On May 12, 2005, at 4:25 AM, Cory Papenfuss wrote:
.. As far as flashes, putting a non-A lens on makes the internal flash fire fully (GN 15.6m @ ISO200 IIRC).
Guide numbers for manual exposure with the DS' built-in flash are listed on page 149 in the manual.
Even with a MF 'A' lens, I think it fires fully (since it doesn't know the distance the lens is focused to). Seems like it should be able to revert to TTL on the internal lens at least, but I don't think it does.
No, A series lenses are fully enabled for P-TTL operation when the lens' aperture ring is set to "A". When you set the aperture to anything else, they operate as a K/M bayonet lens and flash is fully manual.
The DS does not have TTL flash metering as an option without an external flash unit, only P-TTL and full unmetered output. With a dedicated external flash unit like the Sigma EF 500 DG Super, it supports both P-TTL and TTL; you force it to TTL mode with A series and all autofocus lenses by setting the aperture ring off the A setting. With K/M bayonet lenses, you need to be on manual exposure anyway for the lens to stop down.
Godfrey
