Keeping the original JPEG unaltered can be achieved in the same way you keep any other file unaltered - you "Save As" rather than "Save" when you're done editing, and create a separate file.

I've heard this claimed before, but I don't understand it. Raw gives you the ability to recover more detail in some circumstances, but I'd be interested to know of any other things you can't do with a JPEG.

I'm not sure what you mean here. It isn't true that you can recover burned out highlights from a RAW image. If the amount of light falling on the sensor is more than the maximum it can resolve, the detail is gone, and nothing in the world can get it back.

There's no such thing as a "slightly blown highlight". There may be smaller or larger areas of the image where the highlights are blown, but a highlight is either blown, or it isn't.

Agreed. Wireless flash isn't exactly an obscure feature that few people will use, though.

I'm just griping at the way they've implemented it - although if it would have been much more expensive to do it as I imagined they had, it probably wouldn't be worth it.

Although if you think what it needs to be able to do to achieve a choice of leading and trailing curtain sync, I'm not sure I'm being all that unreasonable.

Well I'm very disappointed.

I suppose getting the timing circuitry accurate enough might be too difficult/expensive.

I just thought that it would be able to know that (for instance) after the button is pressed all the way down, it would be x milliseconds to send the final preflash, so the shutter could open any time after that, to coincide with the main flash.

This would mean that the final preflash would have been all gone by the time the shutter was open.

Doing all this optically is a bit pants anyway, though - I bet it won't be the future.

You're quite right, I take it all back, my apologies.

How crap is that!!!

Why on earth can't it know the timing of the external gun's reaction, and the length of time it takes to open the shutter, so that the final pre-flash can fire before the shutter opens?

Grrr...

If you read what I wrote again, you'll see that I distinguish carefully between what happens before the shutter opens, and what happens after.

I've hopefully clarified it a little with what I've added in bold below:

Are you suggesting that the final pre-flash from the camera takes place while the shutter is open?

I hope this isn't the case!

I don't see how it can. AIUI, the sequence of events is as follows:

- camera pre-flash triggers the external pre-flash
- camera does its metering based on the external pre-flash
- second camera pre-flash tells the external gun how much to emit

Then the shutter opens. Then...

If the built-in is master, then both it and the external flash fire.

If the built-in is controller, then only the external flash fires.

In the latter case, I don't see how the camera-pre flashes can affect the exposure, since all they're doing is telling the external gun what to do.

Just to confirm, I've done a few test shots, and the master/controller setting does work exactly as you'd expect - 'controller' fires the external flash (Samsung SEF-54PZF, the equivalent of the Pentax AF540-FGZ in my case) without contributing to the exposure.

As 'master', not only does the built-in contribute to the exposure, but it contributes a variable amount according to whether you dial in a compensation value or not.

There's a setting in the custom menu for the K10D that lets you specify whether the built-in flash should be master or controller in wireless mode.

If it's the controller, I believe it does not contribute to the exposure.

With the (Samsung version of the) AF540, this is correct.

It does work off camera with the 5P cable and the relevant bits on the ends (and indeed with the 5P cable plugged into the flashgun).

It does not work wirelessly, not surprisingly, since there would have to be all manner of control flashes going on, and these only take place after the shutter release button is fully pressed, not half-pressed which is what triggers the AF assist light (which precedes the actual focusing, obviously).