Why are we so forgiving to the lousy ATW?

[Geoff Addis]

Piotr,

In theory I would agree with you, but in practice I have found this often to be acceptable. On thinking abou it, by pressing th WB button are we nt manually doing what the AWB should be doing?

I agree that it's not ideal, but it is better than relying on AWB when such a feature is needed.

Geoff

[Tom Roper]

Originally Posted by Piotr Wozniacki

Suppose the ATW stabilized and set to 3400K (which I assess as more or less correct setting for the actual light temperature); when I press AWB it will go down as low as 2200K, only to revert back to the 3400K within a couple of seconds after releasing the AWB button ! Shouldn't both measuring systems give the same results, or am I missing something here?

I observed this as well, and I do feel that to be one of the compromises of ATW. I've seen it favor to stay between 3400 and somewhere around 6500 on the high end.

[Tom Roper]

Originally Posted by Geoff Addis

Piotr,

In theory I would agree with you, but in practice I have found this often to be acceptable. On thinking abou it, by pressing th WB button are we nt manually doing what the AWB should be doing?

I agree that it's not ideal, but it is better than relying on AWB when such a feature is needed.

Geoff

When I was doing the white card tests, it occurred to me that the WB button was more like a reset of a logic implementation that had taken on a sort of inertia, or tendency of a setting in motion to remain in motion, or the tendency of a setting at rest to remain at rest. But as best as I was able to determine, the key variables were scene brightness, green channel level, damping (ATW speed). An impatient frustration could be the result of misunderstood, overly damped response when ATW speed is low and/or Shockless White is enabled.

I would just comment on Piotr's opinion that ATW is inferior to his V1, and my own recollections about AWB on the XH-A1. When I did the tests, I was looking for something "broken" in the response that would indicate a recursive loop, or trapped condition requiring a reset (WB button). And I thought I found it, until I was able to establish the out of bounds conditions for when the scene brightness was too high for Tungsten, or not low enough for Daylight, and so the ramping would be held. And then I found the role that the green channel plays in the trigger.

It's plausible that the EX1's more sophisticated algorithm in the end doesn't work as well as the "simpler is better" approach used on other cams. Without offering apologies for ATW, we have to exhaust all the possibilities the menu settings offer, and try to understand the situations the ATW was intended to aid.

[Dave Morrison]

Tom, I don't know if this reply will move this thread back up to the top again, but I wanted to add my $0.02 to the discussion. I'm struggling with this ATW issue right now and it's making me nuts. I have a client who wants me to do some walk-thru's of model homes and by "walk-thru", that's what he wants.....one continuous shot from the driveway all the way through the house and back out again; no cuts or edits. I NEVER use this camera on Auto anything but for this project, it seems appropriate and almost unavoidable.

As others have noted (especially Piotr), ATW seems braindead most of the time. I used your settings (Shockless White OFF, AWB speed 5) to see if I could force the EX1 to react quickly as I would need it to do if I was walking, say, from a sunlit room, down a hallway and into a tungsten-lit bathroom. Unless I'm missing something in the menu, it won't make this adjustment....no matter how long I wait.

However, and this is the weird part....if you start with the tungsten-lit room (3200k) and do the ATW setting using the front button and THEN walk into the daylight-lit room, the camera will make the change just fine. However, it won't work going the other way (6500k to 3200k)!! I even tested this at my desk by placing the EX1 in the middle of my desk and pointed it toward a white card at the far end of my desk that was illuminated by a desklamp (tungsten), pressed the ATW button and got a 3200k setting, spun the camera around toward the end of the desk that is lit by indirect sunlight (6600k) and the camera adjusted within seconds. However, if I repeat this test and first point the camera at the 6600k end of the desk, press the ATW button and get the proper white balance, spin the camera back toward the 3200k end of the desk, it just sits there staring at that same white card and does nothing! No change to the white balance....at all. I gave it over a minute or two and nothing changed.

And, if that isn't confusing enough, the camera will only make ONE change in ATW. If I start the shot on tungsten, move to daylight and then back to tungsten, the camera will NOT adjust back....it stays on 6600k. So, it appears that you get ONE adjustment and that's all. I'd be very curious to see if anybody else here gets the same result.

As I said before, I don't want to use Auto "anything" but this client wants one continuous shot and I'll be passing in and out of rooms lit by both daylight and tungsten and probably a fluorescent-lit laundry room or two as well. And, to add insult to injury, he showed me some test walk-thru's that he shot with his crappy little Sony Hi8 camera and he had no problems with these transitions. But, he wants to hire me so he can have these houses in beautiful 16:9 HD (which will all be downsampled to web videos anyway).

I know the carpenter never blames his tools for a crappy product, but this is ridiculous. If I had the money, I'd probably go out and buy a cheap HD camera for these projects just so I wouldn't have to fight with the EX1. Any suggestions?

[Buck Forester]

I don't use ATW anymore, even for run and gun stuff. What I wish the EX1 did better was auto-focus. I don't use auto-focus very often but there are times when it would be beneficial if it were quicker. My little HC9 has a much quicker and accurate auto-focus. Of course it's dealing with a much smaller lens, but since we're 'wishing', that's what I'd wish for.

[Bob Grant]

Dave,
simplest suggestion and how it's very commonly done in your scenario is to light everything daylight. Easy enough to change the practicals indoors to daylight. Keep several daylight CFLs in the kit bag and your problem goes away. Keep in mind that a film camera has no ATW.

[Dave Morrison]

Thanks for that suggestion, Bob. Unfortunately, given the nature of this job (No Budget, No Time) I'm shooting these things VERY quickly which usually means no additional lighting added. At some point, my client would simply give up and shoot these things himself. I need the money right now so I'm simply trying to get this $6000 piece of....um, this camera that shoots beautiful images to simply behave like a basic Auto Everything consumer camera. Trust me, I never bought this camera with the intention of using it like a point n' shoot camera but times are hard and I need to make this work. I'll have a very limited span of time available at each site so changing all the practicals makes perfect sense, but....

[Serena Steuart]

Originally Posted by Andy Shipsides

I'd like to see the camera have a quick white balance preset switch (switching btwn 3200 & 5600)

I must be missing something here because my EX1 has exactly that switch.

[Dave Morrison]

I really am curious if anybody in here can reproduce the test I did to see if this is a bug in the camera or a "feature":

1. set camera for Full Auto (with ATW enabled, too)
2. set your White Balance in an area lit by daylight
3. start the shot in that lighting and move into another area lit primarily by tungsten (you don't even need to roll the camera....it works this way all the time)
4. the ATW will fail to adjust to the tungsten lighting by itself

Conversely, if you do the test by starting in the tungsten lit area and move into the daylight lit area, it will automatically adjust (the speed of the change depends on the Shockless White and ATW Speed settings you are using).....and it will only make ONE adjustment during that shot....it won't change back if you return to the tungsten-lit area.....werid.

[Jeff DeMaagd]

Originally Posted by Erik Phairas

I'd be happy with a dail or at least let us grab the color temp in the direct menu and scroll up or down until we like what we see.

I think several things that in the "direct menu" or whatever that's called really need to be separate buttons and not virtual controls and not the cut-down version of that functionality we get with the switches on the side.

Originally Posted by Piotr Wozniacki

I will defend my standpoint. The technology is there (my V1E never let me down with ATW), only it hasn't been properly implemented in the EX series.

White balance setting, at least pressing the white balance button, seems to work pretty well when I try it on my EX3.

[Dave Morrison]

I don't think he's talking about the button not working properly. We're talking about the "Auto Tracking White" function being lame.

[Leonard Levy]

Well Dave I did try playing with the ATW and I think I did what you asked. In short, its true, this circuit sucks and there is no excuse for it from Sony.

Perhaps we should all email Juan Martinez en masse.

My experience was that in general it would adjust to daylight eventually OK. Sometimes it was faster than others and sometimes painfully slow. The fastest seemed to be when I white balanced under tungstun then walked into the daylight room. It seemed slower when walking back and forth between rooms, but I did not test that carefully.

Going from daylight to tungstun was considerably worse . It did always make some degree of adjustment but it only took me about halfway there and was still too warm, though not nearly as orange as when I would first walk in the room.

I had my shockless white turned to off BTW. I imagine since I had white walls that I would have been better off using the shockless white at 2 seconds or so and trying to have some white in the picture while hitting the white balance button as I changed rooms. Not avery elegant solution though. It truly sucked.

I haven't needed it yet but someday I'm sure I will.

[Max Allen]

Nice posts Tom Roper, I hope your tests continue. As for ATW, have been shooting and engineering for close to 30 years myself, as if that number means much. In my opinion it is just another tool in the bag. After analyzing temperature variations, there have been situations where I've used ATW across several applications. Painting many cameras in a live broadcast situation, shooting ENG and EFP, studio, SD and HD. I've received a few statues for my work and some seem to think that I'm good at what I do, but I don't really.

ATW is obviously not a first choice. When it first came out we had B+W viewfinders, no color LCDs. Shooters came back with unexpected results. The key to using ATW is to realize that it is neither accurate nor reliable. Sony realizes this. But, tungsten to daylight typically seems to produce roughly workable results. And if you only have a black and white viewfinder I would refrain. ATW is my last choice. But saying ATW is for amateurs is like saying you're an amateur if you use auto iris. Over several thousand jobs I have probably used ATW more than I have auto iris, after I know what I'm dealing with.

Normally, I balance a camera to a test chart with a scope and a remote control panel and store it in my silo of scene files. If I don't have a chart, I manual white balance rather than auto white balance. I haven't tested the EX1 ATW yet so can't comment. Just to say, until you know what is happening inside the camera and how to work with the technology's limitations, hesitate to knock it. ATW can be useful.

For Dave's walk-through job, I believe you can store 3 temps with EX1 using Preset, A and B and just flip through them as you hit different temperatures. Use Shockless white to ramp the change so in effect you will have 'manual ATW'.

Cheers

[Dave Morrison]

Originally Posted by Max Allen

For Dave's walk-through job, I believe you can store 3 temps with EX1 using Preset, A and B and just flip through them as you hit different temperatures. Use Shockless white to ramp the change so in effect you will have 'manual ATW'.

Cheers

Thanks for the tip, Max. I guess I misunderstood how "Shockless" worked. I thought it only worked when using ATW. I didn't realize that it would affect the WB changes as you flipped the physical switch. I'll have to play with that tomorrow.

[Mike Chandler]

Originally Posted by Doug Jensen

I agree that the EX1 and EX3 should have a 3200/5600 toggle switch for preset white balance. That was a big oversight by Sony.

Originally Posted by Serena Steuart

I must be missing something here because my EX1 has exactly that switch.

Serena's right. If your WB menu is set for preset, mem a, mem b, and atw assigned to an assignable button (say, instead of "lens info"), you can set your white balance on A for 5600 (by finding a source at that CT and setting WB). That gives you preset 3200, A at 5600, B for white balancing off a card, and ATW for tracking changes on the fly,( so long as you don't change the wb on your A setting.)

Originally Posted by Dave Morrison

I really am curious if anybody in here can reproduce the test I did to see if this is a bug in the camera or a "feature":

I'm not getting your result, Dave, but Full Auto Mode makes the atw transition even slower. In both manual and auto mode, the atw does change from tungsten to daylight and back again, but in full auto , the change takes twice as long. I'm also noticing that Tom's brightness variable comes into play. In manual mode, when changing from tungsten to daylight, the atw kicks in after 1-2 seconds, whereas when moving into tungsten from daylight, the change never takes less than 5 or 6 seconds. In full auto mode, however, those times are more than doubled, with atw kicking in on daylight after about 5 seconds and in tungsten after 10.

The shockless white setting at 0 vs. 3 makes the atw kick in marginally faster, but the atw speed is irrelevant as to when atw will kick in. It simply quickens the change once it does kick in. I could never get the tungsten balance to happen more quickly than 5 seconds, and as Bob says, this may be a function of the ex3 taking more into account, or...it just sucks.

The question remains as to the utility of atw. Is it better to have it on with the change coming in belatedly, or to simply shoot w/out it, leave one of the color temps incorrect, and then correct that one in post? I think it's better left to post, where you can dissolve the change in precisely. Or leave atw on, and just correct the first 2-10 seconds of each transition, tho I'm thinking that would be more difficult to do.