A time lapse blur into frozen, flashed subject?

[Bombsight]

Going to shoot drag races this weekend and was wanting to try something.


I'm wanting to open the shutter with the car on the starting line, or as its coming off of it ....and create a blur of its forward motion ....then capture a solid image of it ....sharp, vibrant and frozen about 30'off the starting line ..... all in the same image.


Is it possible?


I'mknow the "start-to- blur" is no problem. Shutter open for 3 seconds and then closed with a wide aperture and boosted ISO, depending on lighting. Most likely shooting around sunset.


..... but capturing the car in all of its color and sharpness (like its standing still), once the shutter is open, is whats confusing.


If I were to use a flash (off camera and hand held) after1-3 seconds from start,closing the shutter as soon as the flash is activated ..... would that stop the blur, freeze the motion,and give me the image of a racer with a blurred trail from the starting line?


Has anyone ever tried this? What are my options.


Thanks for any help.

[Sean Setters]

What you need is the off-camera flash set to rear-curtain sync. Usually, a flash fires as soon as the shutter opens. However, you can set the flash to fire at the end of the shutter just as it's about to close. That would get the results you're looking for. However, Canon doesn't make this easy...


If you were shooting with a Nikon camera, you could set rear-curtain sync from the camera. The camera would fire the trigger (sitting on the camera's flash shoe) at the right time to sync all flashes with the rear curtain. However, Canon's rear-curtain sync is much more complicated. Canon's rear-curtain sync is controlled via a TTL pin instead of the center pin. Therefore, in order to use rear-curtain sync with an off-camera flash, you must use a master flash (like a 580EX) on camera triggering Canon flashes off-camera. Using ETTL, you can use a master flash to trigger off camera flashes, or you can use a master flash (and Radiopopper PX trigger/receivers to trigger off-camera flashes) or else use the Pocketwizard Mini/Flex on camera as a master (I believe that's possible).


There is a possible work-around, but it's a little complicated. Basically, you need a 580EX on camera set to rear-curtain sync. You use the light coming from the 580EX (when it fires) to optically trigger other flashes. Considering you'd be at a race where there will likely be dozens of flashes going off all the time, this method is unlikely to work well for you (and may burn up your optically triggered flash).

[Geoff]

Sean beat me to the punch line.[]


The trick will be to balance your ambient light and flash while using a rear curtain sync. Here was my attempt at a similar photo this summer.





photo data: canon 50D, ISO 400, f8, 1/20th, 28-70 2.8L at 28 mm.





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[Sean Setters]

If you could position yourself a little ways down the track, close to the track, you could possibly use an on-camera flash (set to rear-curtain sync) to get something that looks pretty good. You'd need to calculate a shutter speed that starts as the car is beginning its run at the starting line and ends as it's near you. That might get you what you're after (something like what Geoff did in the above picture).

[Bombsight]

That's exactly what I'm wanting to do..... only a little longer of a blur. That shouldn't be a problem with the speed of some of those cars.


I'm shooting with a 5DMKII or a 7D..... Cant make up my mind..... Low light sensation or fantastic focus.


I'm leaning toward the 5DMKII because of the high ISO superiority. Focusing shouldn't be an issue as long I use center point AF, right?


I have a 580EXII.


Rear curtain sync, huh? I'm going to have to read up and study on that issue.... Never have used it.[*-)]


Any links for dummys out there on that issue?


.... btw, thanks for the responses.

[Shea Design]

MENU / External Speedlite control / Flash function settings / Shutter sync / 2nd curtain (synonymous with rear curtain).


Remember you can whip pan the camera too and burn in that 2nd curtain flash for other looks. Combine with mode 2 pan?


-Shea

[Chuck Lee]

Here's some food for thought: At least things I'd consider....right or wrong


1) Make sure when you are composing the shot that there isn't anything very bright behind the car when you want it to be illuminated by the flash. This causes ghosting like you see in the bike photo example. The car will look transparent.


2) You will want to use a large aperture (smaff f stop) like f4.0 or less on the 5DMkII. This will maximize the light from the flash. You will obviously be throwing light from a considerable distance.


3) Adjust ISO to control exposure of flashed subject.


3) Snoot your speedlight if possible. (The Honl 8" comes to mind) That will help focus the light blast on the car and not blind every spectator in the park. LOL. The Honl will act as an amplifier and maximize your flash burst. It will also focus the light just on the car andleave the blur trail showing better against a dark background. Otherwise that area will be flash lit as well.


4) Use at least a 1/2 CTO - 1 CTO gel to balance for the race parks lights. I hope they're something other than sodium vapor but I would imagine they probably are. 1 CTO will help dramatically but won't completely erase the yellowing effects. It will also slightly diminish the power of your strobe. I think -1/2 stop. Someone, please correct me if I'm wrong on that.


5) Try shutter speeds of 1 -3 secs and pop your flash manually. Practice beforehand and see if you can get your timing down. I've done a few like that and you'd be suprised how easy it is to sink yourself.


6) If the ambient light is not creating enough of a blurr, turn up the ISO and stop up. If you get to f2.8 and still can't get a good balance then you'll need more flash power or need to get closer. If the opposite is true then lower ISO/stop down or lower ISO and reduce flash power.


Note: Remember, aperture controls flash exposure, shutter speed controls ambient, and ISO balances the two. You will be shooting in M mode.


Have fun and hope to get a few keepers. We all learn as we go. The creative stuff is what really makesphotography fun.


I tried drag shutter circular blurred flash images of my kids while they were decorating the Christmas tree last year. I can't say that out of the 12 plus attempts I got anything jaw dropping but I did get a couple of interesting keepers and the practice of trying. The shake and bake stuff worked pretty well. The lights on the tree showing up in flash photos. It's a cool effect.


Good Luck...It is a noble quest.