I just purchased a SB400 to learn more about flash photography. I read several very interesting blogs on Nikon CLS.
The manual says the SB400 works in iTTL mode but I infer from the blog that in fact there are two modes, TTL and TTL-BL. As the SB400 does not have a mode switch, my question is:
Does the SB400 work in TTL mode if I put the camera (D90)in Manual + spot metering and in TTL/BL in the other modes with matrix metering, such as, Aperture/Shutter priority?
This appears to be a fascinating yet complex topic to grasp.
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#1. "RE: SB400 Flash Modes" | In response to Reply # 0Arkayem Charter MemberMon 21-Dec-09 03:18 PM
I thought I would repeat my reply to you from my blog, and see if anyone else here at Nikonians has any other suggestions:
I don't own an SB400, so I can't test it. I think you already know that the instruction manual only mentions iTTL and not iTTL-BL mode. However, I believe that is just an error in the manual, and it really does have both modes, but I think you could help us find out for sure.
We know that the pop-up flash works in iTTL when in Spot metering and iTTL-BL when in Matrix metering. What I'd like you to do is compare the pop-up to the SB-400.
Do the following with both the pop-up and the SB400. Keep the SB400 pointed forward for this test.
Conditions: outdoors, bright sun, subject in the shade.
Position a neutral colored subject (like a person, statue, doll, etc) so that there is a bright background behind.
Adjust the zoom to make the subject fill only the center portion of the frame; ie, leave plenty of frame area for Matrix metering to make a good measurement of the background.
Camera P mode (at first), ISO 200, FEC 0ev
Do not focus and recompose (because the camera meter uses whatever is under the focus point at the time the shutter press is completed).
Take two control pictures of subject without flash.
Control Picture 1: Flash OFF, Camera Matrix Metering. Expected results: background exposed correctly, subject underexposed by an amount determined by the amount of ambient light in the shade. Write down the f/ stop and shutter values for this picture. We'll call them the 'Matrix Metering Settings' for use later.
Control Picture 2: Flash OFF, camera Spot Metering, spot on middle of subject. Expected Results: background overexposed (blown out), subject exposed correctly. Write down the f/ stop and shutter settings the camera chose for each. We'll call these the 'Spot Metering Settings' for use later.
Camera Manual Mode.
Note: If you leave the camera in one of the auto modes, the minimum shutter speed will be fixed at 1/60th when the flash is turned on. We don't want to introduce another variable.
Turn Flash ON, 'Spot Metering Settings', spot on middle of subject. Expected results: background overexposed (blown out), subject too bright and probably blown out a bit depending on how much ambient there is.
Flash ON, Matrix Metering Settings. Expected Results: background exposed correctly, subject exposed correctly (significantly darker than it was in Spot metering mode).
Run the same tests for the pop-up flash and the SB400. The results will be identical if the SB400 has iTTL-BL mode.
If these things all happen as I have indicated, then the SB400 indeed does have iTTL-BL mode, and it is enabled by Matrix Metering and disabled by Spot Metering.
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Russell MacDonald Photography
Nikon CLS Practical Guide
#2. "RE: SB400 Flash Modes" | In response to Reply # 1nikon50 Nikonian since 02nd Nov 2009Mon 21-Dec-09 07:18 PM | edited Mon 21-Dec-09 07:52 PM by nikon50
Great answer Russ,
I have a sb400 and have wondered the same thing.
I just took two shots, one on spot, one on matrix and opened them both up in Capture nx and yes spot shoots TTL and Matrix shoots TTL-BL.
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