Weird valleys in histogram, 0 sharpness?

[AlphaZeta00002]

Hoping to get started soon capturing in VirtualDub with my ATI 600 USB (thank you LordSmurf!). I noticed while trying to drop to zero sharpness my histogram looks weird with pronounced "valleys". Wondering if this is an issue, and if I should just capture at Sharpness = 1 to avoid? I have an ES15 inline from a Sony handycam with built-in TBC functionality as well.

As a bonus question, should I capture from 16 to 255 per this post? Or would I be better off capturing between 16 - 235?

[lordsmurf]

These are posts about this. It's essentially a quirk of the ATI 600, but not a negative.

Remember that histograms are measurement tools to assist, to aid. Starting at graphs alone will also yield non-quality video. So look, use, but don't OCD over-analyze. Use your eyes, too.

[AlphaZeta00002]

Okay - I'll be sure to factor that advice in.

I have seen some conflicting info on my second point. Is my understanding correct: the 600 USB can picture from the range of 16 - 255 (red on the right hand side of the histogram). This means we capture "illegal" values in the YUV space? I'm a little confused on when/if I would need to press back to a 16 - 235 space? Or is it best practice to just capture in the 16 - 235 space to start? Sorry for the confusion on my end.

[lordsmurf]

16-235 is the legal space, 0-15/236-255 is illegal for YUV. You can either adjust values legal with a proc amp, or these get concatenated/clipped. Most capture cards only capture legal, not an expanded illegal range.