So, yesterday I was not able to overheat HVL-60M indoor, using E-TTL HSS mode. But it overheated in when I provoked it, using full 1/1 power. Today I performed two tests: (1) out-door shooting, using HVL-60M as fill-in flash in bright daylight at 15 meter (16 yard) shooting distance and (2) indoor test, where I just fired flash in manual mode at 1/2 and 1/1 output levels.
Test 1, outdoor photography
My hypothesis was that using HVL-60M as fill-in flash at sunlight from long distance is pretty hard task because it has to compete with the highlight created by Sun, to fill in shadows.
So, I mounted Carl Zeiss 135mm F1.8 to my Sony SLT-a99 in order to provide space between the subject. Longer distance will stress HVL-60M even more, was my thinking. I abandoned to test the flash in real shoot, saving models. Instead of that I shot a tree :)
I shot mountain pine from 15 meters (16 yards). My camera was in P mode with fill-in flash, 1/160 sec, F4, ISO 100. I had camera in Drive/Lo. I just pressed the shutter button and waited. This as not a real-world situation. Camera just continued and continued, HVL-60M didn’t skip any flash. At least I did’t notice that. I shot 380 continious shots from the 15 m distance in sunshine until I overheated HVL-60M. So, it’s theoretically possible, but I really don’t believe that it ever occurs in my practical use.
People from DPreview forum asked to count flashes-to-overheating at lower power levels. Due to time limits I did this test at 1/1 level two times and 1/2 leve also twice. For some reason, I had slightly different numbers, but here are the results:
at 1/1 25-41 flashes until overheating
at 1/2 58-64 flashes overheating
HVL-60M is not going to overheat in real-life shooting scenarios. You are able to provoke overheating, shooting 25-41 flashes at full power or 58-64 flashes at 1/2 power. But it’s not worse than Nikon SB-800, about 25 frames at 1/1.
Guide number 60 is an advantage and disadvantage at the same time. In most cases you need only 1/32 or so and the flash is very capable then, able to shoot 10 fps endlessly, no problem. But flushing all huge energy at 1/1, stresses output electronics and batteries. In this case heat is your enemy.
Would I buy it? No, but because of too high price. At 30-40% lower price, I’ll take it and will trust it in my shoots 100%.