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In looking at the characteristics of a TV-camera called VEC-255-IP, I came across: DIP switch modes: 1) "AES" - auto electric shutter 2) "DC IRIS".

What is an auto-electric shutter? Is it different than a global shutter?

OnBreak.
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Roman Dosaev
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  • Could you give an example of where you've seen "auto electric" used? – Philip Kendall Feb 20 '18 at 11:37
  • As an owner of a DSLR, I have never heard the term "auto electric". Could you please provide an example? There's the possibility that this is some proprietary name. – flolilo Feb 20 '18 at 11:38
  • I think you asking about the electric shutter you find on mirrorless cameras, but we need more before tacking this question. – Hairy Dresden Feb 21 '18 at 16:45
  • @Roman Dosaev, are you located in Eastern Europe? I recognize that term as one used by soviet camera manufacturers mid-century. I'd need to know which manufacturer or reseller is using this term. If you can name the camera they are referring to it would help to know if the term is correctly applied. – PhotoScientist Feb 21 '18 at 18:28
  • I thought about this a bit more. I had been assuming a consumer camera such as point and shoot or SLR. Are you asking about AES in surveillance and industrial camera applications? https://duncansonline.ca/FAQs/AutoIrisElectronicShutter.htm – PhotoScientist Feb 21 '18 at 19:15
  • @PhotoScientist, yes, I am from Russia. And asking about network TV-camera called "VEC-255-IP". There is only one mention about the shutter used in this camera according to the documentation (unfortunately written only russian): DIP switch modes: 1) "AES" - auto electric shutter. 2) "DC IRIS". – Roman Dosaev Feb 22 '18 at 06:31
  • Do I get bonus points for knowing the answer without being able to read the manual? – PhotoScientist Feb 22 '18 at 22:11

2 Answers2

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This is a bit of an apples to oranges scenario but I will try to answer the spirit of the question. Auto Electric Shutter (AES) is the mode where a desired Iris value is set and the resulting shutter speed is chosen by the camera. This tends to have drawbacks in the versatility of the camera but has the advantage of allowing a camera to be manufactured with either a manual or a fixed iris, eliminating costly and unreliable motors.

In Auto-Iris mode the exposure is chosen by the user and the camera automatically adjusts the Iris. This is more common in industrial and surveillance applications where the noise-response curve is more critically optimized than it is for consumer applications. Note that to many sensor developers, the Iris and indeed lens are considered "external" This means that an automatically operated iris is an "accessory" as far as the control circuitry of your camera is concerned. It makes sense, then, that your camera would have a switch to turn on iris power.

Some cameras will operate in either mode, some will be limited to one. A webcam, for example, usually has a fixed iris and AES. In either AES or A-I, the setting of the dependent parameter occurs via some sort of control loop. This is often a PID loop and can be implemented in hardware or software. So that DIP switch on your camera basically switches it from Aperture Priority to Shutter Priority

An abridged note on nomenclature:

  • Industrial calls it AES, Photographers call it Aperture Priority
  • Industrial calls it Auto Iris, Photographers call it Shutter Priority

  • Industrial calls it an Iris, Photo calls is Aperture, Imaging Science calls it a field stop

  • Many years ago there were Soviet made cameras which featured a spring actuated shutter which was set via light meter. They were called Auto Electronic Shutter and are probably also unrelated

  • Electronic Shutter means there is no mechanical shutter and is not necessarily related to AES

  • Global Shutter is a type of sensor not actually a type of shutter, although it does serve as the "shutter" for cameras with no mechanical shutter

Now let's address global shutter. I'll make this brief since it is only tangential to the question. In global shutter (which is a misnomer) the entire sensor is "read out" at once. This means that every pixel has its value pulled out at virtually the same time (in the span of tens of microseconds.) This allows the sensor to stop motion. Global shuttered sensors can be used without a mechanical shutter but aren't exclusively so. Adding a "slow shutter" to a global shuttered device increases its contrast and reduces noise. The opposite of global shutter is rolling shutter. This type of sensor is read out line by line. To further complicate things, manufactures have figured out how to make rolling shutters global. And global shutters that can operate as rolling shutters.

The bottom line? Rolling vs Global shutter is about the sensor. Your camera has a global shutter which allows it to use Automatic Electronic Shutter. They are not different modes, they are technologies which work together.

PhotoScientist
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I don't think that is a good question for photo@SE, because this is about a video surveillance camera with ethernet interface. I do speak Russian, so might provide some info. From the camera's manual:

enter image description here

Translated:

DIP switch camera modes:

  1. “AES” (Auto Electric Shutter) – when using lens with manual control of the aperture
  2. “DC IRIS” – when using lens with automatic aperture control

From what I know about cameras, this means that AES mode will cause camera to run in auto shutter speed mode or aperture priority (as aperture is essentially fixed by lens). When you can't automatically control lens aperture, you set your camera, and then camera will automatically adjust shutter speed when light gets dimmer or brighter.

aaaaa says reinstate Monica
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