Nikon SB-800 and D70

I read for the D2H and D2x, the SB-800 speedlight can use FP mode to actually sync faster than the 1/250s limit of the camera.

...and I see conflicting info of whether it can be pulled off on the D70. So far, I cannot do it.

So the question is, can this be done on the D70 and if so, how do you do it? My assumption until I hear directly from Nikon is that the d-70 cannot use FP to sync faster than 1/500.

Hey Rich,

What do you mean by FP mode? Let me know, and I'll try it on my D70/SB800 when I get home.
Tim
(from mtbr.com)

Just found this link:

http://forums.dpreview.com/forums/re...ssage=13455762

and

http://forums.dpreview.com/forums/re...essage=8243461

Dude, you so ROCK!

off to do Edgerton pix! :D...actually, I want to do better fill flash for sports shots...I think this is the ticket!

PS: I'm sure the consequence is going to be mismatched exposure problems...but it's going to be cool to do this stuff!

lidarman-
I haven't read any of the info in Nikon high-speed flash sync. But with the Canon slr/flash combo, the tradeoff with high-speed sync is a shorter flash range. Just keep that in mind. It makes it tough to do wide angle stuff with flash. If you need more power, try manually zooming your flash and pointing it at just your subject, instead of trying to fill the whole frame. I do that for most wide angle bike photos with flash. I like the spot effect of having the flash focused just on the rider, anyway.

Quote:

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Originally Posted by Photo-John

lidarman-
I haven't read any of the info in Nikon high-speed flash sync. But with the Canon slr/flash combo, the tradeoff with high-speed sync is a shorter flash range. Just keep that in mind. It makes it tough to do wide angle stuff with flash. If you need more power, try manually zooming your flash and pointing it at just your subject, instead of trying to fill the whole frame. I do that for most wide angle bike photos with flash. I like the spot effect of having the flash focused just on the rider, anyway.

---

Thanks for that note and good points about the flash focus. I will experiment. The goal of course is to add a little fill for fast action and shorten the depth of field.

I did some experiments at a national lab shortening up flash pulses since I use a lot of flashlamps for the laser work I do. I can see why the companies make speedlights the way they do but you can have a flash that puts out as much light for faster shutter speeds. One thing the sb800 does allow you to do is up the intensity so you can make up for it that way.

Three shots: Obviously this example is not ideal for fill flash, I just wanted to demonstrate how the DOF can be limited and still have use of a flash.

1/1250 f4.5 no flash for reference of DOF.
http://tinypic.com/52lxjn


1/500 f9 TTLBL fill flash
http://tinypic.com/52lxlz

1/1250 f4.5 (sync override using tape as discussed earlier) manual fill using 1/64th full flash...kinda hot but notice DOF compared to using the limited sync max of 1/500
http://tinypic.com/52lxmr

One thing is for sure, there is plenty of light coming out of the flash.

Thanks for posting this. It's interesting to note how the quality of light changes in each image. I like the last one the best.

The problem with mtb photos and high-speed sync, is you usually aren't that close. It's the limited flash range that's the problem. I always get confused when I try to sort it out. I assume the flash has to increase the output to compensate for a shorter duration. But I would think that it would actually have more reach, then. There's some detail I'm missing. I know that when you use high speed sync, you definitely have less reach, though.

By the way, my dad studied optical physics at CSU. I think he got his doctorate there. His work was with lasers, too.

Quote:

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Originally Posted by Photo-John

The problem with mtb photos and high-speed sync, is you usually aren't that close. It's the limited flash range that's the problem. I always get confused when I try to sort it out. I assume the flash has to increase the output to compensate for a shorter duration. But I would think that it would actually have more reach, then. There's some detail I'm missing. I know that when you use high speed sync, you definitely have less reach, though.

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It might have to do with the pulse length of the flash, which I intend to measure with a scope and a photodiode. If the flash pulse is 1/500 s long, then when you open the shutter for 1/1000 of a second, you get half the light since the flash is still spewing out light when the shutter closes again. So what you said makes sense. The reach is dependent on the amount of light and the duration. So twice the distance and cutting the light in half would require 4 times the light. The feedback on the camera measures and compensates but can't make up for the timing part.