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Anyone know the contact configuration of Nikon Flash


austinphoto

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<p>Does anyone know the contact configuration of the new digital and the old Nikon Flashes? I have an old sb 23 that I would like to be able to use on a digital camera. I really would like the ttl feature to work, but think that the contacts have been changed. Can someone explain what the contacts on the flash are for, asides from the main hot shoe. One of those other contacts must be for ttl. If my sb800 works ttl on my film camera, what is the difference between the new flashes and the old flashes. Having it work ttl would be extremely useful for me, as I am using it in a close up situation for macro work.</p>
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<p>"but think that the contacts have been changed" - it is not just the contacts. </p>

<p>New flashes operate on completely new principle, at least as far as TTL is concerned. </p>

<p>Some of the flashes, e.g. SB-800 are fully back compatible with most all old Nikon cameras, but some newest flashes e.g.SB-900 dropped back compatibility mode in the "name of progress" - or who knows why ? - certainly not for economical reasons, since the newer flash is much more expensive.</p>

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"New flashes operate on completely new principle"

 

 

 

 

The TTL Metering was used in earlier film cameras and was done using light reflected off the film when the shutter opened exposing it.The flash relies on the camera body to do the metering and instruct it how long to fire. The little sensor on the base of the mirror room does the trick.

 

 

 

 

i-TTL: The new digital cameras has no film to reflect the light , and relies on the internal camera metering system used to mesure normal(without flash) exposure , placed above the pentaprism.

The camera comand flash to lounch a preflash used to calculate correct exposure. The exposure it's link with the active focus point. Power and distance to the subject are the two variables used to calculate flash exposure, knowing where the lens is focused increases the odds of that spot being exposed perfectly.

i- TTL system fires the pre-flash when the shutter is fully depressed which allows it to meter and compare both ambient and pre-flash a split second before the shutter opens and the main burst of flash fires.

 

 

 

 

Sorry , the only way to use your flash is the MANUAL MODE.

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<p>The contacts are the same layout, but as Frank and Paul indicated above TTL flash on Nikon digital cameras involves a completely different protocol. The reason for this is basically because light reflects differently from a DSLR sensor than it does from the emulsion side of film, so the OTF metering needs to be completely different. Your SB-23 simply doesn't have the "brains" to function in TTL mode on any Nikon DSLR. So you're stuck with full manual if you want to use the SB-23 on a DSLR.</p>

<p>You SB-800 works in TTL mode on your film cameras because it was designed to be backwards compatible (I think this compatibility was dropped from the new SB-900). It basically has two brains - one for film (TTL) and one for digital (iTTL).</p>

<p>At one time I had a diagram of the contact layout, but can't lay my hands on it right now. The center contact is of course the sync contact. Looking from the rear of the camera, the small contact on the left in the flash ready signal. For the two small contacts on the right, one is the TTL quench signal contact, and IIRC the other is what Nikon calls a "monitor" contact (data transfer for autozoom function and the like perhaps).</p>

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<p>That can't be right. There has to be a bidirectional serial data link between the two and a communication protocol. That's how the camera knows the user has dialed in flash compensation on the SB, and how the SB displays the ISO, etc. etc.</p>

<p>Reverse engineering it is not for the faint of heart.</p>

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<p>"There has to be a bidirectional serial data link between the two and a communication protocol." - yes, it is right. The second direction of the communication comes back as a visible/IR pre-flash protocol through the lens (iTTL) and not via hot shoe pins. The Nikon's hot shoe pinout alone is not able to close the communication loop. This is something that RadioPopper's users have trouble to understand.</p>
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<p>Dan, as Martin said, the pins are totally redefined when the flash is in iTTL mode. The only thing that works normally is the "X" line. Ready, quench, and monitor become SIO - serial data, SCK - bit clock, and RW - byte clock, respectively.</p>

<p>This actually predates iTTL, and started in the late 80s with the second generation of Nikon AF cameras, the N2020. Those kept "quench", but used digital communication on the former "ready" and "monitor" lines for zooming the flash head, communicating ISO from camera body to flash. I believe SB-24 was the first flash to implement this. I think the use of RW started with SB-26, the first Nikon preflash flask, for N90. By the time D1, SB-28DX, and D-TTL rolled around, Nikon was old hat at serial communication.</p>

<p> </p>

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<blockquote>

<p>Sorry , the only way to use your flash is the MANUAL MODE.</p>

</blockquote>

<p>You can also use "A" mode, where the little sensor on the flash meters the exposure. But personally, I wouldn't. The reason TTL caught on in the film days was because A mode wasn't even accurate enough to work consistently with the wide dynamic range of color print film. With the narrower dynamic range of digital, it really is time to get a new flash.</p>

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<p>This is along the lines of my thread <a href="http://www.photo.net/nikon-camera-forum/00SGu7">http://www.photo.net/nikon-camera-forum/00SGu7</a> about the SB-26, and I've come to the conclusion that we are goosed as far as the SB-26 and new digital cameras are concerned. I wish that Nikon had made SOME form of compatibility between them, but it seems not. Old is out, new is in. They need to sell the new flashguns. If there was any way you could get some compatibility by mucking around with the contacts, I'm sure some HongKong/China based company would have come out with a nifty hotshoe adapter of somekind, which we could have bought off ebay, which would have been real nice, don't you think so ? Slip on the adaptor to the hotshoe, and the flashgun to the adaptor and hey presto the auto zoom and TTL works !<br>

As to the mention that the SB-800 works on TTL with older cameras, not sure about that. Borrowed one last year to use on my F4, and although the auto zoom head worked, the exposures were grossly overexpossed, until I found out about the TTL and i-TTL thing and figured that was the problem.</p>

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<blockquote>

<p>Slip on the adaptor to the hotshoe, and the flashgun to the adaptor and hey presto the auto zoom and TTL works !</p>

</blockquote>

<p>Andrew, DSLR TTL is beyond what you can do with an adapter, as Metz found out twice, first when they couldn't make a D-TTL adapter work for their existing flashes and had to design brand new flashes with electronics fast enough for the 18 pulse D-TTL preflash, and again when their new D-TTL flashes proved too slow for the more complex 64 pulse iTTL "preflash with message".</p>

<p>But an adapter that sits between flash and camera and even with an iTTL camera makes a pre-digital SB-24-28, a pre-AF SB-12-22, a D-TTL SB-28DX or SB-80 perform all these functions is possible...</p>

<ul>

<li>zoom</li>

<li>read ISO from the camera</li>

<li>set the flash range indicators</li>

<li>operate in "A mode"</li>

<li>use on camera selection of rear curtain and red-eye reduction</li>

<li>locking the camera to a "flash safe" shutter speed</li>

<li>work the ready light</li>

</ul>

<p>I built one I call <em>FlashThing</em> . I have no plans to market it at this time. Whenever I market anything, my lawyer advised me to sit down and ask "what's the worst that can go wrong if the product goes berserk". In the case of <em>FlashThing</em> that would be the simultaneous overheating of 8 devices, each containing a high voltage power supply and a grand total of 32 NiMH cells. I wish I was more comfortable about selling it, it's really impressive: has a whopping big processor and connects the hot-shoe of a Nikon camera and up to 8 Nikon flashes (how do you think I came up the info I provided earlier in this thread?) and synchronizes zoom, modes, etc. It also does pretty much anything a "Time Machine" flash controller can do, in color, but that's another story...</p>

<p>I'm currently working on what I call "booster mode". Plug in one iTTL master flash (SB-800 or SB-900) and up to 7 plain old SB 80DX, SB28, 26, 24, 15, etc... and <em>FlashThing</em> lies to the camera about exposure compensation, does the preflash with the iTTL flash, then lets loose with the main flash by digitally controlling the iTTL and D-TTL flashes and using duration control on the pre-digital flashes.</p>

<p>So, yeah, to just run one flash, and using overseas production, a little $50 adapter that sits between camera and flash and lets an old SB-26 zoom, set the camera to a flash safe shutter speed, and operate A mode, or some of the other features I listed, is certainly possible. I bet it could even use "booster mode" with the internal iTTL flash on D70, D80, D90, D200, D300, D700...</p>

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<p>Wow, Joseph you have been busy ! Good on ya. 'Flashthing' sounds interesting. You actually built a working model and it performs those functions ? Thats what I was talking about. Surprised that no commercial company has one on the market yet. Anyways, by the time it happens, if it happens, I will have gotten rid of the old flashgun and gotten a new one.</p>
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  • 2 months later...

<p>Joseph,<br>

sorry to intrude, i've been sniffing the iTTL protocol on my D90/SB-900 combo and things seem a little different from your bidirectional SPI statment sp and q seem to be SPI byte streams with rdy being a clock. Could you please tell me the combination you were using?<br>

PS Nikon have gone to unbelievable lengths to make this difficult! (it's almost like they don't want us doing it <grin>)</p>

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  • 8 months later...

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