Flash and analog exposure display

I've searched several threads for the answer to this question and have had no luck thus far. I'm using a D80 and SB-600 to take some indoor photographs. I'm shooting in manual and I select my desired aperture. ISO is set at 400. The exposure meter in the viewfinder, because of the lower amount of light is telling me that I need a slower shutter speed. I understand at this point that the camera is measuring the amount of ambient light and that the flash will gather the necessary information to determine proper exposure. At this point, What do I select for a shutter speed? It's a handheld shot, so obviously I don't want to select the slower shutter speed based on what the camera tells me. Do I select a shutter speed that is simply fast enough to avoid blur based on my focal length? Does it matter how fast otherwise? Is the analog exposure display useful when I'm using flash? Thanks.

--
Larry S.

I ran into the same issue when i bought my sb600 now when i use a 50mm lens i set s to 50 and change A based on histogram and highlight flashing. This is all for indoors shooting
Much Thanks

Snowman99 said:

It's a handheld shot, so obviously I don't want to select the slower shutter speed based on what the camera tells me. Do I select a shutter speed that is simply fast enough to avoid blur based on my focal length? Does it matter how fast otherwise? Is the analog exposure display useful when I'm using flash?

Click to expand...

You could do that, but the shutter speed may not need to be that fast if the ambient light level is low enough. If you want primarily the flash exposure, all you need is a shutter speed high enough to prevent the ambient light from registering a (possibly blurred) image. In manual exposure mode, the analog exposure display tells you how 'underexposed' the ambient light will be at a given shutter/aperture setting. So you can pick settings that will let the flash dominate the lighting. (If you actually want some effect from the ambient light, which can look much nicer in some cases, you can use A mode and let the camera pick the shutter speed--but at slow speeds, it is likely this will give you some blur as well as the sharp flash-lit image. You pays your money and you takes your choice.)

Hi Larry,

First, one has to distinguish between fill flash (where, usually, the frame has sufficient light and the flash "fills" the shadows-reducing the dynamic range) and "non-fill" flash.

From your question, i understand you are referring to the non-fill case and that's what I'll refer too.

In this case it boils down do the balance between the existing light level (power) and the flash power.
In flash photography the following rules applies:

a. The object (under the active focus point) exposure is set by the flash (and governed by ISO, flash power, and aperture). Note that as the flash burst is substantially shorter that the (typical) shutter speed, SS does NOT affect the object exposure!

b. The exposure of the background is (usually) set the the ISO, Aperture ans SS (as usual). The reason for this is that the power of flash decreases in proportion to the SQUARE of the flash-background distance. (e.g., if the object is 2 meters from the flash and the background is 4 meters, then, in TTL mode, the object will get the correct exposure while the flash will "contribute" only 25% ( [2/4] squared) to the exposure of the background. The exception (and that's why I've used usually in the beginning of b), is where there is a small difference of the distance of object and background from camera-naturally in that case the background will be also properly exposed.

You'll probably set your flash to TTL or TTL-BL mode. I'll begin with TTL.
In TTL flash mode to camera sets the exposure for the object.

In TTL-BL the camera "averages" the flash power to (at least partially) illuminate the background as well.

As the flash has a power limit, it can illuminate the background only for nearby background. Thus, TTL_BL is suitable mainly for indoors/ object close the background situations. Otherwise--use TTL.

To sum up the practical setup (in TTL mode):

1. Set your regular exposure settings to your liking for the background (e.g., a -1 EV will result in somewhat dark background, a -3 EV or lower- in black background).
2. Recompose and shoot.
3. Analyse results and , if necessary, adjust and shoot a second shot.

I hope that clarifies it.
In addition, I highly recommend the following:
http://strobist.blogspot.com/2006/03/lighting-101.html

--
Regards,

Michael Badt

Photos gallery: http://www.flickr.com/photos/mibadt/

Snowman99 said:

I'm using a D80 and SB-600 to take some
indoor photographs. I'm shooting in manual and I select my desired
aperture. ISO is set at 400. The exposure meter in the viewfinder,
because of the lower amount of light is telling me that I need a
slower shutter speed. I understand at this point that the camera is
measuring the amount of ambient light and that the flash will gather
the necessary information to determine proper exposure. At this
point, What do I select for a shutter speed? It's a handheld shot,
so obviously I don't want to select the slower shutter speed based on
what the camera tells me. Do I select a shutter speed that is simply
fast enough to avoid blur based on my focal length?

Click to expand...

Your two options are:

1. Simple (main flash): Set your camera's fastest x-sync speed (1/200 for the D80). This wil minimize any impact of ambient light, so the flash will be your main light source. Use TTL mode on your SB-600.

2. Complex (trying for balanced fill flash): Select the slowest shutter speed you can handhold. In that case, the contribution of the ambient light will be determined by your shutter spped. If the analogue exposure display still shows more than 3 EV underexposure, you need to open up the aperture more and/or increase the ISO. If the ambient light is low enough, you may run out of useable f-stops or ISO values without ever getting "balance". In that case, give up trying for balanced fill-flash and set up as for main flash (option 1). If the analogue exposure display tells you that you are within the 3EV range, set TTL BL mode.

Snowman99 said:

Does it matter how fast otherwise?

Click to expand...

Yes, it matters if you are trying for fill flash, otherwise not.

Snowman99 said:

Is the analog exposure display useful when I'm using flash?

Click to expand...

Yes, very much so.

You might also want to look at this page: http://dpanswers.com/nikon_flash2.html
--

• gisle [ http://folk.uio.no/gisle/album/ ]

Thanks, Michael. I appreciate the time you put into your response. The picture is starting to get a little clearer. I'll check out the link as well. Thanks, again.
--
Larry S.

Thanks for the response. I'm a little new at this, so I appreciate the help. The simple option probably answers my question, but the more complex one is what I'm really looking for. I prefer the warmer look of the natural light, so I'll work on that. I'll check out the link as well. Thanks again for your help.
--
Larry S.

Gisle
I like that link you sent. Very informative.

gisle said:

Snowman99 said:

I'm using a D80 and SB-600 to take some
indoor photographs. I'm shooting in manual and I select my desired
aperture. ISO is set at 400. The exposure meter in the viewfinder,
because of the lower amount of light is telling me that I need a
slower shutter speed. I understand at this point that the camera is
measuring the amount of ambient light and that the flash will gather
the necessary information to determine proper exposure. At this
point, What do I select for a shutter speed? It's a handheld shot,
so obviously I don't want to select the slower shutter speed based on
what the camera tells me. Do I select a shutter speed that is simply
fast enough to avoid blur based on my focal length?

Click to expand...

Your two options are:

1. Simple (main flash): Set your camera's fastest x-sync speed (1/200
for the D80). This wil minimize any impact of ambient light, so the
flash will be your main light source. Use TTL mode on your SB-600.

2. Complex (trying for balanced fill flash): Select the slowest
shutter speed you can handhold. In that case, the contribution of
the ambient light will be determined by your shutter spped. If the
analogue exposure display still shows more than 3 EV underexposure,
you need to open up the aperture more and/or increase the ISO. If
the ambient light is low enough, you may run out of useable f-stops
or ISO values without ever getting "balance". In that case, give up
trying for balanced fill-flash and set up as for main flash (option
1). If the analogue exposure display tells you that you are within
the 3EV range, set TTL BL mode.

gisle said:

Does it matter how fast otherwise?

Click to expand...

Yes, it matters if you are trying for fill flash, otherwise not.

gisle said:

Is the analog exposure display useful when I'm using flash?

Click to expand...

Yes, very much so.

You might also want to look at this page:
http://dpanswers.com/nikon_flash2.html
--

• gisle [ http://folk.uio.no/gisle/album/ ]

Click to expand...