[bobbotron]

Sounds good .... So you have the V6 plus Pentax flash on the camera in pass-through mode I guess .... What mode of optical triggering do you use on the RF60, and what sort of shutter speeds can you get down to ?

I don't have the v6 trigger yet, just the two flashes plus an existing sigma P-TTL flash. I have some cheap cowboy radio triggers that work well for off camera flash... but not for HSS.

I haven't gotten around to trying HSS with the cactus yet, I just got these last week and haven't had time to experiment yet, I'll try optically triggering from the pentax to the cactus and report back when I do. I do have the long pentax P-TTL cord + adapters, so I can at least do some interesting things with the two and not have the P-TTL flash bound to the camera's position.

I CAN report that the multi mode on the cactus is A+++ awesome.

---------- Post added 12-17-15 at 09:28 PM ----------

I really wasn't planning on buying the two, but I'm really happy to have both, together I have a really complete system now.

[awaldram]

Are you sure the Acon is limiting in any way?

I'd be surprised to learn that the P-TTL system used flash IDs at all.

Isn't it the case that all flashes issue the pre-flash at the same time and the camera has no way of knowing which flash contributed what?

Ratios can still be established by working out an overall flash exposure and then dividing it to the flashes according to the ratios specified.

And how would you divide it to each flash what ratio it was firing without some means of addressing it uniquely.?

The only way you can get flashes to fire at different powers is if you can talk to them uniquely the V6's do this by the a.b.c.d groupings and P-ttl must use ID's of some kind else you would only be able to fire all ate the same power (be that 1:2 to achieve correct exposure)


Give it a whirl two p-tt flashes 1 half distance to the subject take test shot .... if exposure is correct (closest flash fires 1/4 of farthest) then they have been addressed uniquely . But if the subject is over exposed but >1stop then your correct and P-ttl has no address-ability.

Appoligies for the subject he was sat on the sofa looking willing

[Class A]

And how would you divide it to each flash what ratio it was firing without some means of addressing it uniquely.?

I'd do it by working out the overall exposure needed for the scene and then calculating the required individual levels based on the ratios specified.

The way I understood your test, it doesn't prove that individual metering is performed.

I'd test it by setting two flashes to 1/2 contribution each and letting them fire on a wall from the same distance, preferably with snoots to see their individual contributions. This should produce two equally bright spots.

Next, I'd move one flash further away and take a second shot of the wall. If the spots remain equally bright then individual metering occurred. If the spot produced by the flash further away becomes darker then only overall metering takes place.

EDIT: I would have tried that test myself, but I just re-learned that my second dedicated flash only supports TTL, but not P-TTL. In other words, I don't have two P-TTL flashes to perform the test with.

[Class A]

Most of my HSS shots are in the range from 1/400th - 1/2000 sec, so hopefully that restriction won't be a problem

I just did a test and it seems my earlier statement about 1/2000s being the maximum supported speed without black bars occurring is only correct when using the V6 as an intermediate optical trigger which then forwards radio signals to the flashes.

I just tried optically triggering the RF60 directly and it seems like the triggering on the main flash in HSS mode works fine up to 1/8000s. Testing wasn't that straightforward as my Metz 58 AF-2 does not support being used as an HSS master, so I had to use its regular P-TTL HSS mode and had it block its own flash while still allowing the optical triggering to happen but it seems that direct optical triggering of an RF60 is quick enough to forgo triggering on the pre-flash with a manual delay setting.

Looking forward to hearing about your own results.

[mcgregni]

The Cactus gear arrived today, and I've had a quick play with the RF60 as slave and V6 on camera .... So far so good, channel 1, group A, can't get simpler than that and I've been able to control the power and the flash zoom with no issues. I've set short distance mode as I'm just working for now in the living room. And yes, I appreciate being able to switch the flash on and off with one press on the A button.

TTL psssthrough works fine with the AF-540FGZII on top of the V6, and I was able to get HSS shots from the Pentax flash and compensations all worked good. I observed the RF60 stop firing after the max sync was exceeded. Next I have to get and figure out the optical slave stuff for HSS with the Cactus, but that will be another day.

For now I'm working out a 3 flash set-up for tomorrow as the girls have a ballet show and the Christmas tree is getting decorated, so plenty of photo ops for Dad hopefully .... Well, I might be lucky! I'm saving on having to buy another flash stand as the Cactus has a tripod thread, so its up on the Manfrotto looking a bit odd over on its side, but its very practical as the ball-head can get it into any required angle very easily. So I'm a flash-happy bunny ....!

Glad to hear that that HSS limitation doesn't exist with the optical triggering ClassA , thanks for reporting back on that.

[mcgregni]

Just to add that the two systems are working perfectly side by side .... I've got one Pentax flash firing into a reflective umbrella, the RF60 from the other side with a power shoot on, and the on-camera Pentax firing back over my left shoulder into a gold reflector pointed to the subject. The Pentax flashes are working perfectly well as usual in wireless P-TTL mode with the normal ratios and compensations, and the RF60 is working fine with it's control from the V6.

I guess the Cactus flash doesn't play any part in the exposure metering from the camera at all, as it doesn't fire during the pre-flash. It's been easy enough to juggle the balance between the 3, especially as one is on the camera and the V6 is right there as well. I just need to come to some method of deciding which particular light is more suited to the manual flash (from workflow point of view) ....I guess the logical answer is whichever one requires the most frequent fine tuning. With the Cactus set to 1/2ev steps, as is the Pentax with the umbrella, I find the accuracy and precision of the exposure fine tunings to be very much the same between the two ... The Pentax compensations in 1/2ev steps have the exact same precise effect .... It's just that I'd want to put that flash in the position where the least adjustment is required.

Also another consideration on placement and lighting function is the line-of-sight aspect, where clearly the Cactus is going to be the one for those hidden places.