Hi, Tom Reese wrote:
> I will try to do this in daylight with flash equipment set relatively close > to the target for maximum power. My camera will be a bit further away with a > telephoto lens (I don't want splattered fruit all over my lens!). I thought > I'd stop the lens down to f/22 and shoot at maximum flash synch speed. > Hopefully, the flash duration will be short enough to freeze the bullet and > the small aperture will minimize the daylight exposure on the film. At 700 > fps a bullet travels 5.6 feet in 1/125th of a second so I have to eliminate > daylight as a light source. This may require a box with the flashes poking > through holes in the side. A flash duration of 1/50,000 of a second would > give me bullet movement of .168". That might be the best I can reasonable > expect. I don't know what the shortest possible duration of my flash > equipment is. I have an AF400FTZ and a METZ 50 MZ-5. They can supposedly be > operated together. Hopefully the combination in TTL mode will give me the > short flash duration that I will need to make this work. You will need to _eliminate_ daylight. At least, effectively. You will be working with an open shutter - trying to synch the shutter as well as the flash is going to drive you potty. The _flash_ acts as the shutter. Minimum delay between triggering and exposing. Otherwise you will have to trigger the shutter at some point early in the bullet's trajectory, hoping that, by the time the shutter has opened and the flash has gone off, the bullet is somewhere in the frame. It will be complete and utter guesswork. As you will have to open the shutter and then trigger the apparatus, extraneous light needs to be removed. TTL flash will probably not work unless you can arrange a completely white background, close to the plane of focus. It keeps going until it is satisfied that there is enough exposure. Manual flash will have a fixed duration - the lower energy manual outputs of flashes like the AF400T and one of the old, auto/manual third party beasts whose name I forget at the moment will be ideal, as they will be shorter. _One_ flash, to be sure of not getting multiple exposures. Then arrange backgrounds/apertures until you get a suitable combination that exposes properly. One thought - a piece of dowel, of the same diameter as the barrel and long enough to reach the target, can be inserted to give you something to focus to for when you are trying "before and after" shots. Ideally, you should search for some links to get circuits for high speed flash assemblies. I suspect that ordinary equipment is not going to make it. To get enough illumination, it will have to fire for too long. <enablement> Strikes me as ideal work for digital..... </enablement> Certainly will be interested to see the results. mike
