Motion blur question with static model

[bagley_crowder2]

<p>Folks,<br>

I want to take a picture of a model in a tunnel at night with light trails from motorcycles whizzing by her. I want her to be in focus along with the environment, with only the light trails blurring. I would like to light her using moody "loop lighting" with off camera alien bee positioned on the right, and strobe positioned behind her to create a rim light (so I think this rules out rear curtain sync). <br>

What is the best method to accomplish this? I'm thinking composite with two images- take one of her with the lighting I want, and then photograph the motorcycles coming through the cave from the same point and combine? THANKS IN ADVANCE FOR YOUR HELP!</p>

<p>Bagley</p>

[paul_k1664875007]

<p>As I'm not an expert on making composites of two or more pictures (in which case on a side note it would become digital manipulation, and means the question should be posted on Digital Darkroom) I would do it the old fashioned way.<br>

I assume it's not a very long tunnel and the cars therefor will only take a few seconds o pass through it.</p>

<p>First determine by playing around a bit what the longest exposure is at which the tunnel stays dark enough for the desired effect, while at the same time recording the passing cards lights in the way to get the light trail effect you're after.<br>

You of course can do this well before you're doing the shoot with the model, without the model, and even take the test shots hand held since blurry and unsharp won't be important yet at that moment.<br>

If you use a low ISO and close the lens down a few stops, you probably will end up with a shutter speed of several seconds.</p>

<p>When you are going to take the actual picture with the model, put the camera on a tripod, and set up the flash. However don't connect the flash to the camera.<br>

Dial in the settings you found (1st or 2nd curtain isn't relevant, as you basically want the light running from one side of the picture to the other, not just in front or behind the model).<br>

Pose the model, take care you get as little, if possible none, fill in from the available light on the model, as possible, it will risk ruining the effect you're after. And it will also possibly mess up the color/skintone of the model (mixed flash and since it's in a tunnel fluorescent light, not the best combination) so IMO should be avoided as much as possible<br>

Wait till you see a car at the beginning of the tunnel, at which moment you open the shutter.<br>

While the shutter is open, wait till the car is more or less behind the model, and at that moment ignite the flash (most practical would be some kind of remote trigger which you can operate manually).<br />Close the shutter when the car is past the model and far enough to have the light trial from the head lights long enough to get the effect you like.<br>

Check if you have the picture you're after (probably not the first time) and if necessary reshoot.</p>

<p>The whole operation resembles old fashion 'light painting' technique, as used in the past to eg (partially) illuminate buildings or landscapes with a handheld of camera lightsource.<br>

Joe Mcnally did something similar in this item in his blog http://blog.joemcnally.com/2008/07/02/rollin-with-the-pride-of-midtown/<br>

In his picture, the street lights are recorded in the typical yellow/orange color you get when you shoot artificial light (3200-3400K) with the cameras WB on daylight/flash (5500K).<br>

If you want to avoid that (although I personally don't find it disturbing in the Mcnally picture), put some daylight-to-tungsten filter over the flash, and put the WB on the camera on Artificial light. Now the flash and artificial light of the (in your case) car lights and tunnel lighting will be (more or less) balanced.</p>

<p>On a side note, using flash in a dark tunnel with cars passing by? Hope the driver/drivers are friends of yours who are into the plot so they won't be surprised by the flash when they drive by. From that point of view, the digital composite picture is a safer solution</p>

<p>my two cents</p>

[rodeo_joe1]

<p>You should be able to capture the shot live in camera without resorting to compositing.</p>

<p>Rear curtain synch is only relevant if you want to show the vehicle making the light trails lit by flash in front of the trails and not behind them. If all you want to see are the light trails, then it doesn't matter whether you use rear or leading-curtain synch.</p>

<p>All you need to do is extend the shutter time sufficiently to catch the light trails, while keeping the model unlit apart from the flash. This means turning modelling lights off and keeping the motorcycle headlights and any ambient tunnel lighting off the model. The style of lighting used on the model is irrelevant. All that matters is that it's flash and has a duration much shorter than the exposure required to capture the light trails.</p>

[russ_britt3]

<p>Set your f-stop for your flash unit, and your shutter speed to capture the ambient light source.......<br /><br />Example: if your flash to subject distance works out to F-8, but your ambient light (non flash) is F-8 at 45 seconds?<br />Then shoot F-8 at 45 seconds. The flash will capture the model, your slow shutter speed will capture the ambient part of the exposure. <br /><br />Its really that simple I learned this from Don Blair, a great master photographer years ago.</p>