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Forums Lobby MASTER YOUR TOOLS - Hardware & Software Nikon Speedlights & Lighting topic #61065
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Subject: "Q. about High Speed Sync settings on D3S/D700...." Previous topic | Next topic
hollingwD80 Registered since 30th Apr 2008Tue 19-Mar-13 02:28 AM
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"Q. about High Speed Sync settings on D3S/D700...."


Hartselle, US
          

Hello:

I've noticed that the high speed sync setting on my D700 goes to 1/320th, but all my other Nikons only go to 1/250th HSS.

Can anyone tell me why the D700 has the 1/320th setting, and why even my D3S does not and stops at 1/250th?

What's that 1/320th setting for on the D700???

Thanks,
Rich

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Replies to this topic
Subject Author Message Date ID
Reply message RE: Q. about High Speed Sync settings on D3S/D700....
blossombogart Silver Member
19th Mar 2013
1
Reply message RE: Q. about High Speed Sync settings on D3S/D700....
hollingwD80
19th Mar 2013
2
     Reply message RE: Q. about High Speed Sync settings on D3S/D700....
grillij Silver Member
20th Mar 2013
3
Reply message RE: Q. about High Speed Sync settings on D3S/D700....
ScottChapin Moderator Awarded for his high level skills in various areas, including Aviation and Birds Photography
20th Mar 2013
4
Reply message RE: Q. about High Speed Sync settings on D3S/D700....
HBB Moderator Hal is an expert in several areas, including CLS Awarded for his excellent article contributions to the Resources.
21st Mar 2013
5
     Reply message RE: Q. about High Speed Sync settings on D3S/D700....
ScottChapin Moderator Awarded for his high level skills in various areas, including Aviation and Birds Photography
21st Mar 2013
6
     Reply message RE: Q. about High Speed Sync settings on D3S/D700....
ScottChapin Moderator Awarded for his high level skills in various areas, including Aviation and Birds Photography
21st Mar 2013
7
     Reply message RE: Q. about High Speed Sync settings on D3S/D700....
Arkayem Moderator Awarded for his high level skills in flash photography
21st Mar 2013
8
          Reply message RE: Q. about High Speed Sync settings on D3S/D700....
ScottChapin Moderator Awarded for his high level skills in various areas, including Aviation and Birds Photography
21st Mar 2013
9
          Reply message RE: Q. about High Speed Sync settings on D3S/D700....
Arkayem Moderator Awarded for his high level skills in flash photography
21st Mar 2013
10
          Reply message RE: Q. about High Speed Sync settings on D3S/D700....
HBB Moderator Hal is an expert in several areas, including CLS Awarded for his excellent article contributions to the Resources.
22nd Mar 2013
11
               Reply message RE: Q. about High Speed Sync settings on D3S/D700....
Arkayem Moderator Awarded for his high level skills in flash photography
22nd Mar 2013
12

blossombogart Silver Member Nikonian since 26th Feb 2013Tue 19-Mar-13 09:48 PM
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#1. "RE: Q. about High Speed Sync settings on D3S/D700...."
In response to Reply # 0


US
          

I am still learning but I believe it is like this. at shutter speed 1/250 and under the flash acts like a single flash and is timed with the full opening of the shutter. Having it set at 1/320 and above the flash acts more like a stobe, flashing as the small opening of the shutter (front and rear curtains) moves across the image. the 700 has two flash sync settings...1/250 auto fp and 1/320 auto fp.

  

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hollingwD80 Registered since 30th Apr 2008Tue 19-Mar-13 10:30 PM
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#2. "RE: Q. about High Speed Sync settings on D3S/D700...."
In response to Reply # 1


Hartselle, US
          

Hello:
Thanks for the reply. I understand HHS and what it's for, and, how it works. I just don't understand why the D700 can sync up at 1/320th, when all the other Nikons only sync up to 1/250th.

Why does the D700 sync up to 1/320th, and what would that be for. Do you normally just set the HHS to 1/320th, or is that setting for something special?

THanks for any help...

Rich

http://images.nikonians.org/galleries/showgallery.php/ppuser/176900/cat/500


Please visit my SmugMug gallery at nikonrick.smugmug.com

Visit my Nikonians gallery.

  

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grillij Silver Member Nikonian since 14th Aug 2008Wed 20-Mar-13 02:32 PM
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#3. "RE: Q. about High Speed Sync settings on D3S/D700...."
In response to Reply # 2


Piedmont,Qc, CA
          

Rich, I am anxious to read the reason. I had a D700 and never used the 1/320s setting.
I am now using the pocket wizard system with my D3s and PW instructions are not to use the 1/320s. The camera ( any one ) must be set at 1/250.
As a matter of fact I never noticed that the D3s did not have 1/320s.
Jacques G

  

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ScottChapin Moderator Awarded for his high level skills in various areas, including Aviation and Birds Photography Charter MemberWed 20-Mar-13 05:01 PM
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#4. "RE: Q. about High Speed Sync settings on D3S/D700...."
In response to Reply # 0


Powder Springs, US
          

Rich,

Here is half of your answer. At 1/250 the shutter is open for the entire flash duration, taking advantage of your flashe's full power. At 1/320 the shutter closes before the entire flash burst is over and there is a loss of guide number as a result. So it is not true sync at 1/320, but the guide number loss is not critical in most situations. Beyond 1/320 the loss of power is considered to be too much and FP sync is better.

Don't ask me why Nikon engineering left it out of the pro models. Maybe they think pros don't want to work without full sync?

Scott Chapin
Powder Springs, GA, USA
Nikonians Team Member

  

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HBB Moderator Hal is an expert in several areas, including CLS Awarded for his excellent article contributions to the Resources. Charter MemberThu 21-Mar-13 01:19 AM
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#5. "RE: Q. about High Speed Sync settings on D3S/D700...."
In response to Reply # 4


Phoenix, US
          

Scott:

Interesting.

If the shutter time is actually 1/320 second, it is fully open for 0.003125 seconds, correct?

The longest flash duration times (from Nikon user manuals) at M1/1 full power level are:

SB700: 1/1042 = 0.000959 second

SB800: 1/1050 = 0.000952 second

SB900: 1/880 = 0.001136 second.

The three average 1/984 = 0.001016, slightly less than 1/3 of the shutter open time of 0.003125 seconds. With 0.001016 out of the shutter time of 0.003125,, this leaves 0.001054 seconds on either side of it, assuming the pulse peaks in the middle.

Does the flash duration include the rise and fall time, or just some arbitrarily established slice out of the middle? If they are cutting off part of the rise and fall time, this makes sense, as it would explain the slight guide number reduction.

I haven't a clue what is really occurring ... your thoughts?

Thanks for shedding some light on the issue.

Regards,

HBB in Phoenix, Arizona
Nikonian Team Member

Photography is a journey with no conceivable destination.

  

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ScottChapin Moderator Awarded for his high level skills in various areas, including Aviation and Birds Photography Charter MemberThu 21-Mar-13 02:04 AM
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#6. "RE: Q. about High Speed Sync settings on D3S/D700...."
In response to Reply # 5


Powder Springs, US
          

Hal,

I might be mistaken, but I don't think the shutter is fully open for the entire duration of the flash pulse at 1/320. There is a slight almost imperceptible band at 1/320. Since the band is actually there, Nikon cannot call 1/320 a true sync speed. I think the tail of the flash is clipped, which is not that "bright", so the band is not so noticeable.

I dont think the shutter is wide open for .003125 seconds, as that would not account for the time it takes the rear curtain to travel across the sensor, during which time ambient light is still a factor. You know, I have no idea what the travel rate of the curtains are. Maybe its around 1/8000 of a second?

In any event, I think the shutter wide open time at both 1/250s and 1/320s is a lot briefer than the shutter speed time. Otherwise, as your SB900 time suggests, you should be able to sync at 1/880. You cannot though because, I'm guessing, the wide open time at 1/250 is not much longer than 1/880s.

The total shutter time has to be comprised of three parts. The first, where the front curtain is opening. The second, where the shutter is wide open. Finally the third, where the rear curtain closes. The sync period is a lot shorter than the total shutter time.

So, at 1/320s, the curtain starts to close while the flash pulse is decaying and that band is slightly underexposed. When shooting fill light outdoors, it's not an issue. In any event, if you need the speed and fill, you can crop out the banding, if indeed it is an issue.

At least that's my understanding.

Scott Chapin
Powder Springs, GA, USA
Nikonians Team Member

  

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ScottChapin Moderator Awarded for his high level skills in various areas, including Aviation and Birds Photography Charter MemberThu 21-Mar-13 02:22 AM
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#7. "RE: Q. about High Speed Sync settings on D3S/D700...."
In response to Reply # 5
Thu 21-Mar-13 02:29 AM by ScottChapin

Powder Springs, US
          

Another thought. With the PocketWizard CTL system you can use hyper sync that gives you true sync at higher speeds, because the flash triggering is advanced. That advance supposedly causes banding at slower shutter speeds. I haven't thought that one through yet.

That suggests that the flash is normally triggered sometime after the shutter is wide open in order to maintain sync at slower speeds.

Scott Chapin
Powder Springs, GA, USA
Nikonians Team Member

  

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Arkayem Moderator Awarded for his high level skills in flash photography Charter MemberThu 21-Mar-13 03:56 PM
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#8. "RE: Q. about High Speed Sync settings on D3S/D700...."
In response to Reply # 5


Richmond Hill, GA (Savannah), US
          

Hal:

I remember from my days (long ago now) in the camera and flash design group, that the process of flash synchronization is much more complex than it first seems.

The full power flash pulse duration is 6-8ms long if you include the short rise time and the tail. However, the flash duration specification is based on the 90% points on the flash waveform. That's where they get the ~1 ms duration for the maximum power pulse that you quoted.

The shutter cycle time includes the front curtain transition time + delay + rear curtain transition time.

The delay is normally set at the length of the 90% portion of the full power flash (1 ms for Nikon). This is for the 1/250th standard flash sync speed.

The curtain transition time is a spec that has been drastically reduced over the years. Today I believe the fastest run at about 1.25 ms.

So, for maximum normal sync with the flash at full power, the sequence lasts about 3.5 ms like this:

1. open the front curtain (1.25 ms)
2. delay 1 ms (fire the flash during the delay)
3. close the rear curtain (1.25 ms)

You can see that the rear curtain is closing during the tail, and at full power, the tail can still be significant.

At 1/250th flash sync, the entire 90% flash pulse fits into the delay and the rear curtain starts to close after the waveform is down by 10%, meaning the remaining power in the tail is insignificant.

However, if you select the 1/320th sync speed (3.25 ms), the delay period is reduced. This means that the rear curtain will begin to close while the maximum power flash pulse is still high.

You can see that at 1/320th sync the flash will be in its tail if the flash is at full power. At lower flash power settings, the flash completes most of its tail well before the rear curtain starts to close.

So, when you use the 1/320th sync two things will happen: 1) the effective maximum flash power will be less than at 1/250th sync, and 2) the exposure will not be as even across the frame as with 1/250th.

This is why 1/250th is the default, and is recommended, especially if the flash will be firing at or near its maximum power. Also, the reduced power is very close to the power you would get using Auto FP High Speed Sync, so 1/320th really doesn't buy you much.

I think that the 1/320th flash sync option is not offered on the D3, because most professional photographers do not want to use any setting that may produce less than optimal results. It is also related to the beafier shutter mechanism used on the pro cameras to extend the shutter life. This would increase the curtain transition times.

There is a lot more to this than I can remember (inertial delays, acceleration delays, vibration delays, etc.), but maybe I have explained enough that you can get the general idea.

Russ
Nikonian Moderator
Russell MacDonald Photography
Nikon CLS Practical Guide

  

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ScottChapin Moderator Awarded for his high level skills in various areas, including Aviation and Birds Photography Charter MemberThu 21-Mar-13 04:38 PM
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#9. "RE: Q. about High Speed Sync settings on D3S/D700...."
In response to Reply # 8


Powder Springs, US
          

Great stuff Russ! So I guess at 1/400s the second shutter starts to close just as the first shutter is fully open. Them the traveling slits are at speeds in excess of 1/400s or nearly so.

Scott Chapin
Powder Springs, GA, USA
Nikonians Team Member

  

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Arkayem Moderator Awarded for his high level skills in flash photography Charter MemberThu 21-Mar-13 05:31 PM
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#10. "RE: Q. about High Speed Sync settings on D3S/D700...."
In response to Reply # 9


Richmond Hill, GA (Savannah), US
          

>Great stuff Russ! So I guess at 1/400s the second shutter
>starts to close just as the first shutter is fully open. Them
>the traveling slits are at speeds in excess of 1/400s or
>nearly so.

That's correct. And you can experiment with it using externally triggered flashes to see how fast you can go before an obvious dark area appears on the image, signifying that the rear curtain has started closing before the front curtain has completed its transition.

Russ
Nikonian Moderator
Russell MacDonald Photography
Nikon CLS Practical Guide

  

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HBB Moderator Hal is an expert in several areas, including CLS Awarded for his excellent article contributions to the Resources. Charter MemberFri 22-Mar-13 05:10 PM
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#11. "RE: Q. about High Speed Sync settings on D3S/D700...."
In response to Reply # 8


Phoenix, US
          

Russ:

Thanks for the update!

As usual, there are no simple answers to some of these questions.

A few random thoughts:

1) It is obvious why shutters move across the shorter sensor dimension, to minimize travel time.

2) It appears that most shutters have two curtains that start at one side of the sensor, and finish at the other side.

3) Given 1) and 2) above, are there any shutters that start in the middle of the sensor and proceed to the sides, thus minimizing travel time? I stopped thinking about shutters when I sold my pair of Nikon F3 bodies years ago. Too many other areas of interest to investigate.

4) Does shutter inertial delay, acceleration time, etc. occur prior to, or during, actual sensor exposure time?

5) Without the handful of microprocessors and related semiconductor components resident in our cameras, digital photography as we know it would be impossible. I still maintain in my writings and lecturing that these technologies are still in their relative infancy.

Regards,

HBB in Phoenix, Arizona
Nikonian Team Member

Photography is a journey with no conceivable destination.

  

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Arkayem Moderator Awarded for his high level skills in flash photography Charter MemberFri 22-Mar-13 07:03 PM
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#12. "RE: Q. about High Speed Sync settings on D3S/D700...."
In response to Reply # 11


Richmond Hill, GA (Savannah), US
          

From Hal with my comments interspersed:

>A few random thoughts:
>
>1) It is obvious why shutters move across the shorter sensor
>dimension, to minimize travel time.

That is correct for most modern shutters. The Nikon F3, introduced in 1980, had titanium curtains that traveled horizontally. They knew long before then that the vertical shutter would be better, but the horizontal movement made the design of the mechanical film advance and shutter cocking mechanism much simpler. Then, the F4 came out in 1988 without a mechanical film advance lever, so they switched to a vertical shutter.

Another interesting point is that the vertically moving curtains move from the top to the bottom, exposing the inverted image on the film or sensor from the bottom up. This is done so that things in motion, like wheels, will deform in the expected direction; i.e. they lean forward on a race car. Also, gravity is totally compensated for in the design with counter-masses, so the shutter will work equally well in the horizontal or vertical orientations.

>2) It appears that most shutters have two curtains that start
>at one side of the sensor, and finish at the other side.

The 'front' curtain starts out deployed, covering the entire sensor, and it retracts to the stowed position at the bottom, while the 'rear' curtain starts out stowed at the top and it deploys to cover the sensor to end the exposure. Then, both curtains retreat to their initial positions between exposures.

>3) Given 1) and 2) above, are there any shutters that start in
>the middle of the sensor and proceed to the sides, thus
>minimizing travel time?

Not any modern ones. The main purpose of the FP shutter mechanism is to achieve high effective shutter speeds from relatively slow moving curtains. To achieve these high effective shutter speeds the rear curtain starts to close while the front curtain is still moving, thus forming the 'moving slit' that everyone talks about. This slit must remain exactly the same width as it crosses the frame in order to achieve a uniform exposure. This means the two curtains must not only start exactly at the right times, but they must transition at exactly the same speeds.

>I stopped thinking about shutters
>when I sold my pair of Nikon F3 bodies years ago. Too many
>other areas of interest to investigate.

I understand. However, the science behind the FP shutters is absolutely amazing. The low mass curtains we have today are what allow the high curtain transition speeds, which in turn allow the high regular flash sync speeds. The low mass curtains came directly from carbon fiber products developed for the space program.

>4) Does shutter inertial delay, acceleration time, etc. occur
>prior to, or during, actual sensor exposure time?

The most critical delays are the ones associated with curtain start. These delays directly affect the shutter speed accuracy and the flash synchronization. The modern materials used in the shutters to reduce mass (acceleration and inertial delays) and flexing (deformation delays) have been the primary reason that our maximum shutter and flash sync speeds have increased in the last 15 years or so. Back in the 80's and 90's, the maximum flash sync speed was typically 1/60th to 1/80th sec and the maximum shutter speed was 1/1000th to 1/2000th sec.

>5) Without the handful of microprocessors and related
>semiconductor components resident in our cameras, digital
>photography as we know it would be impossible. I still
>maintain in my writings and lecturing that these technologies
>are still in their relative infancy.

The electronics that control the shutters have undergone a total revolution over the last 15 years as well. High speed DSPs coupled with micromachines can now achieve real-time adjustments to the shutter transition speeds while the curtains are actually in transition! This keeps the curtains moving at exactly the same speeds, allowing us to use a narrower 'slit', which allows a higher maximum effective shutter speed (1/8000).

Also, the high frame rates that we now see on DSLRs are a direct result of these new high tech FP shutters.

Russ
Nikonian Moderator
Russell MacDonald Photography
Nikon CLS Practical Guide

  

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