Hey everybody. Thanks for stopping by today -- hope your Friday was great.
Today (or rather, yesterday as I am blogging so late), I got to do some really fun photography. It's always just risky enough to be fun when you mix high end lighting gear with water. :-)
Anyway, I got to help out with a middle school science fair project today! The question for the project was "What flash speed does it take to freeze water from a water balloon?" And the answer to that is... it depends. But I was ready for the challenge!
I have some lighting equipment that truly is built for speed, and I really wanted to put it through its paces today. The particular power pack has the unique ability to choose the flash speed we want to use. In t.1 times, we are able to select a flash speed range anywhere from 1/220th of a second, all the way up to a mind-boggling 1/10000th of a second (!!!)
For a small bit of background, what the "t.x" means is essentially "How much time does it take to get xyz percentage of the flash output released?" So in the case of t.5, you've dumped half of your light and have half to go. In t.1, you've dumped 90% and have 10% left. The problem with t.5 times is that since only half of your light has been put out, you still have enough light remaining to cause motion blur at a duration that "should" freeze motion. Thus, t.1 is the more helpful time measurement, though rarely are times given in t.1. As a general rule of thumb, t.1 to t.5 will be about triple.
So, for "scientific purposes" (and not at all because we wanted to just play with water balloons), we set up a fairly simple studio and got to work.
To do such extreme motion freezing shots, you need a little bit of a special set up, but not to worry as it remains very simple.
There are various ways of doing it. Well, mostly two. :-)
1) You can have a completely dark room, and do a long exposure (5 ish seconds), and you will pop the water balloon (in this case), within that long exposure time, at the same time MANUALLY setting off your flash with some sort of trigger or remote (we used PocketWizards) in the time of exposure, somewhere. This is tricky and a little time consuming, but it is more guaranteed if you are good at is -- the same person firing will be popping the balloon as well.
2) You have a normal studio set up, you don't care so much about ambient, but you have to have different people popping/firing the camera. This is also tricky in its own way, as you will be at a normal studio syncing speed (1/160th, or so) and you will have to time your pictures correctly with the other person. This is a little more frustrating if you're bad at timing with the other person, either popping or at camera.
We chose the second option, and accepted the fact that we'd lose a few balloons here and there!
We used a simple, 5 foot roll of Savage Thunder Gray seamless background paper for our backdrop. We set up a backdrop stand that has a pole with an attachment in the middle, so it can hang over the stand, not unlike a C-stand with a boom arm. On this part, we had your standard hardware store A-clamp that was gripping the balloons. We took a standard sewing needle and used it to pop the balloon. Person 1 was at camera, person 2 at balloon. Person 1 counted "One, two, three, pop!" and shot the photo on the "pop" -- sometimes the timing varied. We lost some balloons, but I would say we had a 80% success rate, or so, which isn't bad at all!
Pretty boring, huh?
We have a single beauty dish, camera left, and a standard 7" reflector off to camera right. The beauty dish and reflector are almost shooting at each other. The standard reflector in the back corner is key.
When you want to light anything to make it really stand out, such as liquid (Water), or something like smoke from a fog machine, you must BACKLIGHT it! Without the backlight, your substance won't get that POP.
ISO settings and aperture varied from shot to shot for the correct exposure. This is because the flash power pack requires lower settings to get the faster flash durations (likewise, to get the slower flash speeds for testing purposes, we had to increase the power sometimes). However, the ISO never raised above 250, and the aperture never beyond f/20.
Again, this is only to get consistent exposure. Any motion blur (or lack thereof) will not be altered by these settings. We ran both lamp heads to the same power pack, so the flash duration was equal on each lamp.
Potential warning, though, for those trying it at home. Remember, you're using ELECTRIC photographic equipment, with WATER balloons. Thus, you have to be very careful with how you have your equipment lying around. Opt for a high power, greater distance set up. Keep your lights away from that water. Who cares if you're sacrificing recharge rate, because you're going to do be doing about one picture every 3 minutes with balloons on hand, and I know of no strobe that can't keep up with 1 flash every 3 minutes. :-) Keep towels around your set up, around your equipment. There are lots of ways to keep water away from your stuff, including covers, etc. but the best way will be to just simply get it far enough away that you don't need to worry about it.
Here's a photo of our set up, pre pop, so you can get an idea of what everything looked like (the tag on the A-Clamp gave me something to focus on), as it was still pretty dark. Later, I had turned on the modeling lamp and gone with that instead.
So, a lot of prep work done, and we could finally start shooting!
For the purposes of the science project, and just for my own curiosity's sake, we started off with a relatively slow flash speed for this particular power pack. (1/220th of a second, t.1 or about 1/600th t.5)
We can see here that this just really isn't that useful of a photo for what our goal is. The water has extremely long blur trails, and even the short motion of the hand with the sewing needle popping the balloon has not been frozen. The duration used for this photo was 1/220th, t.1; 1/660th, t.5
This photo is just slightly better, but there's noticeable blur everywhere, especially in the outer droplets of water. This photo was taken at 1/400th t.1, or about 1/1200th t.5
Here's a very tight crop of the same photo above
Note that this has nothing to do with shutter speed of the camera. Again, in situations like this, the duration of our flash essentially determines our action stopping potential.
Yikes, still not getting good results here.
But, it's easy to see where most studio flashes get caught up and really start having trouble here. Action stopping potential of most strobes that folks own, which will be your monolights, are as follows:
(Times are in t.1, since we started there)
1/966 Bowens Gemini 500 Pro
1/883 Profoto D1
1/683 Elinchrom Style RX 600
1/600 White Lightning X1600
1/520 Elinchrom BX 500Ri
1/266 Elinchrom D-Lite it 400
Granted, we're still just second on the list of monolights at this point, but point still stands. Most flashes won't be so great at stopping intense action. Again, for most uses (blur on hands when jumping, etc) the photographer or client really won't care.
Sadly the flash system doesn't allow for a whole lot of variation at these settings, even when adjusting power, so the next jump we made was to 1/1300th second, t.1.
We're getting there. Actually, we're pretty close unless you really like to pixel peep.
But... *sigh*, on zooming in once more to our tight crop, we see that, though we're getting a pretty neat shot, our movement is not yet completely frozen. The discerning pixel peeper will catch the movement
Summarizing for the sake of page space and readability, the results remain pretty consistent as we approach higher and higher flash speeds: The motion blur becomes less and less, but the equipment is pushed to its limits more and more. The real question you must ask yourself is one of diminishing return and bang for buck. Just like the comparison between an 85mm f/1.8 vs f/1.4 lens ($500 vs $1600) -- is the extra for the slightly faster glass worth it?
To some photographers, absolutely. But for the majority of photographers, if something can get you 90% of the way for 20% of the price, well... it's hard to justify at times.
However, long story short we ramped up our power packs to its best flash speed it can handle: 1/10000th second, t.1. This is about 1/30000th second, t.5. Holy cow! And I think the pictures speak for themselves. So, yes, while the gear to get there may not always be practical, there's one thing we can't deny: It's pretty darn cool.
Please enjoy the photos. :) (Again, it's the same photo with a tight crop afterwards)
Talk about freezing action!!! There are NO blur trails here.
I'll leave it there, folks! Thanks so much for reading, as always. Until next time...
- Nikon D4s
- 70-200mm f/2.8 VR II lens
- Broncolor Scoro 3200s
- 2 Broncolor Unilite Lamp heads
- Broncolor Standard P70 Reflector
- Broncolor beauty dish