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-   -   Expodisc and WB (https://www.dvinfo.net/forum/general-hd-720-1080-acquisition/504188-expodisc-wb.html)

Richard Davidson January 7th, 2012 08:26 PM

Expodisc and WB
Used an Expodisc for the first time while filming a basketball game. As you can guess the lighting is not the best to begin with and for some reason today my camera (Sony CX560V) had some real issues. I am shooting at the highest quality setting and using 60P instead of 60i.

Overall the final product looked better as to brightness and color (not a big change but maybe more stable). I have had issues in this gym that some shots would be much darker than others and the scorer's table is backlit (school's mascot) so every time I pan across the floor the camera adjusts for that light source. Today I did not see the camera working so hard to keep the light balance and thus the final result was better.

What was very different today was the camera had a very hard time keeping focus. At times it was like my camera went crazy and I was getting a message on the display about manual focus setting. I had the camera's low light setting on and late in the game I turned that off and the focus seemed to get better. I always run everything on Auto except for today and the WB setting.

I am assuming that setting the WB changed something that the camera was struggling with so what could that be? If this the result then how do I correct this for future games?


Chris Soucy January 7th, 2012 09:43 PM

Re: Expodisc and WB
Hi, Richard, fancy seeing you here............

I think the 60p is screwing things, bottom line.

You're asking every photo receptor on the entire sensor to get a complete sample every 1/60th of a second, in what you have described as challenging lighting conditions.

By moving to both the ExpoDisc AND 60p in one hit, what you have done is make two changes to your shooting style at the same time, always a bad move, as it's difficult to finger one or the other of the changes when things go wrong.

However, knowing what I do about the ExpoDisc, I can see no reason why it would inflict the sort of injures you're seeing with the focus.

Not having a clue as to how Sony have integrated their Focus system into the rest of the camera, I am a bit behind the 8 ball, but may I suggest you revert to 60i shooting for the next session and see how things pan out (er, sorry about the pan, er, pun).

In reality, 60p may sound fantastic, but there are downsides, and just because it can do it is no reason for you to use it.

Anyway, just for the process of elimination, can the p and revert to i, is my suggestion (upside: save you a shed load of file space and sheer buggering about later as well).

Hope you're enjoying the Vinten VB, BTW.

Catch you later.


Allan Black January 7th, 2012 10:56 PM

Re: Expodisc and WB
I can't see the Expodisc causing your focus problem either.

But which ExpoDisc did you use, the clip on neutral or warm version? I remember their site recommending you buy a 'large' disc to cover all your lens sizes. In my case that won't work because the large lens hood would block the E disc from being held right up against the face of the lens. I'd have to take the hood off to use the E disc successfully.

But I find my clip on neutral vers. is great for mixed lighting, when it changes 'too much' I need to rebalance the WB.

If yours is a clip on neutral, I suggest you double check your cam settings then run more trials with it prior to your next use.


Richard Davidson January 8th, 2012 08:53 AM

Re: Expodisc and WB
When you don't know anything it is easier to make assumptions so I did. I have been shooting several games using the 60P and not had the focus issues like yesterday. The expodisc is a "warm" instead of the "neutral" but I thought I would try it and see if it made things better (overall as to the light conditions it did). As to the focus issue I was hoping in a sense that the WB could have created an issue with focus but had no real basis for that assumption. Right now I do not have a hood on the camera so I was able to cover the entire lens with the disc.

I reset the camera after the game yesterday and put all new settings into it. Maybe it has developed an issue with the focus, after all things do break but I will see next game.

If I have this many issues using a camera on full Auto I hate to think what it takes to run one with manual settings.


Chris Soucy January 8th, 2012 10:02 PM

Re: Expodisc and WB
Well, I think we can can the 60p as the culprit on this one, anyway.

If you've used it on previous occasions without problems, that seems to be that.

These two statements give rise to some pondering though........


I had the camera's low light setting on


the scorer's table is backlit
I'm wondering if that combination of high gain and occasional (implied) direct into lens lighting could have led to the system shutting the iris down to the extent that focus simply wasn't possible.

Guess we'll never know, at least till it happens again and any similarities can be deduced.

I do think I need to have a go at this one though:


I hate to think what it takes to run one with manual settings
To be honest Richard, if you were running with some sort of control over the camera you'd probably get better results.

Auto focus, no problem, you'd never even try to ride that manually at that action speed.

Aperture (Ae mode) well, if you nailed that to 5.6 (say, though in such low light conditions something faster would probably be more appropriate) and let the shutter speed do the walking, it wouldn't be allowed to shut down completely (if that's what it did) and your depth of field would be constant.

Shutter speed: - Ae mode takes care of that.

WB - well, that's what the ExpoDisc is there to improve, though, given the different lighting conditions across the court, it's always going to be something of a lottery.

Zoom - well, no getting away from that one as manual, though having it controlled from the pan bar via a Lanc controller would be a major leap forward in every respect, though I doubt the camera in question has that facility.

Gain (low light option) - as long as turning it on doesn't lead to the iris closing completely with a strong backlight situation (if that's what it did), you're good. The only way to guarantee that is to nail the iris to a set value (see Ae mode, above) and let the shutter speed do the work.

All the above said, we'll wait for the next exciting episode and take it from there, and, as you said, the AF may well have just had a bad hair day, for whatever reason.


Richard Davidson January 9th, 2012 09:44 AM

Re: Expodisc and WB
2 Attachment(s)
Here are two different pics from the same gym same location and the only difference in the settings is the WB. As you can see the scorers table I am dealing with a very problematic light source. First pic everything is on Auto and the second pic everything but the WB is on Auto.

Chris Soucy January 9th, 2012 03:05 PM

Re: Expodisc and WB

What an astonishing difference between the two pictures.

If ever there was a "seeing is believeing" sales pitch for the ExpoDisc, that second one is it.

I think you're being exceedingly modest with the term "problematic".


Richard Davidson January 9th, 2012 03:26 PM

Re: Expodisc and WB
So, some of these issues could be addressed if I have a camera that had some manual settings? I have read the "Which camera should I buy" thread and know no more than I did before I ever read it.

Chris Soucy January 9th, 2012 04:31 PM

Re: Expodisc and WB
I wouldn't be at all suprised if the camera you already have has an Ae mode built in, just a question of finding it, who knows what Sony will have called it, though "Ae mode" would be usefull.

Think "Aperture Priority" and you're there.

That allows you to set the lens aperture to any value between wide open and pretty well closed (the latter definitely not for your type of shooting) and letting the camera work out an appropriate shutter speed to achieve proper exposure.

Given your need to vacuum up every available photon, wide open may well be the best option, though that is something of a moveable feast as the widest aperture at full wide angle zoom will not be the same as the widest aperture at full zoom in, probably by a couple of f - stops.

Quite what the camera will do under those circumstance is anyones guess, I'd suggest you find "it", whatever it's called, set it on and have a bit of play time before shooting for real.

WB would appear to be solved and the only other "must have" manual setting is gain, which seems to be hiding under the "low light mode" banner and is worth experimenting with in conjunction with the Ae mode.

A Lanc connector would be a Godsend in your circumstances but I doubt that camera has it and it's not really a "manual setting" per se, simply a way to get a(nother) zoom rocker and maybe a couple of other controls onto the pan bar of the tripod, making it possible to track fast motion with the zoom without once having to touch the camera itself.

Bottom line, of the manual controls really required (to my mind, anyway) I'd say you already have them, and simply need to get comfortable using them to your best advantage.

For all I know Ae mode may actually deliver up diddly squat, but it won't hurt to give it a try.

As for "Which Camera should I buy", well, low light, low light, low light, repeat after me..........


Richard Davidson January 9th, 2012 04:45 PM

Re: Expodisc and WB
I have "Exposure", "Iris", and "Shutter Speed" that I can adjust. I am assuming that Ae and Iris are the same???? Low setting is F3.4 and high is F9.6 so I am guessing I leave it on F3.4 due to the low light conditions. As for the Low Lux setting it is either "on" or "off" and it didn't seem to really change anything once I used the Expodisc.

As far as lanc control I am using one of my Sony tripod handles zip tied to the Vinten handle so I can control the zoom and record function. Looks bad but works good.

I am not sure if I set the WB manually if that will change any of those settings from "Auto" to "Manual" but I will see later this afternoon. I have a basketball game tonight and another one tomorrow evening. I need something Idiot proof so this idiot can run it correctly.


Adam Gold January 9th, 2012 05:03 PM

Re: Expodisc and WB
I'm going to have to respectfully disagree with Chris here, on a number of issues.

First, other than brightness, I see little discernible difference between the two frame grabs (well, okay, the one on the left is indeed a bit bluer). The color looks similar overall, though, and as the Manual WB and the Expodisc would only affect color and not exposure, it appears that neither are helping you at all. The Auto WB on the cam is averaging all the colors in the frame, and all the Expodisc appears to be doing is basically the same thing by using incident rather than reflected light (because it's not getting fooled by the warm tones of the floor into shifting everything towards the blue end of the spectrum -- but you could accomplish this with a sheet of white paper).

Secondly, using only Shutter to control your exposure is a Very Bad Idea. From moment to moment, your motion will change, going from the stuttery stroby "Saving Private Ryan" look when it's bright and you've forced the cam to use a short shutter speed, to oddly blurry when it gets darker and you've forced the cam to go down to 1/30th or even 1/15th. Your video will look terrible. There's a reason all these consumer handycams are programmed to move the shutter speed absolutely last, when changing Iris and Gain are not sufficient. And it won't solve your problem -- the cam will still be seeing that board and will try to darken the picture. And at that distance, DoF is a non-issue.

That backlit adboard is definitely a problem. But your cam has a "Backlight" mode (P. 36) which will easily compensate for this. But every time that board comes into the frame the cam will still try to compensate. On the 560, you can assign EXPOSURE to the manual dial (P. 41) and lock the exposure completely, if I am interpreting the sometimes cryptic Sony manual correctly. If this is true, you should set a manual WB and let the cam find the right exposure before you begin shooting, making sure that backlit board is not in the frame. Then lock the cam on MANUAL by pressing the Manual button in the center of the Manual dial, and then begin shooting. You must choose MANUAL before shooting, according to the note on p. 41. If this does what I think it does, it will lock your exposure and will not try to adjust when that board comes into the frame. If the board were always in the same part of the frame and you had the cam static at all times, you can just use AE SHIFT to compensate for the board, but as I assume you are panning to follow the action, the moving board will always cause you problems as it appears and disappears and even changes position in the viewfinder (as metering systems focus mostly on the center of the frame).

Unfortunately, there are no cams yet built that are smart enough for you to tell them: "Ignore that really bright sign" and have them understand and respond appropriately. The only way is to totally lock the exposure and control it manually. But you can use SPOT METER (P. 76) to meter for objects that aren't the board. And you can ride the exposure manually just by using the + and - buttons on your LCD (P. 77).

And as you've already noted, the 560 has complete LANC control available via the A/V port.

Can't you shoot from the other side of the court?

Dave Blackhurst January 9th, 2012 06:44 PM

Re: Expodisc and WB
I'm with Adam - I'd set and lock your WB, and set your control button to "exposure", manually adjust it to where you want it...

Assuming that the overall lighting conditions remain relatively stable - you may "blow out" the sign to achieve otherwise good exposure, but it should help. If you try to use AE shift, it may help ut it's a fixed offset from whatever the camera thinks expposure should be, so that sign will still present a problem.

if you're zooming in and out, keep in mind you'll have to fiddle with the exposure to compensate... maybe introducing more problems in the process.

Low Lux shouldn't cause a problem from my experience with it, I usually leave it "on". As long as there is some decent contrast for the camera to "lock" onto, your focus shouldn't be hunting too much, and it sounds like that's what's happening, but trying to manually focus on these little cameras is not exactly easy... and I think you're too close to set to "infinity".

I'm not 100% sure about this, but it occurs to me that by setting some things to "manual", you've lowered the overall load on the intelligent processors, and I suppose it is "possible" (pure speculation at this point!) that with the lowering of the load, it would then use the extra processing to try to fiddle with other settings... like maybe focus??

Richard Davidson January 9th, 2012 08:47 PM

Re: Expodisc and WB
OK, tonight I was in a better lit gym and the camera had very little issue keeping focus for the most part. As I move with the action it would lose it and then lock right back on but I don't think any auto focus could keep up with basketball players running up and down the court.

Dave, based on the way my camera was acting the other night when I had focus issues it seems like it could have been "over loaded" and it something was going to suffer, in that case focus. Tonight I shot the first half with WB set via the Expodisc and at 60P. 3rd period was auto everything and 60P and 4th period was auto everything and 60i. No difference from what I could see for the entire game.

The pics that I posted are one of the worst gyms and it is the kids home gym so we see that one a lot. I would love to shoot from the other side but they never have the bleachers out on that side so getting to a position to shoot at is impossible.

Oh well, I will play more tomorrow and report back.

Dave Blackhurst January 10th, 2012 01:46 PM

Re: Expodisc and WB
Bad light is bad light, and will always play havoc with focusing - basically less contrast to analyze. Your Sony is fairly good in low light, but you may have to allow for it to struggle more when the lighting conditions are bad. Since it's doing fine in "normal" light, it may just be "the ambience"...

Allan Black January 10th, 2012 03:40 PM

Re: Expodisc and WB

Originally Posted by Richard Davidson (Post 1708477)
The pics that I posted are one of the worst gyms and it is the kids home gym so we see that one a lot. I would love to shoot from the other side but they never have the bleachers out on that side so getting to a position to shoot at is impossible.

Richard, others are probably having that trouble including the school photographer, try going to tell 'em and 'carefully' suggest
can they relocate that light and the bleachers.

Maybe others suggested that and they were considering it anyway, you never know.


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