trouble with outdooor highlights - help!

[queenbee288]

I am having a little trouble with outdoor shots. I took some shots in the shade and use 580ex for a little bit of fill flash to brighten it up. Outside the shade there were bright areas of sunshine that are blowing out.In av mode, I focused on the bright areas, locked exposure, recomposed and focused on my subject. Background is still blown out. What am I doing wrong?

Thanks

[DavidW]

If you don't want to lose the highlights in the sunny area, switch to M mode and partial metering. Set the desired aperture using the rear dial (you will need the switch in the upper position to do this, even if you drop back to ON afterwards), point the camera at the sky, half press the shutter button and adjust the shutter speed using the dial by the shutter button so that the 'needle' in the viewfinder is around +1 2/3rds (in other words, one mark off the right hand edge).

If you need a faster shutter speed that 1/250s to achieve this, drop the ISO. If you still can't achieve this, switch the flash to High Speed Sync using the button on the rear.

Leave the flash on E-TTL; you may or may not want a touch of negative FEC depending on just how much fill you need. Ideally you want some negative FEC otherwise you'll have mixed colour temperatures in the lighting unless you gel the flash or the background lighting is the same colour temperature as the flash (around 5000K).


Unless the light is changing wildly, the aperture and shutter speed won't need resetting for the whole series of shots. E-TTL will handle any changes in the shade and hence the amount of fill flash needed.

Don't forget to check the histogram and 'blinkies' - if you're still blowing out, increase the shutter speed. Check, too, that the green 'exposure confirmation' light on the flash has lit; especially if you're at ISO 100, there may be insufficient flash power to expose the flashed area correctly. In that case, increase the ISO.

For every ISO increase, which is a whole stop on the 20D, you need to double the shutter speed to compensate - that's decreasing the shutter speed by three clicks of the wheel assuming that you've left the camera in the default of working in thirds of a stop. Conversely, for every ISO decrease, you need to increase the shutter speed by three clicks of the wheel.


The hazard in what I suggest is that you'll lose shadow detail in the shade area that isn't illuminated by the flash. You may be exceeding the dynamic range of the camera - if there's more than about 5 stops between the darkest shadow and the brightest highlights, you have to choose which to preserve. You can boost the shadows in post-processing (possibly fixed with an adjustment layer using Levels, Curves or Brightness/Contrast and an appropriate layer mask) at the cost of amplifying any noise, but you can't recover blown highlights.

Shooting RAW will help if you finish up with mixed colour temperature lighting or you need to blend exposures to get the lighting right.



David

[queenbee288]

Thanks a lot David. I will give it a go!