April 20, 2015 at 10:41PM

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Sony A7S Video Highlights IRE 110

I'm having a constant issue where my footage is overexposed when viewed on the computer. I have to correct this by reducing the highlights from 110 to 100 IRE. Once this is done - the footage looks identical to what is captured in camera.

When shooting I'm exposing correctly - using the Zebras and the Histogram for reference. I would like to find a setting/solution that allows me to capture video without needing to correct the highlights every single time.

Has anyone experience this? OR is this normal for the A7S?

7 Comments

I shot with the A7s a few times, but never experienced this.

First thing to check is your settings for zebra, since it can be set above 100IRE on a A7s.
Second question: is your computer's monitor calibated properly?
Third question: what picture profile or gamma setting do you use when shooting?

April 21, 2015 at 4:54AM

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WalterBrokx
Director, DOP, Writer, Editor, Producer
9535

Hi Walter,

I've tested this using a variety of picture profiles and settings experiencing the same results.

- For general videography I'm using PP1 - Movie - Pro Gamma.
- I have zebra's set to 95%
- No issues with the histogram it tells me the shots correctly exposed.
- When I view the footage in camera it looks perfect.
- Once it's transferred to the computer the highlights are sitting outside of 100 at 110IRE and I have to bring them back down.

My monitor is a DELL U2711 Calibrated correctly with i1 Display Pro.

After speaking to Sony they don't seem to know what's going on here...

April 21, 2015 at 9:36PM

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I'm having this exact issue from an article in 2012.

http://www.eoshd.com/2012/07/mac-avchd-gamma-issues-the-fix/

This Rec.709 portion of a 601 space (16-235 instead of the full 0-255 the FS100 shoots in) is incorrectly remapped to 0-255 by Quicktime....

...There’s also a sudden drop at the transition between light grey and white, because light grey is 235 and the remaining 16 steps of transition to white is not there any more.

So my biggest question is am I the only once facing this problem in 2015 with the A7S?

April 22, 2015 at 9:42PM

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You should color manage your project. Set the color space of your NLE or a grading software, then make sure the app knows what file's color space is. For the precise output external SDI waveform scopes should be used as well.

April 23, 2015 at 10:47AM

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Einar Gabbassoff
D&CD at Frame One Studio
1454

BTW you can't calibrate your monitor to match rec709 or DCI if you don't have a special software such as Light Illusion's CMS or CineSpace and a dedicated probe. And these things are not cheap.

April 23, 2015 at 10:54AM, Edited April 23, 10:54AM

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Einar Gabbassoff
D&CD at Frame One Studio
1454

I shoot slog2, PP2 or PP4, and I did not have this problem: the stripes correctly show overexposure. However, for various reasons one wants to shoot movies in still mode, and when you set exposure, and start rolling, stripes show up, so I might have to do small clips to set exposure correctly in tricky exposure situations where highlights need to be protected... Could this be related your problem?

April 23, 2015 at 12:32PM, Edited April 23, 12:33PM

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Almosh Taltosh
DP/Director
209

Do you have access to an external HDMI camera monitor that has a Waveform display, so you can check the IRE levels when you are shooting ?

September 26, 2015 at 4:11PM

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Guy McLoughlin
Video Producer
32754

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