NikoDoby said:
Buy an F6 and be done with it boy . . .

Well, I followed your sage advice, Niko. I am now "done" with it.

Testing123 said:
If you add a second and third DUMB slave (some $10 optical triggers) they should work and be counted so long as they provide an insignificant part of the total light and are set in manual mode with a duration shorter than the SB-27 and SB-800 will have.

Example:
SB-27 on camera in (film)TTL mode.
SB-800 as key through beauty dish on face.
Dark background.
SB-XX set to manual mode, on $10 optical trigger 1/16th power, right side rim/hair light.
SB-XX #2 set to manual mode, on $10 optical trigger 1/16th power, left side rim/hair light.

So long as the brains of the system (F90 / SB-27) leaves the SB-27 on for longer than 1/16th duration this should work.

Thanks for your post, Testing. Yes, I used to do exactly that with my pile of cheap VariPowered Vivitar 283s, my Nikon SB-800, and an SC-29 back in the film days. The old Vivitar 283 (now discontinued) was cheap, powerful, and effective. A bunch of dumb strobes, and a handful of $10 optical slaves used to go a long way. Too bad pre-flashes make dumb strobes useless now in CLS set-ups

You also could most likely get away with secondary and tertiary strobes. ;)

So let's say you're going to block the SB-27 from exposing the scene.
The SB-800 becomes your key light.

From all said above it will get wirelessly shut off by watching the SB-27 which will get shut off by watching the film. We all agree on that so far.

Recall that film-TTL flash (and the d-TTL flash which briefly followed it) were crude. Much like the auto mode on a thyristor flash they looked for the quantity of light with one (or very few) sensors. Unlike the beautiful matrix-meter-powered flash exposure system (i-TTL) of today.

SOOO... Theory:
If you add a second and third DUMB slave (some $10 optical triggers) they should work and be counted so long as they provide an insignificant part of the total light and are set in manual mode with a duration shorter than the SB-27 and SB-800 will have.

The 27 will fire, the 800 will see the 27 and fire in unison, the $10 triggers will see those two and fire in unison, the F90 will be quantifying all the light coming in, the two SB-XXs will finish their 1/16th job, the 800 and 27 will continue, the F90 will quench the 27, the 800 will see the 27 quenched and stop itself.

I don't think these dumb slaves are as likely to work as backdrop lights because then they will be contributing a much more significant percentage of the total exposure and the odds of them running longer than the controlled strobes is higher.

studio460 said:
I haven't shot film in so long, I've forgotten some of the tools and techniques. How would I equip myself, given the Nikon equipment below, for wireless-TTL (IR) control over a given Nikon Speedlight?

1. Nikon N90s 35mm film SLR
2. Nikon SC-17 remote TTL cable
3. Nikon SC-29 remote TTL cable
4. Nikon SU-4 TTL slave
5. Nikon SB-27 Speedlight
6. Nikon SB-800 Speedlight

The only item listed above that I don't own is the SU-4. I would buy one, but I don't know what I'd "command" it with, or how I would control the "primary" flash that it's slaving from. I read that I can use the SB-27 as a commander, but I would have to fire the SB-27's flash head to do it (which I don't want to do). If this is my only route, tell me if the following is correct:

1. Mount SB-27 onto N90s hot shoe, and put SB-27 into commander mode.
2. Attach SU-4 to Nikon Speedlight model(s) _________.
3. Fire away.

First, a couple of corrections to my initial post's content:

1. For Nikon film bodies, "wireless TTL (IR)" or, in other words, "CLS," is only possible with the Nikon F6.
2. The SB-27 doesn't have a "commander" mode.

Okay, thanks to Corelli's helpful post, I think I know what's going on now . . . knowing that, given the above equipment (with the exception of an SU-4, which I don't own), I would be able to do the following to achieve wireless OTF TTL control over a remote flash using a Nikon N90s film body:

1. Mount my Nikon SB-27 Speedlight to the Nikon N90s' hot shoe, and set the mode to "TTL" on the SB-27's rear control panel.
2. Set up my Nikon SB-800 Speedlight as an off-camera, remote flash, and set the mode to "SU-4" on the SB-800's rear control panel.
3. Fire away.

I would also be able to attach some sort of homemade "SR-2" to my SB-27's flash head to try to reduce its illumination onto my subject.

studio460 said:
So the OTF TTL sees the off-camera flash

Yes, the OTF just measures the light entering through the lens (reflected by the film surface), but it does not matter where the light comes from (on-camera flash, off-camera flash or ambient light).

Oh. Duh. So the OTF TTL sees the off-camera flash (this is the part I wasn't getting), then quenches the on-camera flash when it sees adequate exposure--which merely functions to communicate to the SU-4 to turn off the remote flash. Thank you for your thorough explanation!

Hi studio,

think of it as a watering system for a lawn. You got one tank filled with water (on-camera flash) and a control system that checks how wet the soil is (OTF metering in the camera). When you water the lawn you open a valve on the tank and keep it open for a while (flash duration) until the soil is wet enough (OTF metering reports correct exposure). Now the valve is closed by the control

Now you add a second tank (off-camera flash) that watches the valve of the first tank. As long as this is open the valve of the second tank will also be opened. Now the watering system starts and the first tank will open the valve. But you inserted an obstruction into the valve (SR-2) so the throughput will be less (lets say 10 liters/minute). The second tank will have a higher throughput (say 300 liters/minute). After some time the control system will find, that the soil is wet enough (OTF metering) and will shut down the first valve. This will also shut down the second valve. The metering system does not care if the water came from the first or the second tank, it only watches the wetness of the soil and in this setup the main amount of water came from the second tank.

To get back to your question: the off-camera flash will adjust for the reduced on-camera flash and the OTF does not care (and does not know) where the light comes from. It just realises that enough light got reflected from the film and this will shut down the on-camera flash - even if the light comes from a constant light source like the sun...

Testing123 said:
So it appears that all the SU-4 system is doing is watching the on-camera strobe (the only one in communication with the meter) and quenching its attached slave when it sees the light go out. So long as it can see the on-camera strobe it doesn't really matter if the on-camera strobe is bright or not, better optical triggers have long looked for the IR spectral fingerprint of a strobe instead of for just any old bright light.

Thank you for that detailed reply, Testing. I realize that old-school film TTL uses a reflected reading off-the-film (OTF) to measure flash output in a 35mm SLR. But if the primary, on-camera strobe's output is reduced by several stops by the SR-2, and if its only control over flash output is its duration, how is the OTF TTL reading still accurate for the slaved flash? "Something" must be "adjusting" for the SR-2, right?

studio460 said:
Thanks for your reply, Corelli. I just don't "get" that part of it. How can the on-camera flash "quench" the remote flash when it sees "enough" exposure, if it's not really exposing at its normal power, since the SR-2 is reducing its output?

1 - Recall that in speedlights power is moderated through duration. The strobe tubes used are not variable power, so the illumination duration is what variates.

2 - Recall film-TTL flash works by the speedlight defaulting to firing at full power (full duration) and only stopping when the third contact (quench pin) is "pulled low" (grounded).

3 - Recall also that film-TTL flash works by metering the light reflecting off of the film itself. This is why there are no pre-flashes. (Or more correctly pre-flashes are the new method needed when one could no longer "look at the film" (digital sensors have nowhere near the same reflective properties of film))

So it appears that all the SU-4 system is doing is watching the on-camera strobe (the only one in communication with the meter) and quenching its attached slave when it sees the light go out. So long as it can see the on-camera strobe it doesn't really matter if the on-camera strobe is bright or not, better optical triggers have long looked for the IR spectral fingerprint of a strobe instead of for just any old bright light.

Correlli said:
So once the speedlight at the SU-4 has lit the scene enough for the metering system, it will tell the on-camera flash to stop. When the on-camera flash stops the SU-4 will also see that and tell the attached speedlight to stop as well.

Thanks for your reply, Corelli. I just don't "get" that part of it. How can the on-camera flash "quench" the remote flash when it sees "enough" exposure, if it's not really exposing at its normal power, since the SR-2 is reducing its output?

I think it's all moot now anyway, since the SU-4s are pretty expensive, and for now, I'm just going to go with a 10-meter TTL cable. When I get an F6, this will all be history anyway. I'll be able to switch between complete, wireless, i-TTL controlled, multiple-Speedlight photography just by switching my SU-800 commander from body to body.

Hi studio, the on-camera flash does not need to be strong. It should just be strong enough so that the SU-4 can see it (I never tried it with the SR-3IR only with the SR-2). the moment the on-camera flash starts the SU-4 will trigger the speedlight that is attached to it. You probably know that film TTL metering usually works by metering the light that is reflected from the film surface during the exposure. So once the speedlight at the SU-4 has lit the scene enough for the metering system, it will tell the on-camera flash to stop. When the on-camera flash stops the SU-4 will also see that and tell the attached speedlight to stop as well.

So it will not work if you totally block the on-camera flash and you should also not point another speedlight right at the SU-4, but as you can rotate the hotshoe on the SU-4 you should always be able to point it at you on-camera flash.

Does this help?

Nikon SU-4 Wireless Remote TTL Flash Controller: What's the deal with these?

Okay, I've downloaded and read the SU-4 instructions and I still don't get it. Here's the link to the SU-4 manual (which is really just a one-page instruction "sheet"):

http://www.nikonusa.com/pdf/manuals/Speedlights/SU4.pdf

Some excerpts: "When using your camera's built-in Speedlight as the master Speedlight, use the diffuser SG-2 [the SG-2 looks much like the SG-3IR, pictured above] to reduce the brightness of the master Speedlight, thereby avoiding direct light on the subject which often results in harsh shadows . . . In the AUTO mode, the SU-4 also controls the duration of the slave flash unit in sync with the master flash unti to provide the correct flash exposure."

How does it do this if the master flash is blocked? The SU-4 works in film TTL, the old-school OTF type of TTL, so how would the slave flash "know" how much is "enough" if the master flash is partially obstructed?

For hours last night, I was struggling to understand how one would use the SU-4 in a multi-flash set-up without having an equally powered, on-camera master flash (which the SG-1 seems designed to address), but just couldn't make sense of it. Does anyone here have any experience using SU-4s in this application, who could share their insights?

P.S.

[I finally gave up and just ordered two, 2-meter, Nikon-compatible, TTL remote cables from Pearless. They're electrically identical to Nikon SC-28s (successors to the SC-17s), but longer. Another blogger mentioned he uses as many as three SC-17s, chained together. So now I'm goiing to try to daisy-chain these together, and see if it works. I'm no longer wireless, but at least I can still maintain film-TTL capability between my N90s and an off-camera, SB-800.]

Correlli said:
I chose the SB-700 as I thought that I could still get a used SB-27 or similar if I really needed it for the FM3a. So I am happy that I did get it as it also has got the SU-4 mode . . .

Yes, unlike the SB-600s, the SB-700s support SU-4 mode. It may also be worth noting that other than SU-4 mode, both the SB-600 and SB-800, are the most forward- and backward-compatible flashes in the current Nikon Speedlight line-up. As you are already aware, neither the SB-700, nor the SB-900 support old-school "film TTL."

Correlli said:
. . . Thanks for sharing your experience, studio!

No problem! I'm glad my post was useful to someone!

Good to know. Last week I wanted to get me a second speedlight and I didn't really know if I should get the SB600 (that I could still use with my FM3a in TTL mode) or the SB700 (newer etc). I chose the SB-700 as I thought that I could still get a used SB-27 or similar if I really needed it for the FM3a. So I am happy that I did get it as it also has got the SU-4 mode.

For film I can now use my SB-900 with the cord, the SB-700 in SU-4 mode and the Lunasix F meter to get the correct balance etc.

Thanks for sharing your experience, studio!

Slaving SB-600 Speedlights in non-TTL "SU-4" Mode: [Edit: you can't!]

Assuming I'm exposing manually with a flashmeter; now, I somehow have to sync all of my Speedlights from my Nikon N90s film SLR. I own a pile of Wein IR and optical slaves, but they're all buried somewhere in the garage, and I can't seem to find them.

[Edit: the SB-600s do not support "SU-4" mode, and do not have built-in slaves--each SB-600 would need an SU-4 to slave (in non-TTL mode) from a primary flash.]

So, I guess I'll just attach a long coiled PC cord to my N90s, and run it to my primary key, an SB-800. Now, in light of the newly discovered information that SB-600s lack any sort of non-iTTL slave capability, I'd have to re-mount each SB-600 onto an optical-slave shoe, every time I want to switch from iTTL/SU-800 shooting, to non-TTL shooting on a film SLR. Then, when I want to go back to iTTL/SU-800 shooting, I'd have take every SB-600 off its shoe (because slaves don't have 'off" switches), and remount it to its stand. Hmm . . . sounds like way too much hassle.

All of these workarounds are making a darned good case for buying a new F6. With both an F6 and a CLS-capable DSLR, I would be able to switch between shooting film and digital, both, with complete wireless-iTTL Speedlight control, just by swapping an SU-800 between the two bodies. Thinking real hard about that one now . . .

Correlli said:
That is what I meant. In my SB-700 manual it is called SG-3IR.

Yes! (I was just about to order one, but they're out of stock.)

So, imagine this . . . I'll have an entire SU-800 + multi-Speedlight lighting set-up, all for my D7000. But, since I'll have a pretty model to shoot (I pushed her to next weekend, so I could skiing), I'll also want to shoot 35mm film with the same set-up. Of course, the problem is that the SU-800's CLS-based system only works with CLS-capable bodies (of which, the F6 is the only CLS-capable film body), and now I have to re-light with a film-based TTL system.

That means, a visible primary flash, an SG-3IR, and an SU-4 . . . wait; does this even work? All the SU-4 is going to do is "match" the TTL exposure computed for the primary, isn't it? Which is useless, if you don't want any light from the primary hitting your subject.

Nikon SG-3IR

I may end up just setting every Speedlight to manual mode for the film part, metering the whole scene, and shooting the old-fashioned way.

studio460 said:
Nikon actually makes an accessory designed specifically to block the on-camera flash from illuminating your scene when you want to use your on-camera flash just as a commander. It's a small flag that sits in the hot shoe.

That is what I meant. In my SB-700 manual it is called SG-3IR.

Nikon actually makes an accessory designed specifically to block the on-camera flash from illuminating your scene when you want to use your on-camera flash just as a commander. It's a small flag that sits in the hot shoe. Think I'll try that. Thanks for your posts, Corelli!

Another thing you might want to try is to have some kind of IR filter in front of the SB-27 that is on the camera. I know that there is an accessory for the on-camera flash of the current cameras that blocks the visible light (SG-3IR). You could use something similar to make the on-camera flash less prominent...

Correlli said:
One more thought: did you check if your SU-800 commander unit is compatible with the old film TTL system? If so you could setup the SB-27 to the SU-4 and use the SB-800 in SU-4 mode. That would give you two flashes in TTL mode controlled by the SU-800 and no flash on camera.

I was wondering that, but thought it'd be too good to be true. Checking on that now . . . No. It's a CLS-only system, and lists the F6 as the only compatible film camera.

One more thought: did you check if your SU-800 commander unit is compatible with the old film TTL system? If so you could setup the SB-27 to the SU-4 and use the SB-800 in SU-4 mode. That would give you two flashes in TTL mode controlled by the SU-800 and no flash on camera.

Gotcha! Thanks for all your help, Corelli!

Damn! Now I have a really good reason to start Jonesing over an F6. Thanks, Niko! Too bad the F100 doesn't support CLS--those are MUCH cheaper used.

studio460 said:
So, starting wirh the N90s (which does have TTL/matix-balanced flash capability), how would I use the above to wirelessly command any Nikon TTL Speedlight without firing the main flash? I think the answer may be: you can't?

I think the best option for me may be to connect an SC-17 to my SB-27, and use the SB-27 as the flash-tube, TTL commander. Then set my SB-800 on top of an SU-4 and see what happens.

Yes, I don't think you can wirelessly control a set of flashes without firing the main flash. The influence of the main flash can be reduced if you take it away from your model (the further you are away the more prominent the second flash will become) but you can't turn is of as far as I know. But as I said I am not 100% sure about this because I never owned any of the more advanced film bodies but I always used the FM2/FM3a ones (FM3a does have TTL).

As I said you might not even need an SU-4 for the SB-800 (at least you don't need one for the SB-900 or SB-700). The SB-800 has got photocells build into the unit for CLS and in the menu you should be able to set it to SU-4 mode (instead of REMOTE). In this mode it does not wait for the CLS "comm" flashes but fire as soon as the main flash does and stop when the main flash does. Older flashes like the SB-27 did not have a photocell on board so for these units you would need an SU-4 to use it in this kind of setup.

If you already own an SU-4 you might want to pick up one of the older Speedlights (the pre-digital ones) and you got a third one for your setup. If you attach a non-CLS Speedlight to the SU-4 you need to set it to TTL.

Thanks for your post, Correlli, but I'm still a bit confused. Just to be clear, I'm not trying to have a CLS system with a non-CLS body. I'm just trying to figure out how to use "old-school" TTL control over, possibly, a similarly old-school flash unit. But I think most Nikon flashes are all backwards-compatible, so it doesn't necessarily have to be limited to legacy flashes, I'm just limited by what my legacy body can do.

So, starting wirh the Nikon N90s (which does have TTL/matix-balanced flash capability), how would I use the above to wirelessly command any Nikon TTL Speedlight without firing the main flash? I think the answer may be: you can't?

I think the best option for me may be to connect an SC-17 to my SB-27 (just so I can point it away from my subject), and use the SB-27 as the flash-tube, TTL command er. Then set my SB-800 on top of an SU-4 and see what happens.

Hi Studio, I don't think that any film body other than the F6 is compatible with the CLS. So the setup might be a little different from what you are user to. The SB-800 might have an SU-4 mode to fire it remotely outside of the CLS. There are usually two modes: automatic (start with the master and be on as long as the master is) and manual (start with master and fire the manually set power).

So you can use the Sb-27 on the N90 or detached with the cables you mentioned and the SB-800 in SU-4 auto mode and you got a TTL setup. I mostly used a pc sync cable with the one flash (almost sure the SB-27 has got one), the SU-4 in manual mode and a flash meter. This gives you a lot more control.

Hope this helps