EFCS: electronic front curtain shutter

biz-engineer · 09-20-2016, 07:44 AM

Does anyone knows what are the limitation of EFCS, and why is can't be enabled all the time?

photoptimist · 09-20-2016, 08:00 AM

If the sensor is exposed to light, it's constantly generating a current that accumulates in the photosite pixels. The EFCS has to drain that charge so that the photosite has zero charge at the beginning of the exposure. But such circuits always have some resistance which means that the pixel begins the exposure with some residual charge in proportion to the pre-shutter intensity of light.

In photographic terms, the sensor will have a faint ghost of a image of the light from before the official shutter time.

biz-engineer · 09-20-2016, 09:48 AM

Originally posted by photoptimist

In photographic terms, the sensor will have a faint ghost of a image of the light from before the official shutter time.

Not suitable for subjects in motion then.

Gimbal · 09-20-2016, 10:03 AM

Originally posted by biz-engineer

Not suitable for subjects in motion then.

No, and mostly because of a rolling shutter effect.

biz-engineer · 09-20-2016, 10:12 AM

Originally posted by Gimbal

No, and mostly because of a rolling shutter effect.

I thought the rolling shutter effect we see in video was due to the electronic second curtain (basically the long time to acquire information from the photosites after exposure).

Gimbal · 09-20-2016, 10:43 AM

The information we have so far does not say it is a first curtain only implementation though. PS uses electronic curtains only. So most likely it will be something similar.

**clackers** · 09-20-2016, 03:03 PM

Second curtain too with the firmware upgrade, and yes, unsuited to moving objects.

Cheap P&S cameras are often electronic shutter only and suffer accordingly.

biz-engineer · 09-20-2016, 10:16 PM

Originally posted by clackers

Second curtain too with the firmware upgra

Where do you read this?

**clackers** · 09-21-2016, 01:55 AM

Originally posted by biz-engineer

Where do you read this?

I now don't know how I came to think that. The Ricoh press release says electronic shutter, but the forum news says it's only EFSC.

Forget I said it! 😀

Edit: It was the speculation here:

https://www.pentaxforums.com/forums/190-pentax-k-1-k-1-ii/330063-firmware-1-30-new-functions-post3777766.html

Paul2660 · 09-21-2016, 03:27 AM

The message from Pentax is a bit confusing since they reference both electronic first curtain and electronic shutter.

EFC enabled in Live View is what I believe will be added. But as someone has pointed out in pixel shift mode the camera appears to use a full electronic shutter as you don't here and focal shutter noise during the operation.

So it might be possible to enable a full electronic shutter for normal use in Live View. If so this would be a first as far as I know.

Nikon allows EFC only and its use is a bit restrictive.

Paul C

MJKoski · 09-21-2016, 04:20 AM

Both have their uses. Fully electronic would be cool during multiexposure series.

biz-engineer · 09-21-2016, 04:48 AM

Originally posted by Paul2660

But as someone has pointed out in pixel shift mode the camera appears to use a full electronic shutter as you don't here and focal shutter noise during the operation.

Yes, correct. Pixel shift used uses "first curtain" and "second curtain" electronic shutter but we actually don't know if the implmentation of the electronic shutter in live view mode will be the same as the one used for pixel shift.

---------- Post added 21-09-16 at 13:49 ----------

Originally posted by MJKoski

Fully electronic would be cool during multiexposure series.

Yes... I'd welcome this... if it is also implemented for multiexposure , that would be awesome.

09-20-2016, 07:44 AM	#1
biz-engineer Pentaxian Join Date: Feb 2015 Photos: Gallery Posts: 12,232	EFCS: electronic front curtain shutter Does anyone knows what are the limitation of EFCS, and why is can't be enabled all the time?

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09-20-2016, 08:00 AM	#2
photoptimist Pentaxian Join Date: Jul 2016 Photos: Albums Posts: 5,126	If the sensor is exposed to light, it's constantly generating a current that accumulates in the photosite pixels. The EFCS has to drain that charge so that the photosite has zero charge at the beginning of the exposure. But such circuits always have some resistance which means that the pixel begins the exposure with some residual charge in proportion to the pre-shutter intensity of light. In photographic terms, the sensor will have a faint ghost of a image of the light from before the official shutter time.

09-20-2016, 09:48 AM	#3
biz-engineer Pentaxian Join Date: Feb 2015 Photos: Gallery Posts: 12,232 Original Poster	Originally posted by photoptimist In photographic terms, the sensor will have a faint ghost of a image of the light from before the official shutter time. Not suitable for subjects in motion then.

09-20-2016, 10:03 AM	#4
Gimbal Pentaxian Join Date: Apr 2007 Location: Sweden Posts: 2,106	Originally posted by biz-engineer Not suitable for subjects in motion then. No, and mostly because of a rolling shutter effect.

09-20-2016, 10:12 AM	#5
biz-engineer Pentaxian Join Date: Feb 2015 Photos: Gallery Posts: 12,232 Original Poster	Originally posted by Gimbal No, and mostly because of a rolling shutter effect. I thought the rolling shutter effect we see in video was due to the electronic second curtain (basically the long time to acquire information from the photosites after exposure).

09-20-2016, 10:43 AM	#6
Gimbal Pentaxian Join Date: Apr 2007 Location: Sweden Posts: 2,106	The information we have so far does not say it is a first curtain only implementation though. PS uses electronic curtains only. So most likely it will be something similar.

09-20-2016, 03:03 PM	#7
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Second curtain too with the firmware upgrade, and yes, unsuited to moving objects. Cheap P&S cameras are often electronic shutter only and suffer accordingly.

09-20-2016, 10:16 PM	#8
biz-engineer Pentaxian Join Date: Feb 2015 Photos: Gallery Posts: 12,232 Original Poster	Originally posted by clackers Second curtain too with the firmware upgra Where do you read this?

09-21-2016, 01:55 AM	#9
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by biz-engineer Where do you read this? I now don't know how I came to think that. The Ricoh press release says electronic shutter, but the forum news says it's only EFSC. Forget I said it! 😀 Edit: It was the speculation here: https://www.pentaxforums.com/forums/190-pentax-k-1-k-1-ii/330063-firmware-1-30-new-functions-post3777766.html

09-21-2016, 03:27 AM	#10
Paul2660 Forum Member Join Date: Jun 2016 Posts: 67	The message from Pentax is a bit confusing since they reference both electronic first curtain and electronic shutter. EFC enabled in Live View is what I believe will be added. But as someone has pointed out in pixel shift mode the camera appears to use a full electronic shutter as you don't here and focal shutter noise during the operation. So it might be possible to enable a full electronic shutter for normal use in Live View. If so this would be a first as far as I know. Nikon allows EFC only and its use is a bit restrictive. Paul C

09-21-2016, 04:20 AM	#11
MJKoski Veteran Member Join Date: Aug 2016 Posts: 1,784	Both have their uses. Fully electronic would be cool during multiexposure series.

09-21-2016, 04:48 AM	#12
biz-engineer Pentaxian Join Date: Feb 2015 Photos: Gallery Posts: 12,232 Original Poster	Originally posted by Paul2660 But as someone has pointed out in pixel shift mode the camera appears to use a full electronic shutter as you don't here and focal shutter noise during the operation. Yes, correct. Pixel shift used uses "first curtain" and "second curtain" electronic shutter but we actually don't know if the implmentation of the electronic shutter in live view mode will be the same as the one used for pixel shift. ---------- Post added 21-09-16 at 13:49 ---------- Originally posted by MJKoski Fully electronic would be cool during multiexposure series. Yes... I'd welcome this... if it is also implemented for multiexposure , that would be awesome.