[WMBP]

What was the shutter speed of your test shot?

Our K10D is not supposed to support HSS wireless flashing (Notice you only have a Wireless Flash mode, not a Wireless HSS mode in the camera). There has been one ist that supports wireless HSS iirc, but I don't remember which model.

Your onboard can still trigger the external unit with it set to HSS, I just don't believe you actually get HSS out of it. I'll test this out when I get a chance.

Hmmm.... [scratching head]

Woops. Never mind.

I did take a test shot earlier with a shutter speed of 1/350th sec and would have sworn that the flash did fire. But now that I try again, I'm not sure what I did earlier. It would appear that I faked myself out, because I can't get it to work again. Just went back and looked at the picture I took. EXIF info says the flash did NOT fire and it's pretty obvious on second look that it didn't fire. So looks like I completely faked myself out. Too much testing for one day.

So I was wrong about this "discovery" and I take back that comment. And we're back to three advantages to cable connection to the external flash: no accidental triggers; ability to do HSS; and ability to use external flash when location of the external flash or the circumstances prevent wireless from working.

Thanks for following up, AVANT.

Will

[Arpe]

Thanks for all this Will, and respondents. When you get it all sorted a summary would be good!

I'm always toying with buying a flash, but hate the idea of having to take it with me, but you are swaye towards getting one.

[WMBP]

Thanks for all this Will, and respondents. When you get it all sorted a summary would be good!

OK, Arpe, here you go.

My original question dealt with a very limited setup: one K10D with a built-in flash, and one Pentax AF 540 FGZ detachable flash unit. I have been trying to understand the ins and outs of wireless triggering of the 540 when it's off the camera. NOTE there are other ways to do wireless, for example, Pocket Wizards. I've not used 'em but they sound great and I expect I will graduate to them sooner or later. But this thread is about making the most of what you get basically for nothing extra when you have a K10D and a 540 flash unit. I'm going to call what I'm interested in here "basic wireless," to distinguish it from other forms of wireless lighting that involve additional equipment and costs.


How basic wireless works

So, if you have a K10D and an AF 540 FGZ flash unit, you can use the flash off the camera in wireless mode. Wireless triggering has lots of advantages. It's cheap, for one thing: you don't have to buy cables. It is also easy and flexible. It allows you to place the flash some distance from the camera, not just a foot away on a bracket, but three feet away in your hand (one hand holds camera, other hand holds flash unit), or five or ten feet away if you have a confederate hold the flash or set it on a stand -- and you don't have to string a three foot or ten foot cable between camera and flash, and you also don't have to spend the hundreds of dollars required to buy fancier radio units like Pocket Wizards.

The 540 has two wireless slave modes -- SL1 and SL2. You will almost certainly want to use SL1, which is the default.

SL2 seems to be the older method, where any other flash triggers the off-camera unit. The problem with SL2 mode is that the triggering flash might not be from your camera -- it might be from someone else's camera; this of course causes you to have to wait for your flash to recharge and runs down your batteries.

If the unit is in SL1 mode, however, communication between the camera's built-in flash is more controlled, more reliable and less prone to accidental triggering. In SL1 mode, you pick one of four "channels" for communication between camera and flash. These channels are not radio channels, they are in a technical sense not channels at all. I would prefer to use the term "protocols". Anyway, in each channel, the camera uses a series of imperceptibly fast preflashes, patterned in a certain way, to communicate with the flash. Some other camera brands and flash systems use infrared signals, but the Pentax system uses flashes.

Disadvantages of basic wireless

These preflash channels/protocols are proprietary to Pentax, so you don't have to worry about someone with a Canon system setting off your flash, and even if someone else is standing around you shooting with a K10D, in order for that other camera to trigger your flash accidentally, that other camera would have to be using flash, with the flash mode set to wireless, and with the camera configured to use the same channel you're using. Odds of that happening? Small, at best.

Aside from the very small (in my view, negligibly small) risk that someone else's camera will accidentally trigger your flash, there are two other disadvantages to using this wireless arrangement.

The K10D + 540 FGZ combination in wireless mode doesn't support high-speed sync. High-speed sync is mainly used outdoors when you're trying to use fill flash in very bright light. The 540/K10D combination has an x-sync (max normal shutter speed) of 1/180th sec, which is perhaps the biggest weakness of these products. Other systems in the K10D's league these days have x-sync speeds of 1/250th sec or (in a few cases) even faster. But high-speed sync isn't the same thing as a higher x-sync speed -- it's a somewhat special case and has some of its own disadvantages. I very much wish that the K10D + 540 had an x-sync speed of 1/250th sec, but it doesn't; and I don't care too much about the fact that I can't do high-speed sync in wireless mode. You can do high-speed sync using cables.

The final disadvantage of wireless flash is that it only works if the external flash unit can "see" the pre-flash signals sent by the camera. It will NOT be able to see those signals in certain situations, for example, when the sensor on the front of the flash is pointed away from the direction from which the flash signals are coming; or it's very bright outside and the pre-flash signals are simply not bright enough to be noticed; or the distance of the 540 from the triggering flash is too great. Using a cable would solve the problem of the ambient light being too bright and would be a good solution if the flash was mounted, say, on a bracket, so a short cable wasn't a big hassle to use. But a cable is not a practical solution for the problem of distance, if, say, you want to set off a flash that's 40 ft away. In that case, radio triggers like Pocket Wireless seems to be the best solution.


Bottom line

Basic wireless is not the solution to every off-camera flash problem, but it does work reliably in a wide variety of situations, it's easy, and it's cheap. I bought the Pentax hot-shoe adapters (one for the camera, and one for my bracket) + the three-foot cable, and it cost me well over $100. Pocket Wizards are considerably more expensive than that.

I'm always toying with buying a flash, but hate the idea of having to take it with me, but you are swaye towards getting one.

If photography can be compared to flying an airplane, then mastering flash photography is like moving from visual flight rules to instrument flying -- a major step forward.

The general principles of controlled lighting are universal and very well explained in the great book Light: Science and Magic. What makes flash photography somewhat tricky, however, is that you depend on hardware, and unfortunately, the flash hardware is not nearly as standardized as camera bodies are. But boy, it's fun to learn and extremely liberating. I have been a serious photographer for most of my life -- but during most of that time I was not serious about flash. Lately, I've gotten serious about it and I'm having a great time sorting it out.

I will add one last argument in favor not of wireless flash specifically but simply of mastering controlled lighting in a general way. It's an argument made (if memory serves) in Light: Science and Magic. Namely, learning to control the light is both the best and the cheapest way to improve your photography. You may have $10,000 worth of glass in your bag, but if the light stinks and you don't know what to do about it, you might as well quit and go home. On the other hand, with a Pentax K10D or K100D and the $89 kit lens, you will be able to take wonderful photos even when the lighting isn't perfect if you know how to take charge, slap the lighting around and make it your servant. And the lighting is seldom perfect.

Will

[Arpe]

hey I said a summary!

Excellent stuff Will, that has sorted out a lot for me.

Admin - I vote to make this a sticky as it's bound to answer oft asked questions.

[nosnoop]

One thing I want to add about wireless flash is the ease of using multiple slave flashes set up (try that using cables!). And if you attach an external flash on the K10D, you can do wireless HSS.

One advantage of using cable is the ability to use SR (SR is automatically disabled in wireless mode). SR is usually not essential if flash is the main source of the lighting; but may help in specific circumstances where you want to drag the shutter, use ambient light and expose a blur free background with no tripod.

[WMBP]

One thing I want to add about wireless flash is the ease of using multiple slave flashes set up (try that using cables!). And if you attach an external flash on the K10D, you can do wireless HSS.

One advantage of using cable is the ability to use SR (SR is automatically disabled in wireless mode). SR is usually not essential if flash is the main source of the lighting; but may help in specific circumstances where you want to drag the shutter, use ambient light and expose a blur free background with no tripod.

Nosnoop,

That tidbit about shake reduction between disabled in wireless mode is interesting. Where'd you get that? I have pored over the operating manual for the 540 and don't recall seeing it. Of course, after a few minutes of poring, my eyes glaze over and my intake efficiency drops rather dramatically, so perhaps it's there in bold print and I just missed it.

Will

[RBellavance]

Nosnoop,

That tidbit about shake reduction between disabled in wireless mode is interesting. Where'd you get that? I have pored over the operating manual for the 540 and don't recall seeing it. Of course, after a few minutes of poring, my eyes glaze over and my intake efficiency drops rather dramatically, so perhaps it's there in bold print and I just missed it.

Will

That was before firmware 1.10, IIRC.

[stewart_photo]

You've got it, Will. The P-TTL wireless mode is very simple. There are four channels (four unique series of light pulses), which you select as explained in the owners manuals. The flash units used in your wireless setup must also be set to the same channel, again as the owners manuals explain. At that point, the on-camera flash (either internal or external) generates a specific series of light pulses (kind of like simple morse code) when you press the shutter release button, with the remote flash units triggering when they perceive the proper series of pulses for the channel they're set to.

The remote flash units will ignore every other flash seen, from another Pentax camera/flash using a different channel (a different series of pulses) or just random flash pulses from nearby flash units. When the remote flash units perceive the proper series of flash pulses, they will then follow the normal routine of a quick pre-flash for the camera to use to determine exposure followed by the actual flash for exposure.

That's about all there is to it. As far as I can tell, there are no communications from the flash units to the camera. Of course, you have additional options, such as adjusting the output levels of the various remote flash units. The manual cryptically explains how to do that.

stewart

[stewart_photo]

That tidbit about shake reduction between disabled in wireless mode is interesting. Where'd you get that? (snip).

In the notes under "Using In Wireless Mode" in the top half of page 182.

I didn't see any mention of shake reduction in the PDL explaining firmware update v1.10, nor in the readme file, RBellavance. Do you remember where you saw that shake reduction can now be used?

stewart

[stewart_photo]

(snip) And if you attach an external flash on the K10D, you can do wireless HSS.

I thought that was the case also, nosnoop. However, evidently firmware update v1.10 killed that option. Read the PDL explaining firmware update v1.10 (just under the first chart on page one - "HS (High Speed sync) is not available in the wireless mode.").

stewart

[WMBP]

Well, it's always something. Now I can't get the 540 FGZ into P-TTL mode while I'm using it wirelessly.

Camera (K10D) is set to wireless flash in the Fn screen, flash options. The flash unit is turned on to wireless. Both are on channel 2. The flash is set to "slave". The 540 DOES fire when I click the shutter button -- but the only modes available are A and M. The operating manual for the flash unit clearly suggests that P-TTL should be available in wireless mode and I'm 99% sure that I did use it that way earlier. Cannot think or figure out what I've done to cause it not to work now. Anybody have any ideas?

By the way, if I mount the flash unit on the camera's hot shoe, P-TTL is available.

....


Addendum 3 minutes later.

Never mind. Sorted it out. In all the futzing around I've been doing, I somehow slipped the flash unit back into SL2. Can't do P-TTL in SL2, has to be SL1.

Will

[nosnoop]

I thought that was the case also, nosnoop. However, evidently firmware update v1.10 killed that option. Read the PDL explaining firmware update v1.10 (just under the first chart on page one - "HS (High Speed sync) is not available in the wireless mode.").

I think that document refers to the ability to use HSS in wireless flash triggered by built-in flash - i.e. not possible. But if you use external flash, the capability is determined by the flash, and it is certainly possible. I have been using it.

[nosnoop]

That tidbit about shake reduction between disabled in wireless mode is interesting. Where'd you get that?

Not sure if this was mentioned in the manual, but the first time I read about it was in Pentax Japan's K10D FAQ page:

PENTAX¡¡À½ÉʾҲ𡧥ǥ¸¥¿¥ë¥«¥á¥é

And it roughly translates to:
Q. Can I use SR in Bulb (B) mode?

A. No, it is not possible. SR is automatically turned off in Bulb, Remote, Self-timer and Wireless Flash mode.


And I don't think this has been changed with firmware, as far as I know.

[RBellavance]

In the notes under "Using In Wireless Mode" in the top half of page 182.

I didn't see any mention of shake reduction in the PDL explaining firmware update v1.10, nor in the readme file, RBellavance. Do you remember where you saw that shake reduction can now be used?

I must have been hallucinating, sorry :-/ SR is indeed turned off automatically by the K10D when the built-in flash is set to wireless mode.

[RodConn]

Just a little addition re wireless flash - I was confirming the shutter speeds for HSS and found it impossible to set my K10D any higher than 180th when the flash selector was in wireless mode.

Another point of interest was that at ISO 100 & f/1.4 the inbuilt flash alone barely illuminated desk objects one meter away with the control flash when it was in control mode. Further, it simply acted as the normal built in flash when it was in Master mode. These two tests were done with no slave flash obviously.

I tried the above test as MUCH earlier discussions had feared that a significant amount of lighting would have been supplied by the control flash. I am now satisfied that this is not the case

Rod