Go to a  "printer friendly" view of this message which allow an easy print Printer-friendly copy Go to the page which allows you to send this topic link and a message to a friend Email this topic to a friend
Forums Lobby MASTER YOUR TOOLS - Hardware & Software Nikon Speedlights & Lighting topic #20628
View in linear mode

Subject: "Okay so we need preflash but the manual says "impercept" Previous topic | Next topic
Beemer2 Silver Member Nikonian since 07th Dec 2006Tue 30-Jan-07 07:33 AM
2517 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
"Okay so we need preflash but the manual says "impercept"


Scotland, GB
          

The SB-800 manual Page 13 and 36 says "the SB-800 fires a series of imperceptable Monitor preflashes". Now to me imperceptable should mean imperceptable to my eyes and not just to the CCD.

However even disregarding the above I cannot see any difference in the intensity of the D200 built-in flash if it is set to e3 TTL or e3 commander.

Surely if set to e3 commander the built in flash should not appear as bright as e3 TTL?

Beemer2

If only Mozart had had a camera

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

Replies to this topic
Subject Author Message Date ID
Reply message RE: Okay so we need preflash but the manual says "imper
hjens Silver Member
30th Jan 2007
1
Reply message RE: Okay so we need preflash but the manual says "imper
johngardner1956
30th Jan 2007
2
Reply message RE: Okay so we need preflash but the manual says
bens0472
30th Jan 2007
3
Reply message RE: Okay so we need preflash but the manual says
Beemer2 Silver Member
30th Jan 2007
4
     Reply message RE: Okay so we need preflash but the manual says
bens0472
30th Jan 2007
5
          Reply message RE: Okay so we need preflash but the manual says
Beemer2 Silver Member
30th Jan 2007
6
               Reply message RE: Okay so we need preflash but the manual says
bens0472
31st Jan 2007
7
                    Reply message RE: Okay so we need preflash but the manual says
Beemer2 Silver Member
31st Jan 2007
8
                    Reply message RE: Okay so we need preflash but the manual says
bens0472
31st Jan 2007
9
                    Reply message RE: Okay so we need preflash but the manual says
bens0472
02nd Feb 2007
11
                    Reply message RE: Okay so we need preflash but the manual says
HBB Moderator
01st Feb 2007
10
                         Reply message RE: Okay so we need preflash but the manual says
Sportymonk
25th Oct 2012
12

hjens Silver Member Nikonian since 07th Jan 2007Tue 30-Jan-07 10:38 AM
191 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#1. "RE: Okay so we need preflash but the manual says "imper"
In response to Reply # 0


Fredericia, DK
          

>Surely if set to e3 commander the built in flash should not
>appear as bright as e3 TTL?

I don't know for the build-in flash of the D200 and it can be difficult to "see the brightness by eyes", but if you measuring the preflash from the SB800 with flashmeter you mostly would have a lower reading (on mine anyway).

Henning from Denmark
www.HMJ-foto.dk

Henning from Denmark
www.HMJ-foto.dk

Visit my Nikonians gallery.

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

johngardner1956 Registered since 21st Apr 2003Tue 30-Jan-07 01:57 PM
14 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#2. "RE: Okay so we need preflash but the manual says "imper"
In response to Reply # 0



          

You may also notice that the imperceptible flash will cause some people to blink, and the main flash will catch their eyes half shut. That's the beauty of the default setting of the function button on the D200. It triggers the preflash and stores the setting so that the shutter activates only the main flash for the next and subsequent shots, until reset.

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

bens0472 Basic MemberTue 30-Jan-07 04:52 PM
819 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#3. "RE: Okay so we need preflash but the manual says"
In response to Reply # 0


Roswell, US
          

Not necessarily.

The built in flash on the D200 can be configured to operate as the commander AND, simultaneously, contribute to the exposure as an additional flash. This is different from, say, how the built in on the D70 operates in commander mode, when it can only act as a commander and not contribute to the exposure (well, only slightly).

In E3 commander menu, you still have the choice of what mode and what compensation to configure for the built-in. In E3 commander, you can configure the built-in in one of several ways:

  • Set the built-in "mode" to "TTL" or "AA" to have it contribute to the exposure as well as act as commander to groups A and B. You can control the Flash Exposure Compensation by changing the EV setting in the "Comp" field (+/- 1, 2, 3 etc). This increases or decreases the flash output *relative* to the amount determined necessary by the preflashes.

  • Set the built-in "mode" to "M" to, again, have it contribute to the exposure as well as act as commander to groups A and B. In this mode, the values you configure in the "Comp" field will be expressed in fractions (1/1, 1/2, 1/4, 1/8, 1/16...) indicating stops. Obviously, each successively smaller fraction indicates a halving of the previous fraction's output. This sets the output to a specific, manually-determined level.

  • Set the built-in "mode" to "--" to prevent the built-in from contributing to the exposure BUT STILL act as commander for groups A and B. In this mode, you will not configure anything in the "Comp" field. There is no (exposure contributing) level of output when using "--" mode on the built-in.

In all of these modes, if you are using the built-in to act as commander for either/both Group A or/and Group B, then the built in WILL fire the monitor preflashes and, from your perspective, you will not be able to tell a difference between the level of the preflashes in any of them (because, really, there shouldn't be..there should only be a difference in the level of output of the flash that fires at exposure time, i.e. after the shutter opens). Although certainly not imperceptible to the eye, it will not register in your shot.

And, of course, as John said above, explore the use of FV Lock to mitigate closed eyes due to preflashes.

Ben

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

    
Beemer2 Silver Member Nikonian since 07th Dec 2006Tue 30-Jan-07 05:15 PM
2517 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#4. "RE: Okay so we need preflash but the manual says"
In response to Reply # 3


Scotland, GB
          

Ben,

Thanks for the comprehensive explanation. I'm going to try the inbuilt compensation whilst it is in commander mode. However as my previous setting has always been "---" I'm still convinced I am seeing full output although I do not have a flashmeter.

Beemer2

If only Mozart had had a camera

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

        
bens0472 Basic MemberTue 30-Jan-07 07:31 PM
819 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#5. "RE: Okay so we need preflash but the manual says"
In response to Reply # 4


Roswell, US
          

You *will* see output, even when the mode = "--". Many folks tend to incorrectly assume (and even post here) that this setting will result in NO output, but this is simply not correct. The flash MUST fire in order to trigger the remotes. CLS works like this (when all groups are set to TTL mode):

  1. The commander fires a series of preflashes to calibrate its own exposure through the lens.
  2. The commander, through another series of preflashes, communicates to the remotes in Group A, sending mode information, EV compensation, metering info, etc.
  3. Remotes in Group A fire a series of preflashes to calibrate their necessary exposure through the lens.
  4. The commander, thorugh another series of preflashes, communicates to the remotes in Group B, sending mode information, EV compensation, metering info, etc.
  5. Remotes in Group B fire a series of preflashes to calibrate their necessary exposure through the lens.
  6. The mirror raises and shutter opens
  7. The commander fires a triggering flash that (if mode does not equal "---") also acts as a third group in the exposure, the output of which is calibrated by #1.
  8. The remotes fire (for all intents and purposes, simultaneously with #7).


Now, obviously, the built in, in your case, is the commander and, for your purposes, the commander is set to "--" mode. So, because of this, the camera skips #1 and sets its output for #7 to the minimum so as to have minimal impact on the overall lighting of the shot (keep in mind, though, that if you're very close to your subject or your subject or other elements in your scene are highly reflective, you'll see evidence of #7, even at its lowest setting associated to mode = "--". This is true of ANY commander, except for the SU-800 which uses only IR to do all of this preflash and triggering stuff).

So - to test your theory...


Disregard Groups A and B (in fact, don't even have them on or available). Best to put your camera on a tripod. Using a dark wall as your subject, measure the proper exposure (disregarding flash) by putting your camera in manual mode, matrix metering at ISO 400 and the Max aperture for your lens and zero the meter by adjusting shutter speed. Now, set your camera to underexpose by 2 stops by increasing shutter speed two stops.

Now, set your built in to commander, mode = "--". Take a shot (SHOT 1).

Same settings for the camera, same black background, same flash, same camera position, lens, etc. Set your built in to commander, mode = 'M'. Set the "Comp" to 1/128. Take the shot (SHOT 2).

Same settings for the camera, same black background, same flash, same camera position, lens, etc. Set your built in to commander, mode = 'M". Set the "Comp" to 1/16. Take the shot (SHOT 3).

Same settings for the camera, same black background, same flash, same camera position, lens, etc. Set your built in to commander, mode = 'M'. Set the "Comp" to 1/1. Take the shot 9 (SHOT 4).

Same settings for the camera, same black background, same flash, same camera position, lens, etc. Set your built in to commander, mode = 'TTL'. Set the "Comp" to -2. Take the shot (SHOT 5).

Same settings for the camera, same black background, same flash, same camera position, lens, etc. Set your built in to commander, mode = 'TTL'. Set the "Comp" to 0. Take the shot (SHOT 6).

Same settings for the camera, same black background, same flash, same camera position, lens, etc. Set your built in to commander, mode = 'TTL'. Set the "Comp" to 2. Take the shot (SHOT 7).

Your results should be as follows:

SHOT 1 & SHOT 2 should look very similar because, in both, the flash is firing at minimum output (luminosity histos should be very similar if not identical)

SHOT 3 should look brighter than SHOTs 1 & 2 (luminosity histo shoudl be more heavily weighted to the right).

SHOT 4 should look all that much brighter than SHOT 3 (luminosity histo should be even more heavily weighted to the right, if not clipping).

SHOT 5 should be slightly under-exposed (luminosity histo should be slightly weighted to the left).

SHOT 6 should be fairly well exposed (luminosity histo should be even).

SHOT 7 should be slightly over-exposed (luminosity histo should be slightly weighted to the right).

You don't need a flash meter to do these comparisons, just look at the histogram. It'll tell you everything you need to know.

Good luck,



Ben

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

            
Beemer2 Silver Member Nikonian since 07th Dec 2006Tue 30-Jan-07 10:11 PM
2517 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#6. "RE: Okay so we need preflash but the manual says"
In response to Reply # 5


Scotland, GB
          

Ben,

Good exercise which I will try out tomorrow.

In your opinion would putting a filter over the built-in flash have the same functionality (maybe apart from distance) as using an SU-800?

Lastly can I use my SB-800 D200 mounted for focus assist and have the flash not fire? This would be very useful when not requiring flash and I am using my 17-55mm as the lens hood obstructs the focus assist lamp.

Beemer2

If only Mozart had had a camera

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

                
bens0472 Basic MemberWed 31-Jan-07 03:03 AM
819 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#7. "RE: Okay so we need preflash but the manual says"
In response to Reply # 6


Roswell, US
          

Beemer,

You could use a filter on the built-in. Although I've never tried it, some folks have mentioned having used an exposed strip of film to filter most of the visible light from the commander flash. Nikon makes a handly little device, primarily for the macro kit, but also sold separately as an accessory. It's called the "SG-31R" or "SG-3IR", depending upon which of Nikon's localized sites you visit. It's just a clip on device with an IR filter so that it only allows the IR portion of the light from the flash to escape - eliminating the possibility of the built-in polluting the exposure.

Next - I don't think you can use the SB-800 on-camera as the commander and have it completely suppress the triggering flash. Detection of the triggering flash (#7 in my previous post) by the remotes is required for them to fire, but, as with all commanders, if you set the mode to "---", it will fire at minimum output. To keep this minute amount of light from polluting the exposure of your subject, just set the flash head zoom to its highest setting and point the flash head away from the subject but in a direction that will still throw light at the remote. Obviously, this is difficult to do if your remote is in front of or behind your subject, in which case you might use any reflective surfaces around to get some light to the remote sensor. This is easier to do inside than out, but I know that people do it.

Perhaps Hal (HBB) could contribute to this part of the discussion as he has VERY significant experience controlling multiple (13 at last count, I believe) SB-800s with an on-camera SB-800.

Hal - if you're reading???

Ben

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

                    
Beemer2 Silver Member Nikonian since 07th Dec 2006Wed 31-Jan-07 12:48 PM
2517 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#8. "RE: Okay so we need preflash but the manual says"
In response to Reply # 7


Scotland, GB
          

Ben,

Sorry perhaps I did not make one point clear which was to use my SB-800 on my D200 ONLY for IR focus assist i.e. ambient light exposure only and no flash remotes?

Beemer2

If only Mozart had had a camera

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

                        
bens0472 Basic MemberWed 31-Jan-07 03:43 PM
819 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#9. "RE: Okay so we need preflash but the manual says"
In response to Reply # 8


Roswell, US
          

OH...I see and, I don't know.

Never tried it and, thus, never researched it, but I seem to recall reading something in one of these forums a while back about this very piece of functionality. I think it can be done.


Ben

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

                        
bens0472 Basic MemberFri 02-Feb-07 12:44 AM
819 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#11. "RE: Okay so we need preflash but the manual says"
In response to Reply # 8


Roswell, US
          

Beemer,

Was finally able to look into your question. The answer is yes. Page 62 of the SB800 manual (it also happens to be the first topic in the index). Very easy to configure. One simple custom menu setting and you're on your way.



Ben

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

                    
HBB Moderator Hal is an expert in several areas, including CLS Awarded for his excellent article contributions to the Resources. Charter MemberThu 01-Feb-07 02:36 AM
8464 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#10. "RE: Okay so we need preflash but the manual says"
In response to Reply # 7


Phoenix, US
          

Ben, Beemer, et al:

Sorry to be so late.

The IR filter portion of the SG-3IR device (reading from the box one of mine came in) is exactly the size of the lens in front of the strobe tube of the SB800. I took an SG-3IR apart to get at the IR filter so I could experiment with it. The goal was to convert an SB800 into an SU800. Once I discovered this would work, I went ahead and ordered the SU800 anyway. Don't ask me why, because I don't know. It seemed like a good idea at the time.

The SG-3IR lists for thirteen dollars or so, less at street prices. With a rubber band or a couple strips of "Professional Gaffers Tape" it can be easily fastened to an SB800, thereby blocking almost all visible light. If you use the gaffers tape, you can easily block all visible light. I can still see a very dull red glow when the SB800 fires, but I doubt it could be seen more than a couple feet away.

I laughed when I first discovered "Professional Gaffers Tape" at $35 a roll or so. Then I discovered what it will do. You can use it on any surface and when you pull it off, it leaves absolutely no gummy residue behind to attract dirt, dust , etc. Great stuff. I always carry two rolls, one black and one dayglo orange.

The herd is stable at the moment at twelve SB800s, three SB-R200s (still waiting for the fourth to arrive) and the SU800. Saturday I will be up in the new control tower at the Phoenix airport (326 feet to the floor of the "cab" as the controllers call it) shooting some afternoon and evening (twilight) shots of a couple of our new police department helicopters outside, against the setting sun behind the city skyline. Even my herd of SB800s cannot pull this one off. Once the sun sets, I am going to place one helicopter outside the tower some distance away and have the second one above and behind the tower and he will illuminate the first one with his mega-candle power spot light. Should be an interesting afternoon and evening.

The following weekend, I will be at an air force base near here with a police car and officers in front of an F-16 at sundown with the sun setting behind the White Tank mountains to the west. I will take the entire herd out for this one.

Ben, thanks for all your efforts to help Nikonians into the CLS technology. I am still learning just how much thought went into its design. I also know enough about the other brand's speedlights to know that we are the fortunate ones. Thanks again for being there.

Regards to all,

HBB in Phoenix, Arizona

HBB in Phoenix, Arizona
Nikonian Team Member

Photography is a journey with no conceivable destination.

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

                        
Sportymonk Registered since 16th Jul 2007Thu 25-Oct-12 06:18 AM
814 posts Share on Facebook Share on Twitter Share on Linkedin    Click to send email to this author Click to send private message to this authorClick to view this author's profile
#12. "RE: Okay so we need preflash but the manual says"
In response to Reply # 10


Rocky Mount, US
          

Any particular brand of Gaffer Tape that you would recommend?

Nikonians is the Smithsonian of Nikon knowledge. If there is a question they can't answer, I want to see the question.

My Gallery: www.HLDPhotos.com
My Blog : www.HLDPhotos.blogspot.com

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

Forums Lobby MASTER YOUR TOOLS - Hardware & Software Nikon Speedlights & Lighting topic #20628 Previous topic | Next topic


Take the Nikonians Tour and learn more about being a Nikonian Wiki /FAQ /Help Listen to our MP3 photography radio channels Find anything on Nikon and imaging technology - fast!

Copyright © Nikonians 2000, 2014
All Rights Reserved

Nikonians®, NikoScope® and NikoniansAcademy™ are trademarks owned by Nikonians.org.
Nikon®, Nikonos® and Nikkor® are registered trademarks of Nikon Corporation.