Wednesday, December 03, 2008

Splish Splash, redux

I've been meaning to do this for a while. Then I did it. Then I was meaning to blog about it for a while. Which I'm doing now. Anyway, what I'm ranting about is my wish to try getting photos of high-speed splashes of water and milk. I've done this before, but I wanted to try again using the same lighting scheme as I did for my pictures of smoke. Although I don't have the setup shots here, I did take some, but you'll have to use your imagination for the moment. It's a very basic setup: a snooted Vivitar 285HV diagonally behind the water pointing towards it, and then opposite that, on the other side of the water, a piece of white card to reflect back some of the light. This gives a very 'low key' image, as the picture is outlined by light, but is mostly black. You'll see what I mean in a sec, if you don't already...

The actual taking of the photographs themselves is essentially a numbers game. I took about one thousand shots in total, as there is basically no way to tell whether a shot will be good or not until you look at the camera screen, and if you did that after every shot you'd go completely insane and throw the camera out the nearest window. So I put the camera on fine Jpeg and just let it fire away as I was making drops of various sizes. I'll outline quickly the process to get to this end result::

First you need to have a container for the water into which the drops will fall. A glass does the job just fine here. It's also a good idea to have another container (a shallow bowl, say) under the glass to catch all the water - saves cleaning up afterwards which is always good!

The next thing you need is to set up your camera. It needs to be on a tripod because you will be prefocusing and then switching to manual, and the camera cannot move while this is happening or else everything will be blurry. So set up your camera and tripod fairly low, so that the camera is pretty much in line with the top of your glass. I use a Nikon D50, which works pretty well, although I could have done with something with a faster frames-per-second. You definitely need a DSLR for this, as you will need to manually focus. I also used a macro lens, the Sigma 105 f2.8, but you don't necessarily need a dedicated macro lens - one with a decent close focusing distance will do.

Next you need to focus, and this can be pretty tedious. I used a pencil, which I stuck in the water, as close to the middle of the glass as I could. Half-press down your shutter, focusing your lens, then take a picture. Check the screen to make sure it's perfectly in focus. Here's my picture of a pencil:

Pen in Milk

You now need to switch to manual focus, and make sure you don't move the camera or the lens for the rest of the shoot. Although this doesn't mean everything will be in focus, as you won't get all the drops directly in the middle, it will make you have the best chance of getting a high proportion in focus. Which is the best you can hope for really.

Now on to taking the photos themselves. There are a huge amount of variables here, and getting any one of them wrong will probably spoil your photo. Hence the need to take so many. I'll go through any I can think of now.

Shutter speed: Pretty much irrelevant. My photos are lit entirely by flash. If I took a picture with the same settings and turned off the flash, there is nothing but darkness. So your shutter speed just needs to be fast enough to cut out all available light. When your photos are lit entirely by flash, they will be frozen perfectly, as the flash duration is at most about 1/4000, and I think at 1/16th power it's about 1/16000th of a second. So doing this is incredibly more efficient than trying to use shutter speed and ambient light to freeze the action. My shutter speed for most of these photos was somewhere between 1/15 and 1/60, chosen pretty much arbitrarily. If you use a very slow shutter speed, so that ambient light gets in, you might start to see a 'dragged' image - a clear image lit by the flash followed by a blurry one lit by the ambient. It might look cool, I haven't tried it yet!

Aperture: Pretty small. You want to give yourself the best chance to get in-focus pictures, so an aperture of at least f16 will allow you to be slightly off and still be in focus. It also helps to cut out all ambient light, which, as explained above, is what we want to do. A side-effect of this small aperture is that you get cool starburst type effects in your photos, like this one:

Little World

Grooveh huh?

Flash: External flash is fairly necessary here, although I suppose you could use on-camera flash to freeze the action if you wanted, but you'll probably end up with quite flat images. I use radio triggers to fire mine, from ebay. You'll probably want the flash on a low power, 1/16th or less, so that your recycle times will be high and your batteries won't die - again, so we can take as many photos as possible in a short space of time. The manual for my Vivitar 285HV says that after about 20 pops in quick sucession the flash needs a break for a couple of minutes, so keep that in mind before you abuse your flash. Don't blame me if it explodes!

The drops: Now comes the fun part. I tried various methods to get the best drops, and probably the best one was out of a small jug with a thin spout. I tried a dropper, but it's no good as you need a constant stream of drops rather than the ability to control a small number of drops. If you could set up some system that constantly and slowly drops liquid with no human intervention you would be laughing. Fill up your jug just a small bit and aim it, or whatever implement you've decided to use, at the centre of the glass of water and tilt it just enough so that drops come out. Try not to get impatient and tilt it loads, it's best to wait and hope the drops come! Once you have a steady stream, start shooting, and vary the height and distance from the centre to ensure that some of them are in focus. There's no point trying to anticipate the drops falling, just shoot as many as you can and hope for the best. After about twenty shots, check the back of your screen to see if any of them look good. Remember to zoom in to check for focus because if it's a tiny bit out it'll look crappy when you view it on your computer screen. Armed with the information you have now, alter your camera/drop maker settings until you get it just right.

When you're finished with water, try other stuff. Milk works really well, probably better, and it's amazing how different the drops look to the water ones. I also tried dropping objects in, but I didn't manage to catch any on camera. I might try it again though.

If anyone actually made it though that lot, here are some pictures I took from my latest drop-related adventure. I hope this is of use to someone.

Bigger on Top

Glowing Water

Curved Splash