February 2020

Monday, February 17, 2020

How to photograph splashes every time!


Description

Interested in photographing splashing water? In this episode, we'll see how to take splash photography and capture the image every time. As demonstrated by Peter McKinnon, capturing high-speed events can be achieved by repeatedly doing the action and using your camera's burst mode. This doesn't take much equipment but does take quite a bit of time. Today, Harley shows how a little bit of inexpensive equipment can enable getting the splash every time, allowing you to fine tune the image to get it perfect.

Resources

Peter McKinnon’s video: https://youtu.be/1t3iTjAe2Fw
Hiviz: https://hiviz.com/kits/kits.htm
Neewer flash triggers: https://amzn.to/38wv1nk (affiliate link)

About

Here at House of Hacks we do tutorials, project overviews, tool reviews and more related to making things around the home and shop. Generally this involves wood and metal working, electronics, photography and other similar things. If this sounds interesting to you, you may subscribe here.

If you’re interested in learning more about the House of Hacks' values, here’s a playlist for you.

And here’s the most recent video.

For a written transcript, go to How to photograph splashes every time!

Here's a list of the tools I use.

Clock video by Jason H Austin from Pexels.

Music under Creative Commons License By Attribution 4.0 by Kevin MacLeod at http://incompetech.com.
Intro/Exit: "Hot Swing"

Transcript

Want to learn how to take splash photos?

Is an hour for one image to long for you?

Want to get this image...
every...
single...
time?

Stick around and I'll show you how!

\Welcome to the House of Hacks!
If we're just meeting, I'm Harley.
I make stuff and I show you how to make stuff too.

I love Peter McKinnon's work. He's both inspirational and informational in the photography related videos that he makes.

Recently he did a video regarding splash photography where he made some really cool product portraits. The way he did this was to just take a whole lot of images and hope one of them turned out in drive mode. This is kind of a spray-and-pray method if you will.

The advantage to this is it's very inexpensive. Beyond the basic photography
equipment that you probably already have, there's nothing new required.

The disadvantage is it's very time intensive. I think he said it took him an hour to
get one good usable image. Well, if it's taking you an hour to get an image, if
you're trying to dial in on a specific look, it might give you quite a while and
a lot of patience. Or you might settle for something that's not exactly what
you're looking for.

I'm going to show a high speed photography setup that I use to get very repeatable results when dropping things into a water tank. Every time you drop something it's going to show up in the same place in the frame every time.

The equipment that I have is pretty old and it's no longer available but I've left links in the description below for equivalent systems that are available now. The total cost for this is less than $100. So while it is a little bit of investment, it's not very burdensome.

Today I'm going to cover two topics: 1) the equipment and how to set it up and 2) how to set your exposure to get the right images.

To do these splash images, there's really three things that are required: a photo gate which is a light based trigger so when something interrupts a light beam this sends out a trigger signal, and then there's a delay unit because you don't want the flash to go off when the beam is interrupted but rather when the object has had time to drop down into
frame where you want it, so you need a delay that's measured in like milliseconds.

A number of years ago I found these HiViz kits online and when I got mine they were just getting developed and were pretty rough. I got one and it was basically just some components and a schematic. I wired that together on a little point-to-point circuit board and put them in these cases so they're nice and neat and easy to use.

Since that time they've really refined their kits quite a bit and now you get a
whole assembly where you can assemble the kit and put it inside the control
panel that comes with it and the box that comes with it so you get a complete
package.

And then you need a way to trigger the flashes. I'm using a wireless system by
Cactus. These aren't made anymore but there's a new model by Neewer that
looks like it does pretty much the same thing. You don't need all the fancy TTL
stuff that drives up the price on these. You just need a simple on/off switch
because we're going to be running these in manual mode.

You could also, instead of using a wireless system, get one of those little devices that goes on the hot shoe that has a remote trigger input on it. That would work just as well.

First of all, the light beam needs to be set up across the opening of the tank so when
something falls in, it interrupts the beam and sends off the trigger.

The kit came with an infrared LED laser but I found that to be very hard to use
because being infrared it's invisible and trying to get it lined up this
distance so that it could trigger things was very very difficult. I found that a
normal red LED laser works just as well and is much easier to set up since you
can see it. I've got the laser on one side and I've got the sensor on the
other and that's going into the photo gate controller.

The wireless trigger just slides on to the bottom of the flash and now whenever the trigger is put off the flash goes off.

We could take the output from the photo gate and plug it directly into the transmitter for the wireless unit. The problem with this is we'd get an image when the object immediately hit the laser beam and not when it actually got into frame so we'd never see anything.

To solve this problem we use a delay unit that will delay the trigger signal by a
couple milliseconds that it takes to fall from the laser beam to where we
want it in frame and then the output from that delay unit then goes into the
transmitter for the wireless system.

Putting this all together, this is the equipment setup. We've got the LED going to the sensor for the photo gate. It's wired into its control module. The control module for the photo gate's output is wired to the input of the delay unit and the output of the delay unit is wired to the wireless trigger for the flashes.

So now whenever the light beam is interrupted the flashes go off.

Now for the exposure part of the setup.

To freeze action, a high shutter speed is required. And to get high shutter speed, a
lot of light is required. Peter used a combination of a nice light and high ISO.
On modern cameras, a high ISO isn't usually a problem. But without expensive
lighting, getting enough light on the object can be a problem.

An alternative is to use flashes. Speed lights work well for this. An interesting fact about speed lights is the lower the power, the faster the flash. This isn't necessarily
true about standard studio lights. With both studio lights and speed lights on
high power, typically the flash is long enough that motion will blur on you.

An interesting point when using flash is shutter speed isn't very relevant. Most,
if not all of the exposure, is from the flash, not ambient light. So if ambient light is low enough, shutter speed can actually be quite long.


Putting all these facts together, using a low power on the flash, combined with low
ambient light, and also combined with shutter speed in the order of seconds, we
have enough time to be able to trigger the camera and then drop the object. As
long as the shutter speed is long enough for us to do that operation, we're good.

So I have my camera set to two seconds for the shutter speed, f/10 to get a decent depth of field and ISO 200. The flashes are set to 1/16 power.

Once the equipment is set up then we're ready to dial things in. The photo gate
has a sensitivity setting that I find mid-range works best. If it's too
sensitive, random things in the air will cause it to trigger. We want it to be
reliable though when the objects that we're dropping really do pass through
its path.

Then there's the time delay that we need to set. My unit will work in
seconds, milliseconds or microseconds time ranges. I find that for dropping
objects in a set up like this, milliseconds works best. The range that
you'll use will depend on how far the trigger is from where you want it in
frame and how fast the object is moving. We'll dial this in through a series of images with kind of trial and error once we start making photos.

So let's start making them.

When I set up for this shot, the first image captured the item just before it hit the water.

I adjusted the lighting and tried again.

The lighting was better and the item was exactly the same place.

See how repeatable this is?

I then adjusted the delay in one direction and tried again.

This time the flash went off before the item was even in the frame.

I dialed the time the opposite direction and tried again.

This time it was exactly what I wanted.

As we can see from these subsequent images, once it's dialed in, the object will be at the same place in the frame every time.

These images are all sequential. They're not cherry picked from a bunch of different ones.

It's important when dropping things that they're dropped from the same height every time. But things of different weights can be dropped each time without changing the height. You will get a bigger splash though.

As you've seen, every time I drop something, the item is in the same spot in the image.

Over here is a playlist of other photography related videos and down here is a video that YouTube thinks you'll enjoy.

Remember when making things, perfection's not required, fun is!