Originally posted by PhilRich In response to your replies I have run a comparison test between my canon 580EXii flash, and the pentax AF540FGZII flash.
First off, using the same batteries used last night at the wedding recycle time from a full discharge was 10 seconds using the Pentax flash.
Full discharge was forced by using f22 with the camera lens against a black seat cushion blocking incoming light into the camera's sensor.
Using a fresh set of batteries in the pentax flash, full recycling time was 3 seconds. After 2 shots verifying the same recharge time, the same batteries were removed from the pentax flash and inserted into the canon flash. The canon flash recycled in 1 second, verified by a second operation.
This tells me that for my two flashes, the pentax is 3 times slower to recycle from a full discharge than a comparable canon flash.
I appreciate your comments on better batteries, etc., that makes this thread worthwhile, at least for me. I'm aware that in most situations the pentax flash is good enough and produces good exposure results within its limitations, however its not up there with the canon flash quality. My canon flash is about 7 years old and has seen significant use. One thing I like about the canon flash is the flip out white card which the pentax flash lacks.
I've only been on this forum since getting the 645Z but have the impression that Pentax has a way to go to improve customer service and does lack behind canon and Nikon in some applications.
I'm consider whether to sell the Pentax flash and replace it with a Metz or to keep it. I've had it too long to return it.
So your complaint Pentax was crxp was based on 10 sec with flat alkaline !!
I assume you 'new' battery are NiMH ?
Your current recharge is 3 seconds in line with what was promised.
As the Canon and Pentax are both specified to the same re-charge times I can only assume your 580ii was not fully discharged or is faulty
A 1 second recharge for GN58 would melt your poor AA's or your flash the current requirement to charge a capacitor from 0- approx 330V is not something four AA can deliver that is why you have external power sources that can feed HV directly.
My external PSU has 8 AA + the 4 AA in the flash to provide the power required to charge in 1sec
It just physics
if you need 5secs to charge from alkalines you will need 3secs todo the same from NiMH and if you want 1 second charge you need 3 times the power delivery i.e 12 AA's
Here is the Spec for your Canon
Number of Flashes Approx. 100 to 700, with fresh AA-size alkaline batteries
Recycling Time Approx. 0.1 to 6 seconds, with fresh AA-size alkaline batteries
Interestingly Canon 580EXii is optimised for Alkaline use from Pg 8 of their manual
" Using size-AA batteries other than the alkaline type may cause improper battery contact due to the irregular shape of the battery contacts. "
As every other manufacturer optimises for high current AA's it difficult to understand why.
If the 580EXii was capable of 1se recharges off 4AA then how could they sell the cp-e4 ext PSU ?
---------- Post added 31-08-15 at 12:42 PM ----------
Originally posted by gosman Derekkite- as you have noted, the key is not to use any flash on full power. Use an assortment of flash off camera to get a more modeling effect.
Thats a very important point a capacitor takes some serious grunt to shove it up from 0v but will charge considerably faster if it has some potential left in it.
Which I think the OP demonstrated with his non effective full discharge strategy testing Pentax Vs Canon
Not sure what F22 firing auto (presumably ettl Vs pttl ) is supposed to accomplish it certainly wouldn’t necessarily fully discharge a flash capacitor rather putting the flash in manual and test firing 1:1 would probably be more effective
Or to be certain open the flash and use a brinkley stick on the capacitor is probably the only way to be sure of use case.
Best test for the OP would be put both in manual 1/2 power set the camera to continuously fire at a shutter speed low enough to count and see which flash stops first .. That would show which recovers fastest.