofocus has a problem - with objects in the frame at different distances, how does the camera know which is the important object. They tend to use algorithms to make it work. Centre frame is the key area. Any object in the middle gets focussed on. With a static camera the centre screen is often NOT where the important things are. Anything crossing centre might trigger a focus check - and to focus, it has to defocus first. Autofocus is better than it was, but never fault free, and the camera decides when it needs to check, so if the entire screen is out of focus, it might not notice until it changes enough to trigger the refocussing.

Worst case in sport are games with a small ball - cricket, golf, football of the real UK variety and the strange US version where the ball gets carried. OBs for broadcast do the focus manually, because eye and brain do it better. Using autofocus on sport is a fingers crossed experience.

Roger Van Duyn January 21st, 2021 07:51 AM

Re: JVC 4k cams for basketball games
 
Quote:

Originally Posted by Jerel Peterson (Post 1963470)

I'll try the manual focus next game with the 2 stationery cameras. They are up on a shelf in the corner of the gym, I have to climb up on a ladder and can't actually get behind the camera. It's a bit precarious, but flipping the lcd around should let me see it decently enough. So I would set the manual focus on the free throw lane area? That's where most of the action occurs. I just assumed it would get out of focus if players were down in the corners

Jerel, from your description it sounds like your two stationary cameras are zoomed out wide to cover the entire basketball court. If so, just set manual focus to infinity like I mentioned in my previous post and the whole court will be in focus. And it will all stay in focus, the entire court, until someone messes with the controls. It will stay that way game after game even. Set and forget. It will work great as long as the lighting is consistent. Since the cameras are unmanned, I assume they are set to get entire court. But, the setup also works if cameras are set at opposite ends of gym to get each half-court of the game. The entire area in the frame will be in focus and stay in focus if you set to infinity. I've used this method a lot of times for unmanned cameras. Then the camera I man is used to zoom in for close ups. In your case, free throws etc.

Paul R Johnson January 21st, 2021 08:31 AM

Re: JVC 4k cams for basketball games
 
Roger - I'm not sure they power up with the lens in the previous state. I think they always try to go to that infinity setting.

Actually, most of my work is in lower lighting levels, so my depth of field from infinity to the closest place somebody stands often pushes it a little too much, hence why I personally don't set to infinity, but a little more towards the camera, so I have increased sharp focus zone. I guess in a brights sports environment DoF is less critical. I do have one JVC (GY-HM100 that I use on a Ronin) that has autofocus that is pretty good. It gets confused when levels drop, but oddly, that one I use on auto - the only camera I do it on, because on the gimbal, manual focus was impossible to do, but auto gets it right most of the time. A Panasonic of similar design is not very good on auto at all!

Roger Van Duyn January 21st, 2021 11:24 AM

Re: JVC 4k cams for basketball games
 
Hey Paul. I figured he's using it in a (school?) gym with the lights on for the basketball games. Should be very bright. He didn't mention if cameras are connected by cable to a switcher or anything like that, if the games are streamed. I only jumped into the thread because I've had two of the JVC HM-170U cameras for about five years and he didn't seem aware of how to use manual focus set to infinity to get away from autofocus hunting focus problems. The little I've used autofocus on my JVCs I found it pretty slow. The 250 SP are a newer version of the camera that can stream and add graphic overlays. Nearly all my sports jobs were before I got the two JVC cameras. Now, instead if filming on the court (basketball), I film for the court, often in the court room. Filmed testimony for two different murder trials recently. Don't want to get off topic... Most of my sports jobs were back in tape days. My eyesight was better and I was more agile back then. (And the old grey matter ain't what it used to be either!)

One thing I do like about my two JVC cameras is that you can program some of the buttons for different functions. I have programmed one for "instant" (a little slow) autofocus when I don't have an external monitor to really see if focus is really sharp or not. My eyesight isn't so good anymore. Fortunately, I don't have to follow fast action filming witnesses giving testimony and lawyers showing evidence...

Paul R Johnson January 21st, 2021 11:27 AM

Re: JVC 4k cams for basketball games
 
Sounds interesting Roger, actually!

Roger Van Duyn January 21st, 2021 11:41 AM

Re: JVC 4k cams for basketball games
 
Yeah, I used to work in medical laboratories for thirty years. One recent cold case from the eighties, the expert witness was a retired CSI who actually set up the crime lab where I live. We overlapped in similar fields for about five years. I was just starting my lab career, and his was winding down. He actually taught at area colleges some and at seminars for the FBI. He was in his nineties when I filmed his testimony, and still sharp as could be mentally. Very meticulous in the crime lab, as we had to be in the medical lab.

Jerel Peterson February 1st, 2021 09:10 PM

Re: JVC 4k cams for basketball games
 
sorry to not reply for so long. It will be tomorrow night's game that will be the first with manual focus set to infinity. Again, I'm going to be standing on top of a ladder and adjussting the camera with one hand while I hang on for dear life with the other, so I'm not sure if I'll be able to get things set optimally or not.

The cameras are in the side corners, each pointed only at one end of the court--not trying to cover the full court area.


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