Is the Pentax KP's built-in flash only half as powerful as that of the K-7?

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    You've apparently researched this a bit. It might be helpful if you would include references to what led you to ask this. For instance, what is the respective Guide Number for each one? If more of what you've already learned is provided in the question, it's more likely someone will give you a good answer without having to take the time to go dig up again what you've already found. – Michael C Jan 3 at 22:58
  • Really, who cares :) A built-in flash is really a stopgap, and is never really adequate, especially when shooting people. A cobra flash is a huge step forward: more power, zoomable, orientable, usable as "bounce" flash, easier to fit with a diffuser... and for occasional uses the no-name ones are not that expensive and work quite well. – xenoid Jan 4 at 13:09
  • @xenoid "Cobra" flash is a relatively regional term. For most of the world it's either "speedlight" or "speedlite". – Michael C Jan 4 at 15:45

Per Pentaxforums.com the K7 has a guide number of 13 meters and the KP has a guide number of 6 meters.

The inverse square law applies.

The K7's flash provides appoximately 4.7 times more light output than the KP.

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    Yes, 4.7 times the power is correct for GN 13 vs 6. Someone had said half power, but it has to be squared, so closer to 1/4. And 4.7x power is the precise number. 4.7x power is 2.23 EV more exposure. – WayneF Jan 4 at 4:35

Yes, the Pentax KP built-in flash Guide Number is only about half the Pentax K-7.

Page 128 of the Pentax KP user manual specifies the Guide Number at 6 meters.

Page 312 of the Pentax K-7 user manual specifies the guide number at 13 meters.

There is some speculation in online Pentax forums that the KP’s better ISO performance can make up for the weak onboard flash. Others say it is really to only be used as a wireless controller for off-camera flash.

In any case it is a big departure from all other Pentax DSLRs and also DSLRs of all manufacturers which generally have a Guide Number of about 13 meters.

Pentax KP user manual enter image description here

Pentax K-7 user manual enter image description here

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