Originally posted by onesikej8 
so you need the regular flash or an on camera flash and when that fires, the other ones fire?
Originally posted by arnie0674 The wireless flashes are triggered either by the built-in or a hot-shoe flash. The flash on the camera is the master (or controller) and the other flashes are the slaves.
I own a K-r. I am pretty sure my post will be generic to all current Pentax dSLRs, but I'll leave it to other body type owners to correct as necessary...
Other than wishing my Sigma EF-610DG SUPER was a tiny bit shorter when stretched flat (I had to rearrange my camera bag), I like my new flash. The mechanical relationship between camera and flash is rather complex, and to figure it all out you will need to carefully read both the camera manual and the flash manual. To get the most out of your flash - heck in some circumstances to get anything out of your flash - you have to configure both the camera and flash. Plan on spending at least an hour making some test shots - - at least with digital, it only costs you some battery power and a little normal wear on the equipment. My prediction is if you don't do that, you will waste far more time and wasted shots in the field - and probably want to put both camera and flash in the dumpster out of frustration. I decided that until all this becomes second nature that it would be wise to always have camera and flash manuals with me for quick double-checks of my setup. (as an aside - both manuals are available as downloadable .pdf files - - I have them loaded in my tablet/e-reader, which also fits in my camera bag).
First thing... your flash has a power zoom feature. It's all internal so you won't see anything happening. The zoom is not continuous, but uses set focal lengths matching or just wider than your lens. Or more accurately the
effective focal length of your lens. In other words, the LCD on the flash will show you a rounded value 1.5 times what your lens says. It can be a bit disconcerting.
The easiest configuration is to plop the flash in the hotshoe. You will then have a much glorified version of your built in flash - meaning far more power, swivel and bounce. And of course, the flash is high enough to not cast a shadow behind most lens hoods. If this is the only way you will use the flash, you probably just spent too much money.
With wireless P-TTL flash you have a lot of possibilities, but with those possibilities comes complexity. First, wireless is not via 'through the walls' radio frequency. It is accomplished through IR communications embedded in the flash output. It requires both the remote flash AND a flash mounted to the camera - either the built-in flash or another P-TTL capable hotshoe mounted flash. Here is where things get hinky. In addition to making sure that all your flashes and the camera are operating on the same IR-based communications channel, you also have to tell the camera whether the flash mounted on your camera will be part of the final exposure, or if the mounted flash is simply telling the remote flash(es) what to do. Either way, you will see the mounted flash fire when you push the shutter release.
Take your pick. The 'P' in P-TTL either stands for 'Pentax' or 'pre-flash' (maybe both). You can see this initial flash in your viewfinder because it happens
before your shutter opens. This pre-flash checks exposure and tells all the flashes how much power they will need to output. If you have configured your
camera to only provide this controller information, the mounted flash will not fire when the shutter is open. If on the other hand, you have configured the
camera to use the mounted flash for your exposure, it will become the primary light source with all other flashes performing fill-flash light sources according to whatever algorithm Pentax has built into the camera for P-TTL exposure. All of this happens fast enough that it usually looks like one flash to the observer. The proof is when you look at your test shots.
There are many other lighting options available to you such as trailing flash, high speed shutter flash, and manual control. I'm not going to try to cover everything. The important piece to understand is that you typically must make configuration changes at both the flash and the camera to achieve your desired goal. The respective manuals only talk about the settings for its device and make scant mention of what you need to do for the other device. It is up to you to put the two together.
One final observation... Your flash has a built-in diffuser panel. Don't think you only have to use it for wide-angle shots. It may offer all the softening you need without buying and dragging around another piece of photographic gear. Again, its worth a few test shots before you open your wallet.
Post #13 by JimJohnson
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