inon z240 and canon g7x

[xrcjdx]

(originally posted this in canon corner, then realized it is really a strobe question so re-posting here. sorry for the double post.)

after a lot of dives using a g12 with onboard flash and less than satisfactory results it was time to move up and with the help and kind advice of sb members went with a g7x, fantasea housing, and pair of z240s, expecting to grow into the strobes. my answers are probably all there, but the z240 user manual is, as you probably know, a poor english translation.

the g7x in manual mode, unlike the other g series cameras, is compatible with the inon ttl through optical cable option. but i'm not sure exactly how this is supposed to be set.

my assumptions are:

camera uses pre-flash in manual mode
camera flash setting = automatic

z240 set to sttl
acc left in up position
strobe power (ev) left in 12 o'clock position (does this matter at all? is it overridden by ttl setting?)

as far as i can tell, if all goes well these settings should result in correct exposure of the manual settings of the camera.

to go fully manual with the strobe, left knob should be set to m (or full if full dump is wanted). ev knob should then be set to correspond with the camera's aperture setting and that should put you in the ballpark. acc engaged (down and locked). i think this how the strobe knows to ignore the pre-flash? is it just as simple as this? or what have i got wrong/missed here?

leaving early next week for south leyte and this will be the first chance to get the rig wet. it being off season not expecting anyone there to lean on for support (as of now i'm the only diver, which under the circumstances will be great if i can get the strobes to work correctly), and would like to know if i'm in the ballpark with this and understand (or not) some really good earlier posts and information.

-- thanks to reef photo and interceptor for previous helpful posts on the matter

rc

---------- Post added August 12th, 2015 at 11:14 PM ----------

one other issue i forgot to mention - interceptor pointed out that to use sttl it is required that the z240 use the -5 auto diffuser - Inon External Auto Compatible -0.5 Diffuser White but with the strobe came, as far as i can tell by looking at it, this one - Inon -0.5 White Diffuser for D-2000/Z240 (TTL/Manual) which is called ttl diffuser. can this be right or what did i miss?


test fired with the above settings and it works and exposes correctly in the comfort of the house. will know soon enough if the exposure is working underwater.

 

[Interceptor121]

Your understanding is correct. The external auto diffuser is only required if you want to shoot the internal flash in manual and the strobe in Auto. The diffusers provided with the strobe work fine in TTL and manual. One thing to consider is that the battery autonomy of the GX7 is pretty low with the flash in TTL it may further reduce so check out if you want to shoot in manual. If then you want to use manual flash with external auto you need the auto diffuser

 

[xrcjdx]

thanks for that, interceptor. i learned more about these strobes reading your posts in 5 minutes than i did reading the manual for 5 hours. have a bunch of dives coming up later this month and next in puerto galera, leyte, and dumaguete. stay tunes here and canon corner for on the spot emergencies!

ps - you have some great shots on flickr. enjoyed looking.

pps - i was able to answer my own question about the ev adjustments by looking a little more closely at the manual. moving to either side of the 12 o'colck position (B) will result in more or less exposure than selected automatically in the B position. a fine tuner.