Flash Sync Speed

Is there any way of getting the Flash Sync speed above 1/180s on the K10d? I'm trying to do this weeks assignment on the strobist by balancing Sunlight and the flash however I'm finding it very difficult as the flash speed is just too slow to correctly expose for the sunlight.

I know there is a hi speed mode on the 360 and 540 flash units but is this possible to do with other units so I can use them off flash? I've tried with with a couple of old Pentax flash units in manual mode but then I'm limited to 1/180 of a second. Then I tried using my IR flash transmitter and that allows me to go above 1/180 on the camera but then IR trigger won't fire. I'm guessing the hi-speed mode must use something other than the centre pin on the shoe to fire the 360/540 flash units.


Cheers

Rob.

Yes, it's on those guns. No, you cannot do it on any other flash. It's not just a "pin thing", it's a physical impossibility.

It works like this, and is all to do with the two "curtains" in the shutter unit:
In a regular flash shot:
* First shutter curtain opens
* Flash fires
* Second shutter curtain closes behind the first

In an "HS" mode flash:
* First shutter curtain opens
* Before the first has completed its travels, the second starts to close behind it
* Flash fires controlled high frequency bursts of light as the "slot" travels down the shutter.

So, if you are using external flash units the only way to pull the shutter speed down is with an ND filter to cut some of the light, or use a smaller aperture

BTW, all shutter units have a physical limit at which "normal" flash becomes impossible. 1/180 is the tops for Pentax. Other brands have faster or slower speeds.

Might be worth checking out the Strobist blog for some ideas
Matt

Matt,

I was hoping you'd spot that post!

Thanks for the explanation on that and it looks like I'll have to bite the bullet and buy a modern flash unit although I love my Pentax 240 flash. I did spot that the 360 is out there for 135 quid now.

I did think about the ND filter and dropping to F32 but obviously this means I'll have to invent a way of getting the flash to powerup aswell or use it in full power only. Did think that I might use the ND filters from the Rosco gel samples across the flash sensor on the flash to force it to powerup. My photo kit box is starting to look like a bad episode from a Blue Peter with all the card, black straws and duct tape!


Cheers

Rob.

Rob,
Just to mention - you only get "HS" mode when the flash is tethered. You can't do wireless HS mode (just so you know!)

I meant put an ND filter on the lens! You need to ignore the flash (for a minute at least) and bring the ambient light down to a manageable amount. If you can't get lower than 1/180s with f/16, then slap an ND on the lens until you do!

(Or find a little shade )

Once you've tamed the ambient light... then concentrate on the flash

Of course, use ISO100 too!

(Whoops - sorry about the suggestion to read Strobist. DOH! Should've read your post more fully! :roll

Matt

Matt,


I got you on the ND filter on the lens - I was suggesting putting one on the flash sensor aswell so I could continue to use the auto mode (Photo sensor on the flash unit) on my 240 flash unit otherwise it would be underpowered for that aperture.


BTW - Love the pictures on your site.


Cheers


Rob.

Rob,
Ahh! Now I understand
To be honest, you're better off using full manual anyway (unless the situation is very "ad-hoc" and you don't have time to work things out).
One of the great advantages of digital is you can just use a trial-and-error method

And while I think of it... the AF360/540 in HS mode for fill in tend to expose for the highlights. Sounds odd, but shooting a wedding becomes a piece of cake as the dress is always exposed within range You just have to shoot RAW and compensate later

(Thanks for the comment about my images!)
Matt