D TTL Flash Settings...Help

Testa

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Hi All,

I have an on going underexposure problem in program mode with the on board flash as well as the SB80dx. I found this info (below) while searching for this problem. If I follow what it says will the camera not keep the shutter open until it thinks the image is properly exposed.....maybe less than 1/60...Maybe blur?? Can't try on the Camera, I'm at work. Any input would be appreciated. D100 24-85afsG db80dx

Thanks in advance....Bruno

"Any photographers familiar with the Nikon flash system should know that most Nikon SLRs require you to enable "slow-sync" if the ambient light is not sufficient to expose the background. Otherwise, your shutter speed will be locked at the lowest speed (1/60s) in P mode. Check the program line in your camera manual.

With the DX speedlight set to "D-TTL Matrix" (new 3D matrix balanced fill-flash) it amplifies the problem as the camera will try to balance exposure of your subject with that for the background.

Try and test again with the followings before trying to make another review...lol:

1) Turn on "slow-sync"
2) Set your speedlight to "standard D-TTL" (with matrix-balanced icon off), or
3) Set your speedlight to automatic "AA" mode."
 
Hi All,
I have an on going underexposure problem in program mode with the
on board flash as well as the SB80dx. I found this info (below)
while searching for this problem. If I follow what it says will the
camera not keep the shutter open until it thinks the image is
properly exposed.....maybe less than 1/60...Maybe blur?? Can't try
on the Camera, I'm at work. Any input would be appreciated. D100
24-85afsG db80dx

Thanks in advance....Bruno
I'm assuming you're talking about flash indoors.

Keep it simple:

flash on d-ttl
camera on p
aim head up on flash (45 60 degree tilt)
check histogram
adjust compensation + - if need be

I find for indoor flash photos that by aiming the sb80 head
around 60 degrees with zero compensation I get good results.

Hope that helps,

--
. Ben
Nikon D1
Nikon F100
Nikkor 80-200 f/2.8D ED AF
Nikkor 50 f/1.8D AF
Nikkor 28-105 f/3.5-4.5D AF
Nikkor 24-85 f/3.5-4.5 AF-S ED-IF
SB28
SB80-DX
 
Hi Testa

The guidance you pasted is not good - I would suggest ignoring it. In particular, this advises setting the flash to AA mode.

AA mode disables TTL metering and in effect leaves the flash unit to make a best, unmetered-in-real-time guess, from focal distance and aperture, as to what will be the approriate power to fire at.

In AA mode, it can pay no regard to, for instance, the reflectivity of the subject (e.g. caucasian guy in white shirt filling the frame, afro gentleman in black turtle neck ditto).

AA mode thus de-couples the metering process, and though, for some folk taking repetitive pictures in similar envirinments, they could learn a set of settings which "works", it's rather numb logic process will produce more errors than it can ever cure

D-TLL is better, though not as bulletproof by a long way as Nikon's film-plane TTL metering on its film bodies. It does make the odd mistake, but none so crucial as to kill the shot, in most circumstances. It's one of the shortcomings of digitals we will all have to live with and work round for a while yet. Don't get depressed - it's still very good!!

It allows the CAMERA (not the flash unit, as in AA mode) to meter on the actual light arriving at the CCD (image sensor).

If you are getting shots a little under-exposed, and you like full Program mode (we usually run in Aperture priority or full manual, but with D-TTL auto-flash metering) first try biasing the flash a little - +0.3 and then +0.7.

Our own experince is that the shots are not in fact terribly underexposed (in the film context of lost shadow detail), rather, that all digitals, D100 included, have a low exposure latitude. The choice is of blocking out highlights, and a little post-processing on the images (levels) usually yields excellent results.

There are numerous threads on the forum about the "under-exposure problem" (if you view it as that), and a good read through is well worth while.

Regards

Ewen Cameron
 
Hello all,
Thanks for all the help!

I was using a 24-85 afs g lens and having severe underexposure problems in any program mode except manual, especially at 85mm less at 24mm but still random. Nikon Canada went as far as to swap my body for a new D100 but sill no go. Yesterday i tried an old 35-70mm 3.3-4.5 Lens. The peoblem has disappeared.....Works GREAT!! I tried a 70-300mm 4-5.6 D and with this lens i have to ev +.3 to get a acceptable exposure. With these two lenses i don't get the random inconsistencies or severe under exposure. Why would a new lens cause this problem (Deffective Lens??)B.T.W this lens exposes properly without the flash.

Regards...Bruno
 
Ok I have the D100...I have the SB 80; I am taking indoor shots of dancers on stage with varying degrees of light...some hot spot lights...some with no spots and dark lighting...and of course lighting color changes ....any suggestions for settings
Hello all,
Thanks for all the help!

I was using a 24-85 afs g lens and having severe underexposure
problems in any program mode except manual, especially at 85mm less
at 24mm but still random. Nikon Canada went as far as to swap my
body for a new D100 but sill no go. Yesterday i tried an old
35-70mm 3.3-4.5 Lens. The peoblem has disappeared.....Works GREAT!!
I tried a 70-300mm 4-5.6 D and with this lens i have to ev +.3 to
get a acceptable exposure. With these two lenses i don't get the
random inconsistencies or severe under exposure. Why would a new
lens cause this problem (Deffective Lens??)B.T.W this lens exposes
properly without the flash.

Regards...Bruno
 
Testa

Just a possibility - There's a slight, but known problem with the D100 (and all Nikon bodies), with the lens aperture control lever not always engaging reliably with the corresponding tab which operates it on the camera body. If you have the lens set to lock/f22 (so the camera controls can run it) and this lever is disengaged, then the lens will stay stuck down at F22. Even with the camera on D-TTL, the flash just won't have enough horsepower to illuminate for f22 and the result is shronic uinder-exosure.

You can check this easily. Fit the lens. Unlock the aprture ring and set it to (say) f10. Looking through the viewfinder, depress the depth of field preview button and you should see the image visably dim. If it does not, then the levers are not engaged. Easily fixed - just gently bend the tab in the lens mount in the camera body forward a little. It is soft and can easily get bent back. Some lenses may engage on it but other witha slightly shorter tab might miss. This would certainyl explain the radical anomoaly between the two lenses.

Worth a look, anyway.

Su - try aperture priorty at f4 or thereabouts. Leave the flash to itself, on D-TTL, maybe +0.3. Leave the flash straight ahead - no card up or wide angle diffuser down - just plain vanilla. Shoot in NEF. We've found this combo incredibly good for on stage action in rock concerts, strobes, smoke and all, up to 40/50 feet range (17-35 and 28-70 AF-S 2.8's in use). For some reason the flash seems to meter better in really violent conditons like this than it does in "easy" situations.

Regards

Ewen.
 
But with apeture priority I can make sure my shutter speed will be fast enough to catch the action...am I missing something? I am trying to catch dancers...or will the flash stop action?
Testa

Just a possibility - There's a slight, but known problem with the
D100 (and all Nikon bodies), with the lens aperture control lever
not always engaging reliably with the corresponding tab which
operates it on the camera body. If you have the lens set to
lock/f22 (so the camera controls can run it) and this lever is
disengaged, then the lens will stay stuck down at F22. Even with
the camera on D-TTL, the flash just won't have enough horsepower to
illuminate for f22 and the result is shronic uinder-exosure.

You can check this easily. Fit the lens. Unlock the aprture ring
and set it to (say) f10. Looking through the viewfinder, depress
the depth of field preview button and you should see the image
visably dim. If it does not, then the levers are not engaged.
Easily fixed - just gently bend the tab in the lens mount in the
camera body forward a little. It is soft and can easily get bent
back. Some lenses may engage on it but other witha slightly shorter
tab might miss. This would certainyl explain the radical anomoaly
between the two lenses.

Worth a look, anyway.

Su - try aperture priorty at f4 or thereabouts. Leave the flash to
itself, on D-TTL, maybe +0.3. Leave the flash straight ahead - no
card up or wide angle diffuser down - just plain vanilla. Shoot in
NEF. We've found this combo incredibly good for on stage action in
rock concerts, strobes, smoke and all, up to 40/50 feet range
(17-35 and 28-70 AF-S 2.8's in use). For some reason the flash
seems to meter better in really violent conditons like this than it
does in "easy" situations.

Regards

Ewen.
 
Hi su

Flash phography renders the shutter speed of secondary importance, unless there is a great deal of ambient/secondary light. This is unlikely shooting on stage. The lighting may look bright but that because the theatre is deliberatly kept dark - your eye "stops down" to compensate!

The flash itself fires for an incredibly short period - something like 1/10,000th of a second (no doubt someone will know the durations at various powers). In the absence, or near absence of ambient light, it's the flash duration that is effectively your "shutter speed". The shutter speed itself will be of only secondary imporatnce.

D-TTL mode and aperture priority will lock the D100 to a shutter speed of 1/60th. We've had no problem getting sharp shots of air-guitaring rockheads at these settings, but if you get some ambient light smear from motion (which can be a very attractive effect and we sometimes induce it using slow-synch), then shift to manual and set the shutter at 1/125th. The flash will still meter autmoatically, but don't stray too far from f4 or 5.6 - you need more power for that.

I hope this helps.

Regards

Ewen Cameron
Testa

Just a possibility - There's a slight, but known problem with the
D100 (and all Nikon bodies), with the lens aperture control lever
not always engaging reliably with the corresponding tab which
operates it on the camera body. If you have the lens set to
lock/f22 (so the camera controls can run it) and this lever is
disengaged, then the lens will stay stuck down at F22. Even with
the camera on D-TTL, the flash just won't have enough horsepower to
illuminate for f22 and the result is shronic uinder-exosure.

You can check this easily. Fit the lens. Unlock the aprture ring
and set it to (say) f10. Looking through the viewfinder, depress
the depth of field preview button and you should see the image
visably dim. If it does not, then the levers are not engaged.
Easily fixed - just gently bend the tab in the lens mount in the
camera body forward a little. It is soft and can easily get bent
back. Some lenses may engage on it but other witha slightly shorter
tab might miss. This would certainyl explain the radical anomoaly
between the two lenses.

Worth a look, anyway.

Su - try aperture priorty at f4 or thereabouts. Leave the flash to
itself, on D-TTL, maybe +0.3. Leave the flash straight ahead - no
card up or wide angle diffuser down - just plain vanilla. Shoot in
NEF. We've found this combo incredibly good for on stage action in
rock concerts, strobes, smoke and all, up to 40/50 feet range
(17-35 and 28-70 AF-S 2.8's in use). For some reason the flash
seems to meter better in really violent conditons like this than it
does in "easy" situations.

Regards

Ewen.
 
Keep it simple:

flash on d-ttl
camera on p
Leaving the camera in Program exposure mode restricts apertures based upon ISO value. This will limit your ability to balance ambient and flash exposures in low light.
aim head up on flash (45 60 degree tilt)
check histogram
adjust compensation + - if need be
Dialing in flash exposure compensation (which I assume you are referring to) with the camera/flash set to defaults (balanced fill-flash) is asking for random results. You don't know what compensations the camera already applied, and it WILL change those compensations as conditions and other things change. Indeed, one common complaint I get is "the more I dial in flash exposure compensation, the more screwed up the results get." Even more true if you also use exposure compensation PLUS flash exposure compensation in balanced fill-flash modes.

--
Thom Hogan
author, Nikon Field Guide
author, Nikon Flash Guide
author, Complete Guide to the Nikon D100
author, Complete Guide to the Nikon D1, D1h, & D1x
http://www.bythom.com
 
AA mode disables TTL metering
I assume you mean D-TTL, but yes so far...
and in effect leaves the flash unit
to make a best, unmetered-in-real-time guess,
...but wrong now. Actually, AA mode DOES meter in real time during exposure, while D-TTL DOES NOT (it meters just prior to the actual exposure).
In AA mode, it can pay no regard to, for instance, the reflectivity
of the subject (e.g. caucasian guy in white shirt filling the
frame, afro gentleman in black turtle neck ditto).
Basically true, but also mostly true of D-TTL, as well. While Nikon makes a big deal in their manuals about extreme reflectivity conditions (e.g., mirrors), anyone who's shot a bride in a white dress knows that you still have to take reflectivity into account. Meters, whether they be camera or flash, want to make everything into middle gray.
AA mode thus de-couples the metering process, and though, for some
folk taking repetitive pictures in similar envirinments, they could
learn a set of settings which "works", it's rather numb logic
process will produce more errors than it can ever cure
I'm not sure what you mean by "de-couples the metering process."
D-TLL is better, though not as bulletproof by a long way as Nikon's
film-plane TTL metering on its film bodies. It does make the odd
mistake, but none so crucial as to kill the shot, in most
circumstances. It's one of the shortcomings of digitals we will all
have to live with and work round for a while yet. Don't get
depressed - it's still very good!!
The primary advantage of D-TTL is that the flash metering system sees the same thing the lens sees. AA mode doesn't (the flash sensor sees a fixed angle of view and may see things that aren't in the frame; this is not good news for things that are nearer to the camera than the subject).
It allows the CAMERA (not the flash unit, as in AA mode) to meter
on the actual light arriving at the CCD (image sensor).
No, it doesn't. D-TTL never meters off the CCD. It meters off the shutter curtain just prior to opening, and it meters using low-level pulses, not the actual flash produced during the picture. (One reason the film TTL is more reliable than the digital D-TTL is that the film TTL system also meters off the film during exposure, so it sees the full output of the flash; any measuring error on the pre-flash of D-TTL is magnified when the power is fully ratcheted up).
If you are getting shots a little under-exposed, and you like full
Program mode (we usually run in Aperture priority or full manual,
but with D-TTL auto-flash metering)
Uh, you do know that the WAY the D100 calculates D-TTL is different in Aperture priority exposure mode than it is in Manual exposure mode, don't you? This is a SIGNIFICANT difference!
first try biasing the flash a
little - +0.3 and then +0.7.
I'll remind folks that dialing in + flash exposure compensation is not guaranteed to be produced (- is). That's because a flash can't produce more output than maximum. So as you near maximum output, + flash exposure compensation will work less and less reliably.

--
Thom Hogan
author, Nikon Field Guide
author, Nikon Flash Guide
author, Complete Guide to the Nikon D100
author, Complete Guide to the Nikon D1, D1h, & D1x
http://www.bythom.com
 
Uh, you do know that the WAY the D100 calculates D-TTL is different
in Aperture priority exposure mode than it is in Manual exposure
mode, don't you? This is a SIGNIFICANT difference!
Thom,

Would you care to expand on that a little? I would assume it would apply to D1x as well.

Andrew
 
Yup I thought that was the case...and I proved it because every few shots I had to shoot before the flash was ready...sure enough no stop action..though I got some decent shots without flash...thanks again for your help!
Flash phography renders the shutter speed of secondary importance,
unless there is a great deal of ambient/secondary light. This is
unlikely shooting on stage. The lighting may look bright but that
because the theatre is deliberatly kept dark - your eye "stops
down" to compensate!

The flash itself fires for an incredibly short period - something
like 1/10,000th of a second (no doubt someone will know the
durations at various powers). In the absence, or near absence of
ambient light, it's the flash duration that is effectively your
"shutter speed". The shutter speed itself will be of only secondary
imporatnce.

D-TTL mode and aperture priority will lock the D100 to a shutter
speed of 1/60th. We've had no problem getting sharp shots of
air-guitaring rockheads at these settings, but if you get some
ambient light smear from motion (which can be a very attractive
effect and we sometimes induce it using slow-synch), then shift to
manual and set the shutter at 1/125th. The flash will still meter
autmoatically, but don't stray too far from f4 or 5.6 - you need
more power for that.

I hope this helps.

Regards

Ewen Cameron
Testa

Just a possibility - There's a slight, but known problem with the
D100 (and all Nikon bodies), with the lens aperture control lever
not always engaging reliably with the corresponding tab which
operates it on the camera body. If you have the lens set to
lock/f22 (so the camera controls can run it) and this lever is
disengaged, then the lens will stay stuck down at F22. Even with
the camera on D-TTL, the flash just won't have enough horsepower to
illuminate for f22 and the result is shronic uinder-exosure.

You can check this easily. Fit the lens. Unlock the aprture ring
and set it to (say) f10. Looking through the viewfinder, depress
the depth of field preview button and you should see the image
visably dim. If it does not, then the levers are not engaged.
Easily fixed - just gently bend the tab in the lens mount in the
camera body forward a little. It is soft and can easily get bent
back. Some lenses may engage on it but other witha slightly shorter
tab might miss. This would certainyl explain the radical anomoaly
between the two lenses.

Worth a look, anyway.

Su - try aperture priorty at f4 or thereabouts. Leave the flash to
itself, on D-TTL, maybe +0.3. Leave the flash straight ahead - no
card up or wide angle diffuser down - just plain vanilla. Shoot in
NEF. We've found this combo incredibly good for on stage action in
rock concerts, strobes, smoke and all, up to 40/50 feet range
(17-35 and 28-70 AF-S 2.8's in use). For some reason the flash
seems to meter better in really violent conditons like this than it
does in "easy" situations.

Regards

Ewen.
 
Uh, you do know that the WAY the D100 calculates D-TTL is different
in Aperture priority exposure mode than it is in Manual exposure
mode, don't you? This is a SIGNIFICANT difference!
Thom,
Would you care to expand on that a little? I would assume it would
apply to D1x as well.
No, it doesn't. The D100 series sets Standard TTL instead of Balanced Fill-Flash TTL when you use Manual exposure mode; the D1 series does not. Both the D100 and D1 set Standard TTL when you use spot metering, though.

--
Thom Hogan
author, Nikon Field Guide
author, Nikon Flash Guide
author, Complete Guide to the Nikon D100
author, Complete Guide to the Nikon D1, D1h, & D1x
http://www.bythom.com
 
The D100 series sets Standard TTL instead of
Balanced Fill-Flash TTL when you use Manual exposure mode; the D1
series does not. Both the D100 and D1 set Standard TTL when you use
spot metering, though.

--
Thom Hogan
author, Nikon Field Guide
author, Nikon Flash Guide
author, Complete Guide to the Nikon D100
author, Complete Guide to the Nikon D1, D1h, & D1x
http://www.bythom.com
Thanks Thom,

Last time I used Balanced Fill-Flash TTL with D1x/SB28dx was the first time I tried it…

Andrew
 
Testa -

Forget P mode. If you want good results with the onboard or external flash then go to shutter priority, set the shutter speed to 1/180th, and let the camera do the rest of the work. This will produce the results you want.

Leaving it in P or A mode will result in the shutter speed being 1/60th 9 times out of 10 (depends on how much light is available) and blurry underexposed pics.

Make sure you get your flash indicator blinking to ensure there's enough light, if not go up some ISO speed. ALSO, set your WB to "FLASH" vs. auto or whatever else..

Try it, you'll like it, especially with the SB-80DX.. It exposes perfectly this way from 17mm-120mm..

BKKSW
Hi All,
I have an on going underexposure problem in program mode with the
on board flash as well as the SB80dx. I found this info (below)
while searching for this problem. If I follow what it says will the
camera not keep the shutter open until it thinks the image is
properly exposed.....maybe less than 1/60...Maybe blur?? Can't try
on the Camera, I'm at work. Any input would be appreciated. D100
24-85afsG db80dx

Thanks in advance....Bruno

"Any photographers familiar with the Nikon flash system should know
that most Nikon SLRs require you to enable "slow-sync" if the
ambient light is not sufficient to expose the background.
Otherwise, your shutter speed will be locked at the lowest speed
(1/60s) in P mode. Check the program line in your camera manual.

With the DX speedlight set to "D-TTL Matrix" (new 3D matrix
balanced fill-flash) it amplifies the problem as the camera will
try to balance exposure of your subject with that for the
background.

Try and test again with the followings before trying to make
another review...lol:

1) Turn on "slow-sync"
2) Set your speedlight to "standard D-TTL" (with matrix-balanced
icon off), or
3) Set your speedlight to automatic "AA" mode."
 
Forget P mode. If you want good results with the onboard or
external flash then go to shutter priority, set the shutter speed
to 1/180th, and let the camera do the rest of the work. This will
produce the results you want.
I don't agree. With the shutter speed so high, no ambient light will register .. and it usually helps to have some ambient light at least register on the photo.

Also, your aperture is the more important control on your camera, especially with flash photography, as in most cases, depth of field or range of flash should be given priority. By using shutter priority, you are leaving your aperture as a variable .. as if it doesn't matter. It's for the same reason that I wouldn't recommend Program mode.
Leaving it in P or A mode will result in the shutter speed being
1/60th 9 times out of 10 (depends on how much light is available)
and blurry underexposed pics.
Given that you are working within the range of the flashgun's output .. why would it give underexposed photos with 1/60th but not 1/180th ??

Also, why would the photographs necessarily be blurry ?? (Unless you are using a telephoto lens where there is lots of ambient light.)
 
Forget P mode. If you want good results with the onboard or
external flash then go to shutter priority, set the shutter speed
to 1/180th, and let the camera do the rest of the work. This will
produce the results you want.
I don't agree. With the shutter speed so high, no ambient light
will register .. and it usually helps to have some ambient light at
least register on the photo.
It will always have SOME ambient light in the photo, but often the ambient light will be a different temperture than the flash, so it's often better to fill most of the frame with the flash.
Also, your aperture is the more important control on your camera,
especially with flash photography, as in most cases, depth of field
or range of flash should be given priority. By using shutter
priority, you are leaving your aperture as a variable .. as if it
doesn't matter. It's for the same reason that I wouldn't recommend
Program mode.
Yes, I agree with this, but he's in the beginning stages as you can tell by his question.. The BEST way really would be to use manual mode and set the flash manually, but I don't think he was ready for that.
Leaving it in P or A mode will result in the shutter speed being
1/60th 9 times out of 10 (depends on how much light is available)
and blurry underexposed pics.
Given that you are working within the range of the flashgun's
output .. why would it give underexposed photos with 1/60th but not
1/180th ??
I believe it has MORE to do with which mode you use that leads to underexposed pics, more so than the shutter speed. P and A will usally (from my experience) give you underexposed shots. Try it and tell me how it works compared to Shutter Priority..
Also, why would the photographs necessarily be blurry ?? (Unless
you are using a telephoto lens where there is lots of ambient
light.)
A 28-70 F2.8 AFS or a 17-35mm F2.8 AFS, or most zooms are pretty heavy and hard to hold still. Even with a small prime 1/60th is an iffy proposition. And if you go by the rule of shutter speed vs. focal length, and taking into account the 1.5, you should be using 1/60th with a 28-30mm lens to be generious, for consistent results..

Try what I suggested and tell me how it works for you.

BKKSW
 
Sorry to dredge this post up again... I have an event shoot next week (including indoor meetings and dinner/party functions that need flash photos taken) and the last time I did this I was really disappointed with the results--many underexposed shots. Client was satisfied, but I wasn't (I'm not a pro, I do this on the side for a friend's event business). I was shooting with my D100 and SB-50DX (I've since upgraded to an SB-80DX). Since then I've re-read the flash manual several times, plus bought Thom's Nikon Flash Guide book, plus have done a lot of experimenting, all in order to improve my flash success.

Based on all I've read, comments in this forum and my testing I've come up with the following strategy. Please feel free to shoot holes through anything here, and provide any additional advice. And as soon as Thom comes out with a Flash Guide updated for the D100 and DX flashes, I'll be first in line (eBook would be great)!
  • for a somewhat lit, but not bright, meeting/party room, standard D-TTL set on the SB-80DX ( not 3D multi-sensor balanced fill flash), centerweighted metering, front curtain, Aperture priority and +.3/+.7 flash compensation should give me the most consistent results (constantly checking histogram). Will be shooting with 17-35 2.8 and 24-85 G, at mostly people in groups of 2 to 10+. Don't care so much about the background, but want the subject focus to be sharp (small aperture) and the subjects to be properly exposed.
  • with standard D-TTL (again, not 3D multi-sensor fill flash) set on the flash, monitor preflashes still occur and final reading is still taken off the shutter prior to it opening for the best exposure control. Camera exposure is taken into consideration. And you are more assured of getting the + - dialed-in flash exposure compensation you request (within the limits of the flash output). Correct?
  • in meeting rooms the ceiling is usually high and the subjects further away, so stay away from bounce flash unless I'm closer and there's a low, white ceiling. When within 4-6ft of subjects, use the diffuser dome or the built-in (SB-80DX) bounce card to reduce harsh shadows.
  • ambient light could cause some issues with shutter speed and blur, but since most of the exposure should come from flash then shutter speed is irrelevant--short flash duration will reduce/eliminate camera/subject movement blur?
  • realize Manual exposure gives most control, but need to be able to take candid pictures quickly with a minimum of setup.
Anything I'm missing? Thanks for any feedback!

-DougM
Keep it simple:

flash on d-ttl
camera on p
Leaving the camera in Program exposure mode restricts apertures
based upon ISO value. This will limit your ability to balance
ambient and flash exposures in low light.
aim head up on flash (45 60 degree tilt)
check histogram
adjust compensation + - if need be
Dialing in flash exposure compensation (which I assume you are
referring to) with the camera/flash set to defaults (balanced
fill-flash) is asking for random results. You don't know what
compensations the camera already applied, and it WILL change those
compensations as conditions and other things change. Indeed, one
common complaint I get is "the more I dial in flash exposure
compensation, the more screwed up the results get." Even more true
if you also use exposure compensation PLUS flash exposure
compensation in balanced fill-flash modes.

--
Thom Hogan
author, Nikon Field Guide
author, Nikon Flash Guide
author, Complete Guide to the Nikon D100
author, Complete Guide to the Nikon D1, D1h, & D1x
http://www.bythom.com
 
Thanks, Thom, for the hugely helpful reply, and the corrections to my faulty understanding.

I'm a bit daunted at entering into discussion with an acknowledged expert, particularly as I am equally as acknowledged, not least by myself, as being at sub-moron levels of expertise!

My comment about the camera not controlling the flash in AA flash was derived from correspondence we had with Simon Stafford, Techinical Editor of the Nikon Owners Club.

If it's of help to others (Thom doesn't need it!), Simon's advice on this is below (Simon is a super chap, by the way, and very knowledgable), and is of some value in relation to TTL modes as well. Needless to say we promptly abandoned AA mode, which had seemed initially to give better results (OK, after years using Nikon's film F5 TTL metering and getting lazy with its excellence, we were photographing a white cat! - D'oh!);

Regards to all here;

---------------------------------
“I note that you generally use the AA flash
mode which would not be my first choice since in this mode the light sensor
in the SB-80DX controls the flash output without the benefit of the monitor
pre-flash system of other modes. If you are experiencing output problems
using this mode it tends to point the finger of blame at the flash and not
the camera. In AA mode the camera communicates the lens and exposure mode
data to the flash to assist in flash output computations, but essentially it
is the flash unit that controls the exposure.

You mentioned that the spread of the histogram was biased on the horizontal
axis toward the left (dark tone) side. Remember that the histogram is a
representation of the tones in the image and if there are no light / white
tones in your subject then obviously the histogram will reflect this. I have
found that even pointing the flash at a plain white painted panelled door
the flash exposure was controlled by the D-TTL system so that most of the
tone distribution occurred just to the left of the histogram mid-point on
the horizontal axis. This is indicative of the camera/flash combination
working to avoid burnt out highlights in which there is no image data. The
only way I have managed to shift the tone distribution significantly to the
right (light tone) side is by deliberately over-exposing the flash output by
2 stops.

My preferred arrangement is to set the D100 to WB - Flash, D-TTL mode, ISO
200 (400 if I am in a large room with high ceilings or working outside), and
aperture priority exposure mode. The camera will then default to a shutter
speed of 1/60sec regardless of the aperture set. I have just taken a series
of shots over an aperture range of f/2.8 - f/16 at a subject to flash
distance of 3m without any problems using this configuration. I did the same
in AA mode and there is a noticeable difference in exposure accuracy and
consistency, although not to the extent that you describe.

The D-TTL system uses the monitor pre-flash system in which the SB-80DX
emits a series of very rapid and imperceptible pulses of light. These are
reflected off the subject and the camera's flash TTL meter then reads them
to determine the output level of the main flash pulse. The system is
effective up to a range of 20 - 25 feet, but thereafter the light fall off
is such that the levels of reflected light are too small for the camera's
sensor to make accurate assessments.

I should also have said that all CCDs, including those in the D100 and D1
series cameras do have a tendency to bunch up the exposure values between
the mid-tones and the dark tones. This is the principle reason for you
seeing the bias in the histogram display. It has to do with the way the
pixel sites in the CCD react to light. You could try tweaking the Tone
control of the camera, but do take care to make some notes as you 'fiddle'
and only change one variable at a time."
 

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