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Sony DSR-450, auto-iris, lens setup,"Burning"


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#1 Gabriel Gordillo

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Posted 26 September 2007 - 12:13 PM

I own a Sony DSR-450, my lens is the Canon 20x (YJ20x8.5B KRS). When I am shooting indoors using my onboard Frezzi 35w light, my subjects faces tend to be 'burning' as the whites are greatly overexposed. Using the manual iris mode obviously helps bring it down but the viewfinder and the lcd (which shows everything overexposed, bad quality screen), does not help me gauge the amount of light that should be cut down. Using the zebras have helped somewhat but my overall picture gets darker, I also played around with the knee slope and point and that has aided it slightly.

However if I shift my lens to AUTO iris, the sensitivity of the iris is very minimal, it will leave the picture overexposed, this happens also if I am shooting a subject outdoors with a cloudy sky, I have searched for my lens in the MENU lens setup page but I am not sure if that will help in the issues I am having. Any suggestions or ideas will be very well appreciated.


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#2 Michael Nash

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Posted 27 September 2007 - 05:17 PM

I'm not that familiar with the 450, but other Sony cameras have a menu item for AUTO IRIS that allows you to adjust the exposure + or -, in what amounts to about 1/3 or 1/2 stop increments. Other Sony models have a hard switch or button the side of the camera that allows for backlight/spotlight adjustment of the auto iris (you want spotlight, in your case). The 450 might also have a user-assignable button that can control auto exposure level.

But the better thing to do, as an operator, is learn to use your zebra stripes and expose manually. Setting the zebras to 70% should leave just a tickle of stripes visible in the highlights of a Caucasian face, when "properly" exposed. If you're spotlighting a face and you expose for that, the overall image will be darker. You can't have an even exposure across the whole frame if the scene isn't evenly lit! You may need to dim or diffuse your onboard light.
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#3 Daniel Sheehy

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Posted 27 September 2007 - 10:02 PM

Using the manual iris mode obviously helps bring it down but the viewfinder and the lcd (which shows everything overexposed, bad quality screen), does not help me gauge the amount of light that should be cut down.

Sounds like neither the viewfinder, not the LCD are set up correctly... have you adjusted them using the colour bars?
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