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-   -   Tube/Flash advice...? (http://www.wakeworld.com/forum/showthread.php?t=783783)

kitewake 09-24-2010 2:56 AM

Tube/Flash advice...?
My 3rd water shoot went better than the previous ones. The daylight shots turned out pretty good.


But the eve shots with the flash housing were not what I hoped for. I am used to shooting with a long lens, and setting the shutter at 1/1250 or 1/1600. When shooting with a Nikon flash, in mixed light, at shutter speeds over 1/320, the high speed synch really weakens the flash.

On these shots later in the eve...I was at 1/1600...and the flash was way too weak...


For these sunset shots, I dont think the difference between ambient and the subject is enough to drop the shutter to below 1/320 and rely on the flash to stop the action. So the question becomes how low can I go and still stop the action?

I tube shoot with a 17-35mm Nikon f/2.8 about 6'-8 from the rider (when on the water) Up close to the rider like this...do you think I can stop the action at 1/800? How about 1/600? There is no way to tell while shooting with a water housing how the shots are turning out.....so I am looking for any advice here that will save a wasted shoot...

What I want to do is catch a eve light like this...
...during a tube shoot....and get flash exposure of the rider for an effect like this...

Oh...and thanks to Joel, Ryan and Jess for being photo subjects!

scott_a 09-24-2010 1:09 PM

You're shooting wide open at f3.2...I'd stop it down to f8 or so. That will kill the ambient light a bunch and bring out some deeper colors in the horizon, and then you can slow the shutter down to 1/320 or 1/250 and use the flash to stop the action. This will give you an image that more closely resembles the last link you posted of the people sitting in the boat.

AaronATX 09-27-2010 11:16 AM

what housing/flash are you using?

kitewake 09-27-2010 8:25 PM

I am using a Nikon D300, with the Nikon f/2.8 17-35mm. The flash is the SB900. Housings are AquaTech

Scott, will the ambient be weak enough looking into the sunset to do that? I thought that the ability to stop action with a flash was dependent on the level of ambient light relative to the maximum power of your flash. I thought that ambient lighting had to be at least two stops below peak flash power to stop action. If the ambient lighting is stronger, then it will blur the action. Of course with the backlit subject...it is the light on the subject that matters...and I may have already been well within the point I could drop the shutter to 1/320 and stop down, with the flash at high power.

Thanks for the tips...

scott_a 09-28-2010 1:35 AM

Here is what I would do- grab your camera and head outside in the evening and find a spot where you can see the sunset or evening light or whatever so you can sort of replicate the situation that you'll be in when you're out on the tube. Set the camera in Shutter Priority and set it to 1/250th (or your max sync speed) and check what the aperture is...then take those settings and set the camera to Manual and stop down the aperture two stops. This should darken the image substantially...especially in the late evening.
-This will give you the ambient exposure, and you can either repeat this process when you're on the tube about to start shooting or you can practice a bunch at home in the evenings to get a better idea of where to start when you're setting your shutter and aperture.
-The goal here is to get away from using your high speed sync because you lose a bunch of power in that setting. Your SB900 will have more than enough power to make this shot happen.
-One thing to remember is that when the flash is used as the primary source of light (like in this case), the subject is frozen (or blurred) by the flash. The length of time that the flash fires is what dictates whether the action is frozen or not. So since your SB900 has a flash duration of 1/800th at full power and 1/2700th at half power, you will be able to freeze the rider just fine. The background may blur since you're shooting at 1/250th, but that isn't as important...and sometimes that looks kinda cool, actually. In short: the aperture and shutter speed are what you use to balance flash and the ambient light, and then the flash exposes the rider.
-Practice, practice, and practice some more! Learning this stuff on a tube is not going to be fun. Heck, learning this stuff at home can be challenging enough. I would suggest that when you head out to practice in the evening that you find a car or tree to use as a subject and hit that with a flash to see what the image would look like. From there you can try experimenting by adjusting the shutter and aperture to see how those change the look of the image.

Hope this info helps.

kitewake 10-07-2010 6:24 PM


I actually did just that a few days ago to try and get a handle on the settings. I was shooting a small tree in the foreground to mimic the rider...with the sunset in the back. I then shot as I panned. I think it will work...but I have to really pan well to keep the rider from motion blurring at 1/250...even with the flash freezing the action...

Perhaps the best idea is to balance the ISO and aperture to get the right exposure at 1/2 power, as that will freeze action better...

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