question about flash

[stu123]

Im just wondering if it is possible to adjust the brightness of the built in flash, if not, do external flash addons allow me to adjust how bright the flash is when it goes off?

[Geoff M]

Yes it is possible to adjust the light output of a pop up flash, but you will have greater control with an external flash. What camera do you shoot with? This will help in telling you how

[stu123]

I have a Canon EOS 600D.

[ATJ]

By default, the built-in flash should be using TTL (through the lens) metering.

In the old days of film, TTL flash metering used to measure the light reflected off the film, while it was actually exposed, and essentially turn off the flash when it had received "enough" light. With digital this can't be done so instead there are a few pre-flashes of lower intensity to judge the amount of light being reflected from the scene and based on that set the duration of the flash. Note that the "brightness" of an electronic flash is actually controlled by its duration. On full power the flash might last for 1/1000s and then shorter for less than full.

If you find that with TTL your images are overexposed, you can adjust the EV (exposure compensation) of the flash so that it will put out proportionally less light. The light will still be judged from the pre-flashes but the result will be less (shorter duration) than without EV. For example, EV-1 will underexpose by 1 stop.

What is the problem you are trying to solve?

[chrisk]

Just make sure you adjust the flash comp and not the master exposure comp. They are 2 different things.

[Mr Darcy]

Read the following pages in your manual:
90,104, 108, 180-183 (especially 182)
Also Chapter 8 (189ff) but that is only relevant if you have external speedlites as well.
Also check out the chart on p269

[surenj]

Thanks Greg, you beat me to it. Although I didn't see that there can be exposure compensation for the built-in. It doesn't even mention a manual flash mode.

Dpreview seems to confirm this.

Flash *
• Auto pop-up E-TTL II auto flash
• Guide number approx 13
• Modes: Auto, Manual Flash On/ Off, Red-Eye Reduction
• Integrated Speedlite Transmitter, wireless multi-flash support *
• X-Sync: 1/200 sec
• Flash exposure compensation: +/-2.0 EV (0.3 or 0.5 EV steps)
• Coverage up to 17 mm focal length (27 mm FOV equiv.)