We're using my DVX100A to shoot black actors in bright white T-shirts. The extreme contrast is a problem. I'd like suggestions on what settings to use to reduce the contrast so I don't have so much popping at 100% video level. We can't change the costumes and we are already trying to control the lighting. I'm wondering what gamma settings to use to reduce our extreme high contrast. Thanks.
reduce contrast with settings?
- Thread starter dcragoe
- Start date
scannon
Well-known member
This ia a tough one as you have the extreme contrast on the prime subject itself not spread across different ares in the scene..
Cine gamma has the least contrast and more film like response but no knee protection. The other Cine gamma's D and V add a bit of noise but have knee protection.
Both Low and high gamma have mild shifts.
Try tests with normal, cine-like D and low gamma's If you use cine-like you won't have the abilty to set the knee response manually as it has none and you can blow out the highlights so if you try this be careful with lighting.
Try Knee set to low to start rolling off IRE at 80% (or 90% depending on how your zebra's are set). Mid would start to roll off IRE at the mid point between the low and high levels set for the zebra's
Also experiment with Master Ped in the + range. As you increase this the blacks become lighter but too much and the image muddies.
S Cannon
Cine gamma has the least contrast and more film like response but no knee protection. The other Cine gamma's D and V add a bit of noise but have knee protection.
Both Low and high gamma have mild shifts.
Try tests with normal, cine-like D and low gamma's If you use cine-like you won't have the abilty to set the knee response manually as it has none and you can blow out the highlights so if you try this be careful with lighting.
Try Knee set to low to start rolling off IRE at 80% (or 90% depending on how your zebra's are set). Mid would start to roll off IRE at the mid point between the low and high levels set for the zebra's
Also experiment with Master Ped in the + range. As you increase this the blacks become lighter but too much and the image muddies.
S Cannon
Last edited:
scannon
Well-known member
Yes, think of knee as gain in reverse. This circuit detects the intensity of the brightest part of the image and rolls it off (tones it down). In Auto, the circuit determines what it thinks the start point is and adjusts. On Low, anything above 80% IRE gets trimmed back. Low can have the affect of making white look grey but may be necessary. Mid will start at 90% and High @100% out of 109% where all video detail ends.
In digital video 0% is black and 100% is max acceptable brightness. The knee setting is in the scene file settings of F1-F6. You can manually adjust this or leave it on auto (where I assume it is now).
The lower you set the knee the more you extend the camera's dynamic range (the spread between preserving details in shadows and highlights) at the potential for graying white.
Running some tests using the different settings previously suggested may provide an acceptable look that you currently don't have.
BTW if you don't have Barry Green's DVX book and DVD you should get it. It covers all of this and more in great detail and the DVD shows visual examples of how each of the sceen file setting affect the video. It is a very good investment. See the link below.
http://www.dvxuser.com/articles/dvxbook/
Good shooting,
S Cannon
In digital video 0% is black and 100% is max acceptable brightness. The knee setting is in the scene file settings of F1-F6. You can manually adjust this or leave it on auto (where I assume it is now).
The lower you set the knee the more you extend the camera's dynamic range (the spread between preserving details in shadows and highlights) at the potential for graying white.
Running some tests using the different settings previously suggested may provide an acceptable look that you currently don't have.
BTW if you don't have Barry Green's DVX book and DVD you should get it. It covers all of this and more in great detail and the DVD shows visual examples of how each of the sceen file setting affect the video. It is a very good investment. See the link below.
http://www.dvxuser.com/articles/dvxbook/
Good shooting,
S Cannon
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