How to use Sony Exposure Tools for Video
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In this video I describe how to use the Sony exposure tools on Sony mirrorless cameras when shooting video. I demonstrate all of the exposure metering tools including the multi meter, zebras and Histogram on my Sony FX3. I then show how I set my exposure when shooting in different picture profiles including Rec709 and S-log3 and how to use ETTR when using the Leeming Lut.
Table of Contents
These links open the relevant section on YouTube
00:00 – Intro
01:57 – Multi Meter
07:22 – Zebras
12:15 – Histogram
13:40 – Using All of the Tools
14:11 – Using S-Log3
17:17 – Exposing for a dark background
17:46 – Using ETTR with the Leeming LUT
19:22 – Comparing Rec709
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The multi meter reading is marked by the MM icon at the bottom of the display which is followed by the current reading. You can see the meter telling me this shot is 1.7 stops under exposed with the iris at 3.2. The second image shows that corrected with the iris opened to to f/1.8 and the meter reading +-0.0
Multi Meter Modes
I use the function menu to quickly check the metering mode. I have changed the layout of my function menu so you might see different options. See my video on how I set up my FX3 for more details.
Lets start with multi pattern metering. This measures the light in multiple areas in the scene and determines the resulting metering level accordingly. Multi Pattern Metering generally does a great job with judging exposure, especially when a scene is evenly lit.
If increase the back light though the meter reports the image to be over exposed by 1 stop. With the Iris closed to f/2.5 to compensate until the meter says the scene is correctly exposed the foreground now appears under exposed a little.
If this were somebodies face then we may be able to work with that or correct it in post but the important thing to take from this is that when using the multi pattern meter it’s hard to have a good understanding of how well exposed specific areas are within the scene.
Face Priority in Multi Metering
If we jump back in to the Exposure Metering menu you’ll see an option called Face Priority in Multi Metering.
With this switched on the camera will prioritise metering based on any detected faces. It’s important to understand how this works.
As you can see, even though the camera has detected the face here and the face is underexposed the meter is still reporting that exposure is correct and hasn’t adjusted for the presence of a face in the scene. I’ve found that this feature only seems to effect the metering results when using an auto exposure mode. So for instance if I enable Auto Iris you’ll see that the camera will then adjust exposure for the face.
As you can see in the image above, the camera has now adjusted the exposure a little by opening the iris to 1.6, however I’m still not sure that results in correct exposure on the face! (Thanks Gerald).
Centre weighted measures the entire screen and emphasises the area in the middle to meter the exposure.
With the foreground correctly exposed and a brighter backlight in this mode the meter does still detect the brighter background and reports the scene to be 1/3 of a stop over.
With spot metering you can choose between a standard or large spot.
Only the area inside the spot is measured and it’s very useful for measuring specific parts of the scene.
By default the spot stays in the centre of the screen and so you have to pan the camera to measure areas within the scene. One really useful feature is that you can make the spot follow the focus area. To set this go to the Exposure Menu, choose Metering and then Spot metering point and change it to Focus Point link.
With Focus Point Link enabled the metering spot follows the position of the focus point selector. This makes using the spot metering tool much more useful as it allows you to read brightness levels throughout the scene without moving the camera.
Entire Screen Average
As it says in the tin this looks at the entire screen and reports an average metering level.
The advantage of this mode is that it’s less likely to report exposure changes as the scene changes.
Once again this mode doesn’t allow us to ensure correct exposure on the foreground leaving it under exposed so its uses for video in any scene that’s not evenly lit are limited.
Finally we have the highlight metering mode.
Highlight Metering meters only the brightest parts of the scene. This can be useful if you want expose as brightly as possible without blowing out any whites but it’s not very useful for judging exposure of the foreground in this example.
The multi meter can be a useful tool to help with general exposure levels however the zebra display tool offers a more precise way to set exposure for video.
The Zebra display puts moving diagonal lines on any part of the scene that is currently at the brightness level defined by the Zebra settings. This allows you to identify parts of the scene at specific brightness values.
Custom Zebra Settings
When I go in to the zebra settings via the function menu you’ll see theres a bunch of presets that you can scroll through ranging from 70 to 100+. You can choose any of these to display those levels on the screen however I’m going to concentrate on the two custom settings at the bottom, C1 and C2.
Exposing to Middle Grey
Lets start with C1. Firstly you can choose between Standard + Range or Lower Limit. We’ll stick with standard plus range for now and I’m going to set 44% brightness which is where middle grey should fall using a standard rec709 profile.
The range setting allows us to decide how many of the brightness levels each side of our standard setting we also want to include in the zebras. For now lets just leave that at +/- 1 for more precise measurement. As you can see our middle grey is showing zebras at 44% so we have a correct exposure.
Zebras on Skin Tones
If you don’t have a grey card you can also set exposure using any skin tones in your scene. These are going to be less precise than a grey card because skin comes in many shades and is unlikely to be evenly lit however you can still achieve a good exposure with some practise.
If I’m exposing just using skin tones with a rec709 picture profile I like to set my exposure so that skin is just below 70%. I’ll adjust the iris slowly until the zebras disappear from the skin tones. In my opinion it’s always better to be a touch under with skin tones than over when shooting with rec709 profile.
Zebra Highlight Warnings
The other thing we can use zebras for is identifying any areas in our shot that are overexposed to the point of being blown out to white. To help monitor this I use the zebra custom setting C2. I set the type to lower limit which puts zebras over anything thats at or above the setting we choose.
With picture profile 3 I set the lower limit to 108+ which is the maximum brightness for the rec709 picture profile. Now you can clearly see the parts of our image that are blown out to be completely white.
The next tool we have for managing our exposure is the histogram. You can show this by pressing the display button to cycle through the displays until the histogram appears.
The histogram like a bar chart that shows how much information is being stored at each brightness level ranging from black on the left to blown out whites on the right.
In this example you can see that with our middle grey exposed correctly at 44% the whole scene is fitting nicely inside our histogram. If however I raise the backlight the brighter levels on the right of the histogram start filling up with the brightest blown out parts indicated by the bar growing on the far right side.
Whilst the histogram isn’t a great tool for correctly exposing specific parts of the image it can be very useful for having a wider understanding of how the scene is being captured within the dynamic range the camera is capable of recording.
Metering for S-Log 3
When shooting in picture profile 8 (S-Log 3) the recommended middle grey is 41%.
Notice the additional dynamic range we have in the histogram with S-Log 3, with the chart correctly exposed and the same background brightness that we couldn’t capture in rec709 the highlights now fit within the histogram.
It’s also important to understand that when over exposed the histogram starts to fill up at an earlier level. This is because S-Log 3 has a maximum brightness value of only 94% compared to rec709 which goes up to 108%.
With S-Log 3 the C2 zebra settings need to be set to 94+ to show blown out areas. It’s important to understand that if you set this at a higher value then no zebras will be displayed.
Metering Skin Tones with S-Log 3
For exposing to skin tones in slog3 I set my zebras to 52% and then as with rec709 I adjust exposure so that zebras are either just below or just starting to show on skin.