Friday, May 9, 2014

Pentax Flashes

Learning about old kit


Today I learned something new about some flashes that I've had in my collection.


What's great about this bit of information?  The ability to create ratios of strobe lighting has been something I've struggled a bit with in manual mode.  I've been reluctant to use PTTL since relying on the computer sometimes gives a false sense of knowledge.  Still, what this suggests is that when I need to do a fast setup, I can use this function and get the control I want.

How this works - for reference to save on not watching the video - when the Pentax flash is set to wireless mode and in PTTL mode - the first press of the S button allows modification of the ratio.  The second press allows modification of the power override.  Available ratios are 1/1, 2/3, 1/2, 1/3. 

Another thing I learned recently was how reliable the A mode is on these flashes.  Again, in the past, I wanted to avoid using these built in smarts to let me better understand what was happening in a setup.  I've been challenged with handling fill light with subjects that have a bright background and are in shade.  In the past, I've just metered for the shadows and let it be.  I knew that I should be able to pop a fill flash and be satisfied, however, I wasn't comfortable with what would happen.  Yes, manual mode allows a pop of a flash at varying power and that's technically all that's needed.  However, when the subject distance changes, all power estimates are off.

I decided to do some experiments to better understand what could occur when letting the flash dictate the power level.  For testing, I shot against a backlit subject.  I spotmetered for the backlight at ISO 400 at F11 at 1/125.  I set the flash at A mode for ISO 400 and F16 and put it off camera a little ways. 

When the flash was pointed directly at the subject, the exposure was right on.  The fill light was actually a little hot for my taste when reviewing on the desktop, yet it proves the concept.

When the flash needed to be bounced on the ceiling, one stop bump made it work just right.  Ceilings are at different distances and different colors and non-existent outside, so this will be inconsistent.

When I put a Fong diffuser on on the flash, all exposures were ruined.  No power modifications worked - too much light spill from the modifier threw off the automatic function!  I've seen this behavior before and was annoyed by it. 

Why so much effort into the A mode?  Because that's what the Pentax LX camera supports and that's what I shoot 35mm film.