stephen patience Posted February 28, 2009 Share Posted February 28, 2009 <p>All,<br> I'm keen to capture the best pictures of motion with a strobe flash gun - they likes of a bullet going through a light bulb. While I've read up on the techniques and setting the conditions on how to do it, I'm wanting to know what the best type of flash to buy. I've been told a Mertz 45 CL hammerhead will do the job. Do any of you have any recommendations? Thanks in anticipation.</p> Link to comment Share on other sites More sharing options...
steve_levine Posted February 28, 2009 Share Posted February 28, 2009 <p>Prof. Edgerton at MIT (of breaking balloon and splattering milk fame) used specially built strobes that had extremely short durations ,nearing 1/millionth of a second as I recall. A Metz or other commercial strobe will not fire any where near such a short duration. Even if you get a high speed strobe, the biggest issue to over come in this type of work isn't the flash duration. But figuring out how to have the flash fire at the correct moment to capture the action.<br> Google "Harold Edgerton" and read up on his technique.</p> Link to comment Share on other sites More sharing options...
frank_skomial Posted February 28, 2009 Share Posted February 28, 2009 "I've been told a Mertz 45 " - Metz can do by others can do it faster. Metz 45 is not the fastest popular flash by far, with max flash duration is listed as 3.3 milliseconds. There are a number of faster flashes available, e.g. Nikon SB-800 at 1 millisec max duration, that makes it over 3 times faster. You do need to be "told" just read flash specifications. As Steve explained, the trick is in the event synchronization more so than the flash duration/speed. Link to comment Share on other sites More sharing options...
bob_sunley Posted February 28, 2009 Share Posted February 28, 2009 <p>Try here for the basic how to's on what you are interested in.<br> http://www.hiviz.com/GALLERY/galleries.htm</p> <p> </p> Link to comment Share on other sites More sharing options...
stephen patience Posted February 28, 2009 Author Share Posted February 28, 2009 <p>Thanks for your useful contributions. The link above was very helpful. </p> Link to comment Share on other sites More sharing options...
joseph_wisniewski Posted February 28, 2009 Share Posted February 28, 2009 <p>Frank is right on this one, Metz flashes are dogs for high speed work. About twice the duratiom of Nikon or Canon flashes of similar power. And even the Nikon and Canon flashes can't stop a bullet.<br> <a href="../nikon-camera-forum/00Nhm4">Here's a pretty good photo.net thread on the subject of motion stopping.</a><br> I posted several pics there (shattering wine glasses, fruit blasted with a pellet gun, etc) along with the techniques I use. Since the shots require very short duration flash, these were all done at 1/32 power or less. Because there's so little power, I connect several flashes together to get more light. That's OK for flying glass or spraying fruit pulp as the pellet gun blasts a grape.</p> <p>You'll notice that my shots of things exploding don't show the actual pellet that shattered them. My flashes aren'y fast enough for that. Bullets cutting cards are even more difficult. A "slow" bullet moves at about 1000 ft/sec (300m/sec) and is about 1/2 inch (12mm) long. That means, to have it looking somewhat "bullet shaped" instead of just a streak, it has to be less than 10% blurred. So, you need a flash that can get you to 1/10 of 1/2 inch, at 12,000 inches/sec (1000 ft/sec). That's:</p> <blockquote> <p>(1/2 in * 1/10) / 12,000 inch/sec = 1/240,000 sec or 4.2 microseconds</p> </blockquote> <p>The fastest speedlights (late model Nikon or Canon, turned down to 1/128 power) do about 1/40,000 sec (25 microseconds) and make the bullets look pretty blurry. The blur is over half the length of the bullet. Some college photograpy or physics departments have special strobes that go down to 1/1,000,000 sec (1 microsecond) or less, and bullets look great. Those kind of strobes can also be rented, or built (if you're nuts enough to play with that kind of circuitry).</p> Link to comment Share on other sites More sharing options...
stephen patience Posted March 1, 2009 Author Share Posted March 1, 2009 <p>Thanks Joseph. I think I'm going to have to invest in a laser trigger. I'm also looking at a Nikon SB 900 flash and borrow a few other flash guns to achieve this. Did you manage to do an article on high speed and put it on your site as per your earlier post of Dec 20, 2007; 09:49 p.m?</p> Link to comment Share on other sites More sharing options...
joseph_wisniewski Posted March 2, 2009 Share Posted March 2, 2009 <p>Stephen,<br> Unfortunately, life got in the way of the website refresh. I'll be out of this cast soon, and getting back into the swim of things.</p> Link to comment Share on other sites More sharing options...
dan_selvidge Posted July 16, 2009 Share Posted July 16, 2009 <p>I took a class recently at the Edgerton Center at MIT and we used a Prism Science Works SPOT strobe to freeze bullets. This special flash has a 500 nanosecond duration and they run about $3K per light.<br> As for the triggering, they used a Mumford Time machine and the acoustic trigger. It wasn't complicated, just a bit of work getting everything synchronized.<br> You can see some of the still images the class created <a href="http://web.mit.edu/edgerton/6.51s/2009/">here</a><br> Dan</p> Link to comment Share on other sites More sharing options...
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