auxr8220 wrote:im going to reshoot the freeway, i want to see if i can get a group of mates both ways on the freeway and get them to zig zag over the road.
There's obviously quite a bit of danger inherent in that sort of an exercise. You'd need to have the road totally clear of other traffic. And I mean totally clear: even traffic going in the opposite direction could be an issue, as they may be startled by what they see. Perhaps a word to the local boys in blue to ask them if they have any suggestions in helping you to achieve this in complete safety?
Alternatively, a closed road - I'm thinking in terms of hiring a racetrack - might be the best way to go.
Or maybe even find a large open parking lot at night. Not the same, I know, but I cannot emphasise too strongly the need to do this in absolute safety. And FWIW, my background in motor sports goes back even further than my background in photography.
so i can keep the long exposure just reduce the amount of light is coming into the camera?
While the short answer might might be yes, the real answer comes down to the quantum by which you do this.
There are basically just two ways that you can control the amount of light that reaches the sensor: time (shutter speed) and aperture (the size of the hole that lets the light hit the sensor). By making the aperture (size) smaller (which is a larger number - f/11, f/16, f/22), you reduce the light that is available for the sensor.
But you need to balance that in two ways.
The first of these is to achieve the correct exposure, and so, yes, to a large extent, that will achieve what you;re suggesting.
The second is to ensure that you get a pleasant lookign image, and in this instance, that will pertain, I suspect, to the apparent length of the light trails that one can see in the images. In this case, the longer the exposure time (slower shutter speed) the longer the trails, provided the vehicles are moving.
Now that raises for me the question of how long should those trails be? There's no correct answer to that question, except of course to say that it's however long you want them to be. My gut feel is that what I've seen in this image is that they're too long, but that's just my opinion, and in this realm, my opinin isn't all that important.
What is important is your opinion, and how you want the image to look. Given the cost of shooting a dozen images is just your time to shoot those dozen images, my best suggestion is that you do exactly that: shoot a dozen (or more) images. Use a variety of shutter speed and aperture combinations, and just see what works for you.
Play, and then play some more.