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Over and Underexposure and what's acceptable.


Zack Mahar

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I have a questions about what is acceptable in clipping for the highest quality image.

When I interior scenes with windows, I always start by exposing for the outside, then I bounce light off the ceiling to bring in room tone/ambience and bring up the level. I use a Red Komodo so I there are the RGB clipping bars that I use to make sure i'm not clipping. I try to get as much of the image not clipping in the blacks as possible. How important is it to truly no clip in the blacks. I use false color as well to visualize where I'm clipping and what would be acceptable in the grade. 

Do you bring room tone/ambience in? Is this something done on features? and is there a point of acceptable clipping or should I avoid clipping at all costs?

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Often you do manage shadow contrast by adding a low level fill so things hold some detail and don't fall to total darkness. That said sometimes underexposure is a stylistic choice (as is over exposure). One trick I learned is to bring stills from shots you like into a program with scopes like premiere or resolve. This can help you see the levels DP's work with or tries to achieve for a certain look.

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20 minutes ago, Albion Hockney said:

Often you do manage shadow contrast by adding a low level fill so things hold some detail and don't fall to total darkness. That said sometimes underexposure is a stylistic choice (as is over exposure). One trick I learned is to bring stills from shots you like into a program with scopes like premiere or resolve. This can help you see the levels DP's work with or tries to achieve for a certain look.

That's a good tip. I did that a while ago for color grading reference, but I wonder how much of the exposure in the graded version matches the captured image. 

Should the choice to underexpose be reserved for the grade.

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I’m personally of the mind to leave as little to the grade as possible. Often you won’t be in that room, and even if you are, you are saving them time. I work by the notion of “do i care about _____?” If I do, I make sure it has the right amount of detail, if I don’t, I don’t. I also look at the image to see if something, generally a highlight is distracting or not. If it is, I remedy it, if not, then that’s ok. Some things are incredibly bright, some dark.

That said, for windows, I generally try to hold some detail in the outside and will often ask for sheers to be put over a window in the frame. If possible I’ll also try to ND or net it.

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In general people protect a little extra knowing the footage can be manipulated. Its creates a little safety net to for example overexpose a dark shot .5 to 1 stops from what you want the final result to look like.

But you want to get general feel of the shot in camera. You can only manipulate things so much in color grade —I wouldnt push a shot around more then a stop or maybe 2 in any direction.

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You don't need to achieve zero clipping, remember that clipping is something burned-out to pure white with no detail, but if that clipped area is very small in frame, like when a distant flashlight points into the lens or the sun glints off of a passing car, then it's acceptable and not distracting.

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Burned out / no shadow detail depends on the subject matter. The image has the final say, not the clipping bars. That being said, try to get as much detail as you can in the raw image and finalize it in post. Some scenes with a huge dynamic range are near impossible to get no clipping.

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It's a bit tricky with digital because the issue just isn't when the area clips but how it looks as it clips, and whether it clips at the same point in all three color channels.  So by recording more information, you have more flexibility in how you roll off the overexposure to the clip point so that it feels more organic, like how film burns out.  But on the other hand, you don't want to underexpose everything else too much just to hold onto highlights that you don't plan on seeing anyway!  So it's a judgement call.

Add to that the new twist of HDR mastering, where you retain more highlight information in areas that are burned out in SDR. Sometimes that's not what you want, if you were aiming for a view out the sunny window to just be rendered as a white fuzzy mush but now in HDR you can see detail that you didn't want.

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Here...this is a good example of throwing the exposure rules out the window for some projects. A film by Clara Law...The Goddess of 1967 (2000)

'Goddess Of 1967' (2000) Dance Clip D.D.Teoli Jr. A.C. : D.D.Teoli Jr. A.C. : Free Download, Borrow, and Streaming : Internet Archive

Highlights blown and shadow details lost, but still fantastic! And maybe even more fantastic because of the exposure.

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  • 2 weeks later...

This topic is for narrative productions, sure, where there's usually a lot of artistic input as to how a shot looks. But in videography I find myself stressing about clipping parts of shots but it's often unavoidable. In filming a violin and piano performance recently for instance the pianist had a stand light illuminating her music. But because the scene was filmed in natural room light most of the piano score in front of the pianist was clipped. I just couldn't avoid that, given the necessities of camera placement and needing the pianist in the shot as this was specifically requested. But I don't like the clipped look. If I'd gotten rid of the clipping the whole shot would have been underexposed. Is there any other way around this? Videography is often not easy to get a good look.

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To minimize clipping, you need to use a camera with a good dynamic range and then record all of the highlight information that the sensor sends to the recorder, plus adjust your exposure to at least keep the clipping to minimum.  But generally this means recording raw or log and then color-correcting later.

For anyone shooting broadcast video with no color-correction planned, staying in Rec.709, the only thing that helps is knee compression and formats like Sony HyperGamma (if that's still a thing.) If you can create your own LUT to convert log to Rec.709, you could create something similar to HyperGamma, flatten the signal in the shoulder of the exposure, plus brightness compensation for underexposing the signal to hold more highlight detail. Or if you're shooting video on a mirrorless still camera, often the log option is mild enough to not look bad in Rec.709 with only a minimal correction later needed to restore some contrast.

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  • 4 months later...

@Jon O'Brien, Provided you were hired to document this performance and got there before it started, it may be worth carrying some in-line dimmers in your kit for situations like this. Oftentimes lamps/bulbs are bought without thought to the output and more the aesthetic style. I'm sure since the room was filled with daylight she would have still been able to see her music just as easily. Carrying a few in-line dimmers would give you a bit more flexibility on any jobs you have in the future.

Cheers

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