Let me just change that to "I think I understand what's happening..."

As George says, there is the occasional dud, but in difficult situations like weddings I've found it right 9/10 times. And shooting in RAW I've never had a shot that wasn't perfectly usable even with the "dud" situation.

(But there were several times that I should've thought a little more carefully about the settings before taking the shot )

Matt

Actually... I disagree

I have a very high hit rate in P-TTL... but I understand what's happening and I'm just about to outline a number of pertinent thoughts in Pete's thread...

Matt

That is tone mapping

For HDR you must tone map because you're taking 32-bit dynamic range and crunching it into 8.

For regular, single, shots tone-mapping is optional and can be used to even out a wide dynamic range, or create a more "drawing-like" look.

I suggest you take a look at Artizen. Personally I don't like the GUI much, but it does have the widest range of tone-mapping operators (each algorithm will produce a different quality of result). If you do get into HDR, it's frame blending algorithms are superb (much better than Photoshop CS2).

But, in all cases, you're better off shooting RAW as it'll give you at least 4 extra stops of dynamic range (compared to JPG), so you can process a RAW into 16-bit TIFF and then tone map inside Artizen. (I use Silkypix to do the RAW conversion and then HDR and tone map inside Artizen).

Hope that helps!
Matt

Just double checked the Canon data here:
http://www.photodo.com/topic_52.html

Corresponds with the magazine's graph. Pity I couldn't find a Pentax one, except for the MTF data on the original SMC-F 50mm f/2.8 macro: http://www.photodo.com/product_108_p4.html - which looks as razor sharp as I'd expect from the Pentax

'Twill be interesting to hear the magazine's response...
Matt

ROFL!! I nearly choked on my lunch while reading that
Matt

HUH?

What planet were they on when looking at the test results graph?? I've read the "summary" comment three times and it still doesn't make any sense at all

I wonder if they apply the same summary technique to their bank balance? The graph on the left would "be a wonderfully healthy financial situation" Actually, come to think of it, that's what the bank balance would be like after purchasing Canon lenses

Matt

EDIT: Can't remember the last time I actually bought a photo mag

No problem

Without trying to repeat myself I've reposted and expanded the information (to include some Manual and Wireless information) on the following sticky thread:
https://www.pentaxuser.com/forum/viewtopic.php?t=4950

Let me know if I've missed anything
Matt

Ok folks - let's set out some of the "groundrules" about flash.
In my experience, P-TTL is very good indeed at coping with dynamic situations (and from initial quick tests it seems that v1.30 is better than before). But my experience comes from the days of Manual only and Auto flash using fully manual cameras (Pentax S1a to be precise) So let me share some knowledge...

Points (in order of importance):
* Flash is limited in power
Probably the biggest thing in the P-TTL controversy. P-TTL will sort out the exposure but only within the limits of the flashgun. Let's use a car analogy. Most of us have cars with limited power, so we may see a situation where we'd like to accelerate from 0 to 60 in 2 seconds, but even when we push really really hard even to the floor the car won't go any faster.
The flash can be like that - it's limited and has a limited range. Even if P-TTL says "I want loooooads of light for this shot" the flash may very well not have the power and the shot will be dreadfully underexposed. (Ever see people in a stadium trying to use flash photography? How much effect do you think their flashguns will have?? Absolutely zero.)

* Flash distance is dependent on ISO rating and aperture
This is where physics comes in and the "inverse square law", ie double the distance and you quarter your light (because it's falling in 2 dimensions not just one).
For photography this means you need to balance the ISO and Aperture (note: NOT the shutter speed. More on that later) so you get the correct distance.
For those with the AF360 and AF540 there's a little distance scale at the bottom of the LCD. Try the following:
- Set the camera to ISO 100 (fixed)
- Set the camera to Av mode and rack it up to f/22. Your distance will be 0.7-1.5m. Anything further away than 1.5m will be dark!
- Now set the Av to f/5.6 and the distance changes to 0.7m to 6m.
- Set the camera to ISO1600 (fixed) and at f/5.6 the distance will change to 3m-22m.

Woah! With that setting of ISO1600 and f/5.6 if you have someone standing 2m away they will be drastically overexposed! The flash can't turn off quick enough! (A bit like asking a Bugatti Veyron to nudge forward 2cm - you probably won't be able to stop in time )

* Bounce flash messes up the distance
This is where the AF360 and AF540 will turn off the distance scale! The flash distance is no longer the camera-to-subject distance, but camera-to-ceiling-to-subject distance.
Depending on where you are this distance could be enormous. If you're outside then it's infinite

* Balancing the light
This is where some skill comes in (and a tiny bit of knowledge ). When you're trying to take realistic images using flash you really want to balance the ambient lighting with the flash.
For example, let's suppose the ambient reading (ie without flash metering) is ISO200, 1/30s, f/5.6. If you set your flash to use f/11 then you're going to "punch" your way through the image with the flashgun. The flash lighting will be two stops (f/5.6 to f/8 to f/11) brighter than the surroundings and you'll get the "cardboard cutout" look. Bleurgh

Actually, if you set the K10D to auto ISO in Av mode you'll notice that the ISO changes according to the ambient lighting even when the flash is powered on. The K10D is making some pretty reasonable guesses at balancing the light.

* Metering aims for grey
Don't forget that the metering aims for mid grey. If you're taking shots of mostly black or mostly white scenes then you'll almost certainly need exposure compensation (on the camera, not the flash) to "inform" the metering system what you're taking.

* Shutter speed is (almost) unimportant
The duration of the flash is blindingly quick Something like 1/10000s. As a consequence, the shutter speed is not that important - especially when you want to "freeze" action. But this is where you need to learn about balancing the light...
If you want to freeze action and isolate the subject from the surroundings, then you want to make sure the flash is at least one or two stops more powerful than the ambient light.
If you want to make the shot look natural then you need to at least keep the flash and ambient lighting within about -1 to 0 stops.
If the shutter speed is very slow (or the subject is moving) such that a non-flash exposure would produce a streak or motion blur then you'll probably want to put the flash in "trailing curtain" mode (slide switch to the position to the right of the green triangle). This mode opens the shutter and just before it closes it fires the flash - the flash will produce its punch at what will appear to be the "head" of the object so the object looks like it's moving in the right direction (exposure is blur-then-flash). Using the green mode makes the subject look as though it's going in the wrong direction (i.e. flash-then-blur). Think about the time ordering of things...

* Use fully manual for controlled situations
For studio type shots where the conditions don't change - use fully manual. I've outlined some of the details elsewhere, and so won't go into this on this thread

* Pentax DSLR and AF360/AF540 specifics
- In the viewfinder the lightning flash icon will be lit when the flash is charged.

- Immediately after taking the shot the lightning icon should remain lit. If it goes out the shot will be underexposed - the camera wanted more light than the flash could give.

- I would suggest Auto-ISO and Av for general portraiture (e.g. weddings) because then the camera will generally get it right every time.

- If you want to override the flash "effect" you can set the exposure compensation on the AF360/540 using the little dial. Something like -0.5 or -1.0 will allow more ambient light in.

- If you are shooting outdoors and want fill in flash, set the flash slider to "HS". Note that the distance is halved when in this mode (though if the shutter speed goes below 1/180s the flash will go back to "normal" mode).

- If you want attractive catchlights in the eyes (especially for close portraiture say about 2m away) then pull out just the little translucent catch light panel and point the flash straight up (90 degrees). The small amount of reflected light from the catch light panel will produce a subtle fill in with a lovely sparkling catch light.

- If you use a Stofen Omnibounce then you'll halve your effective flash distance. But the flashgun won't know - so you'll have to make mental adjustments when you look at the flash distance scale (or consciously check the lightning indicator in the viewfinder).

- The same rules apply to using Wireless mode. But remember, the flash distance is the flash-to-subject distance, and not the camera-to-subject distance!! For the K10D you can't use "HS" mode in Wireless (but the *ist-D could, and only the *ist-D).

- For controlled situations you can use an "non intuitive" setting I have done the following in a number of situations: Turn off the flash; Set the camera to "M"; Meter the scene using spot metering to try and expose near the highlights; Ensure the shutter speed is under 1/180s; Turn on the flash in P-TTL mode; Take the shot. Every time this is a winner - the flash fills in the shadows without changing the exposure. (I have used this for taking shots in dark rooms that have light streaming in and got shots that have everything properly exposed ).


I'm sure there are things I've missed... but hopefully this "brain dump" (to use the jargon) will shed some extra light on flash usage and to show that, actually, the Pentax flash system is excellent

Matt

You can also find that the flash has completely discharged - it couldn't "reach" that far with the given aperture and ISO rating.

Try picking a sensible ISO rating (200 to 400) and a fairly wide aperture - say around f/5.6.

The flash does tell you whether it managed to light the scene sufficiently.

EDIT: Check the distance scale on the AF360 as you adjust the ISO and aperture

BTW, it might well be worth loading firmware 1.30 in the K10D
Matt

I'd be more than happy to sell them the K10D at the price you mentioned
...then I could afford the new lenses LOL!
Matt