Military Exercise

I was recently invited to photograph the Swedish military at a shooting exercise. After getting over the initial shock, I responded with a "Uh, Hell yeah!". Opportunities like this do not come around often. Never having been in the army, it was a little scary to be so close to live ammunition, but wow was it an amazing experience!

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Soldiers prepare to fire the KSP 58, the Swedish version of the FN MAG

I have been interested in guns from movies since I was young. I was fascinated by their mechanics and I knew some technical info, but it's very different seeing them being used in real life. You don't see barrels being changed after 200 rounds because they get too hot in Rambo, or even Full Metal Jacket for example. So it was nice to capture these details.

Some technical aspects of using weapons feel similar to cameras (point and shoot, aiming, shooting speeds, using your index finger to take a shot etc.). Maybe this has influenced my passion of photography...

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Combining guns and photography reminded me of an article I read recently, a photographer capturing a bullet at the Olympics, using the new Nikon Z9 camera. Despite my camera (Sony A9) being from 2017 it is also capable of shooting 1/32,000th of a second shutter speed and 120 frames per second (albeit with 1080p video), so I thought "why not try it"...

Super Speed

The general purpose support machine guns you you see above (KSP 58) fire 7.62 x 51mm Nato rounds at 850 m/s (2,800 ft/s). That's a lot faster than an Olympic target rifle, so I knew this would be a bigger challenge. However this was not the only gun being fired here, so I turned my attention to the Carl Gustaf GRG m/48 recoilless anti-tank, grenade rifle. This fires at a more reasonable & sub-sonic 290 m/s (950 ft/s).​ About 15% slower than an Olympic target rifle, it would be a little easier to capture, but considerring the significantly larger caliber it should be a bit more exciting to look at!

Bullet Time

I wasn't quite sure what I expected, but I was really impressed by the results. Plus, capturing high speed video of the result from behind made for quite the crowd pleasing shockwave effect on the dry grass. Using a 135mm (Sigma Art) lens allowed me to keep my distance a little while getting a slight angle from behind without getting into the danger zone.

Sound

Standing this close to anti-tank weapons required the use of double ear-protection. I had no dedicated microphone and hadn't even played with the audio levels on the camera so I thought the sound would be useless. To my surprise it was actually pretty great. Those inbuilt Sony pre-amps are really impressive!

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Camera Tech Talk

At the speed of this bullet you should see the following amount of motion blur at each shutter speed (bare in mind that the projectile caliber is 20mm):

  • 290mm @ 1/1,000th

  • 150mm @ 1/2,000th

  • 073mm @ 1/4,000th

  • 036mm @ 1/8,000th

  • 018mm @ 1/16,000th

  • 009mm @ 1/32,000th

The Sony A9 sensor's scan speed of 1/160th of a second, this means that a full frame scan (from top to bottom) takes 6.25ms (miliseconds). Considering the the average size of the projectile on the frame it should scan in roughly 0.01ms. That's quick, but remember the bullet is travelling at 290,000mm/s. If I have done my calculations properly that should equate to a slant of 2.9mm.

Although there are slightly better cameras around for these speeds. The Sony A1 being capable of 50 megapixels @ 30fps (compared to my 24 megapixels @ 20fps) and with a slightly faster scanning sensor (1/240th vs 1/160th), this would only slightly help here. Plus it would cost an absolute bomb (no pun intended)... 

This next image of a bullet from the KSP 58 was taken at only 1/1000th of a second, so the streak you see here is the bullet stretched over the length of 850mm. Is there any chance I could make this work?...

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Although I could push this camera further (5 stops higher shutter speed), it would only take that blur down to 27mm. Considering the bullet caliber is only 7.62mm this will still remain significantly blurred for its size. I guess we will need faster burst rates, higher electronic shutter speeds, faster scanning sensors, deeper buffers and more light. Did I leave anything out?... :)

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Hindsight

I can see a few things I would like to improve on next time. Here's a list of things I would do differently, if I get another chance:

 

  • Using a tripod rather than a monopod (cleaner video & maybe getting closer to the danger zone?)

  • Taking the bluetooth remote so I can take photos and videos from a distance

  • Shoot at the highest shutter speed most of the time (manual settings with Auto ISO)

  • Shoot more stills than video (will give better results for stills, albeit much more difficult)

  • Take the slightly faster 85mm lens for better chance of low noise with high shutter speeds

So, I hope that I get another chance at this. As much as I complained about the harsh lighting on the day it was actually pretty good at getting clean images at high shutter speeds, so fingers crossed that the weather is kind to me next time too...