[Blacknight659]

Not sure I am right or wrong but the K-3 manual (posted below) is where I am getting my information from, and considering you are using pretty much the same setup as me (perhaps a newer flash as I have a AF540GZ) I would think I am not far off the truth. The manual for the k-5IIs is has the same table.

I have to say, I am reading the same thing and is seems to say that PTTL won't "work" for any other lens not mentioned. Maybe the only mean it isn't "supported".

Do you feel it isn't "supported" but may work any ways? Or does the Sigma falls under the A setting mentioned, even though it obviously has full features like other modern Pentax lenses.

[W.j.christy]

I have to say, I am reading the same thing and is seems to say that PTTL won't "work" for any other lens not mentioned. Maybe the only mean it isn't "supported".

Do you feel it isn't "supported" but may work any ways? Or does the Sigma falls under the A setting mentioned, even though it obviously has full features like other modern Pentax lenses.

With my experience it doesn't seem to work, however, this may be where others can help more.


The A mentioned in the manual is a type of older or vintage Pentax Glass not a setting. Unfortunately there isn't a setting to allow the P-TTL to function with a third party lens and flash.

[enoeske]

Pentax is not going to put which third party lenses work with their camera in the manual. They can only say which of their products work with their cameras. However, Any lens with aperture and focal length communication is considered an "A" lens. If it also supports focus distance communication, it can be considered an "FA" lens. Any third party lens that supports thesethese, work with P-TTL. Pentax can't guarantee it because it's not their product.

[Blacknight659]

Pentax is not going to put which third party lenses work with their camera in the manual. They can only say which of their products work with their cameras. However, Any lens with aperture and focal length communication is considered an "A" lens. If it also supports focus distance communication, it can be considered an "FA" lens. Any third party lens that supports thesethese, work with P-TTL. Pentax can't guarantee it because it's not their product.

Ok, I was leaning towards this too. I figured the only needed information for P-TTL to work was Focal setting and Aperture... both are communicated with my Sigma.

[W.j.christy]

Pentax is not going to put which third party lenses work with their camera in the manual. They can only say which of their products work with their cameras. However, Any lens with aperture and focal length communication is considered an "A" lens. If it also supports focus distance communication, it can be considered an "FA" lens. Any third party lens that supports thesethese, work with P-TTL. Pentax can't guarantee it because it's not their product.

I was not aware that Pentax cameras automatically assumed any non-Pentax brand lens was an "A" lens. If that's the case then I will admit I am partially wrong. I appreciate the information.

[Blacknight659]

I was not aware that Pentax cameras automatically assumed any non-Pentax brand lens was an "A" lens. If that's the case then I will admit I am partially wrong. I appreciate the information.

Thanks for the info anyways. I agree, the wording makes it seem like it isn't supported. But it optimistically hope/expect it to work like an A lens.

---------- Post added 03-07-16 at 11:26 AM ----------

Just to bring this back to my original question. Do we feel the metering issue could be resolved with a supported flash... 540FGZ?

I just ordered one of these btw. I was thinking it could be an issue with the flash not properly taking to my camera. Or am I just out of luck until I get a K-3 or newer.

[clackers]

I have the Sugma 17-50 and P-TTL works perfectly with it.

The camera just needs to know from the lens' electrical contacts what aperture the lens is on, so that's all of them except legacy glass without an A setting.

If it doesn't, it can't use P-TTL and it always fires at full strength.

---

Last edited by clackers; 03-07-2016 at 10:59 AM.

[Blacknight659]

I just had another thought.... I mostly had issues when I used bounce flash with My Metz 44 AF-1. I wonder if PTTL is disabled when I point the flash head away from the Front facing position....


Does anybody know about this?

[mcgregni]

There's been a huge amount of discussion and research fairly recently here on PF, following on from my first edition of my Guide .....

https://www.pentaxforums.com/forums/125-flashes-lighting-studio/302328-pentax...nt-thread.html

The conclusion from all of that was that the primary condition for P-TTL was in fact autofocus capability (plus of course the aperture coupling as referred to by clackers above).It is the 'type' of lens, its technologies, that matter, not the manufacturer, so long as it is a KAF mount lens.

I believe the camera manuals that refer to 'A' series lenses are misleading ..... this compatibility will apply to only F & FA type lenses (which are 'A' types also).

Pentax have clarified things further in their AF-360/540FGZII manual which states that P-TTL is only compatible with Autofocus Lenses.

---------- Post added 07-03-16 at 18:08 ----------

I just had another thought.... I mostly had issues when I used bounce flash with My Metz 44 AF-1. I wonder if PTTL is disabled when I point the flash head away from the Front facing position....


Does anybody know about this?

Bounce does not disable P-TTL ...... have you checked out the demo thread I linked to earlier here ... ? That shows P-TTL bounced flash mixed with ambient lighting, and details exactly how it is done, with photo examples. I have not experienced any poor or eratic P-TTL exposures with the K7 and Pentax AF-540FGZ (I & II) models. Bounce may have added to the variables you were dealing with and added to the chances that you were exceeding the limitations of things as per your various configurations, settings and distances.

I have heard plenty of reports from Pentax people saying P-TTL is unreliable with the K5 (and many assume the K7 must be affected too) .... my response is that it is often hard to pin down the exact cause of these experiences, as the location, shooting circumstances, distances, understanding of the flash system and the physical limits, user experience etc are all often so variable.

You may have had power limitations with the Metz 44, depending on the bounce distances, surface reflections, ISO and aperture combinations .... ?