Electronic Front-Curtain Shutter

[george013]

Whatever the heck that is. Sounds like a half shutter design where the sensor data is cleared and the camera starts recording data and after some period a mechanical shutter closes. Being a mirrorless Sony, I can see how / why they would go this way - it's a simpler (i.e. less expensive to manufacture) design and should be more reliable (although fully mechanical focal plane shutters have been around for a very long time and are quite reliable).

From what I read it's basic meant to avoid the shock from the first curtain when it has stopped opening. That's during the exposure. The end of the movement of the second curtain is after exposure.
There're several disadvantages on it. I don't know which, I don't have it.

George

[dje]

From what I read it's basic meant to avoid the shock from the first curtain when it has stopped opening. That's during the exposure. The end of the movement of the second curtain is after exposure.
There're several disadvantages on it. I don't know which, I don't have it.

George

That's my understanding too George. One disadvantage that can occur for fast shutter speeds (as mentioned in the Sony article) is that you can get uneven exposure across the frame. This would occur if the electronic first curtain didn't track the mechanical second curtain very well (resulting in a moving exposure slit that changed width slightly as it moved across the frame). I've never noticed this sort of problem on my a6000 though.

Dave

[dem]

The name "Electronic Front-Curtain Shutter" is somewhat confusing, as it has nothing to do with the front curtain flash and there is no such thing as "Electronic Rear-Curtain Shutter". It should have been called "Electronic-Front-Curtain Mechanical-Rear-Curtain Shutter" or "dual shutter" or "hybrid shutter". I think the whole thing was introduced to make shooting DSLRs in "live view" more usable:

https://www.mhohner.de/newsitem2/efcs

http://www.robertotoole.com/blog/201...hutter-curtain

Then there is a completely different thing called "electronic shutter" on Fuji or "silent shutter" on Sony. Unlike the "Electronic Front-Curtain Shutter" that only mimics the front curtain blocking the light but still uses mechanical rear curtain, the true rolling electronic shutter does not engage any mechanical parts at all and is absolutely silent. That's how smartphone cameras work.

There are many drawbacks of the "electronic shutter" because of the way it works - it slowly reads the sensor line by line and, as a result, all lines of pixels are captured at different moments of time. It takes about 1/15th of a second to scan the whole image. Even if you set shutter speed to 1/30,000s, the last line of the sensor will still be recorded 1/15s after the first line:

Fuji X100t:
http://janssico.com/2014/12/x100ts-e...peed-analysis/

Sony A7rii
http://blog.kasson.com/the-last-word...ilent-shutter/

Sony A6300
http://blog.kasson.com/the-last-word/13858/

With rolling electronic shutter, you cannot use camera flash*, the moving objects are going to appear distorted and there might be some banding under fluorecent light.

With the "Electronic Front-Curtain Shutter" the image is still captured as a whole so you can use a flash. The drawback might be a slower synch speed than that available with the mechanical shutter:

http://photo.stackexchange.com/quest...urtain-shutter

* The LED flashes on smartphones are ON for the whole duration of the shot and can take much longer (e.g. ~1/20 s) than a typical camera flash (~1/1,000 s). That is why a smartphone camera flash does not freeze motion.

[dje]

That's a good summary Dem.

I think the main reason flash isn't enabled for fully electronic shutters is that the maximum flash sync speed is limited by the "curtain speed" (albeit all electronic). If the curtain speed is say 1/20 sec, then this is just not a fast enough shutter speed for general use.

For anyone who is interested, here is a link to the result of the distortion you can get with moving subjects with fully electronic rolling shutter!

Dave

[george013]

The Nikon D70 and some other had an electronic shutter. The official sync time was 1/500 but one could use a much faster speed.
I didn't have one, all from reading. And I don't know how it works.

George