snapsy wrote:
The bands also don't look like the typical Sony PDAF banding - the rows are too regular for that.
OP, can you PM me one of the affected raw files? I'd like to take a closer look.
The rows are not regular, they are noticeably tighter spaced on the (far) left to the center and right. The spacing is not random though, it gets narrower gradually as you move to the left.
mcbroomf wrote:
The rows are not regular, they are noticeably tighter spaced on the (far) left to the center and right. The spacing is not random though, it gets narrower gradually as you move to the left.
I meant regular in terms of what the Sony PDAF row distributions are.
Thanks for the raw. The bands occur in all four color channels. With the image oriented in landscape, the bands are about 40 pixels apart at the top of the image and gradually increase to about 75 pixels apart near the bottom. The bands are rather diffuse, which indicates it's not a sensor readout/ADC issue. Based on the total image height of around 5320 pixels and approx total number of bands, this implies a frequency somewhere around 120Hz, which might support an RF interference theory.
GabrielPhoto wrote:
The times I had banding like that with HSS was because EFCS was on. I disable EFCS anytime I am shooting over 1/1000 specially if I am using flashy and never have that issue after I disable it. Still was hoping for an option to set up a specific speed where EFCS will disable automatically.
Never even disabled EFCS yet so I have no idea what happens when you do. Why can it be disabled anytime you shoot strobes and mechanical shutter even if you shoot at lower shutter speeds that 1/10000 sec? Are there any cons with EFCS disabled?
Anyone figured out what is causing this issue? I just starting seeing it on some of my shots.
I first thought it was due to the flicker inside, but then I also got a few shots outside with the same settings at random times. I don't recall if I was using silent shooting or not though.
I will make sure I keep tabs on the settings next time I encounter this. The banding I'm seeing is more space out, only like 9 horizontal bands spaced out evenly across the frame.
snapsy wrote:
The bands also don't look like the typical Sony PDAF banding - the rows are too regular for that.
OP, can you PM me one of the affected raw files? I'd like to take a closer look.
I get this when using the A9 and HSS all the time above 1/2000s WITH EFCS.
Under HSS the flash is fluctuating. Usually the frequency is so high, that one considers the flash exposure as a kind of continuous light. Old Canon flashes were said to fluctuate at 40kHz. Nikon claims to use 75khz. Reports are there that the cheaper Chinese flashes use much lower frequencies. So it is possible, that you see these bands with EFCS on and even with mechanical shutter (example below). The A7riii shutter needs 1/250s to pass the sensor, not that fast, many DSLRs are faster.
Kronologix wrote:
Anyone figured out what is causing this issue? I just starting seeing it on some of my shots.
I first thought it was due to the flicker inside, but then I also got a few shots outside with the same settings at random times. I don't recall if I was using silent shooting or not though.
I will make sure I keep tabs on the settings next time I encounter this. The banding I'm seeing is more space out, only like 9 horizontal bands spaced out evenly across the frame.
I had this exact same phenomenon with the silent shutter, indoors.
From what I understand from another thread, this happens when you are exposed to certain kinds of AC lighting and your shutter speed is different from the AC power frequency. The workaround is to use a shutter speed close to that frequency or the next multiple, i.e. 1/60 or 1/125 (North America) and 1/50 or 1/100 (depending on AC power frequency in your country). I actually tried this solution here (Canada), and the banding disappeared when I switched to 1/60 or 1/125. So if you want to use the silent shutter indoors, it might be a good thing to do a few tests before the actual event.
I assume that this can still happen if you are exposed to some kind of pulsing light outdoors.
This is 100% an HSS + EFCS issue. My A6300 will start to band in HSS after around 1/500 with the normal shutter setting (EFCS On). Need to disable EFCS to solve this. These cameras use what's equivalent to 50% silent shutter by default. The shutter doesn't need to open to start the exposure with EFCS, so the camera starts it by immediately reading the sensor line by line, which creates the banding.
Disabling EFCS will cause a double shutter reaction:
1. The shutter will close as soon as you hit the shutter release button.
2. The shutter will open to start the exposure.
3. The shutter will close again to complete the exposure.
It's not as instantaneous as EFCS On, but it's not terrible like DSLR Live View (similar function).
And yes, banding will also be caused by using the silent shutter indoors with artificial lighting. Similar issue, but a different way of achieving it. Only a global shutter will solve these problems.
Now, for a solution, one thing you can do is to shoot an evenly lit wall/foam board with the same settings and flash/strobe/artificial lighting. Fire off a few shots, as the banding will move around a bit. Then you can add one of those images as a layer over the original banded image in PS (16-bit TIFF), invert the color, and use it as a luminosity layer to cancel out the lines. Note that if you use anything like Clarity or Dehaze, they will alter the edges of the banding, so save that for a final trip in your RAW editor.
