Electronic shutter and long exposure noise reduction

[DanK]

I'm still getting used to my R6 II, which has all three shutter modes, mechanical, electronic, and electronic first curtain (EFCS). An excellent explanation of the pros and cons of each is here: https://photographylife.com/mechanic...c-shutter-efcs. It all seems clear to me other than this passing reference at the end:

Lastly, if you need to use specific options that the electronic shutter prevents (like long exposure noise reduction), you obviously should use a different shutter mechanism.

And indeed, I've read that some cameras gray out the long-exposure option if the electronic shutter is chosen. My R6 II does not gray out that option.

I'm assuming that the issue is that with an electronic shutter, there is nothing to block the light to create the black frame. However, if the camera has a mechanical shutter (the Z8 and Z9 apparently don't), there is no reason that the mechanical shutter couldn't be closed for the black frame even if it isn't used for the capture. I assume that's what my camera does.

Somewhat off topic: if this is right, this would suggest that the Z8 and Z9 lack long-exposure noise reduction. Is that right? the other drawback of not having a mechanical shutter or at least electronic first curtain is the risk of banding under artificial light. I haven't used fully electronic shutter with indoor shots, which usually mix flash and ambient light, but I have done a bunch with EFCS and haven't noticed banding.

[Manfred M]

My understanding is that the issue with the pure electronic shutter is the "rolling shutter" effect that can create a slanted image due to the relatively slow polling of the exposed pixels. What Nikon appears to have done with the Z8 and Z9 and its stacked sensor is to improve the read speed to eliminate this effect.

The stacked sensor means that the data is handled quickly when the image is taken and polling the data to read it is not a limiting factor. This sensor technology is expensive, but I suspect that it is less expensive than adding a mechanical shutter, which is why Nikon went in that direction.

I'm not sure that the other issues you have mentioned are actually an issue, but as I do not use either of those two cameras, I have no actual real-life experience. I've used the Z9 a couple of times and really liked it, other than its weight.

[DanK]

Manfred,

If you look at he article I linked, it shows concrete illustrations of all of the issues other than long exposure noise reduction, presenting identical shots with all three shutter modes.

Dan


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[pschlute]

My camera has the option of FCES, which I use on static subjects as it eliminates any shutter shock from the first curtain travel when used with a tripod and a long lens when using shutter speeds 1/30-1/200

Like Manfred I believe the main drawback of ES or FCES is the rolling shutter effect.

If you are using the camera to take images where you would wish to have dark-frame-subtraction noise reduction, I cannot see any benefit of electronic shutter (or EFCS) at all.

[Stagecoach]

Somewhat off topic: if this is right, this would suggest that the Z8 and Z9 lack long-exposure noise reduction. Is that right?

Just had a look at my Z8 and it has 'long exposure noise reduction'. It works with any speed slower than 1s.

[Manfred M]

Manfred,

If you look at he article I linked, it shows concrete illustrations of all of the issues other than long exposure noise reduction, presenting identical shots with all three shutter modes.

Dan


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Dan - some of what is written in that article makes sense, but it came out last year and since then a number of cameras using stacked sensors have come out and that has fundamentally changed how electronic shutters are viewed. Nikon is the only brand that has gone 100% electronic shutter; Sony with a similar sensor has not gone as far. I suspect other camera manufacturers will follow suite as removing the shutter mechanism reduces the cost as well as some warranty issues quite nicely.

The images I looked at had no issues with rolling shutter, which is really why this technology was implemented.

In terms of noise reduction, the article is not clear on raw versus JPEG. With my older Nikons, long exposure noise reduction applied to JPEGs only and did not impact raw at all. Those cameras use a technique called dark field noise reduction and with that functionality activated, the camera would take two shots; one where the image was captured and a second one with the shutter closed but the sensor active for the same length of time as the initial exposure. Any noise in the sensor in dark field mode is removed in the initial normal capture. This technique is quite effective, BUT your exposure time is effectively doubled. While this is not an issue with relatively short exposures, it is a problem with a long exposure. A 15 second long exposure plus a 15 second dark field exposure meant that the photographer has to wait 30 second between shots.

[DanK]

Thanks for the replies. A lot to digest.

First re rolling shutter: I understand the issue, and I understand why faster readouts led Nikon to rely on ES for the Z9 and Z8. I also understand how long-exposure (black frame) noise reduction works. I've used it for many years for my very long-exposure night photographs, some of which have shutter times over 5 minutes. I didn't know, however, that some Nikon cameras in the past only offered this for JPEGs. Canons have done it on raw files as long at least as far back as the 50D. I have always used it on raw files.

The article I posted suggests--consistent with other things I have read---that EFCS is sufficient to avoid rolling shutter, at least for the camera he used (a Z7). There isn't a need to go to the fully mechanical shutter.

My main reason for posting is the mechanics of long-exposure noise reduction with ES. Some cameras don't provide it. Given that the Z8 (and therefore presumably the Z9 does, that raises the question of how a black frame is captured if there is nothing physical blocking the light path to the sensor. Do those cameras have a "shutter" that's not used as a shutter per se but that drops down to protect the sensor when the camera is off (as newer Canon mirrorless cameras do)? If so, the camera could drop that for the black frame. If not, I wonder how it's done. On my camera, I suspect the camera simply closes the shutter for the black frame even when the camera is set to ES.

I found the article interesting because of the other differences it discusses, none of which would be affected by readout speed: sharpness, flare, banding, and bokeh. The bokeh issue makes perfect sense after the fact; it's a parallax issue. I'll probably use EFCS less than I would have because of reading this.

[Stagecoach]

My main reason for posting is the mechanics of long-exposure noise reduction with ES. Some cameras don't provide it. Given that the Z8 (and therefore presumably the Z9 does, that raises the question of how a black frame is captured if there is nothing physical blocking the light path to the sensor. Do those cameras have a "shutter" that's not used as a shutter per se but that drops down to protect the sensor when the camera is off (as newer Canon mirrorless cameras do)? If so, the camera could drop that for the black frame.

Checking the Z8 with 'long exposure noise reduction' selected, with a 10 second exposure and the lens removed, the sensor protection shutter closes during the duration of the 10 sec dark frame.

[DanK]

Checking the Z8 with 'long exposure noise reduction' selected, with a 10 second exposure and the lens removed, the sensor protection shutter closes during the duration of the 10 sec dark frame.

Thanks. Mystery solved. That makes perfect sense.