Clackers' Beginners Tip 23: Flash Extenders Pt 1

beholder3 · 06-01-2022, 09:00 AM - **2 Likes**

Originally posted by swanlefitte

Strobist has been using electronic shutter and flash since his Nikon d70 to get a higher synch speed without hss with a simple trick.
Strobist: Hacking Your Camera's Sync Speed, Pt 1

I think he has not done it "since his Nikon D70" but rather "up until his Nikon D70".

The D70 used a very noisy CCD sensor and as such did have a global shutter, with an "near immediate" sensor readout - faster than the flash burn time.

Modern (much better performing) CMOS sensors in ILC all do not have global shutters and this leads to the slow sensor read out times (I think a current 2800 EUR Sony A7 IV takes around 1/20 seconds to read the sensor). These times are way to slow for a flash. It would only shed light on around 1/6th or less of the image frame height.

swanlefitte · 06-01-2022, 04:36 PM - **1 Like**

Originally posted by beholder3

(I think a current 2800 EUR Sony A7 IV takes around 1/20 seconds to read the sensor).

I think you are right. How does that reconcile with the sensor with mechanical shutter only having like 1/6000 secs? If the sensor can all be read collecting 1/6000 time, then why must the electronic shutter be so slow? I believe David Hobby (strobist) did change to a compact fuji with a leaf shutter. Then get endorsed by Fuji and shut up.

**clackers** · 06-01-2022, 04:41 PM - **1 Like**

Originally posted by swanlefitte

I think you are right. How does that reconcile with the sensor with mechanical shutter only having like 1/6000 secs? If the sensor can all be read collecting 1/6000 time, then why must the electronic shutter be so slow? I believe David Hobby (strobist) did change to a compact fuji with a leaf shutter. Then get endorsed by Fuji and shut up.

Yeah, the issue is not the shutter speed (the time an individual pixel is exposed), it's the delay between the first pixel at the top left and the last pixel at the bottom right being read ... Clackers' Beginners Tip 3: Electronic Shutters - PentaxForums.com

swanlefitte · 06-01-2022, 05:54 PM - **1 Like**

Originally posted by clackers

Yeah, the issue is not the shutter speed (the time an individual pixel is exposed), it's the delay between the first pixel at the top left and the last pixel at the bottom right being read ... Clackers' Beginners Tip 3: Electronic Shutters - PentaxForums.com

But why can it read it all with mechanical shutter but not with electronic. I know with electronic it takes its sweat time. But it doesn't when an actual shutter is there. We know it doesn't have to as it doesn't. So why does it does? Hidey Hidy Hidy Ho.

**clackers** · 06-01-2022, 06:59 PM - **1 Like**

Originally posted by swanlefitte

But why can it read it all with mechanical shutter but not with electronic. I know with electronic it takes its sweat time. But it doesn't when an actual shutter is there. We know it doesn't have to as it doesn't. So why does it does? Hidey Hidy Hidy Ho.

You've lost me, I'm afraid, Chris.

All the pixels are read, whether the shutter's mechanical or electronic.

They can both expose 1/6000s, but for the mechanical shutter the lag between the pixels at the top and the bottom might be 1/180s, but electronic it could be as Beholder points out 1/20s and so movement/distortion in the frame is noticeable, because there are no curtains.

beholder3 · 06-01-2022, 10:49 PM - **1 Like**

Originally posted by swanlefitte

But why can it read it all with mechanical shutter but not with electronic. I know with electronic it takes its sweat time. But it doesn't when an actual shutter is there. We know it doesn't have to as it doesn't. So why does it does? Hidey Hidy Hidy Ho.

The short of it is that with a slow readout sensor with electronic shutter at no point in time the whole sensor is "open" at the time the flash burns and for as long as the flash burns.

Good reading: Electronic shutter, rolling shutter and flash: what you need to know: Digital Photography Review

06-01-2022, 04:41 PM - 1 Like	#18
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397 Original Poster	Originally posted by swanlefitte I think you are right. How does that reconcile with the sensor with mechanical shutter only having like 1/6000 secs? If the sensor can all be read collecting 1/6000 time, then why must the electronic shutter be so slow? I believe David Hobby (strobist) did change to a compact fuji with a leaf shutter. Then get endorsed by Fuji and shut up. Yeah, the issue is not the shutter speed (the time an individual pixel is exposed), it's the delay between the first pixel at the top left and the last pixel at the bottom right being read ... Clackers' Beginners Tip 3: Electronic Shutters - PentaxForums.com Last edited by clackers; 06-01-2022 at 05:23 PM.

06-01-2022, 06:59 PM - 1 Like	#20
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397 Original Poster	Originally posted by swanlefitte But why can it read it all with mechanical shutter but not with electronic. I know with electronic it takes its sweat time. But it doesn't when an actual shutter is there. We know it doesn't have to as it doesn't. So why does it does? Hidey Hidy Hidy Ho. You've lost me, I'm afraid, Chris. All the pixels are read, whether the shutter's mechanical or electronic. They can both expose 1/6000s, but for the mechanical shutter the lag between the pixels at the top and the bottom might be 1/180s, but electronic it could be as Beholder points out 1/20s and so movement/distortion in the frame is noticeable, because there are no curtains. Last edited by clackers; 06-01-2022 at 07:06 PM.

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06-01-2022, 09:00 AM - 2 Likes	#16
beholder3 Pentaxian Join Date: Dec 2011 Posts: 3,112	Originally posted by swanlefitte Strobist has been using electronic shutter and flash since his Nikon d70 to get a higher synch speed without hss with a simple trick. Strobist: Hacking Your Camera's Sync Speed, Pt 1 I think he has not done it "since his Nikon D70" but rather "up until his Nikon D70". The D70 used a very noisy CCD sensor and as such did have a global shutter, with an "near immediate" sensor readout - faster than the flash burn time. Modern (much better performing) CMOS sensors in ILC all do not have global shutters and this leads to the slow sensor read out times (I think a current 2800 EUR Sony A7 IV takes around 1/20 seconds to read the sensor). These times are way to slow for a flash. It would only shed light on around 1/6th or less of the image frame height.

06-01-2022, 04:36 PM - 1 Like	#17
swanlefitte Pentaxian Join Date: May 2015 Location: Minneapolis Photos: Gallery Posts: 4,068	Originally posted by beholder3 (I think a current 2800 EUR Sony A7 IV takes around 1/20 seconds to read the sensor). I think you are right. How does that reconcile with the sensor with mechanical shutter only having like 1/6000 secs? If the sensor can all be read collecting 1/6000 time, then why must the electronic shutter be so slow? I believe David Hobby (strobist) did change to a compact fuji with a leaf shutter. Then get endorsed by Fuji and shut up.

06-01-2022, 05:54 PM - 1 Like	#19
swanlefitte Pentaxian Join Date: May 2015 Location: Minneapolis Photos: Gallery Posts: 4,068	Originally posted by clackers Yeah, the issue is not the shutter speed (the time an individual pixel is exposed), it's the delay between the first pixel at the top left and the last pixel at the bottom right being read ... Clackers' Beginners Tip 3: Electronic Shutters - PentaxForums.com But why can it read it all with mechanical shutter but not with electronic. I know with electronic it takes its sweat time. But it doesn't when an actual shutter is there. We know it doesn't have to as it doesn't. So why does it does? Hidey Hidy Hidy Ho.

06-01-2022, 10:49 PM - 1 Like	#21
beholder3 Pentaxian Join Date: Dec 2011 Posts: 3,112	Originally posted by swanlefitte But why can it read it all with mechanical shutter but not with electronic. I know with electronic it takes its sweat time. But it doesn't when an actual shutter is there. We know it doesn't have to as it doesn't. So why does it does? Hidey Hidy Hidy Ho. The short of it is that with a slow readout sensor with electronic shutter at no point in time the whole sensor is "open" at the time the flash burns and for as long as the flash burns. Good reading: Electronic shutter, rolling shutter and flash: what you need to know: Digital Photography Review