DTTL, TTL, Manual

I am not sure if there is a tread on this already but, can someone shed some educated light on the reason some housings will not allow DTTL and the main difference between it and TTL normally used.

Or, point me to the tread already discussing this.

Thanks:o

I will resumarize quickly, however you will find a more detailed explanation if you do a search here on "D-TTL"

D-TTL is a preflash system that Nikon developed for their digital SLR's. D-TTL does not read the reflected light off the film plane like film cameras do. Instead it fires a series of preflashes before the shutter is opened (Something like 18 preflashes in the case of the D100) and uses the TTL sensors to read this reflected light. The camera uses that feedback to set the power and duration of the "main" flash which fires while the shutter is open.

The Nikon N80 body - on which the Nikon D100 and the Fuji S2 are based - comes with three flash modes:

1) TTL,

2) balanced fill flash

3) 3-D multi-sensor balanced fill flash.

The latter two flash modes require preflash - whether you are using the S2, the D100, or the Nikon N80 film camera. That means you will need a Nikon SB28DX, SB50DX or SB80DX to utilize these modes - period! Those are the only three flashes that will do it.

The first mode however - "regular old TTL" is what we underwater shooters are used to. It will still work on the Fuji S2 using literally any flash. This is not the case with the D100.

HTH

James Wiseman

Then the same would be for the 5000?

That being true, what is the effect of setting the strobe setting to TTL on a 90dx?

Thanks again for the input.

No, it's not the same for the 5000. The ttl system on the 5000 is totally different.

Set the strobes on TTL and fire away with the 5000 - it works great. I used a YS90DX with my 5000 in TTL and got great results. The camera fires a preflash but it contributes nothing to the process - I think it is some kind of software bug honestly but I could be wrong.

All my shots from the flowergardens 4-02 were taken using that setup.

HTH

James

I thought I was totally losing what little understanding I thought I had.

I thought that but, after reading the treads on the D100 I was totally questioning my understanding. Apparently I am not so lost.

I had limited opportunity to do comparative shots when I was out with the Aquatica prototype. I had a hotshoe connection issue thus we could not get the strobes to fire on demand.

I can't wait to really put it through it's paces soon. Again thanks for the clarification.

Get then new firmware version for your camera and install it immediately!

Looks like you can FINALLY do away with that annoying and useless preflash.

Cheers

James

Looks like it may reduce shutter lag also. Thanks for the heads up.