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Forums Lobby MASTER YOUR TOOLS Nikon Speedlights & Lighting topic #46539
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Subject: "Exposure compensation; camera or flash" Previous topic | Next topic
jackman1107   philadelphia, US  Registered since 20th Jan 2008 Sat 16-Jan-10 02:57 PM
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"Exposure compensation; camera or flash"



I need a basic lesson in flash/camera exposure compensation. I went to "The Class" a couple years ago, pre SB-900. I know the procedure to make it happen; the question is "What is the basis for use?" Ie ... Is there a formula to follow, or is this hit or miss? My notes are long gone; is a there a "starting point," or once again, "I use this point ..."

thanks,
jack

  

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Replies to this topic
Subject Author Message Date ID
Reply message RE: Exposure compensation; camera or flash blw Moderator Awarded for his high level of expertise in various areas
16th Jan 2010
1
Reply message RE: Exposure compensation; camera or flash jim thomas Silver Member
16th Jan 2010
2
Reply message RE: Exposure compensation; camera or flash jackman1107
16th Jan 2010
3
     Reply message RE: Exposure compensation; camera or flash blw Moderator Awarded for his high level of expertise in various areas
16th Jan 2010
4
     Reply message RE: Exposure compensation; camera or flash picmax
29th Jan 2010
24
          Reply message RE: Exposure compensation; camera or flash Arkayem Moderator Awarded for his high level skills in flash photography
29th Jan 2010
25
          Reply message RE: Exposure compensation; camera or flash blw Moderator Awarded for his high level of expertise in various areas
29th Jan 2010
26
Reply message RE: Exposure compensation; camera or flash Arkayem Moderator Awarded for his high level skills in flash photography
17th Jan 2010
5
Reply message RE: Exposure compensation; camera or flash jim thomas Silver Member
17th Jan 2010
6
     Reply message RE: Exposure compensation; camera or flash blw Moderator Awarded for his high level of expertise in various areas
17th Jan 2010
7
     Reply message RE: Exposure compensation; camera or flash jim thomas Silver Member
18th Jan 2010
17
     Reply message RE: Exposure compensation; camera or flash Arkayem Moderator Awarded for his high level skills in flash photography
17th Jan 2010
8
          Reply message RE: Exposure compensation; camera or flash PATTON21
17th Jan 2010
9
          Reply message RE: Exposure compensation; camera or flash blw Moderator Awarded for his high level of expertise in various areas
18th Jan 2010
10
          Reply message RE: Exposure compensation; camera or flash Arkayem Moderator Awarded for his high level skills in flash photography
18th Jan 2010
11
               Reply message RE: Exposure compensation; camera or flash PATTON21
18th Jan 2010
12
                    Reply message RE: Exposure compensation; camera or flash Arkayem Moderator Awarded for his high level skills in flash photography
18th Jan 2010
13
                         Reply message RE: Exposure compensation; camera or flash PATTON21
18th Jan 2010
14
                              Reply message RE: Exposure compensation; camera or flash Arkayem Moderator Awarded for his high level skills in flash photography
18th Jan 2010
15
          Reply message RE: Exposure compensation; camera or flash jim thomas Silver Member
18th Jan 2010
16
               Reply message RE: Exposure compensation; camera or flash Arkayem Moderator Awarded for his high level skills in flash photography
18th Jan 2010
18
                    Reply message RE: Exposure compensation; camera or flash PATTON21
19th Jan 2010
19
                         Reply message RE: Exposure compensation; camera or flash jackman1107
19th Jan 2010
20
                         Reply message RE: Exposure compensation; camera or flash blw Moderator Awarded for his high level of expertise in various areas
19th Jan 2010
21
                         Reply message RE: Exposure compensation; camera or flash Arkayem Moderator Awarded for his high level skills in flash photography
20th Jan 2010
22
Reply message RE: Exposure compensation; camera or flash z1gary Silver Member
20th Jan 2010
23

blw Moderator Awarded for his high level of expertise in various areas   Richmond, US  Nikonian since 18th Jun 2004 Sat 16-Jan-10 03:09 PM
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#1. "RE: Exposure compensation; camera or flash"
In response to Reply # 0



Fortunately with Nikon flash, the exposure compensation makes sense once you know what it does.

Exposure compensation on the camera affects the entire frame, flash or otherwise. If you have a Speedlight on the camera and you set the camera's EC to -1, the result is a 1-stop decrease in the ambient exposure AND a 1-stop decrease in the subject (ie flash) exposure.

The EC on the flash affects ONLY the flash exposure, and moreover it is additive with the camera's. So if you take the above scenario but now set +1 EV on the flash (that is, the camera's at -1 and the flash is at +1), the result is that the background is a stop darker than normal but the main subject IS normal. The subject is exposed at -1 + 1 = +0. This is a good automated way to make the subject pop off a background.

It's hard to offer a formula here, because there are a lot of reasons why one might need compensation, and also because there are a lot of interactions with other settings, such as slow sync and the default maximum shutter speed.

> I went to "The Class" a couple years ago, pre SB-900

The 900 makes no difference whatever in these calculations. In this sense it operates identically to the 800/600. It's just that the button presses are a lot easier to remember on the 900.

_____
Brian... a bicoastal Nikonian and Team Member

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jim thomas Silver Member  Edmond, US  Nikonian since 12th Jan 2003 Sat 16-Jan-10 03:12 PM
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#2. "RE: Exposure compensation; camera or flash"
In response to Reply # 0



Use camera ev comp to adjust ambient light. Use flash comp to adjust "subject" light.

Be sure to take into account that the camera comp also adjusts the flash output. Therefore it may be necessary to counter the camera comp with flash comp the other direction. Only trial and error will tell you whether that is the case.

I recommend these books on that subject:

"Using the Nikon Creative Lighting System" by Mike Hagen; and

"The Hot Shoe Diaries" by Joe McNally.

I hope that this is helpful. Good luck.

JDT

  

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jackman1107   philadelphia, US  Registered since 20th Jan 2008 Sat 16-Jan-10 04:19 PM
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#3. "RE: Exposure compensation; camera or flash"
In response to Reply # 2



Thanks- I think what I read was;

The camera compensation adjusts ambient light; ie overall picture, and the flash takes care of the subject. So, if I wanted a subject to "POP" during an outdoor shot, I would add more flash; and inversely if I wanted the surroundings to be better exposed (?) I'd increase camera compensation.

So, I increase the flash output, leave the camera at zero, and get more subject exposure. Decrease the flash, camera at zero; and surroundings are better exposed. Why then, would I increase the flash and decrease the camera? or vice versa? It would seem to me everything could be taken care of just using the flash control; assuming the flash is always used. It's like math.

1+5=6
2+4=6
3+3=6

Or, am I missing the picture? Have I just taken the same exposure 3 different ways?

Am I missing the subject exposeure is flash related, and is completely different from the ambient exposure which is camera related?

jack

  

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blw Moderator Awarded for his high level of expertise in various areas   Richmond, US  Nikonian since 18th Jun 2004 Sat 16-Jan-10 09:42 PM
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#4. "RE: Exposure compensation; camera or flash"
In response to Reply # 3



> The camera compensation adjusts ambient light

The camera's meter reads and adjusts for ambient light. The camera's EC applies to its meter and to the flash.

> the flash takes care of the subject

The flash's meter reads and adjusts for the subject. However, it is subject to the EC on the camera, as well as its own EC.

> if I wanted a subject to "POP" during an outdoor shot

Not sure what you are wanting here. If you want the subject to be properly exposed and on a mildly underexposed background, you'd set the camera's EC to underexposure and the flash's EC to the reverse: you want the flash to be at net 0EC, since it is to be properly exposed. This was the scenario I gave above. However, it has nothing to do with indoor or outdoor.

> if I wanted the surroundings to be better exposed (?) I'd increase camera compensation.

I think you're wanting the surroundings to be brighter, I think more than normal. If you had no EC on the camera, you'd get the surroundings (ie ambient) normally exposed at +0 EV. But if you want them brighter, you can turn up the camera's EC, say to +1. But because the EC applies to the flash too, the main subject will now also be overexposed. If you want it normal, you'd want to dial in -1EV (the opposite) on the flash.

> the subject exposeure is flash related, and is completely different from the ambient exposure which is camera related?

This is correct.

Consider the slightly more complicated default case, where the camera's maximum flash shutter speed is 1/60th. If you're shooting indoors with normal lighting - that is, fairly dim - with a kit lens - say, f/4.5 - you will almost certainly end up with drastic underexposure indicated on the camera's meter, since a normal exposure would probably be something like 1/15th, f/4, ISO 200. (The 1/60th will be chosen as the flash is turned on, assuming you have not previously overridden this default.) The scene will meter at about -2.5 stops. If you release the shutter now, the exposure is 1/60th, f/4.5, ISO 200 and if for some reason the flash does not fire, it will be pretty dark. But assuming the flash does fire, it will then meter the main subject and adjust the output level to get the subject to come out normally. The result will be a fairly typical flash picture: normal subject, very dark background.

If you were to override the default maximum flash shutter speed and set it to, say, 2 seconds, then retake this same scene, you'd get 1/10th, f/4.5, ISO 200 - and then the ambient exposure will be normal. Then when the flash goes off, it will meter the main subject, and of course it will be normal too. The result is a very different thing: the background will be normally exposed, as opposed to being -2.5 stops off due to the default maximum shutter speed. Of course, you may well find that any subject or camera motion will now be quite obvious.

But now let's say that there's no subject motion and your lens has VR, so motion isn't an issue. But now you want the background a little darker. This is the scenario above, with the camera's EC at -1 stop and the flash at +1. The result is the background 1 stop underexposed and the subject normally exposed.

_____
Brian... a bicoastal Nikonian and Team Member

My gallery is online. Comments and critique welcomed any time!

  

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picmax   Boise, US  Registered since 03rd May 2007 Fri 29-Jan-10 02:50 AM
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#24. "RE: Exposure compensation; camera or flash"
In response to Reply # 3



The exposure mode of the camera matters. The best is to set camera exposure mode to manual and flash to TTL. You then have independent control of both ambient exposure and flash exposure.

Here is a more detailed explanation.

http://dptnt.com/2010/01/balancing-flash-and-ambient-exposure/

Max

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Arkayem Moderator Awarded for his high level skills in flash photography   Richmond Hill, GA (Savannah), US  Charter Member Fri 29-Jan-10 03:15 AM
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#25. "RE: Exposure compensation; camera or flash"
In response to Reply # 24



>The exposure mode of the camera matters. The best is to set
>camera exposure mode to manual and flash to TTL. You then have
>independent control of both ambient exposure and flash
>exposure.
>
>Here is a more detailed explanation.
>
>http://dptnt.com/2010/01/balancing-flash-and-ambient-exposure/
>
>Max

I agree that you can shoot fill in the method you describe, but why not use the TTL-BL mode? That's what it was designed for.

I can set the camera to shoot fill in TTL-BL mode much much faster than I can set the camera up the way you suggest. If you are shooting fill of the bride and groom running from the church to the waiting limo, you simply don't have time to set it up in manual and regular TTL.

Also, TTL-BL does an extremely accurate job of adding fill. I don't think I could do a better job if I took all day and used Camera Manual and regular TTL.

Russ
Nikonian Team Member
Russell MacDonald Photography
Nikon CLS Practical Guide

  

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blw Moderator Awarded for his high level of expertise in various areas   Richmond, US  Nikonian since 18th Jun 2004 Fri 29-Jan-10 04:51 AM
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#26. "RE: Exposure compensation; camera or flash"
In response to Reply # 24



> The best is to set camera exposure mode to manual and flash to TTL. You then have independent control of both ambient exposure and flash exposure.

The standard controls offer the ability to control ambient and flash exposure separately. Moreover, although manual clearly offers this option, it is easily done in auto exposure modes too (A, S, P). It just takes using exposure compensation on the camera and flash. For example, if you want the background to be slightly underexposed in order to emphasize the (normally exposed) main subject, set the camera's exposure compensation to -1EV AND the flash's to +1EV. This can sometimes be easier to use, since it allows the camera to respond to changing light conditions.

_____
Brian... a bicoastal Nikonian and Team Member

My gallery is online. Comments and critique welcomed any time!

  

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Arkayem Moderator Awarded for his high level skills in flash photography   Richmond Hill, GA (Savannah), US  Charter Member Sun 17-Jan-10 02:31 AM
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#5. "RE: Exposure compensation; camera or flash"
In response to Reply # 0
Sun 17-Jan-10 02:32 AM by Arkayem


>I need a basic lesson in flash/camera exposure compensation.
>I went to "The Class" a couple years ago, pre
>SB-900. I know the procedure to make it happen; the question
>is "What is the basis for use?" Ie ... Is there a
>formula to follow, or is this hit or miss? My notes are long
>gone; is a there a "starting point," or once again,
>"I use this point ..."
>
>thanks,
>jack

Jack,

I think it is best to first understand that when shooting flash outdoors in bright light, you need to add 'fill'. Adding fill is automatic with the flash in TTL-BL mode. In TTL-BL mode the flash adjusts its output to make the subject brightness match the ambient background. So, most outdoor daylight flash should usually be done with TTL-BL. The camera should be in either P or S modes, unless Auto FP is turned on, in which case it can be in A mode.

Indoors, flash is normally primary, so you should use regular TTL. With regular TTL the flash knows nothing about the ambient, so it simply adds to it. That's why, for indoor shooting most people use camera Manual mode and set the aperture and shutter to underexpose the ambient by about 3 to 3 stops. This effectively takes the ambient out of the equation and the total lighting on the subject is from the flash.

And Brian and Jim are exactly right. The camera ev does, indeed, adjust both the flash power and the camera ambient exposure, while the Flash EC adjusts only the flash. The main thing you have to watch out for when shooting fill is blowing out places on your subject's clothing or face. You should guard against this by using negative Flash EC. I usually set my flash at -.3 or -.7 ev, and I leave the camera alone.

Russ
Nikonian Team Member
Russell MacDonald Photography
Nikon CLS Practical Guide

  

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jim thomas Silver Member  Edmond, US  Nikonian since 12th Jan 2003 Sun 17-Jan-10 07:38 PM
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#6. "RE: Exposure compensation; camera or flash"
In response to Reply # 5



One suggestion: I do not think one should assume that the photographer will want to capture the subject only, therefore electing to make the background go dark. Unless shooting in a studio most photographers will probably want to include the background. In that case obviously one will want to adjust the ev to properly light it (although perhaps a bit darker than the subject).

Just be aware that the advice given to underexpose assumes that you do not want the background to be lighted.

JDT

  

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blw Moderator Awarded for his high level of expertise in various areas   Richmond, US  Nikonian since 18th Jun 2004 Sun 17-Jan-10 07:51 PM
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#7. "RE: Exposure compensation; camera or flash"
In response to Reply # 6



> I do not think one should assume that the photographer will want to capture the subject only, therefore electing to make the background go dark.

I didn't say that. And in fact, the example given in post #1 does not make the background "go dark." It merely darkens it a little bit - specifically by one stop - which means that the background IS rendered and included, just not as much as the main subject. The example given in post #4 is NOT a recommendation, but describes what happens when one takes the DEFAULTS - when you're 2-4 stops underexposed, yes the background goes pretty dark.

> the advice given to underexpose assumes that you do not want the background to be lighted.

No, it doesn't. The advice I wrote above assumes that you want to underexpose, by a relatively small amount (although of course one could change the -1 to -5EV), and in fact the background will in fact be lit fairly well.

_____
Brian... a bicoastal Nikonian and Team Member

My gallery is online. Comments and critique welcomed any time!

  

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jim thomas Silver Member  Edmond, US  Nikonian since 12th Jan 2003 Mon 18-Jan-10 05:09 PM
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#17. "RE: Exposure compensation; camera or flash"
In response to Reply # 7



Hi Brian,

You apparently thought my comment was addressing yours. It was not; rather it addressed Russ's. See my additional comment below.

Deep breath. Everything is alright.

JDT

  

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Arkayem Moderator Awarded for his high level skills in flash photography   Richmond Hill, GA (Savannah), US  Charter Member Sun 17-Jan-10 08:15 PM
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#8. "RE: Exposure compensation; camera or flash"
In response to Reply # 6



>One suggestion: I do not think one should assume that the
>photographer will want to capture the subject only, therefore
>electing to make the background go dark. Unless shooting in a
>studio most photographers will probably want to include the
>background. In that case obviously one will want to adjust the
>ev to properly light it (although perhaps a bit darker than
>the subject).
>
>Just be aware that the advice given to underexpose assumes
>that you do not want the background to be lighted.
>
>JDT

That's not quite true. If you underexpose the ambient by 2 to 3 stops, the background will obviously be darker, but it will still be plainly visible in the image. You don't get a black background until 5 or 6 stops underexposed.

However, the reason you should underexpose the background is not to darken it. Here are the reasons:

1) You want to underexpose the ambient because when shooting flash indoors, because it takes a very slow shutter speed to fully expose the background, typically 1/8th second, which allows lots of ghosting and blurring if there is any subject or camera movement. The subject will be sharp (flash frozen) if you handhold at 1/8th, but there will be ghosting if the subject is moving even a little, and you need to use a tripod to use 1/8th shutter if you want to eliminate background blur (which may or may not be a problem, depending on whether you blur it with focus).

2) A second reason you want to underexpose the ambient is to reduce the color balance problems on the subject when the ambient lighting doesn't match the flash exactly. Of course, if you gel the flash to make it match the ambient, this will also fix this problem.

3) A third reason you want to underexpose the ambient is to reduce the chance of overexposure of the subject. When using regular TTL, the flash adds to the ambient, so you always have to set a negative FEC to avoid overexposure of the subject. The problem is that the amount of FEC to set in becomes a guess, and it is easy to mess that up.

In fact, these are the reasons the Nikon cameras all have a 'flash shutter speed' that limits the shutter to 1/60th when using camera A or P modes. That keeps the blurring to a minimum while still exposing the background to a dark but visible level.

Personally, I don't like even 1/60th, so I use camera Manual mode and usually set the shutter no slower than 1/80th, which further reduces blurring during things like dancing or walking or speaking (moving arms).

Russ
Nikonian Team Member
Russell MacDonald Photography
Nikon CLS Practical Guide

  

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PATTON21   US  Registered since 08th Jan 2010 Sun 17-Jan-10 11:28 PM
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#9. "RE: Exposure compensation; camera or flash"
In response to Reply # 8



If I am to stick with the on-camera d90 flash, should I be in A mode outdoors for fill flash? From my reading, it sounds that if I am in A mode, the camera will meter the scene accordingly, and the flash will meter the subject accordingly. Thus, the final image will be exposed by the camera AND the flash will be additive to this reading. Given I do not have TTL-BL, how do I add just the "right amount" of fill flash? Must I use negative EC on the flash to "guess and check" the outcome?
Also, how do you add fill flash if the subject is also the scene. Such as photographing an object at rest on a bench, given the object takes up a large part of the scene.

  

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blw Moderator Awarded for his high level of expertise in various areas   Richmond, US  Nikonian since 18th Jun 2004 Mon 18-Jan-10 12:34 AM
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#10. "RE: Exposure compensation; camera or flash"
In response to Reply # 9



> If I am to stick with the on-camera d90 flash, should I be in A mode outdoors for fill flash?

You probably want to be in TTL mode, perhaps with a little negative flash compensation. A mode (as a flash mode, not as in aperture-preferred auto exposure) on flashes requires an external sensor, which I'm pretty sure that the D90 does not have. (External Speedlights such as the SB-600 and SB-900 do have them.)

> how do you add fill flash if the subject is also the scene

Pretty hard, actually. At least with an external flash (I'm not too good with the internal flashes as I don't have one), you might use a bounce approach, but with the built-in I don't see how you'd do this.

_____
Brian... a bicoastal Nikonian and Team Member

My gallery is online. Comments and critique welcomed any time!

  

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Arkayem Moderator Awarded for his high level skills in flash photography   Richmond Hill, GA (Savannah), US  Charter Member Mon 18-Jan-10 01:38 AM
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#11. "RE: Exposure compensation; camera or flash"
In response to Reply # 9



>If I am to stick with the on-camera d90 flash, should I be in
>A mode outdoors for fill flash? From my reading, it sounds
>that if I am in A mode, the camera will meter the scene
>accordingly, and the flash will meter the subject accordingly.
> Thus, the final image will be exposed by the camera AND the
>flash will be additive to this reading. Given I do not have
>TTL-BL, how do I add just the "right amount" of fill
>flash? Must I use negative EC on the flash to "guess and
>check" the outcome?

It's very obscure in the documentation, but the D90 pop-up flash is in TTL-BL by default. So, when you use the pop-up flash in aperture priority outdoors in the daytime, you will automatically get balanced fill flash.

>Also, how do you add fill flash if the subject is also the
>scene. Such as photographing an object at rest on a bench,
>given the object takes up a large part of the scene.

When using the D90 pop-up flash in bright ambient conditions, everything is automatic. The camera aperture and shutter will be automatically set to the ambient conditions and the flash will add fill to make the subject and equal brightness with the ambient.

This system works best when the subject is darker then the ambient, so the flash can add fill to brighten it. When the subject is already brighter than the ambient, TTL-BL doesn't work well. This is the case most of the time indoors under artificial light. This is when you want to use regular TTL.

To use regular TTL with the D90 pop-up flash, you have to put the camera in spot metering mode. Then, the flash is forced into regular TTL mode. Regular TTL often works better than TTL-BL for indoor, low ambient conditions, but you have to understand more about it, to make it work better. Maybe that's why Nikon doesn't explain this.

Russ
Nikonian Team Member
Russell MacDonald Photography
Nikon CLS Practical Guide

  

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PATTON21   US  Registered since 08th Jan 2010 Mon 18-Jan-10 02:25 AM
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#12. "RE: Exposure compensation; camera or flash"
In response to Reply # 11



Thank you for the replies. I will attempt to run a little experiment when I get home with what I have learned. If I understand correctly, in low ambient light, such as a living room, if my camera is in matrix metering, Aperture PM, flashed popped-up, I am really in TTL-BL. If I switch to spot-metering, this will change the "mode" to TTL. The difference in these two modes is that in the former, the camera will try to add light to achieve ambient balance. In the latter, the camera will meter the subject and use the amount of flash necessary to...?
What is the difference in light exposure theory here?

  

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Arkayem Moderator Awarded for his high level skills in flash photography   Richmond Hill, GA (Savannah), US  Charter Member Mon 18-Jan-10 03:39 AM
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#13. "RE: Exposure compensation; camera or flash"
In response to Reply # 12
Mon 18-Jan-10 03:43 AM by Arkayem


>If I
>understand correctly, in low ambient light, such as a living
>room, if my camera is in matrix metering, Aperture PM, flashed
>popped-up, I am really in TTL-BL. If I switch to
>spot-metering, this will change the "mode" to TTL.
>The difference in these two modes is that in the former, the
>camera will try to add light to achieve ambient balance. In
>the latter, the camera will meter the subject and use the
>amount of flash necessary to...?
> What is the difference in light exposure theory here?

Your comments are all correct.

In TTL-BL, the camera must be in either matrix or center weighted metering, and the metering data is sent to the flash computer (actually resides in the camera, but the algorythm it is executing at the time is strictly for the flash). The flash computer analyzes this metering data and compares it to the focus distance and the monitor preflash energy to determine how to set the flash to expose the subject equally bright as the ambient. The flash has no idea what settings you make on the camera and doesn't care. It only looks at the metering data prior to where the camera settings are made.

In regular TTL mode, the entire flash power setting is made by analyzing the monitor preflash energy. The metering data is not sent to the flash, so the metering mode is irrelevant as far as the flash goes. The spot meter measures the subject, but that only is used to set the aperture and shutter. It has no effect on how bright the flash lights the subject.

Another thing that most people do not understand is that for the brief instant the flash is firing, even on the weak preflashes, it is several orders of magnitude brighter than the ambient; maybe 1000 times brighter. This means any contribution that ambient might make to the preflash energy measurement is negligible; normal variations in ambient have no effect on the brightness that the flash lights the subject. (I worded this carefully, because changes in ambient can affect the aperture, and if the aperture changes, the flash power will change in order to maintain a constant subject brightness).

Therefore, in regular TTL mode, you can say that the exposure of the subject is made by the flash plus whatever ambient contribution the camera settings allow. This means that in bright ambient conditions, where the ambient is contributing heavily to the exposure of the subject, there is a serious risk of overexposure since the flash contribution will always be the same. That's why, in regular TTL mode, you normally need to apply some negative FEC (flash exposure compensation). I normally shoot in TTL in normal indoor lighting with -.3 to -.7 ev FEC. And the brighter the ambient, the more negative compensation you have to use.

If the ambient is bright, or you will slow the shutter to allow the ambient to make a big contribution, it is best to use TTL-BL and let the flash adjust its power for the ambient.

All these concepts apply equally to the pop-up flash and external flashes like the SB-800.

Hope that helps,

Russ
Nikonian Team Member
Russell MacDonald Photography
Nikon CLS Practical Guide

  

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PATTON21   US  Registered since 08th Jan 2010 Mon 18-Jan-10 04:22 AM
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#14. "RE: Exposure compensation; camera or flash"
In response to Reply # 13



Ah, I think I understand. You are saying that when I am in TTL-BL, the camera is aware of the ambient light, even if I have chosen A and S values that would expose the scene very darkly. That is to say the camera is aware of the ambient regardless of how I adjust the A/S. That information is provided to the "flash" so that it can boost the subject's exposure to the same level as the ambient.
If I am in TTL mode, I (camera) choose how to expose the ambient, while the flash determines how to expose the subject. Here is my project when I get home from the library. (I am studying for my medical boards) I want to take a picture of my girlfriend who is standing 10 feet in front of a small shaded lamp in a dark room. The only ambient light is the small light. It gives off a nice glow!
If I set my camera in M mode and dial in F2.8 S100 ISO 400 that lets in the exact amount of light I want for the background. Then turn on spot metering, and have her stand in front of the light while spot metering off of her face, the flash will expose her face to "0 flash EV"
I tried something like this before in TTL-BL and she yelled at me because she looked "old" and the light was not flattering. I suppose a bounce flash instead of my pop-up would be a lot better.

  

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Arkayem Moderator Awarded for his high level skills in flash photography   Richmond Hill, GA (Savannah), US  Charter Member Mon 18-Jan-10 04:37 AM
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#15. "RE: Exposure compensation; camera or flash"
In response to Reply # 14



>Ah, I think I understand. You are saying that when I am in
>TTL-BL, the camera is aware of the ambient light, even if I
>have chosen A and S values that would expose the scene very
>darkly. That is to say the camera is aware of the ambient
>regardless of how I adjust the A/S. That information is
>provided to the "flash" so that it can boost the
>subject's exposure to the same level as the ambient.
> If I am in TTL mode, I (camera) choose how to expose the
>ambient, while the flash determines how to expose the subject.
> Here is my project when I get home from the library. (I am
>studying for my medical boards) I want to take a picture of
>my girlfriend who is standing 10 feet in front of a small
>shaded lamp in a dark room. The only ambient light is the
>small light. It gives off a nice glow!
> If I set my camera in M mode and dial in F2.8 S100 ISO 400
>that lets in the exact amount of light I want for the
>background. Then turn on spot metering, and have her stand in
>front of the light while spot metering off of her face, the
>flash will expose her face to "0 flash EV"

Yes, but if you set the camera settings so slow that the single lamp is contributing a lot to the exposure of her, then you have to decrease the flash FEC to keep from overexposing her.

> I tried something like this before in TTL-BL and she yelled
>at me because she looked "old" and the light was not
>flattering. I suppose a bounce flash instead of my pop-up
>would be a lot better.

In TTL-BL mode, where you are allowing lots of contribution from the single lamp, the flash will reduce its power somewhat and should help with the overexposure problem, but you will still have 'direct' flash which is harsh and unflattering. Try putting a thin sheet of white paper (toilet paper??) in front of your flash and shoot a closeup of her (not sure how you'll hold the paper, but that's for you to figure out). That will greatly soften the light, and should make a very nice picture, but the range will be only a couple of feet at most.

It would be much better to buy an SB-600 flash!

Russ
Nikonian Team Member
Russell MacDonald Photography
Nikon CLS Practical Guide

  

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jim thomas Silver Member  Edmond, US  Nikonian since 12th Jan 2003 Mon 18-Jan-10 05:07 PM
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#16. "RE: Exposure compensation; camera or flash"
In response to Reply # 8



Hi Russ,

These are just definitonal differences: "dark", "black", etc. The point I am making is that one should always first decide how one wants the photo to appear. I do not agree that one will always want to underexpose the background...note that I did not say it would always go black with a 3 stop underexposure.

There is no substitute for taking into account the entire scene, including whether the subject is moving, etc. In many situations 1/60th is all you need in shutter speed. There are no absolutes here. I think you are basing your advice on the kind of shooting your normally do, and that is fine. However, one size does not fit all.

JDT

  

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Arkayem Moderator Awarded for his high level skills in flash photography   Richmond Hill, GA (Savannah), US  Charter Member Mon 18-Jan-10 10:51 PM
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#18. "RE: Exposure compensation; camera or flash"
In response to Reply # 16



>Hi Russ,
>
>These are just definitonal differences: "dark",
>"black", etc. The point I am making is that one
>should always first decide how one wants the photo to appear.
>I do not agree that one will always want to underexpose the
>background...note that I did not say it would always go black
>with a 3 stop underexposure.
>
>There is no substitute for taking into account the entire
>scene, including whether the subject is moving, etc. In many
>situations 1/60th is all you need in shutter speed. There are
>no absolutes here. I think you are basing your advice on the
>kind of shooting your normally do, and that is fine. However,
>one size does not fit all.
>
>JDT

Jim,

Your comments are right.

However, my replies on this thread have been mostly directed at people who have little or no experience with, or understanding of, flash photography.

For someone who doesn't understand the things you are mentioning, it is much easier for them to get good images by simply underexposing the ambient and letting the flash be strongly primary so it handles the entire exposure.

Regards,

Russ
Russ
Nikonian Team Member
Russell MacDonald Photography
Nikon CLS Practical Guide

  

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PATTON21   US  Registered since 08th Jan 2010 Tue 19-Jan-10 03:03 PM
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#19. "RE: Exposure compensation; camera or flash"
In response to Reply # 18



We will all have different opinions on how to use flash. It feels like a whole different type of photography. Here is another question for you guys...

I placed a wine bottle on an open window with a night city scene behind it. I then used manual mode to set the ambient light the way I wanted it. Then, I used the flash in TTL mode to add a little bit of light to the wine bottle. This exposed the bottle correctly, but changed the white balance of the city into a very orange hue. How do I prevent this? The bottle is perfectly exposed and white balanced, the city however, has turned totally orange.

  

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jackman1107   philadelphia, US  Registered since 20th Jan 2008 Tue 19-Jan-10 09:46 PM
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#20. "RE: Exposure compensation; camera or flash"
In response to Reply # 19



NX2

  

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blw Moderator Awarded for his high level of expertise in various areas   Richmond, US  Nikonian since 18th Jun 2004 Tue 19-Jan-10 11:20 PM
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#21. "RE: Exposure compensation; camera or flash"
In response to Reply # 19



One way to do this is to put a gel filter on the flash to make the flash output match the background - in this case, incandescent. Then set white balance to incandescent. All of the light will then be the same color.

> NX2

That'll do, but it's a lot more work. Photoshop will do the same thing, but it's going to be a hassle too. Both would be, essentially, raw conversions with two different white balances.

_____
Brian... a bicoastal Nikonian and Team Member

My gallery is online. Comments and critique welcomed any time!

  

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Arkayem Moderator Awarded for his high level skills in flash photography   Richmond Hill, GA (Savannah), US  Charter Member Wed 20-Jan-10 03:18 AM
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#22. "RE: Exposure compensation; camera or flash"
In response to Reply # 19



>We will all have different opinions on how to use flash. It
>feels like a whole different type of photography. Here is
>another question for you guys...
>
>I placed a wine bottle on an open window with a night city
>scene behind it. I then used manual mode to set the ambient
>light the way I wanted it. Then, I used the flash in TTL mode
>to add a little bit of light to the wine bottle. This exposed
>the bottle correctly, but changed the white balance of the
>city into a very orange hue. How do I prevent this? The
>bottle is perfectly exposed and white balanced, the city
>however, has turned totally orange.

The orange color was an indication of lots of tungsten lights, so using a tungsten gel on the flash, and setting the WB to tungsten can sometimes work pretty well.

Otherwise, you have to extract the subject from the background in photoshop and adjust color balance separately for the background. This is not really that hard to do.

Russ
Nikonian Team Member
Russell MacDonald Photography
Nikon CLS Practical Guide

  

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z1gary Silver Member  Crystal River, US  Nikonian since 02nd Oct 2006 Wed 20-Jan-10 05:29 PM
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#23. "RE: Exposure compensation; camera or flash"
In response to Reply # 0



Great thread...thanks Nikonians!!!
Gary

  

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