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Photography Question 
AJ Norris
 

Racing Photography at Night


 
  racing night time
racing night time
© AJ Norris
Canon EOS Digital ...
 
 
I photograph dirt track late models for a few of the local drivers. During the day the photos are great, but as the sun goes down the photo quality goes down as well. I have a Canon Rebel XT and use a 430 ex flash. I shot on Tv mode at 1/500 and have the ISO cranked all the way up and I get a very noisy picture which I expect, however usually only a part of the car is heavily lit. Other photos that I've seen around the track have the entire car lit up as well as some of the track surrounding the car. Granted those photographers are using Metz, Norman, etc flashed but I would hope that I should be able to get a brighter pick overall.


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5/3/2007 8:23:17 PM

 
Alan N. Marcus   Hi AJ N,

Your results are typical wherever: Night photography – using flash – high –shutter speed. You are using shutter priority i.e. you select the shutter speed, chip logic chooses the aperture.

Consider that the electronic flash you are using has an exceeding fast duration. A high speed flash is capable of arresting motion regardless of the camera’s shutter speed. You are setting the shutter at 1/500 sec. and there is no need. Let’s explore what would happen if you used a lower shutter speed.

If you used a lower speed like 1/60 sec. the flash will arrest motion however the ambient light from the floods above will be allowed to contribute to the exposure. This is true because both film and chip accumulate light. This is exactly what you need to have happen. This will solve you grievance which revolves around the fact that the light from a flash falls off rapidly with distance. Each doubling of the distance, say the difference between 9 feet and 18 feet bring about a light fall off by a factor of 4. Stated another way, If 100 watts arrives at 9 feet, only 25 watts arrives at 18 feet. That translates to a two f/stop decrease in power. This drop off is too extreme for uniform exposures over the entire length of the chassis of a racing car.

Countermeasures:
a. Use a lower shutter speed to allow ambient light to record.
b. Step back! If the electronic flash has the power and will permit. Use a longer lens to allow composing at increased subject distance. This act reduces the ratio of the distance front of car to rear, this will even out the exposure.

Best of luck,

Alan Marcus
ammarcus@earthlink.net


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5/3/2007 10:10:05 PM

 
AJ Norris   Thanks for the reply Alan. As far as stepping back, I really can't as I stand behind a jersey barrier so that I don't get hit by the cars. With the shutter speed, how slow do you think I can put the shutter speed while keeping the sharpness of the car. The car is going about 90mph when it goes past me. I know its trial and error but I wasn't sure if you had any guidelines or pointers about shutter speed. Thanks, AJ


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5/4/2007 4:40:15 PM

 
Alan N. Marcus   I suggested 1/60 sec. I know this will not freeze the motion of the cars. You can try 1/125. This probably won’t arrest the motion. What to do? You need the slow shutter speed to record the surrounds and the car. Your only option is called panning. This is a technique whereby you follow the motion of the car, keeping it centered in the viewfinder. The idea is match the pace of the cark keeping the camera moving i.e. synchronized to the motion of the car. Now the trick is to squeeze off the picture without stopping the camera. That’s going to take a little practice. Stated another way; the camera stays in motion while the shot is taken.

Matching the motion of the car as you swing the camera will go along way towards arresting the motion of the car. You might find that with practice you can eliminate the flash and take your shots using only the ambient light. What will happen is the motion of the car will be mostly arrested and the background will become blurry due to camera motion. This technique will give an illusion of speed. If you use the flash, you will get a clear, frozen auto chassis together with some streaking that will add to the sensation of speed.

Your only other option is a super fast film/chip and a super fast lens to gather more light. A lens with an aperture of f/1.4 would be ideal.

Best of luck,

Alan Marcus


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5/4/2007 6:28:43 PM

 
AJ Norris   What about bumping the EV up to 2...Right now I have it at the default 0. Are there anyother settings that I could adjust that would give me a little more help? Thank you.


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5/4/2007 6:59:59 PM

 
Alan N. Marcus   Ev or “exposure value” is a system used to express the light energy of exposure. In an elegant manner a single value Ev symbolizes the sum of the aperture value and the time value. By adjusting this value you are applying a correction factor. Stated another way: If by knowledge or experience you known that a particular scene will result in under or over exposure, you apply a correction that overrides camera logic. Thus you bump up the Ev if you think an under exposure will result or conversely you reduce the Ev to avoid an over exposure. The camera will respond by altering the shutter/aperture combination per your wishes. I don’t think this will accomplish your goal.

I think panning is your best bet. A car coming directly at you or reseeding from you requires no panning. This direction of motion is arrested using a show shutter speed. A car crossing your path at a 90° requires the fastest pan and the highest shutter speed. A car that transverses at a 45° requires a moderate pan and a moderate shutter speed.

You can practice various methods, i.e. no pan vs. pan and with and without flash. I think best will be pan with flash, camera set to highest ISO equivalent speed. A super fast lens like f/1.4 won’t hurt.

Alan Marcus


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5/4/2007 7:52:54 PM

 
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