[fredlewin]

I have four -for some of you maybe silly- questions about the external Flash AF-540 FGZ on the K20d.

Does the selected flash mode (Auto discharge, Auto flash+ Redeye reduct, Flash On+ Red-eye, Slow-speed sync, Slow-speed sync+ Red-eye, Trailing curtain sync slow and normal) also affect the external flash AF-540 FGZ or only the built-in flash?

Given: I want the following settings and flash mode:
Slow Speed Sync and on the K20d Tv OR P with Tv.

Question: Do I have to set the K20d flash mode to SLOW or does this the K20d automatically when the Shutter Priority is slower than 1/150 ?


Given: I want the following settings and flash mode:
High-Speed Sync and on the K20d Tv OR P with Tv.

Question: Do I have to set the K20d flash mode to “Flash On“ only and on the AF-540 FGZ to HS?

Confusion: On page 145 in the K20d Operating Manual says: “High-speed flash sync is only available when the shutter speed is faster than 1/180 sec.“ but in the AF-540 FGZ Manual on page 76 (High-Speed Sync Mode Photography) it says: “ Set the camera using the Av or Tv dial so than the shutter speed is faster than 1/150.
What is right?

Question to the Leading and Trailing curtain sync mode:
Do I have to set this on the K20d AND on the AF-540 FGZ or on the AF-540 FGZ only?
When only on the AF-540 FGZ then “Flash Only” on the K20d?

For infos a warm thanks in advance.
Fredlewin

[philmorley]

here is a link with chart

Flash settings on camera and flash [Page 1]: Pentax SLR Talk Forum: Digital Photography Review

Phil

[philmorley]

sorry seems that *isteve has taken done the chart. I had a copy saved so here it is (I also assume k20d is same as k10d) (I hope he doesn't mind)

[fredlewin]

Thnx a lot for that. Do you know what the numbers in parenthesis means?

[philmorley]

cut and paste from the excellent work by *isteve (to give him the credit for this)

Modes explained as follows.

(1) Auto exposure mode in P, Av and Sv mode: the camera will force a shutter speed required to avoid shake (depending on focal length) and will use flash to compensate to achieve correct exposure. If ambient light is high enough to achieve correct exposure without flash at required aperture, the flash will simply supply fill light at the focus distance.

(2) Fill flash mode - the camera will meter as if no flash is attached whatsover. Low or high shutter speeds can be set if desired/required to provide correct or adjusted ambient exposure of background and flash will then simply provide fill for the object at the focus distance in either trailing or leading synch mode, or high speed synch mode.

(3) Auto exposure mode in M, Tv and TAv mode: The camera will default to a shutter speed (green button) required to freeze action (depending on focal length) at will use the aperture from the program line. Flash will be used to compensate for underexposure. Shutter speed can be reduced if desired to increase ambient exposure and when ambient exposure is within range, flash will simply be used for fill.

It should be noted that HS mode is only available in M and Tv modes. If set in these modes, the flash will act purely as fill only, and the camera will meter as if no flash is attached.
So, the easiest ways to force fill flash are:

1. To set slow synch in Av mode
2. To set HS mode in Tv mode
3. To set HS mode in M mode

The advantage of mode 3 is that you can alter the background exposure without affecting the flash setting. If you use EV comp in other modes, it will also alter the flash output.
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