New to wireless flash - SB910 questions

[Lipoly]

I have upgraded from a D5000/SB400 to a D800/SB910. I have read the SB910 manual (many parts multiple times), but I have a few questions about wireless operation.

1. When the flash is set to remote, and the camera to Commander, the camera preflashes and takes a picture like I would expect. However, I was trying to compare shots using the popup...I set the camera to TTL, but the SB910 still fired. The camera emitted no preflash and the SB910 appeared to fire a brighter flash than when in commander mode. I had thought that the SB910 would be disabled if the camera was on TTL. Does the SB910 simply signal off any "bright" light? Could I put the SB910 on remote and fire a P&S and have it fire (if the P&S flash fired)? How is the flash determining zoom, output, etc in this situation?
2. It appears the popup flash is contributing to the exposure instead of just directing the SB910 when in Commander mode. I tested this by positioning the SB910 in an area that I assumed would create some shadow on the subject, yet the subject was illuminated as if the popup contributed. If this is the case, how do you disable the popup contributing to the final shot?
3. When only the SB910 + camera is used (using the pop-up to command), it seems I can only use the SU-4 type wireless (instead of the "Advanced Wireless Lighting")? By the naming ("Advanced") I'd assume I'm giving something up by using SU-4 mode? The manual describes how to use each mode, but doesn't appear to give any guidance on when you would choose one over the other.

 

[Vautrin]

This is some advanced stuff... The thing I do is I take a picture of the flash unit in question (or in the mirror) to see what's firing.

You can then see if you're indeed correctly in commander (infared won't light up) or if it actually lights up like a flash...

And, yes, you can slave a flash so it fires if any flash fires. This is common with flashes... For instance, I have a studio with 3 flashes. I set one on wireless trigger and two on slave (they fire when they see any flash). If I really need it I can do the same with hot shoe flashses and add in the pop up flash

 

[Awiserbud]

In commander mode the cameras in-built flash is used to control the off camera flash in remote mode, yes the cameras flash can slightly contribute to the exposure, but you can control the amount of light the camera emits, since the flash only requires a small amount of light signal it is possible to reduce the cameras flash output by reducing it in the commander sub menu, if you set it right down to -- it will only fire the minimal amount, just enough to signal the off camera flash unit.
you can also change the power of the remote flash unit in the commander mode menu, change the TTL mode in there to manual and select the amount you want.
there are also filters you can put over the cameras built in flash to reduce more so any light unnessesarily contributing to the exposure. although it appears the remote flash unit is recieving a flashed light source to trigger i believe its actually a bit more technical than this as it actually sends information to control the flash, not just trigger it.

 

[Awiserbud]

Not sure how the SB910 compares with the SB700 (which is what i use) but i also remember having to select Advanced mode instead of SU-4 mode to allow control of the power and zoom from my D7000.

 

[Lipoly]

Thanks guys. At this point it appears my popup is fully illuminating the subject when it fires. I have not tried the mirror test, but that is an excellent idea.

 

[cgipson1]

set the popup to -- in the commander menu... that way it will only pre-flash,.. and not add to the exposure...

 

[Lipoly]

Thanks cgipson1...that fixed it. Just tried some photos and this allowed me to produce some "creative" lighting w/o the popup contributing.

My only question that remains is when should someone choose SU-4 over the "Advanced Wireless Lighting" or vice versa?

 

[gardy]

Thanks cgipson1...that fixed it. Just tried some photos and this allowed me to produce some "creative" lighting w/o the popup contributing.

My only question that remains is when should someone choose SU-4 over the "Advanced Wireless Lighting" or vice versa?

su-4 mode is used when your wanting to trigger the flash with any other flash without CLS meaning you can set it to fire whenever it sees any flash including that of a point and shoot, basically an optical slave built in.

 

[Lipoly]

Thanks cgipson1...that fixed it. Just tried some photos and this allowed me to produce some "creative" lighting w/o the popup contributing.

My only question that remains is when should someone choose SU-4 over the "Advanced Wireless Lighting" or vice versa?

su-4 mode is used when your wanting to trigger the flash with any other flash without CLS meaning you can set it to fire whenever it sees any flash including that of a point and shoot, basically an optical slave built in.

I'm assuming there must be more differences between SU-4 and "Advanced" other than that though?

 

[gardy]

When your using CLS the camera will tell the flash when and at what power to fire, assuming the flash, and commander mode in camera are set to ITTL. SU-4 mode is the mode of the flash that will fire the flash when it detects a flash from another flash source in manual mode. example: i set my SB-700 su-4 mode, manual power select and set it in front of me, with my girlfriends D3000 (does not have CLS) i set the built in flash to manual power and turned the power all the way down. when i took the shot it fired the SB-700 (which was set to 1/2 power to exaggerate it a bit). however if the built in flash or commander flash your using is not set to manual it wont fire the remote flash. i hope that makes sense.. and please if someone needs to correct me on anything please do.

 

[Lipoly]

Thanks gardy, that makes sense, and was helpful.

 

[Vautrin]

it may be interesting to note firing a flash just means the SENSOR needs to sense a flash.... It's possible to put a business card or something in front of your pop up flash so no light from it comes to your subject, but the "spill" from the side still lets the flashes fire...

You can also control flashes with similar things, blocking where exposure will be...

Also, personally, I find full manual mode for all my flashes easier to control. It's a little more work but you can set exactly what flash will fire at what power and I think it's easier to get "dramatic" effects than TTL.

Because TTL is going to get you the "best" exposure of your shot. But maybe you don't want the whole shot exposed -- just part of it... Maybe you're going for dramatic lighting...

Dial in exactly what you want and you're better off...

 

[gardy]

Thanks gardy, that makes sense, and was helpful.

No problem, I knew kinda how it worked but I figured when you were asking about it was the perfect time to pull the camera, manual, and google out and tinker for a bit. Even though I only have a D90 and Sb-700 it's all pretty much the same, or should be. Lol

 

[gardy]

Also, personally, I find full manual mode for all my flashes easier to control. It's a little more work but you can set exactly what flash will fire at what power and I think it's easier to get "dramatic" effects than TTL.
..

Also for me easier to understand when your still learning how to effectively shoot with flash, weather it be for a perfectly exposed shot or a dramatic low key portrait.

 

[cgipson1]

Thanks cgipson1...that fixed it. Just tried some photos and this allowed me to produce some "creative" lighting w/o the popup contributing.

My only question that remains is when should someone choose SU-4 over the "Advanced Wireless Lighting" or vice versa?

SU-4 Mode Nikon CLS - SB-900 SU-4 Mode As mentioned.... just sets basic (sense a flash, and go off for nikon flashes... just like standard optical flash manual setting use)

Advanced Wireless lighting will allow a remote TTL exposure from multiple flashes (sort of) and any other settings...