Tuesday, September 9, 2008

White Sky Dreaming

If only the world was sunny every day. We'd have lovely blue skies in all our photos and the world would be great. But often we get grey, overcast days.

Sometimes they have a bit of blue in the sky which looks nice to the eye, but when you take a photograph the little bit of blue or light grey turns out pure white. Nothing there. Zip, zilch, nada. Hands up if you have some of these photos in your collection. We all do, don't sweat it.

Because it's cloudy there's no sun hitting the ground and your camera can't handle the contrast difference between the very bright sky and the very dark ground.

If you expose for the sky, everything on the ground will go black. Not a good look. So you expose for the ground (which is usually where the subject of your photo is) and the sky goes pure white.

Gone are the clouds, any trace of blue or detail whatsoever. The picture above isn't the perfect example of that but it was as close as I could find so bear with me!

For a travel photographer white skies are a killer. Blue skies are perfect but even if they're not blue they need to be interesting. Dark brooding skies are so much better than white skies. In conditions like these I usually tend to shoot things that don't have any sky in them. That means the wide-angle goes back in the camera bag and I concentrate on close-ups and macro shots, long telephoto shots with no sky - that sort of thing.

But there's another way you can get around white skies and that's to use your flash. The above shot was taken with natural light. I say it's not a perfect example of the white sky phenomenon because I actually made the picture quite dark to try and retain some detail in the sky. As a result you can see the ground is way too dark. But you can still see there's parts of the sky that are white with no detail. So I tried using the flash on top of my camera.

And this is what happens. The part of the picture that is lit by the flash is controlled completely independently of the part of the picture that the flash doesn't reach.

What that means is - the flash is only lighting up the eagle sign. It has no effect on the background whatsoever. The exposure on the background is controlled by your shutter speed. The faster your shutter speed the darker the background, the slower your shutter speed the brighter the background.

This gives you an amazing amount of control over two planes of light at the same time. Brightening and darkening my background has no effect whatsoever on the eagle sign. The eagle sign is only lit by the flash. So that means that you can brighten or darken the eagle sign and the background independently.

So what I've done here is fire the flash to lighten the sign. Then I've given myself a faster shutter speed to darken the background. I'm not that happy with the shot because the dark mountains behind the sign are too dark for my liking but in terms of bringing back the detail in the overcast sky it's done the trick.

So here's how to do it. There are two ways depending on what kind of a camera you have.

The first way can be used for those of you with both SLRs and point-and-shoots and is the easiest. You have a button on your camera that looks like this +/- . It's called the exposure compensation button and you can either move it to the plus side or the minus side. As you go towards plus (usually by spinning a little dial somewhere) the picture gets brighter, head towards the minus and it gets darker. Check your manual on how to do it on your particular camera and have a play with this feature without using the flash and you'll see your pic getting brighter and darker.

Here's the thing. That button only affects the background, not the flash. As soon as you put your flash up (or stick it on if you've got an external one) the flash exposure part is all automatic. So when you have a bit of a play with this button with the flash up you'll see the background get either brighter or darker while the main subject will stay exactly the same. How cool is that?

The other way to do it is to put your camera into Manual Exposure mode. Take a reading off the main subject of your picture and remember your aperture and shutter speed, then set your camera on those settings in manual mode. So let's say for argument you've got 1/60 second at f5.6. Set those parameters in manual mode. When you've done that you just adjust your shutter speed and leave the aperture where it is and the sky will change but not the flash-lit part. If you dropped your shutter speed to 1/30 second the sky would be even whiter! Not good. But by increasing your shutter speed to 1/125 second or 1/250 second you will give yourself a darker sky with all the detail you need.

For those of you with external flashes with high speed sync you can actually increase your shutter speed to as high as 1/8000 second or something silly like that giving you a pitch black background and making it look like the picture was taken at night!

Usually something between totally white and totally black looks the best. :)

So the next time you're out and about on a grey old day and your skies are turning totally white, try using your flash and see if you can darken your skies to give yourself a nicer look.

No comments: