p.1 #1 · Sony A7 IV Variable Electronic Shutter Problem 1/120s
I encountered an issue shooting an event over the weekend with my A7 IV running the latest firmware 1.01 and using GM lenses. I am finding that the exposure preview will go dark specifically when using electronic shutter at a 1/119.9s shutter speed. It will go dark briefly with AF-S and stays dark with AF-C, although neither affects the exposure if you capture the image. It also goes away if you change by a single increment, for example to 1/120.6. I also believe that switching to MF eliminates the issue, though I need to test again. I also have not tried this in sunlight yet. Below is a video I made after the event at home showing the issue. I start with 120.6 where there is no issue then switch to 119.9 in both AF modes. Below that is an explanation of how I originally found it at the event. I would love to know if others have the same issue and if there is a fix. Here is the video:
For context on how I found this, the event required me to shoot silently using electronic shutter indoors. I visited the venue several days in advance and found that using a shutter speed of 1/119.9 best eliminated banding (closest to double the flicker rate of the lights) and planned to use that on the day of the event. I did that test using manual focus as I was shooting against a white wall to best detect the banding.
On the day of the event I used the same settings and tried to take images using AF and discovered the issue you can see in the video. At the time I didn't know that trying 1/120.6 would solve it. I resorted to using S-AF as the black out was brief and I could still compose. This was not ideal as the subjects were always moving and I wouldn't want to deal with this again. I want to find out if this can be fixed as I chose the 119.9 setting specifically because it had the least banding. The difference with 120.6 was small, but it was still observable when shooting a burst of images.
p.1 #2 · Sony A7 IV Variable Electronic Shutter Problem 1/120s
I just tried this on my A7IV with 50 GM and it does exactly what you're describing. If you turn off the Live View setting then the display doesn't go dark when the AF activates. Unfortunately I'm on the newest firmware so I don't know if this is something that existed on the previous version.
p.1 #3 · Sony A7 IV Variable Electronic Shutter Problem 1/120s
First update: I chatted with Sony support and they asked me to try two things. First:
Turn the camera off.
Remove the batteries and let it sit for a full minute.
Turn the POWER switch to the ON position
Press and hold the shutter button for 30 seconds.
Release the shutter button.
Turn the POWER switch to the OFF position.
Reinsert the batteries.
Turn the POWER switch to the ON position.
Second:
If the first one doesn't help, please follow this one, This step Initializes all the settings to the default settings.
MENU → (Setup) → [Reset/Save Settings] → [Setting Reset] → Initialize
I tried the first and it didn't work. I haven't yet tried the second as I will need to re-load my settings, but I'm doubtful anyway as I don't think I have changed any setting that creates this. I was able to try with MF and as I thought, it doesn't present the issue since the darkening happens when I half-press the shutter. I was able to try this in broad daylight with a fast lens and I found that the darkening is by a certain number of stops. In other words, if there is a lot of light and I overexpose, then I can still see the subject on the LCD when I half-press, but it is quite a few stops darker, maybe 5-6 stops or more. However, the darkening is not from stopping down the aperture as I I have tried this at f/1.4 and the depth of field is unaffected. I will chat with them again.
UPDATE: I chatted with them again and they said they are escalating to a technical specialist team and will email me or call me back.
p.1 #4 · Sony A7 IV Variable Electronic Shutter Problem 1/120s
Also like I mentioned if you go into the settings and turn off Live View Setting the display won't darken, but then you won't see the preview of how the exposure actually looks. According to the manual
Live View setting is under:
Shooting -> Shooting Display -> Live View Display Set
I use back button focus, and it's the same thing. Darkens as soon as I hit the button to activate autofocus.
p.1 #5 · Sony A7 IV Variable Electronic Shutter Problem 1/120s
Based on other observed phenomena like increased visible aliasing on the EVF/LCD during AF it's likely that the sensor's sampling rate changes during AF, probably to increase the number of samples delivered to the AF system to increase speed and tracking performance. I'm guessing the issue you're seeing is a bug between the AF-increased frame rate and the specific rate you dialed in, with respect to how the camera handles the mismatch of rates for the LV feed.
