Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
01-26-2010, 06:09 AM   #1
Junior Member




Join Date: Mar 2009
Location: Texas
Posts: 40
Wireless P-TTL Question

How many flashes can be supported in Wireless P-TTL using the on-board flash as a commander? And if so, how many flashes can be supported?

I haven't seen any documentation on using multiple P-TTL flashes as wireless slaves, but sometimes there is a brief mention every now and then.

Does anyone have any experience shooting wireless P-TTL with multiple slaves? And if so, can they share?

Thanks!


Last edited by Kazy; 01-26-2010 at 06:18 AM.
01-26-2010, 09:25 AM   #2
Veteran Member




Join Date: Aug 2007
Photos: Gallery
Posts: 1,563
I'm not the true expert, but this is the way I understand it works:

1. The initiating flash (for instance the build in flash) does a pre-flash trigger, all flashes do the pre-flash.
2. After which the camera calculates the amount of output power needed.
3. Then the main flash trigger is send. All flashes that can see the trigger flash and are on the same channel will contribute.

Since the flashes don't know about each other, and the light calculation is done independent of the number of flashes used.

I can only wonder if with multiple flashes the output calculation is done right.
If it initiates a flash with -3 Ev based u pon the 3 flash preflash, will 2 or 3 flashes with -3Ev have the same effect if the setup was done with only 1 flash?
The more I try to reason the logic the more I cannot see what the difference is.
If you'd work with 3 flashes and they all contribute for 1/3 of the light on the subject, -3Ev for 3 flashes * 1/3 = -3Ev for 1 flash.
The same logic works for 5 of 99 flashes I guess...
01-26-2010, 10:10 AM   #3
Veteran Member
AndrewG NY's Avatar

Join Date: Dec 2006
Location: Chappaqua, NY
Photos: Gallery
Posts: 679
I have an AF540FGZ and a pair of AF360FGZ's and have used them all simultaneously. I don't know that there's a maximum. Note that the commander doesn't know anything about the flashes--you set each flash up separately with with flash comp and contrast-control ratio (e.g. 1/1, 2/3, 1/2, 1/3). You can control all together with flash comp on the body. Flashes don't "talk" back to body, and system is all optical so if the slave sees the controller/master, it will fire. Camera just observes at the effect of firing all flashes during pre-flash, then tells all flashes what the output level will be--not individually, just one level; each flash applies that level to its own configured contrast-control ratio & comp.
01-26-2010, 10:55 PM   #4
Junior Member




Join Date: Mar 2009
Location: Texas
Posts: 40
Original Poster
Thanks for the quick answers. I've just ordered one P-TTL flash (Sigma EF-530 Super), and was wondering whether I could upgrade to another one and control them both using the on-board flash on my K200D.

01-27-2010, 02:59 AM   #5
Veteran Member




Join Date: Jan 2008
Location: Ste-Anne des Plaines, Qc., Canada
Posts: 2,014
I use three Sigma flashes, and I've used all three of them together in wireless P-TTL mode without problems using the on board flash as master or controller.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, flashes, p-ttl, pentax help, photography, slaves
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Wireless TTL with Nikon Flashes! dlacouture Pentax Film SLR Discussion 2 11-04-2010 04:32 PM
Wireless P-TTL test results adamfogerty Pentax Camera and Field Accessories 3 06-20-2010 05:18 PM
Metz 48 P-TTL wireless display Arpe Flashes, Lighting, and Studio 4 12-12-2009 08:19 AM
Go TTL wireless or PocketWizard? jboyde Pentax Camera and Field Accessories 6 12-10-2009 11:50 AM
Dual 540fgz - *NON*wireless ttl EdZarts Pentax Camera and Field Accessories 5 04-16-2007 09:48 AM



All times are GMT -7. The time now is 04:17 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top