Rolling vs. Global shutters and new security lighting

[PKR]

I love most advancements in technology. This is pretty cool but, maybe not good for some photographers. I don't think film users will have a problem with this?

From PetaPixel:

"LiShield is a Smart LED Bulb Prevents Photos by Confusing Cameras

PetaPixel

LiShield is a new LED light bulb technology that helps protect privacy by confusing cameras to prevent unauthorized photos. The bulb is the creation of a team of researchers at the University of California, San Diego.

LiShield works on any digital camera that uses a rolling shutter and protects a physical scene from photography by flickering its smart LEDs in specialized waveforms to ruin the look of the captured photos with vertical bars across the frame. It can even create colored bars to further “encrypt” the scene as well as convey other information within the patterning.

It does have a weakness, though: the team says that protecting against cameras with a global shutter is impossible for LiShield.

The ability to randomize the waveform means that it is protected against recovery methods that might work to counteract the effect of the LiShield. On the flip side, “authorized” cameras are still able to shoot images, as the LED will communicate the waveform it is using so that a clean image can be recovered.

The waveforms create a barcode, something that could be detected automatically and decoded by sites such as YouTube. This would then enable automatic detection of copyrighted materials.

More:
https://petapixel.com/2017/11/03/led-light-bulb-protects-privacy-confusing-cameras/

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[willie_901]

In Still Photography Rolling Shutters Are Evil

In Still Photography Rolling Shutters Are Evil

Never, ever use a rolling electronic shutter with a still camera unless there is a good reason to do so.

Many digital cameras offer the option of a using an electronic shutter. At this point in time, these are rolling shutters. Some have a menu option that automatically switches to the electronic shutter when the shutter time becomes very short.

At first, an ES seems like a good idea. There are no mechanical components to wear out, they are perfectly silent and it is inexpensive to offer very short shutter times.

However, there can be serious disadvantages.

• Flash/strobe use is impossible
• Subject motion causes serious, irreversible spatial distortions
• Depending on the subject distance, even a small amount of photographer motion can cause distortions. This is not motion blur as the shutter time or IS can freeze motion. Instead, it is spatial distortion. This is rare but possible.
• Both fluorescent and LED lighting cause banding artifacts. LED lights with variable color technologies (often used at concerts) can cause spectacular problems.

People who gratuitously use ES mode for still photography often conclude their camera is defective. Of course, it isn't.

Global shutters are different and are not susceptible to spatial and banding distortions. However they significantly reduce frame rates. As pixel count increases, frame rate decreases.

Rolling shutters are practical for many smart-phone cameras because their problems decrease as sensor area decreases.

The LED modulation technology mentioned above will be very effective to frustrate, anger and alienate smart-phone photographers.

 

[PKR]

Willie;

I figure most smartphones use rolling shutters as they save on sensor cost and are good on battery life - they use less power. Do you know of any phones that use a global shutter?

Also, I read that some high end cine cameras use rolling shutters. This must be a differently designed shutter system?

"On the opposite end of the rolling shutter spectrum is the ARRI Alexa/Alexa Mini/Amira, which all use the same ALEV III CMOS sensor block, but you would be hard-pressed to find rolling shutter artifacts in all but the most strenuous of situations. Some filmmakers have even remarked that cameras with faster rolling shutters have a more filmic aesthetic than cameras that employ global shutters."
https://www.bhphotovideo.com/explora/video/tips-and-solutions/rolling-shutter-versus-global-shutter

I seen the Alexa up close. Not a cheap camera. ARRI must have done something different in the design, or have a correction system for the artifacts?

It seems the target of this security lighting is phone cameras, as you suggest.

 

[Big Ursus]

I always use the electronic shutter option on my Fuji X-T2 because I want to shoot absolutely silently. I use the mechanical shutter only when I need flash. The only unexpected effects of the electronic shutter so far have been some bicycle racers' elongated bodies - which I quite liked.

 

[PKR]

I always use the electronic shutter option on my Fuji X-T2 because I want to shoot absolutely silently. I use the mechanical shutter only when I need flash. The only unexpected effects of the electronic shutter so far have been some bicycle racers' elongated bodies - which I quite liked.

So, when making a capture using the rolling / electronic shutter, it doesn't trip the shutter actuation counter - as you're not using the mechanical shutter?