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Sony HVR-Z1 / HDR-FX1
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Old July 18th, 2006, 12:39 PM   #1
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Exposing for HUGE contrasts

This may be a question Boyd would have experience with...

I have an FX1, so some of the niceties of the Z1 aren't available to me (this year!).

When filming staged productions as a third party (e.g., dance shows, etc), you never have control over backdrops, costumes, etc. So I'm wondering the best way to account for a variety of extremes in exposure. The light level never changes, but the contrast and levels vary widely based on costuming.

Here's a setup I was recently at:
  • Portable stage, camera centered about 40 ft away.
  • Backrop: Black fabric arch with alternating bright orange/red strips hanging in the back of the arch (all behind the stage).
  • Lighting:
    • 4 Par 56/300W each w/Bastard Amber filter, camera left (40ft from stage).
    • 4 Par 38/150W each, w/No-color blue filters, off of the front corner *stage* left (camera right--about 10ft from stage).
    • 8 Par 38/150W each, pale lavender filters, flanking stage left and right (4 each side).
Performers skin ranged from white to hispanic. Costumes were ranging from deep purple velvet to bright bright white cotton (thankfully not all at once...).

I kept the camera on 1/60, with F-stop ranging from 1.8 to 2.4. Gain was +3db.

In the end the bright whites were very hard to work with against the background. There was plenty of detail, but when I color-corrected to bring out that detail, of course the other stuff was WAY dark!!

Anyhow, I got everything color-corrected to a more-or-less acceptable level (the orange and red backdrop kindof run together, still...). However, life would be better if I could correct the exposures in camera. Are there any tips/tricks with the FX1 (or Z1 that might be applicable) that can help in this situation? Does anybody have Picture Profile settings the you switch between for this kind of stuff?

There are, unfortunately, not rehearsals for these events, so I must be prepared in advance. I just find it difficult (for example) trying to go from filming a black-velvet costume against a black background to filming a white costume against a the same background. Keeping in mind the only thing I control is the camera & sound....I'd like to have some camera settings written down or something that I could switch to for different exposure requirements, and some suggestions from those more experienced seems like a good starting point.

Thanks,
Matt
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Old July 18th, 2006, 12:59 PM   #2
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Matt, these are very tough situations to deal with on any camera and smaller DV cameras are even tougher since you don't have the iris control at the lens.

My best suggestion is, before the show, have the lighting guy bring up the lights to the brightest and get a grey card or even a white card. You never want to over expose, especially on skin tones. I would rather under expose by a stop or so and color correct, or level correct in post shot by shot.
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Old July 18th, 2006, 01:14 PM   #3
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Yeah, it is really tough to deal with these problems and I don't have any suggestions other than shooting in manual and riding the iris knob the whole time. Basically you're just dealing with the limits of DV/HDV for a situation where you can't control the lighting. Wide shots will always be the biggest problem. If you can stay zoomed in on one or two people much of the time then there are usually less issues.

I also agree that you should underexpose when in doubt, since once you've blown out the highlights they can't be recoverd in post. Fortunately the FX1 and Z1 have pretty nice iris controls which allow subtle changes once you get used to the knob. My VX-2000 and PDX-10 are much worse at this; there's no way to make a manual change that doesn't show as a noticeable jump in brightness on those cameras.

Are you using zebra patterns? They help a lot. I leave mine set at 100, and this gives me a good idea of how far I can go without blowing something out. Once you have some experience shooting performances you start to understand what the finished video will look like based on what you see on the LCD, and this helps a lot. But beyond that, I really don't think there's a lot you can do.

Have you looked at our "sticky" about shooting performances?

http://www.dvinfo.net/conf/showthread.php?t=60275
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Old July 18th, 2006, 05:22 PM   #4
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Boyd, Michael,
Thanks for the responses. I actually have some of those sticky's subscribed to, I think. I should read them again.

I really wish the iris knob were better located (now that I've used it a bit). It's really hard to pan, focus, shutter adjust, and iris adjust (e.g., catching somebody walking down the dark aisle up to the stage...) at the same time! A Lanc with iris control added would be nice...Even so, it sounds like the iris is my best option, with maybe the push-to-focus button. I turn zebras on every once in a while--perhaps I should just leave them on and that would help...

And practicing the camera adjustments on a regular basis, which I just this second thought of (again!).

Thanks,
Matt
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Old July 18th, 2006, 05:58 PM   #5
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Why are you adjusting the shutter speed as you shoot? That could make things look strange...
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Old July 18th, 2006, 08:10 PM   #6
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In the FX-1 you have many profiles. P-1 is used for HDV and P-2 is used for 4:3. Inside the menu is the AE menu. When TAPING a play, use the AE to cut down on the overexposed areas and lock it in to the minus area. This prevents that common "Que-Tip" look of the actors faces in the wide shots.

Do not use shutter speed as it causes mud in dark areas and can fool your DOF....causing focus problems.


The problem with stage shows, especially wide shots, is the contrast ratio in regards to lighting. 1/3 inch chips are notorius for making uneven lighting worse in the contrasted areas.

The AE function, when adjusted manually is a secret that few shooters utilize. Most shooters play all night long with Zebra stripes and iris control, which causes dark then light contrasts.

Lou "FX-1" Bruno
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Old July 18th, 2006, 09:41 PM   #7
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Boyd,
I only rarely play with shutter speed--if a performer is entering from the back where there is no light, I like to get at least a little bit of exposure. Usually the iris and gain can handle it, but sometimes not. but again, only rarely!

Lou,
The FX1 manual really doesn't say a whole lot about the AE Shift feature. There's a lot on the 'net about cameras featuring AE Shift controls, but not much theory. Any pointers to some documentation, or is that a visit to the library for photo/video books? Also, do you ever mess with the AGC limit?

Thanks,
Matt
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Old July 18th, 2006, 09:58 PM   #8
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I've adjusted the shutter during stage performances without any strange problems. In fact it worked out quite well. I adjusted it from 60 to 250 depending on the brightness of the stage.

I found it gave me smoother results than adjusting the iris and it gave me more room for adjustment.
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Old July 19th, 2006, 03:20 AM   #9
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I was nosing around the Tiffen site this morning, noticed the "extreme contrast" filter. Dampens highlights without blooming, apparently.

I'm often in a similar situation, but use the Z1 (with black stretch) - it's worth it! :)
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Old July 19th, 2006, 07:34 AM   #10
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I limit most of my cameras when I observe excessive grain. 15 db is fine in the FX-1. AE SHIFT is NOT a commonly used function as it always involves a menu setting. However, videographers have used the setting more often for dance and stage shows. Unless the light is constant or not too contrasty, stay away from higher shutter speeds.

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Originally Posted by Matt Vanecek
Boyd,
I only rarely play with shutter speed--if a performer is entering from the back where there is no light, I like to get at least a little bit of exposure. Usually the iris and gain can handle it, but sometimes not. but again, only rarely!

Lou,
The FX1 manual really doesn't say a whole lot about the AE Shift feature. There's a lot on the 'net about cameras featuring AE Shift controls, but not much theory. Any pointers to some documentation, or is that a visit to the library for photo/video books? Also, do you ever mess with the AGC limit?

Thanks,
Matt
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Old July 19th, 2006, 08:09 AM   #11
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I use 12db of gain on my FX1 most of the time in these situations, 60th, indoor preset, PP2, zebras at 100% to make sure faces are OK. White costumes will sometimes be too bright and need some realtime adjustment of iris. These settings will give exposure in most cases of bright dance shows etc of about F4 to F5.6 which will give good depth of field. I focus once close to front of stage and leave for the show. I too would like black stretch for these situations. It is interesting that my old Sony PC10 has much better detail in the shadows than the FX1, the worst is my TRV50!!

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Old July 20th, 2006, 01:06 PM   #12
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That's the thing the common consensus is to stay away from changing the shutter speed. When the camera is in auto it changes the shutter based on light without anyone the wiser. This led me to experiment with the shutter for a stage show in manual mode.

I've done stage show where I have changed the shutter (don't know if 250 is high. I don't think it is) and it has worked at well. It gave me more increments of subtle changes than adjusting the iris alone. This was on a sony pd 170.

However, I have found no one to verify this as a valid technique except for the auto mode in a sony camcorder.
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Old July 21st, 2006, 12:54 PM   #13
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regarding the Tiffen 'extreme contrast filter'....i've read in a book called 'dv shooter' today that filters to control contrast need to be carefully matched to specific cameras as results are so variable, and in the authors experience the best for the fx/z cams is the 'Tiffen half black diff'

If i've understoood correctly these are actually diffusion (ie:softening) filters.

From a stills background i can understand why they could create the impression of less black blacks and take off some of the harshness of dv but i dont see how they actually give any more info in shadows.

Then theres the 'side effects' of softening!

Anyone have a better understanding of their relevance/effectiveness for contrast control??

(hope this still falls within topic!)
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Old July 21st, 2006, 01:20 PM   #14
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Quote:
Originally Posted by Michael Donne
regarding the Tiffen 'extreme contrast filter'....i've read in a book called 'dv shooter' today that filters to control contrast need to be carefully matched to specific cameras as results are so variable, and in the authors experience the best for the fx/z cams is the 'Tiffen half black diff'

If i've understoood correctly these are actually diffusion (ie:softening) filters.

From a stills background i can understand why they could create the impression of less black blacks and take off some of the harshness of dv but i dont see how they actually give any more info in shadows.

Then theres the 'side effects' of softening!

Anyone have a better understanding of their relevance/effectiveness for contrast control??

(hope this still falls within topic!)
Filters per se don't give more info into the shadows. What happens is that they allow you to open the iris a bit more and then details show up.

But contrast filters are a delicate question for DV, and HDV perhaps to a lesser degree. They tend to soften the image and that leaves it a bit unfocused, IMHO.

About the Tiffen filters: aren't you referring to "black dot" filters?
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Old July 21st, 2006, 02:11 PM   #15
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Well, i'm just quoting a book and dont really know what im talking about so i have no knowledge of 'black dot'....the book said 'half black diff/fx' i'm sure.

I notice a topic here http://www.dvinfo.net/conf/showthrea...ghlight=tiffen the last reply on which gives a reference to a tiffen tutorial....that throws a bit more light on the subject and leads me towards a 'black diff fx 3' or maybe 'black pro mist 1'.

your explanation Carlos makes sense....are you saying on balance you personally wouldnt take this option to counter contrast because resulting softening is unacceptably high (maybe a daft question cos i guess it depends on content....im interested from the point of view of shooting room interiors i dont have the option to light)?
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