Actually, the "focal" as you call it is the aperture. You really don't need to have it at 3.2 or 2.8 or whatever.
As long as the combination of aperture/shutter speed is correct you will get a correctly exposed image. That "2" you refer to is actually a half-second (1/2").Based on you last image I would suggest an aperture of f/5.6 together with a shutter speed of 2 secs. Bracket your exposures (keep the aperture constant and vary the shutter speeds) and pick the best one. Btw, the reason your aperture varies as you zoom is that yours is not a constant-aperture zoom. As you zoom out to the longer end the aperture will get smaller (number gets bigger).
Your shutter settings once they get as long as 1 second usually have the " after the number
So 1" is 1.0 second, 1.5" is one and a half seconds, 2" is 2 seconds, but just 2 without the " sign is a half second (1/2)
I disagree with BanglaBob, you need to manually control BOTH your shutter and aperture, or the camera will be unpredictable. However, he is correct in that the camera will probably set up the maximum aperture (lowest number) if the light is dim. But in longer shutter settings it may not do that.
Sorry, you seem to have mis-understood me, troop. What I suggested is to bracket the exposures by manuallysetting the shutter speed to say, 1 sec. while manually setting the aperture to f/5.6. Then, while manually maintaining the same aperture (5.6), take a series of further shots at 2 secs., 4 secs., 8 secs. etc. Then you will have a series of images of varying brightness. You can then select the best combination that works for that particular flashlight output at that distance. Then use that combination. Everything has to be set manually for consistent results. Even the white balance should not be left to the camera to decide (auto) but be set to "daylight".
But I think that with any particular type of flashlight, you need to use the same settings for all the lights that you compare it to, or it is not a valid comparison. So if I shoot a thrower at 1" and f2.8, then compare it to a couple other throwers, I need to use 1" and f2.8 for them as well or the images you see on your monitor will not accurately reflect differences between the beams.
I have no doubt that the Small Sun C10 is brighter in lux @ 1 meter than the Jacob A60. But I don't see the Small Sun out throwing the Jacob A60 at 70yds or farther from what I have seen and what my camera sees as well. It appears in my tests that the huge reflector on the Jacob A60 is winning out in this case.
Absolutely. If you're comparing 3 flashlights in the same region of brightness, then you must use the same camera settings. So when comparing the Olight M3X to the Crelant or STL-V2 ie. you might use say, 1 second shutter speed at f/5.6 while comparing them.
But the next time you do a comparison it might be between a few lights of much lower intensity (ie. some single CR123 lights). Then, at a particular distance you might use, say, 8 seconds at f/5.6. Why I mention bracketing your exposures is that prior to doing the comparison, you have to arrive at the best camera setting that will give you the best images. It's important not to over-expose digitally-captured images, because any over-exposure will cancel out the difference between the given flashlights (the brightest part will look the same between lights). A quick check with the histogram (on the camera lcd) is needed to make sure that there's no burnt-out images (over-exposure). Hope this helps...
Heatsinking is rather poor in the A60, I don't trust it at 2.0-2.1A that a good battery will push. I like this flashlight and use it regularily, so I want it to last...
ILF likely used a good battery which made his A60 surpass the C10-S aspherical. (!)
At the last metering my UltraOK Tactical with alu C8 reflector at 1.78A registered 40 kcd. Earlier, the stock plastic reflector did a little better, IIRC.
All my lux measurements are carried out at 8m (to let reflectored throwers achieve proper focus) and converted to 1m equivalent. Compared to some other member's readings, mine mostly result a bit high, due to the Max Hold method used, which is fast and less likely to miss the hottest spot within the hotspot.
