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Sony VX2100 / PD170 / PDX10 Companion
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Old May 1st, 2006, 01:17 AM   #1
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Zebra.

I have never really used the zebra mode on my vx all I know is that it is used for adjusting exposure levels and what exactly do the nd filters do? My vx demands them on everytime is bright/too much light is it just a light reducer? I heard that its no good to use your nd filters something to do with quality of the picture its best off using your exposure and shutter speed.
But back to the main question, whats the point of having 2 zebra modes 70 and 100? I would like to master the zebra/lighting technique with my vx.
can someone please help me.
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Old May 1st, 2006, 01:45 AM   #2
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If you switch your zebras on (either the 70 or 100 - it doesn't matter) and go outside into the sunlight with the camera in the auto-exposure mode, you'll get an idea of what the camera will 'tolerate'. I suggest you use the 100 setting for starters as the zebras will then show you the area of the picture that will be 'pure white' on your TV screen.

If you then switch to the 70 mode the zebras come on screen as an 'early warning system'. Areas that have 70 zebras are in danger of becoming white-outs, but you're still safe. Lots of folk like this mode better - I don't, but it's what you're used to that matters.

Now when you shoot in manual exposure (as you invariably should with movies) you'll get a zebra 'warning' when areas of your frame are whiting out. If this gets too much then you can dial down the aperture, raise the shutter speed or introduce ND filtration - all of which reduce the exposure on the chips.

Now to the ND filters. It's very important you use these as diffraction at small apertures causes loss of sharpness. NDs are much better than using high shutter speeds (for various reasons), so use them whenever possible, and often before the v'finder silently screams for them.

Believe me, using the in-built NDs gives much smoother, better movies than using high shutter speeds - but then you can test this for youself today. Video is the great teacher; silent, accurate, repeatable, forgiving, cheap and reliable. The v'finders are wysiwyg, so go forth Garrett and experiment.

tom.
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Old May 2nd, 2006, 01:14 AM   #3
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thanks alot for your very informative reply and useful information.
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Old May 2nd, 2006, 01:55 AM   #4
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Thanks for your feedback Garrett. Let us know how you get on. I should add that the slow shutter speeds can be very useful for special effects and for stationery nighttime shots, but remember that when you drop below the default 1/60th (NTSC) you lose half the vertical resolution.

But shooting at f/4 and 1/3rd sec at night will still look a lot better than shooting at 1/60th and max aperture and +18dB of gain up. High shutter speeds are also very useful when you use the VX in the progressive scan mode as a motor-drive still camera. Don't use the ND filters in this case, simply up the shutter speed to sharpen each frame and soak the light.

If you go too far - to 1/1000 sec and faster, say, CCD smear becomes a bit of a problem, so beware.

tom,
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Old May 2nd, 2006, 02:42 AM   #5
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a 70% zebra pattern indicates proper exposure for blue sky, green grass and with a touch of zebra around the edges of a caucasian face that will be spot on too. Always approach the proper exposure from the underexposure side when using zebras.

100% zebra indicates the max exposure if you want to just have a bit of detail at that spot in a scene. 100% zebra is not overexposure on any of my Sony cameras but it is close.
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Old May 2nd, 2006, 03:22 AM   #6
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Good points Mike - approaching the zebras from smaller apertures is important because of the hysterysis loop built into the system - i.e. the zebras appear at a different exposure point if approached from wide apertures.

And so too on mine - I still have a small amount of detail recorded even when the 100% zebras are filling the area. This is fine on the timeline and my connected monitor, but I've noticed that this last vestige of detail can disappear when replayed off DVD on other people's TV sets.

The zebras are also an on-board indication of the vignetting that occurs with all lenses at wide apertures. It's easy to demonstrate, you aim your camcorder at an evenly lit grey card (say), turn on the zebras and open to maximum aperture. Then change the shutter speed to bring the zebras in and out and you'll notice the edges of the frame lag a good two stops behind the centre.

Nothing to worry about of course unless you're a fanatical shooter of artist's paintings or if you plan to stitch progressive scan stills together in Photoshop.

tom.
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Old May 5th, 2006, 05:02 PM   #7
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I was almost going to post a zebra thread myself.

I was shooting a slide presentation where a doctor is in a white coat at the podium in low light seemed like the auto setting was overexposing it. I was using 100% zebra and his face and coat was getting zebraed. I'm not sure if its better to under expose by a little. Its confusing because with digital photography you don't ever want the high lights blown.
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Old May 6th, 2006, 09:00 AM   #8
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That's right; treat digital photography like shooting slides - you get back what you shot. Colour neggaitive film will take three stops of over-exposure easily, but digital must not be over-exposed as once it's gone, it's gone.

Sounds like you could've made good use of the spotlight mode, Pete. It's a very intelligent mode (unlike the backlight mode) so go on - give it a go next time you have white man in white coat on dark stage.

tom.
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