[mcgregni]

Pentax Flash Guide - 2nd Development Thread

Dedicated System Flash versus Third Party Radio Manual Systems


This is the 2nd main development area for the next version of my Guide to the Pentax Flash System. Here I want to explore the key pros and cons for each type of flash system.

I personally would like to see a bit more discussion on non-P-TTL flashes, but I'd understand if you considered it off-topic.

Once one goes beyond a single flashgun, P-TTL starts to show its limitations and many flash users shoot with manual flashes even when they are only using one light source for reasons of predictability, consistency, and triggering (e.g., in sunlight and/or involving light modifiers).

If the guide is meant to be just a P-TTL guide then its current focus is justified. However, if it is meant to be addressing flash photography with Pentax cameras in general then I think it should say a bit more about available alternatives and list the trade-offs.

The Guide is clearly about the Pentax dedicated system, but it is also intended to help with buying decisions and so part6 of the scope has to be helping with that ..... that involves identifying the strengths and weakness of the different choices.

Near the start of the guide I intend to add a section that defines 'Dedicated' system flash as well as summarises the key benefits of the dedicated flash types and offers up some benefits of radio controlled systems as well. The idea is to lay down some solid guidance on what type of system may suit different needs, both photographer types and particular shooting situations. I will start it off by throwing out list on both side ..... then I hope to sit back and see where I've got it wrong and what I've missed !!

DEDICATED SYSTEM FLASH - BENEFITS

Flashes are automatically configured for the cameras 'out the box'
More suited to on-camera quick changing situations (weddings, events etc)
Flashes offer a range of modes and creative features in one unit
Automatic Flash Exposure control, with a choice of modes as needed
The wireless option with built-in flash controller offers a quick and simple solution
High Speed Sync and Rear Curtain sync are integral
On-Camera working is convenient with flash and ambient exposures controllable from the camera / flash control panel
Automatic operations such as flash head zooming, in-out to HSS mode
Range and distance indications for quick distance assessments and adjustments


RADIO SYSTEM KEY BENEFITS

Cheaper flash units, allowing a more cost effective multi-flash set-up
Radio triggering is more reliable in a wider range of situations
More suited to complex studio and locations set-ups
Some newer systems offer some automation from the camera position (zooming and manual power control)
More advanced configurations for complex set-ups (eg 'Groups' for controlling power ratios of different zones)

On the other side of it are the obvious disadvantages:

Dedicated systems flash is more expensive per unit and less suited to multi-flash set-ups beyond about 3 units (including the built-in).

Radio systems are more varied in their configuration requirements and amount of related equipment needed (eg triggering units, aerials, hotshoe attachments) and each system has different requirements.Each system needs to be studied and understood individually .... it would be a big job to write a single guide that covered all radio flash systems !

OK ... there's a starting point. Tell me what you think. Is it a fair summary on both sides, and what things have I missed ?

[delegopa]

Looks like a good summary to me.
Not sure about the current dedicated Pentax system, but most dedicated systems still communicate settings over a optical wireless connection. The master flash has to signal the settings by flashing multiple times for one picture. This leads to a higher energy consumption than using RF communications. Also the range is limited by the power of the master flash, usually considerable shorther than with RF.

[mcgregni]

Yes, the Pentax system is optical as well. It has to communicate the flash mode and tell the slave units to send out the measuring pre-flash ... Then the camera calculates the power output and another optical signal is sent to the slave to tell it!! Quite amazing really, but yes, I hadn't thought about the extra power drain involved.

I've heard it said that the pre-flashes can cause peoples eyes to blink and cause problems for portraits. I think manual flash mode should reduce the flashes as you don't need the power information sent. Thanks for that information, that is another plus for the radio systems.

[Tanzer]

One of my relatives is particularly sensitive to the preflash -- a good 30% to 40% of my photos of him show his eyes closed or half-closed. So that means I have to waste even more power, taking additional shots just to make up for the bad ones.

And that's when it's just him. If you multiply the average probability that someone in a larger crowd will blink, by the number of people in the picture, pretty soon it gets to be a real problem when you have a large group situation.

[howieb101]

One of my relatives is particularly sensitive to the preflash -- a good 30% to 40% of my photos of him show his eyes closed or half-closed. So that means I have to waste even more power, taking additional shots just to make up for the bad ones.

And that's when it's just him. If you multiply the average probability that someone in a larger crowd will blink, by the number of people in the picture, pretty soon it gets to be a real problem when you have a large group situation.

The absence of pre-flash is one significant advantage of going manual. Particularly with bigger group shots. People with closed eyes ruin shots and some people can't stop themselves no matter how hard they try.

Howie be

[mcgregni]

It's clearly an advantage of radio systems, so I will add that point into the guide when outlining the differences. The extent of the effect with optical systems will vary, obviously depending on individual people and their sensitivities, but also with the flash mode. Using manual on the slave unit/s will reduce the pre-flashing a little, and you can influence it a bit by avoiding direct bare flash from the master unit.

I shot some indoor portraits recently with a black background ...I had one AF540 in a softbox off right at 90deg to the subject working in manual mode, and the other AF540 was on-camera in master mode. This flash was bounced up and slightly left (ceiling and some wall) with a Gary Fong Lightsphere attached ... The LED catchlight was also activated. So no bare flash into the eyes, but plenty of front fill and balancing bounce light visible to the subjects. I had no problems at all with two subjects and around 30 frames, all eyes nicely open and good smiles.

So I'm sure it depends on things like the angle, diffusion and directness of the pre-flashing into the eyes, so we can take some control. I appreciate of course that in some situations there's not much choice apart from direct flash .... Although I'd have thought that most of those situations would involve Dedicated on-camera flash, not radio controlled wireless set-ups .... ?


There's a new article up on the homepage describing a successful portrait session using P-TTL exposures exclusively, and there was no report of closed eyes etc. Maybe again there, it was because of the diffusion and softness of the lighting that helped?

[awaldram]

no blinkies is not an advantage of radio triggers its an and advantage of Non P-ttl flashing

The k3 internal flash can happily so Manual flash so no blinkies
Auto Thyristor flash also don't pre-flash so no blinkies

Also you probably only want a summary for RF flash as its a mine field and requires in depth investigation.

There is Basic single pin hot shoe

1 Standard Cheapy normally 4 channel RF usually transmit on 344Mhz (US) and 433Mhz (Eu) very unreliable and subject to interference
2 better Quality unit use 2.4Ghz

Then there is multiple control like the Catcus V5's which wil allow grouping
Next comes TTL pass though - so you can put a TTL trigger on the transmitter

The a sub branch that allows power/zoom control of the remote flashes this cna either require dedicated flashes or generic (Cactus V6 uses TTL data stream to control power of generic flashes)

The last is full P-ttl triggers of which the current main one is the Oaktec units but there is another startup approaching retail .
And of cause though these are RF triggers they also have pre-flash.

So to describe the pro's on cons of P-ttl vs Triggers is a moving goal post and depends on flashes triggers etc

This will give you a generic breakdown of flash triggers
http://dpanswers.com/content/radio_flash.php

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Last edited by awaldram; 09-11-2015 at 09:51 AM.

[Tanzer]

The absence of pre-flash is one significant advantage of going manual. Particularly with bigger group shots. People with closed eyes ruin shots and some people can't stop themselves no matter how hard they try.

Howie be

Agreed. Another advantage of going manual for large group shots is that you can use multiple flash units, for more even lighting. I guess the OP mentioned that already.

[mcgregni]

You can use multiple flash units for Pentax Dedicated wireless as well ... Is there any limit to the number of dedicated slave units that will be triggered by an optical P-TTL control flash? I accept that it is more cost effective and probably more controllable to use radio systems and their more sophisticated group settings to manage complex multi-flash set ups.

Personally I think a 3 flash dedicated set-up (2 flashes plus the built-in camera flash) is a convenient and manageable wireless system .... It's enough for me certainly for quick domestic use and with diffusers and modifiers can produce quite sophisticated creative lighting. I accept that trying to manage more dedicated flashes than this could be difficult, and the cost adds up.

[Tanzer]

For some reason I keep thinking that Wireless P-TTL is a two-way protocol that would only work with one wireless slave. I can't explain why that would be necessary, or even make any sense. So I stand corrected.

If it's one-way communication, then I don't see why there would be any limit to the number of slave units.

[Class A]

Here I want to explore the key pros and cons for each type of flash system

Thanks for attempting to complete the picture.

You are coupling two aspects -- exposure automation vs manual control and optical triggering vs radio triggering -- which is not ideal, but somewhat defensible as in practice mostly two out of the four possible combinations are used.

However, note the Aokatec triggers that allow the combination of exposure automation with radio triggering and that there is the option to use manual flash power control in combination with optical triggering.

Regarding the P-TTL advantages:

Flashes are automatically configured for the cameras 'out the box'

I'm not sure what "automatically configured" is referring to.
You don't have to configure a manual flash either. The vast majority of radio triggers also work out of the box and don't need any configuration.

I don't think you have a real point here. You mention the practical advantages of system-dedicated flashes later so this point seems 100% redundant to me (plus I'm not sure what it even tries to express).

More suited to on-camera quick changing situations (weddings, events etc)

Why are you restricting this to "on-camera" use?

Granted, exposure automation works best in the "on-axis" scenario, but P-TTL also supports some off-camera usages relatively well.

Flashes offer a range of modes and creative features in one unit

P-TTL flashes do not offer more modes and creative features than manual flashes (outside the P-TTL and HSS P-TTL modes).
If you are referring to rear-curtain sync, for instance, then you shouldn't repeat that point.

Automatic Flash Exposure control, with a choice of modes as needed

What modes are you referring to?
The camera modes (e.g., P, Av, Tv, ...)?

The wireless option with built-in flash controller offers a quick and simple solution

I'd say the optical triggering option using the built-in flash offers a quick solution for simple scenarios.

Note that HSS is not supported in this scenario and that the built-in flash has limited reach, thus further exacerbating the limitations of optical triggering.

On-Camera working is convenient with flash and ambient exposures controllable from the camera / flash control panel

I don't understand this point. You can exert the same control using a manual flash, but typically using a simpler interface.

Also, some radio triggers have a dedicated user interface that surpasses the often not very direct flash user interfaces. Using the camera and a radio trigger can thus be quicker than using camera menus and complicated flash interfaces.

Automatic operations such as flash head zooming, in-out to HSS mode

My Metz flash does not support automatic transition to HSS. I have to manually choose the HSS P-TTL mode for HSS to become available.
Are Pentax flash units different in this respect?

I'd also add that flash head zooming is only useful for on-camera use and unwanted in any other application.


Regarding the manual flash advantages:

Cheaper flash units, allowing a more cost effective multi-flash set-up

I'd say to write "much cheaper" instead of "cheaper" would not be an exaggeration, in particular when considering FGZ II prices.
The cost advantage already manifests itself for a single flash system. I don't think it is appropriate to restrict it to "multi-flash set-up"s.

Radio triggering is more reliable in a wider range of situations

It is also much more flexible, allowing flashes to be put inside softboxes, or flashes that are rear-mounted to light modifiers to be turned away from the camera (e.g., for backlighting), or flashes to be put in fridges, behind corners, etc.

More suited to complex studio and locations set-ups

I disagree with this characterisation.

If we are being honest, P-TTL only works well for single flash, on-camera usage. Anything beyond that, is not a "complex studio or location set-up". I'd say manual control is more suited to anything but the most basic single-flash, on-camera usage. Even with just two flashes (which is not much, if you want to take control over your lighting), P-TTL fails to deliver any reasonable control over lighting ratios. Other flash systems (e.g., Nikon's CLS system) are less limited in this regard, but I'd say if you want to make a fair comparison then the shortcomings of P-TTL regarding multiple flash control and even off-camera lighting have to be acknowledged.

More advanced configurations for complex set-ups (eg 'Groups' for controlling power ratios of different zones)

Again, I think this not an ideal way to phrase this fact.

I'd say manual flash control with a good radio trigger system gives you control options for multi-flash setups.
You don't have to use them and there is typically no need to "configure" anything. You simply get the control one needs if one wants to use more than one flash effectively.

I'd add to the manual flash advantages that results are predictable and consistent. This is extremely helpful when batch-processing multiple images, e.g., using Lightroom.

Regarding the P-TTL disadvantages:

Dedicated systems flash is more expensive per unit and less suited to multi-flash set-ups beyond about 3 units (including the built-in).

I'd say even just beyond 1 unit P-TTL fails to deliver. There is a simple contrast mode for two flashes that will very rarely meet one's particular lighting needs.

I'd add that P-TTL necessitates a delay from pressing the shutter release button to getting an exposure due to the need for a pre-flash and respective exposure calculations. This delay makes it much harder to capture certain moments as they happen. An already configured manual system will respond instantly, giving one a better chance of capturing something that may never occur again.

A further problem is that P-TTL may fail to provide the desired exposure when there are reflections of the flash in the scene or when there is a close-by reflective surface (e.g., someone with a white shirt walking into the scence). In general, exposures will vary from frame to frame if the scene is dynamic, making post-processing of multiple images much harder compared to a manual approach.

Another problem with P-TTL is that a number of cameras introduce their own P-TTL quirks. The K-5 (II) series has a P-TTL overexposure problem and the K-3 series unnecessarily further prolongs the delay between pressing the shutter release button and getting an exposure beyond the typical P-TTL delay.

Regarding the manual flash disadvantages:

Radio systems are more varied in their configuration requirements and amount of related equipment needed (eg triggering units, aerials, hotshoe attachments) and each system has different requirements.

This would be a challenge for someone trying to provide a comprehensive guide to all trigger systems. For a single photographer, however, they will make an initial decision for one system and then just learn the latter. Needless to say that learning a manual trigger system is far, far easier than being on top of P-TTL with all its interactions with various camera modes.

Many modern flashes have radio triggers built-in and hence one does not need to deal with more gadgets compared to P-TTL, except for the on-camera trigger which will more often than not be an advantage as one has a dedicated user interface for changing flash power levels and zoom settings, as opposed to requiring camera menu diving or the operation of often less than intuitive flash interfaces.

As a further disadvantage regarding manual systems one could mention the need to establish adequate flash power levels in advance, before correctly exposed images can be expected. This disadvantage can be alleviated by experience and modern cameras have quite a latitude for recovering from underexposure, for instance, but provided P-TTL works well with a certain scene, it certainly is the quicker approach to a correct exposure.

Finally, you may want to take into consideration that manual flash power control is rather popular among professional photographers (cf. David Hobby, "The strobist") because it puts the photographer in control rather than some more or less understood camera algorithm and limited ways of reading exposure levels. Even Joe McNally, who has done a ton of promotional videos for Nikon's CLS system, has responded to whether he uses Nikon CLS for his professional work with a great, big smile.

[awaldram]

Agreed. Another advantage of going manual for large group shots is that you can use multiple flash units, for more even lighting. I guess the OP mentioned that already.

You can use as many flashes as you like in P-ttl it not a 'Manual feature'

Even further your can get contrast control by dialling whatever off set you require on each flash , Unfortunately Pentax does not support grouping remotely like Nikons CLS which quite perversely means something like Cactus V6s gives more local control than Pentax OeM solution something they should address.

But whether you need to walk to the flash to configure or not P-ttl offers as much control as manual but with the added benefit of being able to react to changes in lighting conditions dynamically so is the go to solution for moving subjects (groups or not) or when using fill in changing conditions.

---------- Post added 12-09-15 at 07:54 AM ----------

You can use multiple flash units for Pentax Dedicated wireless as well ... Is there any limit to the number of dedicated slave units that will be triggered by an optical P-TTL control flash? I accept that it is more cost effective and probably more controllable to use radio systems and their more sophisticated group settings to manage complex multi-flash set ups.

Personally I think a 3 flash dedicated set-up (2 flashes plus the built-in camera flash) is a convenient and manageable wireless system .... It's enough for me certainly for quick domestic use and with diffusers and modifiers can produce quite sophisticated creative lighting. I accept that trying to manage more dedicated flashes than this could be difficult, and the cost adds up.

Agreed though having used 2+1 for a long time I'm coming to the conclusion that 3+1 is a more flexible option as often I need to blow out backgrounds or hair highlight so the additional flash gives me those options without messing with the 'traditional' lighting (clam or left/right).

I use the term 2+1 to signify in camera wireless use if you had a k3ii it would be 3 and 4 flashes .

Though I have always carried between 3 and 8 external flashes (when on a flash shoot) I've used them as banks of two but as above found a 3rd light drastically improves the result in non ideal shooting environments.

---------- Post added 12-09-15 at 07:57 AM ----------

For some reason I keep thinking that Wireless P-TTL is a two-way protocol that would only work with one wireless slave. I can't explain why that would be necessary, or even make any sense. So I stand corrected.

If it's one-way communication, then I don't see why there would be any limit to the number of slave units.

From observation I think it goes something like this

1 attentions flashes
2 fire preflash
3 set yourself to x output
4 fire
So I think it is unidirectional I think that one of the reason grouping and remote power etc are missing.

---------- Post added 12-09-15 at 08:22 AM ----------

I disagree with this characterisation.

If we are being honest, P-TTL only works well for single flash, on-camera usage. Anything beyond that, is not a "complex studio or location set-up". I'd say manual control is more suited to anything but the most basic single-flash, on-camera usage. Even with just two flashes (which is not much, if you want to take control over your lighting), P-TTL fails to deliver any reasonable control over lighting ratios. Other flash systems (e.g., Nikon's CLS system) are less limited in this regard, but I'd say if you want to make a fair comparison then the shortcomings of P-TTL regarding multiple flash control and even off-camera lighting have to be acknowledged.


Again, I think this not an ideal way to phrase this fact.

I'd say manual flash control with a good radio trigger system gives you control options for multi-flash setups.
You don't have to use them and there is typically no need to "configure" anything. You simply get the control one needs if one wants to use more than one flash effectively.



Finally, you may want to take into consideration that manual flash power control is rather popular among professional photographers (cf. David Hobby, "The strobist") because it puts the photographer in control rather than some more or less understood camera algorithm and limited ways of reading exposure levels. Even Joe McNally, who has done a ton of promotional videos for Nikon's CLS system, has responded to whether he uses Nikon CLS for his professional work with a great, big smile.

I agree in general with everything you pointed out but the above
First I;d like to further clarify your point on 'mixed' lighting , Given Pentax's strange preference for 'ambient priority in all modes but 'X' and Manual most people get in a mess with P-ttl as soon as the light levels drop.
Whereas since the k3 the internal flash has manual power levels in the menu and as such is to my mind easier and more intuitive to achieve the results you expect.
i.e in P-TTL you need to know what your doing or you'll get hopelessly overexposed flash under low light as ISO goes through the roof, Whereas in Manual you can follow any of the well written webinars and get great results.

Ok on to your point of multi flash and P-ttl I completely disagree

Every Pentax P-ttl flash offers at least 4 stops control and I believe the new version more.
You walk up to a Pentax flash press 'S' and dial from +1 to -3 stop compensation,
or on the Metz from SL mode press 'select twice and dial in ev you require (again +1 to -3)
This is exactly the same as CLS but without grouping and remote access.
Pentax 'contrast control' is a dumbed down feature to allow 2 flash setup and predefined ratios it should not be confused with flash compensation it just set a ratio of 1:2 for the two flashes.
It a pointless feature as you still need to address the flash and can just as easily dial -1 on a flash as click to contrast control.

i.e you cant say Nikon CLS is the bees for multi flash set-up and Pentax is rubbish when Pentax offers the same functionality (but having to address the flashes rather than remote control)

[mcgregni]

Let the FLASH WARS commence !!

Guys, I'm delighted to see such considered and well argued debate about this. It's exactly what's needed of course, and the surge of information coming through is brilliant. I am determined to add a balanced and fair discussion of these alternatives into the flash guide and everyone's contributions here are making that happen. I will also be adding a thanks and acknowledgment listing in the Introduction as well, to include all of you who are helping.

ClassA and Awaldram, there's a lot to absorb and respond to from your posts, and I will have to tackle that tomorrow. I have decided that I will avoid a bullet point listing style of pros and cons, because that inevitably has duplications and ends up potentially giving a false impression. Instead I will write up a half page or so summary of the key features (NOT 'benefits' or Weaknesses'), but features of each system. The idea is that the reader will form their own idea of what will best suit their own situation.

For now, just going back to Tanzers point ....I understand the optical wireless system we have to be one-way communication. The control on-camera flash sends information to the slaves, and the slaves can only receive that, they don't send information back. For P-TTL auto-exposure measurement, the slave flashes send their measuring pre-flash to the subject when triggered by the controller unit .... The camera light meter analyses the exposure from those pre-flashes and the the camera calculates the power output for the actual exposure. This information is sent optically from the control flash to the slaves immediately before the actual exposure ....again, just one-way information flow.

Thanks again guys for giving me so much support and plenty to get on with. I will respond tomorrow and we try and thrash out the very best guidance possible to the Dedicated vs Radio Manual War ....I mean question

[mcgregni]

I’m responding now to the two previous detailed posts from ClassA and Awaldram, and after that I hope we can thrash out an agreeable and fair description of both alternative systems.


Firstly, lets face it …. We will all take up defensive stances for the approaches we have personally chosen. We are naturally biased towards our own approaches and probably had negative experiences of the things we didn’t choose finally. So, I will try and take advantage of the experience of people but also strip out the bias …. If that’s possible! I said I’ll try!


The whole reason for the Pentax Flash Guide was my feeling that radio controlled alternatives had a ‘better press’. However, I was sure that the Dedicated System flash can offer plenty to a lot of Pentax users, and that radio systems will not necessarily be the right choice for all. I also felt that people may not have been getting the best out of the Dedicated system, and a single resource where the whole system and camera flash functioing as well could be explored was clearly needed.

So this new section of the guide I am developing (at ClassA’s suggestion) is to offer up the best advice about what each type of system can best offer, and let individuals go and explore and choose themselves.

P-TTL vs Manual
OK …. Now, about definitions. You won’t find me describing the Pentax flash system as ‘P-TTL’. It has been often termed this, but I avoid it because frankly it is a lot more than this! To me, P-TTL is just one single flash exposure mode that is always available on a Dedicated system flash. There are other exposure modes such as TTL, Auto-‘A’ and Manual, all available depending on the particular flash unit.


I don’t think that Dedicated system flash should be defined by the P-TTL flash exposure mode. It is a feature of most dedicated flashes to offer a choice of flash exposure modes, which may be more suited to different photographic situations, and in the case of Auto-A mode, a versatile choice for non-coupled lens types. And of course full Manual is available, just like on ‘Manual’ radio controlled systems.


I am also aware that some radio systems allow some automatic mode communication, such as the ‘TTL Passthrough’ feature on Cactus, and optical triggering options. But in general, it is Dedicated System flash that offers the choice of flash exposure modes to suit the situation.



‘Configured Out The Box’
This could be described better, accepted. I mean that you can go online or into a shop and buy a Pentax flashgun, or a Metz or Sigma that are ‘For Pentax’, and you know that you can just put it on the camera and switch on and it all works. It is not the same simple process for choosing a radio system. As the vast number of threads asking questions about the matter demonstrate, it requires more research and understanding of the particular requirements and features of each system – do they need hot-shoe adaptors, separate triggers, cold-shoe devices to function etc. I just want to make that distinction. I would not try and say that beginners should avoid anything other than Dedicated flashes, but it is a consideration for individuals to think about.


As shown by the recent article about Pentax wireless flash in the studio, P-TTL mode can be convenient and effective even for wireless multi-flash set-ups. I also agree with ClassA that automatic exposure modes are better suited to situations where the lighting and positions of things are changing and more dynamic, regardless of whether the flash is on-camera or off.

I will make just one reference to the additional sync modes that are usually included in a top range dedicated flash, such as HSS, Second Curtain, and Multi-flash. I will add in also about the additional features that the newest models offer, such as the LED, AF Assist Spot Beam, and LED catchlight.
I meant in relation to the simple scenario with the built-in that it was a quick and fairly easy way to get wireless flash going, in combination with one or perhaps two off-camera dedicated flashes without having to also set up a radio trigger. Would I be right in assuming that once the channels are configured on a radio system that it is all remembered and so you don’t have to make all the settings again each time?



I will make the point that radio control interfaces are specific to the purpose and more direct than some dedicated flash interfaces and camera custom menu diving.

The Pentax flashes, when set to HS mode, will automatically switch in and out of HSS operation when the shutter time gets shorter than 180th…… so if you’re hovering around 180th sec then the flash will automatically jump back to normal mode at 180th sec, and then jump straight to HSS mode when you set 250th sec. This is an added convenience.


Automatic flash head zooming can be useful for on-camera shooting, again especially for those dynamic situations. However manual flash head zoom is also important for off-camera working with both system types, both to conserve battery power and also for creative purposes.


I will make a further plus point for radio systems like the latest Cactus one that offers flash head zooming from the camera position (and power control). We do not have zooming control from the camera position for a Dedicated slave flash, nor do we have manual power control from the camera position. We do however have P-TTL flash compensation from the camera applying to slave units, which can be very handy. However this is useful in fairly simple set-ups, say one or two slave flashes. The radio systems offer more sophisticated and easier control over lighting ratios for multi-flash set-ups.

In practice indoors the optical communication system signals will reflect and bounce around meaning that it is rare for you to need absolute direct line-of-sight. But outdoors in sunlight then the power of the optical signal becomes an issue. Radio systems do not have these limitations and can even be used in hidden locations out of sight of the actual scene.


I’m not able to agree with ClassA that dedicated wireless systems only work well with a single off-camera flash. I have found my two Pentax flashes to work very well off-camera, triggered by the built-in flash, and it is easy to control lighting ratios both with P-TTL flash compensation and full manual flash exposure mode. Full manual provides the same reliable and consistent exposures as manual output settings on radio triggered flashes … there’s no reason they would not. I would be inclined to go with the information provided by awaldram in relation to multi-flash Dedicated system working potential.



P-TTL can be more convenient and give quick accurate exposures, but needs monitoring and flash compensation, and may not give the same consistent exposures for multiple frames. However switching to manual mode resolves this. This characteristic is a feature of the flash exposure mode, not the system technology type. Dedicated system flashes have the advantage here in that they offer the range of flash exposure modes. They are therefore more versatile devices.
I will gladly write ‘much cheaper’ about the radio triggered flashes, but of course it could be argued that as more multi-functional devices the top dedicated units offer very good value for what they provide.


The need to establish initial power output levels for manual mode working is common to both systems, so its not really a pro or con of each system as it is a feature of the exposure mode.


Joe McNally and co have a specific creative lighting style that is obviously well suited to their chosen radio controlled systems. But that does not mean that every professional would choose the same systems. It really depends on the shooting scenario …. Look at the banks of cameras and flashes at sports events, political speeches, outside courtrooms etc …. I doubt that you would see the name Cactus or Yongnuo sitting on top of many of those professionals cameras.


OK, there’s a response for now! I look forward and welcome further debate and the jury is still out on exactly how I will word my descriptions of the features of each system type in the guide.

[awaldram]

we do however have P-TTL flash compensation from the camera applying to slave units

In addition when tunning P-ttl wireless

You can set the flash compensation on each flash in use to set the flash balance , sometimes terms Contrast control.
Subsequently you cam use the 'on Camera' Flash compensation setting to alter the overall light levels not affecting your preset contrast level on each flash.

On intelligent wireless (i.e cactus V6) you can set each RX to be in a group then control that groups output remotely with only one setting so this makes altering contrast control easy from the camera , But you can't easily alter the overall level with out having to turn each group down the same amount.

Personally its horses for courses setting up I prefer the Cactus type system , But in use I prefer dedication.

Another trick not mentioned so far is you can mix and match (with pass-through TX)

You can use manual triggered flash (wireless multiples) to set your 'ambient level' then use P-ttl (again multiple wireless) to fill.spot your subjects

So Manual, Auto and P-tll flashes can all be used and integrated together, This is just the same as Nikon's CLS system just a lot cruder in implementation and you need some knowledge of what your trying to achieve and what each flash system will add (Ambient,Fill spot etc etc ), But the same is true for Nikons CLS if your using it to the max with a mix of iTTL and manual.

As a Point on Pentacs silly 'fill' ratios I believe Nikon skirt this with two modes in itll
1 TTL Normal flash as you'd expect from a P&S (flash ignores ambient , camera adjust exposure for flash only) this is what Pentax does in 'X'
2 TTL-BL Balanced lighting flash output is reduced to match 'bright' ambient conditions this is what pentax does in Green,P,Av,Sv,Tav etc etc