Some VERY interesting TIP pages from Nikon for

[JR1]

D810, 4s etc

http://nps.nikonimaging.com/technical_solutions/

[Shadowman]

Interesting that they would include Picture Controls.

[NorthernFocus]

I'm amazed with several aspects of the "front curtain shutter".
1) Why the weird name? Why not just electronic shutter?
2) Why Nikon hasn't made a bigger deal of adding this feature. Particularly with the reputation that the D800/810 has for requiring such exacting technique.
3) The most obvious question, why hasn't this always been used in live view mode?

But better late than never. It's an awesome feature.

[george013]

I'm amazed with several aspects of the "front curtain shutter".
1) Why the weird name? Why not just electronic shutter?
2) Why Nikon hasn't made a bigger deal of adding this feature. Particularly with the reputation that the D800/810 has for requiring such exacting technique.
3) The most obvious question, why hasn't this always been used in live view mode?

But better late than never. It's an awesome feature.

It's not an electronic shutter like that was in the D70 and/or D70s. I don't know why they don't use that.
What I understand of it is that it is a way to prevent shuttershake. And it's only to be used with mirror-up.
When you shoot, the mirror goes up, first curtain opens, wait for the mirror-up delay to pass, then the exposure starts and ends normally when the secund curtain closes. Resulting in an uneven exposed photo. That's what I understood from it.
Why the warning for uneven exposed photo's only counts for certain lenses I don't get.

George

[dje]

When you shoot, the mirror goes up, first curtain opens, wait for the mirror-up delay to pass, then the exposure starts and ends normally when the secund curtain closes. Resulting in an uneven exposed photo. That's what I understood from it.
Why the warning for uneven exposed photo's only counts for certain lenses I don't get.

George

George I think that there is a bit more to it than that. I can't believe it would be designed to produce un-even exposure. It seems to me that the sensor data is read row by row starting from the top but collection of charge on each row is enabled electronically in a progressive way row by row. So as you move down the rows, sensels are in reset mode until the "electronic shutter" reaches that row, The timing of this progression must occur at the same rate as the rear curtain mechanical shutter so that even exposure is achieved.

Dan I think they use the term "first curtain shutter" because it is only the first curtain that is electronic with the rear curtain still mechanical.

As an aside, non-DSLR cameras use fully electronic shutters in the main.

Dave

[NorthernFocus]

...As an aside, non-DSLR cameras use fully electronic shutters in the main...

Exactly so. Which is the reason for wondering why they don't simply call it electronic shutter. Maybe because the shutter closes after the exposure.

[dje]

Exactly so. Which is the reason for wondering why they don't simply call it electronic shutter. Maybe because the shutter closes after the exposure.

Dan as I understand it, the shutter still operates on a first and second curtain basis with the second curtain following the first. The shutter speed is determined by the time gap between the first and second curtain. It's just that the first curtain is electronic but the second is still mechanical. So it's not a fully electronic shutter.

Dave

[NorthernFocus]

Dan as I understand it, the shutter still operates on a first and second curtain basis with the second curtain following the first. The shutter speed is determined by the time gap between the first and second curtain. It's just that the first curtain is electronic but the second is still mechanical. So it's not a fully electronic shutter.

Dave

That's also how I understand it. And what I tried to say. Splitting hairs aren't they? OK yes it is an accurate literal description. Bottom line is that nothing physically moves immediately prior to the image capture.

[dje]

Bottom line is that nothing physically moves immediately prior to the image capture.

Yes exactly. The closing mechanical second curtain doesn't cause a problem with shake of course but I do have to ask "why not fully electronic "!

[IzzieK]

Thanks for the links...very helpful to a learner like me.

[george013]

George I think that there is a bit more to it than that. I can't believe it would be designed to produce un-even exposure. It seems to me that the sensor data is read row by row starting from the top but collection of charge on each row is enabled electronically in a progressive way row by row. So as you move down the rows, sensels are in reset mode until the "electronic shutter" reaches that row, The timing of this progression must occur at the same rate as the rear curtain mechanical shutter so that even exposure is achieved.

Dan I think they use the term "first curtain shutter" because it is only the first curtain that is electronic with the rear curtain still mechanical.

As an aside, non-DSLR cameras use fully electronic shutters in the main.

Dave

I believe you immediately. But I can't give the exception for the certain lenses a place. Faster as the sync-time results in uneven exposure.

When using the electronic front-curtain shutter with a shifted or tilted PC-E lens, adjust settings for a shutter speed slower than 1/250 s. Faster speeds may result in uneven exposure.

From http://imaging.nikon.com/lineup/dslr/d810/spec.htm

Electronically-controlled vertical-travel focal-plane mechanical shutter, electronic front-curtain shutter (in mirror up release mode)

[dje]

But I can't give the exception for the certain lenses a place. Faster as the sync-time results in uneven exposure.

Yes George that one has me puzzled too. I just found this reference which seems to provide a plausible explanation - relating to the angle of incidence of the light onto the sensor and the fact that the mechanical (second curtain) shutter is a little way out from the front of the sensor but the electronic first curtain is "on the sensor".

Dave

[JR1]

Thanks for the links...very helpful to a learner like me.

NOT just you, me also

[george013]

Yes George that one has me puzzled too. I just found this reference which seems to provide a plausible explanation - relating to the angle of incidence of the light onto the sensor and the fact that the mechanical (second curtain) shutter is a little way out from the front of the sensor but the electronic first curtain is "on the sensor".

Dave

It looks a plausible explanation to me too. Thanks.

George

[pnodrog]

Yes exactly. The closing mechanical second curtain doesn't cause a problem with shake of course but I do have to ask "why not fully electronic "!

I assume discharging the sensor is fast but clearing(reading) the sensor takes more time as the A/D conversion needs to be done. 10bit A/D maybe fast enough but a 14-16 bit A/D conversion possibly takes long enough that it would start to be significant for very short exposures.

[dje]

I assume discharging the sensor is fast but clearing(reading) the sensor takes more time as the A/D conversion needs to be done. 10bit A/D maybe fast enough but a 14-16 bit A/D conversion possibly takes long enough that it would start to be significant for very short exposures.

Thank you LPaul for your enlightenment. Your comment seems reasonable to me, even though it is only 5AM here !

I guess this comes down to the fact that we have a CMOS rolling shutter here rather than a CMOS global shutter. As I understand it, the latter contains a memory element for each pixel which allows a global exposure and then read out at the end. It seems that lower end cameras must use a global shutter (which is fully electronic). Presumably the performance limitations associated with the current technology of global shutters are preventing their use for DSLR's ?

Dave

[pnodrog]

Thank you LPaul for your enlightenment. Your comment seems reasonable to me, even though it is only 5AM here !

I guess this comes down to the fact that we have a CMOS rolling shutter here rather than a CMOS global shutter. As I understand it, the latter contains a memory element for each pixel which allows a global exposure and then read out at the end. It seems that lower end cameras must use a global shutter (which is fully electronic). Presumably the performance limitations associated with the current technology of global shutters are preventing their use for DSLR's ?

Dave

Back-lit sensor technology will probably change everything in the near future. At this stage sensors for DSLR's are optimised for sensitivity and low noise so I expect the real estate around each well is limited to essential junctions(electronics). It maybe that for a global shutter you need to provide double wells (sample and hold) which would take up even more precious space.

About 2 years ago I had a bit of a read on sensors but I am no longer up to date so I am just making assumptions on what is happening.

[dje]

Back-lit sensor technology will probably change everything in the near future.

OK , looks like I have some more reading to do ..... damn

[pnodrog]

OK , looks like I have some more reading to do ..... damn

Good if you are doing it I won't bother... While you are reading I can make myself miserable trying to capture "THE" photograph. Ansel Adams must have left at least one - just have to find it.