K-3 body or AF-540FGZ - which light should assist?

Prakticant · 06-05-2016, 01:40 AM

Yesterday I found strange behaviour of the above combo (paired with Pentax DA* lens+shade): I was shooting indoors, with some daylight coming in through windows & doors (more or less 1/100, 1:5.6, 400 ASA). When focussing I noticed than green K-3 body assist light was on (visible on thick DA* lens & shade), not the AF-540FGZ red stripped light. Flash was set for indirect bounce head position (with Omnibounce flash head attachment).
I believed the combo should use in-flash focussing assistance rather than in-body one.
In-menu AF Assist Light setting was on, camera in P[rogram] mode, camera Flash On mode setting, flash unit in P-TTL and one of the three 'white' other than green modes ('trailing curtain' mode I believe, but camera body setting overrides this mode).
Question:
When K-3 body + AF-540FGZ combo uses in-flash focus assist light, and when it uses in-camera focus assist light?

mcgregni · 06-05-2016, 02:02 AM

The camera AF assist light needs to be switched off in your camera settings.

Then use the 'SB' (spotbeam) mode on your flash, accessed via the mode button.

Prakticant · 06-05-2016, 08:58 AM

Originally posted by mcgregni

The camera AF assist light needs to be switched off in your camera settings. Then use the 'SB' (spotbeam) mode on your flash, accessed via the mode button.

You are right, the AF Assist Light in K-3 menu has to be switched-off.
What is more:
* While in-camera focus-assist light operates when in Live View, the flash-unit near-infrared spot-beam does NOT assist when K-3 is in it's Live View;
* Autofocus mode has to be set-up as Single (AF-S);
* K-3 shooting mode might be in Continuous Shooting mode;
* AF-540FGZ settings overide in-camera K-3 body settings (slow speed / trailing curtain sync);
* When K-3 is in Live View, one cannot set AF-540FGZ flash metering mode to Auto nor to Manual, but you can set AF-540FGZ Auto metering mode before you switch K-3 to Live View;
* Some of the AF-540FGZ modes are not accesible when K-3 AE metering (incl. AE-Lock) is engaged.
Actually, it's a little bit weird (and AF-540FGZ manual does not cover K-5 nor K-3 bodies).

06-05-2016, 01:40 AM	#1
Prakticant Senior Member Join Date: Jul 2010 Posts: 274	K-3 body or AF-540FGZ - which light should assist? Yesterday I found strange behaviour of the above combo (paired with Pentax DA lens+shade): I was shooting indoors, with some daylight coming in through windows & doors (more or less 1/100, 1:5.6, 400 ASA). When focussing I noticed than green K-3* body assist light was on (visible on thick DA lens & shade), not the AF-540FGZ* red stripped light. Flash was set for indirect bounce head position (with Omnibounce flash head attachment). I believed the combo should use in-flash focussing assistance rather than in-body one. In-menu AF Assist Light setting was on, camera in P[rogram] mode, camera Flash On mode setting, flash unit in P-TTL and one of the three 'white' other than green modes ('trailing curtain' mode I believe, but camera body setting overrides this mode). Question: When K-3 body + AF-540FGZ combo uses in-flash focus assist light, and when it uses in-camera focus assist light?

06-05-2016, 08:58 AM	#3
Prakticant Senior Member Join Date: Jul 2010 Posts: 274 Original Poster	Originally posted by mcgregni The camera AF assist light needs to be switched off in your camera settings. Then use the 'SB' (spotbeam) mode on your flash, accessed via the mode button. You are right, the AF Assist Light in K-3 menu has to be switched-off. What is more: * While in-camera focus-assist light operates when in Live View, the flash-unit near-infrared spot-beam does NOT assist when K-3 is in it's Live View; * Autofocus mode has to be set-up as Single (AF-S); * K-3 shooting mode might be in Continuous Shooting mode; * AF-540FGZ settings overide in-camera K-3 body settings (slow speed / trailing curtain sync); * When K-3 is in Live View, one cannot set AF-540FGZ flash metering mode to Auto nor to Manual, but you can set AF-540FGZ Auto metering mode before you switch K-3 to Live View; * Some of the AF-540FGZ modes are not accesible when K-3 AE metering (incl. AE-Lock) is engaged. Actually, it's a little bit weird (and AF-540FGZ manual does not cover K-5 nor K-3 bodies). Last edited by Prakticant; 06-05-2016 at 09:42 AM.

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06-05-2016, 02:02 AM	#2
mcgregni Veteran Member Join Date: Sep 2012 Location: Surrey, England Posts: 2,603	The camera AF assist light needs to be switched off in your camera settings. Then use the 'SB' (spotbeam) mode on your flash, accessed via the mode button.