p.1 #1 · What causes this? (silent mode Sony A7R II)
I'm reviewing a rented Sony A7R II. Took some pictures in silent mode in a restaurant and got these weird stripes. They were gone when I shot in normal mode. I assume it's the lighting in the place that causes this, as I didn't encounter it anywhere else (including in a bank building with fluorescent lights).
Does anybody know what kind of lamps those are and what this effect is called?
p.1 #4 · What causes this? (silent mode Sony A7R II)
johnvanr wrote:
I'm reviewing a rented Sony A7R II. Took some pictures in silent mode in a restaurant and got these weird stripes. They were gone when I shot in normal mode. I assume it's the lighting in the place that causes this, as I didn't encounter it anywhere else (including in a bank building with fluorescent lights).
Does anybody know what kind of lamps those are and what this effect is called?
Thanks.
This is well known in the mirrorless world due to a non-global electronic shutter. Your silent mode does not capture the entire image from the sensor in one instance, instead the exposure starts at the top (or bottom) of the sensor one line of pixels at a time until the bottom (or top) line of pixels is reached. This total exposure time, even though each line of pixels is exposed for a short time, takes about 1/15th sec or so. Thus for 60 Hz lighting you capture 4 full sinusoidal cycles of variation in the light output as the sensor lines get exposed from top to bottom of the sensor. You can't use silent shutter in this situation.
On my m43 gear (GX7) I've been caught by this and have to remember to turn it off.
p.1 #5 · What causes this? (silent mode Sony A7R II)
jhinkey wrote:
This is well known in the mirrorless world due to a non-global electronic shutter. Your silent mode does not capture the entire image from the sensor in one instance, instead the exposure starts at the top (or bottom) of the sensor one line of pixels at a time until the bottom (or top) line of pixels is reached. This total exposure time, even though each line of pixels is exposed for a short time, takes about 1/15th sec or so. Thus for 60 Hz lighting you capture 4 full sinusoidal cycles of variation in the light output as the sensor lines get exposed from top to bottom of the sensor. You can't use silent shutter in this situation.
On my m43 gear (GX7) I've been caught by this and have to remember to turn it off....Show more →
p.1 #6 · What causes this? (silent mode Sony A7R II)
Others will surely have a better, more complete explanation than the one I gave, but it's a start.
When someone comes out with a truly global shutter - i.e., all the pixels get exposed at the same time - this will be eliminated to a great degree.
Mechanical shutters technically suffer this same issue as they typically take 1/250 sec or so for the exposure to happen - the time between the leading and trailing shutter may be 1/8000 sec, but the slit travels across the sensor (electronic or film) at a relatively slow pace. 1/250 sec is too short to resolve a 60Hz variation in light output so you don't see it (though you may see a slight overall image brightness variation from shot to shot - it won't be very much.
p.1 #9 · What causes this? (silent mode Sony A7R II)
If you look at the stripes you can see their color changes from a brownish red to a green during each half cycle. That's because the many different color phosphors used in the fluorescent lamps all have different decay times. Averaged out to the human eye the light looks white.
p.1 #10 · What causes this? (silent mode Sony A7R II)
Jhinkey got this right. It's the way the CMOS sensor is doing full electronic shutter. Even though you set your shutter to 1/400, the time it scans each line of pixels is far slower. Here's an attempt at a laymen's explanation. Silent shutter is like a horse race. The gun used to signal start is the shutter speed. After the gun is shot, each horse still has to run around the track to get to the end. The image is not fully captured till all the horses crosses the finish line. Each horse represents a line of pixels. The gun shot was instant, but the horses aren't. It's how CMOS, LCD, and memory is read -- a line at a time. I'm not sure what it is for the new Sony sensor, but the performance is somewhere probably in the range of 1/15 - 1/30. Far safer to use the mechanical shutter. This isn't a problem with mechanical shutters.
CMOS silent shutters are really just a one trick pony at the current time. There's a time to trot out that pony, and you really need to know when to use it. It's not something you want to use all the time.
p.1 #11 · What causes this? (silent mode Sony A7R II)
Happens this weekend at a wedding I was shooting with the A7s. Even happened outside with silent shooting. I believe that it is an characteristic of silent shooting.. I switched to normal and the banding disappeared.
p.1 #15 · What causes this? (silent mode Sony A7R II)
a2rob wrote:
Happens this weekend at a wedding I was shooting with the A7s. Even happened outside with silent shooting. I believe that it is an characteristic of silent shooting.. I switched to normal and the banding disappeared.
You should not have issues outside with silent shooting (fully electronic shutter) as the light is not cycling at 50/60 Hz, though if there is any rapid movement you could get some interesting images of moving bits. If you were using EFCS you might have issues at high shutter speeds, but that's another separate issue.
p.1 #16 · What causes this? (silent mode Sony A7R II)
I should also add that not all indoor lighting is going to produce this effect with fully electronic/silent shutter - in that situation I make some quick test images to see if my shutter speeds are going to be problematic and then decide what to do from there.
This a good example of how these wonderfully featured electronic image-taking gizmos require some detailed attention to how they are being used or the user can get a bit of a surprise when viewing the images long after they were taken. I've been caught by the fully electronic shutter on my m43 gear before and now am much more mindful of my settings, particularly for indoor events.
p.1 #17 · What causes this? (silent mode Sony A7R II)
I think I read somewhere that Sony have a patent to eliminate this, along with rolling shutter. The idea is to give each pixel their own memory cell, so during an exposure, the pixel value is stored in the dedicated cell, and then read from there to the memory card. Quite neat!
p.1 #18 · What causes this? (silent mode Sony A7R II)
Here is a good article on electronic shutter effects. It was written for the Panasonic GH3 but applies to all rolling-shutter electronic shutters - the only difference will be the frequency of the bands due to different readout rates
p.1 #19 · What causes this? (silent mode Sony A7R II)
jhinkey wrote:
You should not have issues outside with silent shooting (fully electronic shutter) as the light is not cycling at 50/60 Hz, though if there is any rapid movement you could get some interesting images of moving bits. If you were using EFCS you might have issues at high shutter speeds, but that's another separate issue.
Its the silent shooting operation, even states it in the manual..
p.1 #20 · What causes this? (silent mode Sony A7R II)
sflxn wrote:
Jhinkey got this right. It's the way the CMOS sensor is doing full electronic shutter. Even though you set your shutter to 1/400, the time it scans each line of pixels is far slower. Here's an attempt at a laymen's explanation. Silent shutter is like a horse race. The gun used to signal start is the shutter speed. After the gun is shot, each horse still has to run around the track to get to the end. The image is not fully captured till all the horses crosses the finish line. Each horse represents a line of pixels. The gun shot was instant, but the horses aren't. It's how CMOS, LCD, and memory is read -- a line at a time. I'm not sure what it is for the new Sony sensor, but the performance is somewhere probably in the range of 1/15 - 1/30. Far safer to use the mechanical shutter. This isn't a problem with mechanical shutters.
CMOS silent shutters are really just a one trick pony at the current time. There's a time to trot out that pony, and you really need to know when to use it. It's not something you want to use all the time....Show more →
Does this not mean that you would be unable to freeze movement using the silent shutter for anything moving faster than the readout from the sensor?
