flash at above 1/180 ??

Can I use flash at above 1/180 on my K10 ?? Which way does the trailing curtain move ? bottom to top ? I'm using RF trigger and external flash. TIA

You can use high speed sync only when using dedicated flashes. With one flash on the hot shoe and another one as a slave, you can go wireless too. But you can't do it with RF trigger.

The limitation of 1/180s is a mechanical one.
That is the fastest speed where both curtains of the shutter are completely "open".

When using dedicated flashes in P-TTL "HS" mode the flash has to "pepper" the frame with light as the leading and trailing curtains of the shutter unit move across the sensor in a slit.

You see, 1/1000s is achieved not by incredibly fast movement, but by the trailing curtain starting before the leading one has reached the end of its travel.

There have been numerous other threads on the subject

All cameras have such limits. Other makes might be 1/250s, but that's not even 1Ev difference.


As with the other threads.... what are you trying to achieve?

Matt

This I already know, thanks Matt I'm actually trying to get the banding effect. It's in a Strobist blog where he uses 1/320 (1/250 being the top sync) on his Nikon to produce a dark band across the bottom of his image. Very effective ! link

Ah! I see

Certainly a lot easier and more controllable to do it in Photoshop

I had problems with a radio trigger anyway (trying out a friend's that works on his 5D and 30D ok). Certainly you'll have to use a 'dumb' flash connection, because the following points may apply:

* AFAIK the camera will prevent higher than 1/180 if it knows there is a flash. That rules out dedicated flashguns. You'll have to connect to the PC connector of the K20/K7, *ist-D, or use an adapter on the other dSLRs

* It's likely that even the PC connector and hotshoe will not trigger at speeds faster than 1/180s. The firmware in the dSLR may prevent the trigger at higher speeds because it 'knows' it'll produce lighting issues.

* Radio triggers etc have their own limitations and restrictions.

I may be able to test it out for you by setting something up on my K20D...

Matt

Matt

Is this something that can be done on a Nikon, but not a Pentax ?? or is he fooling his camera into doing it ?? I't's not urgent, but I saw it and thought I must have a go I'm like that !

The RF trigger only has one contact (X), so the camera doesn't know it's there (correct?), therefore it's inability (unwillingness) to fire above 1/180 shows a hard limitation. Looks like the answer is no