P-TTL

Just a quickie.
Do i need to use a P-TTL flash unit with my K10D.

Thanks

The short answer is - no, but for full information refer to Mattmatic's various threads on the subject.

I have just shot a wedding using a metz 45-ct5 and have some well exposed shots. Not too sure about the content, but that is up to the client to decide. Any flash that has a trigger voltage less than 30v is fine (I have this from the Pentax technical support) but you need to know how to use them. After 30 years of using manual flash it seems quite easy, but to a newcomer it could be quite daunting I suppose. It's fun learning though.
Harry

As stated, you do not need PTTL, but the K10D does not support TTL.
So you would have to work totally on manual settings.

Not quite

The K10D supports P-TTL, A and M mode flash guns.
I have some very nicely exposed shots using a Metz 50MZ5 set to "A" mode and the K10D set to "Av" (which just happens to be what I use).

With the flash set to "A", the flashgun makes the judgment about how much light the scene needs. You only have to make sure the ISO and Aperture match between camera and flashgun.

Matt

What about the Pentax AF280T as i,ve seen one on E-Bay.

The AF280T does work with the K10D and I have one for sale

As I said in my previous post, the K10D supports P-TTL, A, and M. Since the AF280T doesn't have P-TTL you'll get A and M modes.

For flash specific information: http://www.bdimitrov.de/kmp/flashes/index.html

For the AF280T you'll get 2 levels of "A" and three levels of "M". It's a bulky flashgun but does have tilt and swivel

Matt

I hesitate to disagree with you, Matt, but here goes!

I think that when the camera is on Av, the flashgun is simply acting as though the camera is on M. The shutter speed is restricted to 1/180 or slower because the body senses a mounted flashgun, and the flashgun will usually be producing most of the light in the picture, so the actual shutter speed is irrelevant.

The point is that I don't think that the flashgun is:

a/ Controlling the shutter speed, or
b/ Considering the amount of natural light falling on the sensor/film. It is working purely on the amount of light it (the flashgun) is producing, and modifying it to fit in with the ISO and the aperture. It is assuming there is no natural light.

G

Sorry, perhaps I was lacking in how I described what I meant. (I tend to either ramble on or cut things too short -- gotta find a happy medium somehow. )

As far as I was concerned, when the A mode of the flash is used, I still consider it manual, as the camera settings are static and need to match what the flash is going to do. (or vice-verse, the flash has to match how the camera is set).
The flash will adjust for the flash settings, but there is no communication between flash and camera to balance each other out without some other human intervention.

I believe the concept is the same. But thanks for the clarification.

What I meant was not totally manual

With Pentax flash guns in the "A" mode you do have to manually set up the camera to match the aperture that the flashgun specifies. Yes, the flash is doing the reading of the light (and not what's on the sensor), but it will take strong ambient light into consideration in that it is reading a light level and cuts off the flash when the appropriate level is reached.
As you know you can fool the flash and create a balance between ambient and flash by lying about the aperture.

Still, that said, the Metz 50MZ5 flash with an SCA3702 will actually track the camera in Av mode - ie the flash will continuously adjust its settings according to the ISO and aperture. However, in this case you cannot force a balance between the camera and flash easily because you can't lie about the aperture But again, the flash is making the decision about how much light - and not the camera.


And finally... it's worth saying that "M" and "A" mode flash is really extremely easy when you have a digital SLR with an LCD review! If it's wrong, just do it again!!
Matt

You are right that it will take account of ambient light, but it will not treat this information any differently whether the camera is in Av mode or M mode.

In fact, I wonder if it fixes the shutter speed in Av mode. In which case Av and M are definitely identical, as far as the flashgun is concerned.

G

If you enable slow speed sync in the flash menu of the K10D then they are different Av will set up for ambient light, whereas M requires a manual operation to set the shutter speed.

In normal flash, the camera will automatically switch the shutter speed to a "flash-safe" speed when it detects the flash. M mode will allow the setting of other speeds (though I think it will limit the upper speed to a flash-safe setting... will have to check later).

Av mode is great if you switch between flash and no-flash and don't want to think about it.

M is great if you want to finely adjust the balance between ambient and flash when using a tripod (effectively the shutter speed and aperture regulates ambient, while the aperture alone regulates the flash).


Matt

Is it possible for someone do a list of Pentax (or third party) flash units that are P-TTL.

For Pentax: http://kmp.bdimitrov.de/flashes/AF/index.html

However, it needs to be updated to show the AF200 FG, which is very new.

Apart from that, Sigma, Metz, and (I think) Jessops have P-TTL flashes in their ranges.

G