Maurice,

This is a great way to experiment and I salute your analytical mind. That said, it would be simple to just connect the flash to the camera and not to the camera axe – no need to worry about shutter delay in this case.

blaise

Ah – I understand. It’s at the end when you explain how to set the delay that I thought this was the purpose of the exercise

That said, what you are measuring is of course lag between flash and camera. If you wanted only the camera lag, ie time between trigger and camera flash then you would need to add the flash lag as well right?

Blaise

Hi Maurice!

Just found your post about measuring the shutter lag, because I was doing some photographs of an ignited H2 (hydrogen) balloon.

Typically, if you want to capture short processes, there is the option to put your experiment in a dark room, set the shutter to bulb mode, take a microcontroller such as the camera axe and some acoustic/optical sensors to trigger a bunch of compact flashes running at very low power or an air gap flash just when you need it. That way, you can realize exposure times around 1/10000-1/25000th of a second or few microseconds in case of the air gap flash.

The problem with bulb exposures is, that you cannot photography glowing or otherwise “self illuminated” objects, since you would get a massive overexposure at exposure times in the region of many seconds. Also an exploding firecracker will leave smeared traces, because the burning debris will illuminate the sensor as long as the bulb state lasts.

So I needed to revert to using the camera’s shutter (ranging as short as 1/8’000th of a second on a Nikon D300, D700, etc.) and synchronize it to the event I wanted to capture. This introduces great delays, mostly because there are mechanical parts involved as you’re also pointing out in your video blog article. The biggest portion of the “shutter lag” is IMHO introduced by the mirror, which needs to be flipped up before the first shutter curtain can get going.

In consequence, I’m using “Mirror Lockup Mode” (“Mup” on Nikon cameras) to eliminate this delay and trigger the shutter using a home brewn firmware modification of the well known Photoduino because Nikon DSLRs need to have the focus line high to trigger the shutter in Mup mode.

I found out that this perfectly worked with H2 – but failed with H2+O2 (aka. “Detonating Gas”), mostly, because the burn time is much faster (see http://www.youtube.com/watch?v=qOTgeeTB_kA a cool slomo video and explanations).

So the problem is, how to indeed MEASURE the shutter delay (minus Mup time) to find out why the experiment failed. I decided to use the Arduino again to trigger the shutter but programmed it to immediately start incrementing a 8-LED-bar (showing the binary counter value) in 100us intervals. The neat thing is: If you photograph this bar (assume 11110001, where “1″ means a lit LED) , you can calculate the shutter lag from the (binary) number that is displayed on the DSLR monitor by just multiplying it with 100us (24.1ms in my example). This – of course – ends at a delay of 25.5ms, but its pretty easy to extend the range by adding a delay(20); in the Arduino code prior to the counter loop.

Advantage of my approach is, that you also get an impression of the jitter: Shutter lag has quite a big deviation around its mean value because of the mechanical parts involved.

Others do an audio recording of the shutter sounds and analyze this, but I consider that pretty crude.

Keep up the good work!
Volker