distavision.jpg st_zoomlens_f.jpg NASCA赛车时速非常之高。相机有足够的速度来抓拍200mph的动作，但是当你需要抓拍整个赛场的赛车时，你会怎么做呢？广角镜头会带来正如成像集中这样的画面扭曲，但是如果你一位的扩大变焦倍数来获得赛场的镜头的话，你只利用了你镜头感光元件的一部分，带来的结果是更多的噪点，和失真的图像。摄影师Rick Graves已经创造出了一个专为高速赛车定制的摄影方法来解决这个难题，而且已经拍摄出了非常漂亮的NASCAR赛车照片。
这个改良过的相机被称为dubbed DistaCam，利用一个高速的马达和一个带有缝口的金属盘子，有点像pinhole相机。还需要一些数字上的调整。焦距需要事先调好，马达的速度要和赛道上奔驰的赛车速度关联，长焦镜头的光圈也要准备就绪。一旦设置好数据，照相机就要对准赛道上一英尺宽的一点，然后祈祷飞驰的赛车将会从这点经过，你就不停地连拍。赛车刚好完美经过的事也不是经常发生的。连拍后的照片通过Photoshop将它们缝合起来，形成完整地图片。当我们说所的都做好后，完成后的照片将会像怪兽一样有100英尺那么厂。酷啊！他们就是用这样的把戏来摄影的。
Hacking NASCAR: The Ultimate High-Speed Photography KitRick Graves can stop time. OK, not really, but he can freeze 43 NASCAR racers clocking almost 200 mph. How? The pro shooter modified his Hasselblad into what he calls a DistaCam — adding a high-velocity motor, locking the shutter open, and inserting a metal plate with a laser-cut slit. Whenever Graves triggers the motor, film zips past the slit at up to 1,400 rpm, capturing stills of the speeding cars. "Failure is a necessity," he says, "and a lot of times, success is luck."
4 Steps to Shooting Stills at 200 mph1 MeasureGraves determines focus distance with a laser rangefinder. He then uses real-time stats from the Web to match the camera motor's speed with that of the racers — too slow and the cars appear stretched, too fast and they compress (like numbers 2 and 38, above).
2 Do Some Quick MathUsing a dozen formulas he has stored on his Treo, Graves figures the aperture of his telescopic lens, frame width, and motor speed. Then he aims his camera at the 4- to 6-inch slice of pavement that the cars will pass over.
3 Load the Film and Cross Your FingersGraves waits until the cars are tightly bunched before attempting a shot. He triggers the motor just before the first car enters the frame (adding a fraction of a second to let the film motor hit top speed).
4 Scan Onto PCAfter developing the 66-inch roll, Graves scans 10 inches at a time. He stitches these sections together in Photoshop and spends several hours removing hairlines and spots. The photo file, up to 3 GB, has been printed as large as 280 feet by 7 feet.
这个太强悍了，更具体的效果什么的看这里吧：http://www.wired.com/gadgets/digitalcameras/magazine/15-07/st_nascar
