The *ist-DS does exactly the same as the *ist-D (except maybe exposure is slightly better controlled).

So, either:
a) Sigmas don't work as they should on the newer bodies
b) You have a dud pair (which is highly unlikely)

Doesn't look good for you
Matt

Just tried it with the *ist-D and it worked exactly as I described. A controller with a slave off will produce a dark image.

Will try the *ist-DS later...

In Tv mode the aperture stays wide open - it's metering for ambient light. To be honest, you don't generally do that with flash as it's either P, A, or M mode.

Matt

Doesn't sound right to me...

I can check later with my *ist-D and *ist-DS with the Pentax guns, but I know for sure that if the *ist-D pop-up is used as controller-only in a dark room and the slave isn't on, the image is super dark.

As for Tv mode - I suspect that the displayed aperture will never change. It'll want to open up the aperture wide enough to let ambient light in. It may stop down the aperture when you fire the flash - so you'll have to check the info on the resultant images

Again, I can check that later.

Matt

Yes, your line of thinking is correct...

One more thing you can try:
* Turn off the slave flash and your exposure should be very, very underexposed in controller only mode (do it in a dark room)

Other things to check: try disabling sensitivity correction (Auto ISO) on the camera and see if that makes any difference.


I worry slightly about Sigma because I've heard they reverse engineer the body-flash and body-lens protocols, and I wonder if things have changed a little since the *ist-D days (which is when Sigma did the flash).
But let's eliminate all other possibilities first...

Matt

Looking at the (fairly dreadful) manual on page 24, I would say that "When only-off camera flash is triggered" is the section you want.

So, it would like the flash on the camera should have "C1 CL" on the display, while the slave should have "C1 SL".

If this still doesn't work:
* Try swapping the flashes and see what happens
* Turn down the power of the on-camera flash by setting exposure compensation to -3 (page 21,22)

Hope that helps!
Matt

Welcome to a-board

Can't comment on the Sigmas, but with two Pentax AF360/AF540 this is the what you need to do:

1) set the flash on the camera to "Controller" (if it was "Master" then it would fire and contribute to the exposure)
2) set the remote flash to "Slave"

You will still get the tiniest effect from the controller. On my *ist-D you get a tiny dot of a catch light when doing portraiture in controller-only mode.

I'll have a look at the Sigma manual later and see how it compares...

Matt

Liam,
It's listed on the price list at a touch over £8.5k
https://www.pentaxuser.com/pages/pricelist/pl_mflens.htm

Some comments about it here:
http://photo.net/bboard/q-and-a-fetch-msg?msg_id=000m15

Finding a sample image is proving a challenge ...
Matt

Liam,
This monster is on Bojidar's site. Weighs an impressive 8kg!!! You'd need a monster tripod to go with it

http://www.bdimitrov.de/kmp/lenses/primes/extreme-tele/M2000f13.5.html

It's obscene
Matt

Andy - granted
Yes, looking at the prices Pentax always come out far cheaper... and in most cases I prefer the "look" of the resultant image (i.e. beautiful soft out of focus areas). It'll be interesting to see the price of the new 16-50/f2.8 etc...
Matt

Nikon don't have full frame users in the digital domain