When I shoot with my Triopo speedlight I have to set my camera to f/5.6 and 1/100 with the flash at 1/4 power.

If I increase the flash power, the picture is black. If I change the shutter speed or aperture, the picture blurs.

I want a simple way to adjust both the flash and camera to any shooting mode I need . Note that I am using a 55-200 lens.

  • Just double checking, in which way do you increase the flash power? If you get an exposure at a lower power and didn't change shutter or aperture, you should end up with an over-exposed image if you boost flash power, not black. – AJ Henderson Apr 3 '14 at 14:41

You might actually be doing something different than what you think. "Increasing flash power" would mean creating higher light intensity for the same amount of time. However, with some flashes, "increasing flash power" just means the same amount of energy being radiated, just in a shorter amount of time.

To show the difference: the first case you would burn 2 candles instead of 1 candle for 1 seconds. The second case, you burn two candles for half second instead of 1 candle for one second.

So basically, what I think is: you have the latter type of flash. Which means that if you try to increase flash power, it will radiate the same energy in a shorter amount of time. However, if your camera is not in sync with that (the shutter is not in sync with the flash) then you will get underexposure. And obviously, if you are underexposed, you will get blur whatever you do with your aperture or shutter speed.

Probably you are just getting a fraction of the real power of your flash.

The real test for this is: go into a dark room (completely dark), change to long exposure mode (BULB), and manually trigger a flash, then finish shooting. Then switch to your shutter setting, and make another picture. Now, because the flash emission is very rapid, you should see exactly the same picture! (Basically the flash "freezes" the shot). If you do not, you have the problem I described. (You may want to switch to Manual focus, to avoid infinite focus hunting in the dark...)


The easy way (which is probably not the best or most accurate way) would be to use the "MA" (autothyristor; "semi-automatic" in the manual) mode on the flash. The flash has a built-in sensor that will automatically cut the light off at a "good" power level. You may need to compensate with flash exposure compensation (FEC). This is an older technology that was used before TTL preflash metering to automate setting the flash's output power.

Just keep in mind that your flash is manual-only, and that you cannot use a shutter speed faster than your camera body's sync speed (typically 1/200 or 1/250s).

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