YS-D2 paired with YS-03 & YS-01 with YS-03

Asking the below because I am wondering if I can upgrade from a single YS-03 to ultimately i.e. 2 Ys-D2 by buying one YS-D2 first and somehow pairing it in a way that makes sense with the YS-03 before I am ready to spend money on a second big flash. I am intentionally asking in a way that may help me better (with the answers) to understand what is going on.. So, I am trying to figure out my gradual upgrade path options and to understand:

My limited beginner understanding is (everything is a question here, as I might be quite wrong in my understanding):

- that I could pair my YS-03 with a (yet to obtain if it currently was in stock anywhere) YS-01 even in manual mode if I slave the YS-03 off the YS-01 set to manual. Then the YS-03 will put out light with the same flash duration as the YS-01 and because they use the same flash bulb the output will be close enough to the same - will be matched to each other.

- which leads me to think that if I were to pair my YS-03 with a yet to obtain YS-D2 instead, but in the same manner that I will get flashes of the same duration out of each device, but of differing intensity since the YS-D2 has a bunch more power. Is that possibly the right thought?

- If so and if that difference is less than 2 F-stops, could I then crank the exposer compensation on my YS-03 up to match the two ... except of course my YS-03 does not have such a pretty knob... ---- and cranking anything down on the YS-D2 won't do any good because it will only change duration not brightness and the thereoff slaved YS-03 will only match the light pulse duration.

- Which leads me to think that I cannot match those two flashes using them in manual mode, slaving the YS-03 from the Ys-D2 unless I have a neutral density filter or scuvh to rob the YS-D2 of the amount of light necessary to even their output at the same duration...

- And if so, is it pretty much the same if I ran each in e-TTL indipendently triggered off the clamera flash ?

It doesn't matter that the two flash units are different, one with higher maximum output than the other. Reflected light off the target (scaled with light emitted to it by the strobes) is what matters because in TTL this is what the camera sensor measures in order to instruct the strobes what intensity to emit for the second exposure pulse.

Even for two identical strobes on the same target, one could be angled differently from the other making their contributions to the overall lighting unequal. That would be equivalent to setting the two strobes at different intensities. Combined reflected light, whether from strobes of different power, or different pointing angle, or reflecting off different parts of the target is what the camera sees. The same would be true of multiple strobes (4?) pointing in the general direction of the target. And ambient light makes another contribution to total reflected intensity which the camera sensor measures in the first TTL probe pulse. The same is true in Manual mode, except in that case it's up to the operator to adjust either or both (or more) strobe intensities for highlights and shadows.

The problem is that what the TTL system calculates in an pulse length and it will be an average between the two flashes. It puts out a pulse to measure and each flash will mimic the duration. But there's no escaping the fact that the there is a two stop difference between the two strobes, how much of that difference is due to "size" of the tube and how much is different durations is unknown, but is likely mostly size or power of the tube.

What you could do is put the widest diffuser on the D2J and leave the YS-03 bare and that should make their output about equal. The wide diffuser on the D2J costs 2 f stops. Or if you want them both diffused use the 2 stop diffuser on the D2J I'm guessing the standard diffuser on the YS-03 is about 1 stop or so which gives you a 1 stop difference which could be more manageable. You could try it out on land to see how they respond.

Thanks. That's pretty much exactly what I figured after I read the D2J comes with 2 diffusers, one of which reduces the linear distance output by two stops....

.... but then things got weird ... in a good way... "Santa" splurged and agreed to getting 2 of the nice strong strobes...

When you see him, tell Santa to stop by my place.