Originally posted by snostorm Hi Noam,
... what practical application is there for a shallow flash head angle? ... I haven't found much use for any of the intermediate angles,...
The only relevance that I can see your tests having for me is that I now know to check to see if the head has been inadvertently tilted a touch ... IMO, you're spending a lot of time and effort to point out a fault in the P-TTL flash protocols that Pentax will probably have little or no motivation to correct.
... I would think that their priorities would be to put the work into developing a new system, not to patch up the one that would be replaced.
... With P-TTL flash, I know that I've got a pretty wide range of exposure latitude with both Ev comp and Flash comp to work with. I can work around just about any metering problems within the system that exists as long as the work-around is consistently effective.
Scott
Hi Scott,
Thanks for your comments. There is no particular practical application to using a slight tilt as I did. It was for the purpose of the test. I opted for as similar as possible shooting conditions (and that includes flash position and direction), in order to eliminate variables and help isolate the real problem (apparent firmware bug in camera or flash). I demonstrated that everything being equal (including flash angle) we get very different exposures, which is a bad thing.
The flash should not overexpose as a result of being "inadvertently tilted a touch". It should simply work, and it is realistically capable of doing so, as has been demonstrated in the well-exposed shots (straight forward, tilted down, and even bounced in wireless TTL!). P-TTL is a good and capable system apparently ruined by a silly bug. The relevance of my test is that it helps exposing and isolating that silly bug, which can and should be fixed by the manufacturer, for the benefit of us all. We pay good money for it and It should work as advertised. I don't think it's a fundamental fault or limitation of the aging P-TTL protocol. It's a bug that hopefully can be easily fixed.
Perhaps I should stress the importance of fixing this bug. It is not limited to my convoluted test shots. I decided to perform the test after using the flash with my new K-5II and shooting normal subjects at "normal" bounce angles (e.g. ceiling) like you do, and getting lots of ill-exposed shots. Fixing this bug will make P-TTL the consistent and dependable system that it should be and has been with older DSLR models (according to many people's testimonies, the bug does not occur with K10D, K20D and older models).
Exposure and flash compensation are important features that have many good uses - from dealing with dark or bright objects, reflective objects, to creatively balancing tones and shadows. Working around P-TTL bugs is not one of them. True, I will probably be able to live through it with constant chimping and tweaking of flash compensation, but it's not how it should be, and it's not something I, you, or any other customer, should put up with. And I think the manufacturer's priorities should definitely include supporting existing customers rather than leaving them out in the cold and fixing problems only in subsequent models.
I spent hours performing the tests and writing these lengthy posts not (god forbid) to pick up a fight, argue, or bad-mouth Pentax or Sigma. On the contrary. I’m doing this as a service to myself, the Pentax user community, and even Pentax and Sigma themselves, helping expose and diagnose a problem, and hopefully motivating them to fix it.
I urge other users to contribute. Any further information and experience will help complete the picture. Please do not suffice with anecdotal evidence (“mine works great” or “Yea, I had this happen to me too once”), if you can. Perform a methodical test and share your findings.
With enough data, I hope we will be able to make a difference - approach the manufacturers and get some answers and hopefully solutions.