I've seen professional portrait shots where a person is stationary in front as the main subject while background activity (people walking, cars moving, etc) are blurred in the background. I'm not talking DoF here, but actual motion. Think industrial portraiture with perhaps a warehouse supervisor as the subject with employees, forklifts, etc showing movement in the background. I'm assuming that is captured by stopping down to limit the light collected, choosing a longer exposure, and then capturing the subject in the foreground with a flash. Is this the right train of thought? If so, how do you eliminate possible blur if the subject moves at all? Also, if you do stop down, that would increase DoF, correct? I would want the background to be slightly out of focus. Short of simply experimenting, any suggestions?
That would be my approach, Longer shutter with a subject freezing flash.
dweaver wrote:
I've seen professional portrait shots where a person is stationary in front as the main subject while background activity (people walking, cars moving, etc) are blurred in the background. I'm not talking DoF here, but actual motion. Think industrial portraiture with perhaps a warehouse supervisor as the subject with employees, forklifts, etc showing movement in the background. I'm assuming that is captured by stopping down to limit the light collected, choosing a longer exposure, and then capturing the subject in the foreground with a flash. Is this the right train of thought? If so, how do you eliminate possible blur if the subject moves at all? Also, if you do stop down, that would increase DoF, correct? I would want the background to be slightly out of focus. Short of simply experimenting, any suggestions?
I've seen professional portrait shots where a pers... (
show quote)
I like that effect, but the flash would freeze the action in the background. You could use an exposure of a few seconds, with the subject remaining still. You might need a ND filter.
You could also use software to place a sharp subject onto a blurry background.
http://www.ephotozine.com/article/how-to-create-motion-blur-in-photoshop-13112
How does one set up a camera (I'm using a Canon 7D with Canon SpeedLite) to flash on a longer exposure? Do you have to manually trip the flash or is there a setting that will trip it during the exposure? I'm assuming it may be at least a 2-second exposure to capture the motion.
Jerry, just saw your response. Hadn't thought about the ND but that makes sense. And yes, I suppose I could green screen the subject. Thanks.
tradio wrote:
That would be my approach, Longer shutter with a subject freezing flash.
OK. I get the idea. Long shutter and small aperture so as not to overexpose the subject. I've seen lots of shots like that, but Google didn't give me anything.
I believe this technique is called "dragging ths shutter":
http://neilvn.com/tangents/flash-photography-techniques/dragging-the-shutter/Good luck.
dweaver wrote:
I've seen professional portrait shots where a person is stationary in front as the main subject while background activity (people walking, cars moving, etc) are blurred in the background. I'm not talking DoF here, but actual motion. Think industrial portraiture with perhaps a warehouse supervisor as the subject with employees, forklifts, etc showing movement in the background. I'm assuming that is captured by stopping down to limit the light collected, choosing a longer exposure, and then capturing the subject in the foreground with a flash. Is this the right train of thought? If so, how do you eliminate possible blur if the subject moves at all? Also, if you do stop down, that would increase DoF, correct? I would want the background to be slightly out of focus. Short of simply experimenting, any suggestions?
I've seen professional portrait shots where a pers... (
show quote)
Great tutorial, Neil. Thanks! I had never heard the term 'drag the shutter'.
dweaver wrote:
I've seen professional portrait shots where a person is stationary in front as the main subject while background activity (people walking, cars moving, etc) are blurred in the background. I'm not talking DoF here, but actual motion. Think industrial portraiture with perhaps a warehouse supervisor as the subject with employees, forklifts, etc showing movement in the background. I'm assuming that is captured by stopping down to limit the light collected, choosing a longer exposure, and then capturing the subject in the foreground with a flash. Is this the right train of thought? If so, how do you eliminate possible blur if the subject moves at all? Also, if you do stop down, that would increase DoF, correct? I would want the background to be slightly out of focus. Short of simply experimenting, any suggestions?
I've seen professional portrait shots where a pers... (
show quote)
Just take an exposure long enough to blur those who are moving and have the subject stand as still as they can.
The shutter speed necessary depends on the movement speed you need to smear.
You can use flash....you don't have to. It's all in the "subject" not moving while the background people move.
dweaver wrote:
How does one set up a camera (I'm using a Canon 7D with Canon SpeedLite) to flash on a longer exposure? Do you have to manually trip the flash or is there a setting that will trip it during the exposure? I'm assuming it may be at least a 2-second exposure to capture the motion.
You need to just set your camera in Shutter priority mode...let the camera take care of the aperture.
Set an ISO as low as you can.
I prefer to shoot manually, it's easier for me to understand so If it were me, I'd get a good exposure: pretend it's cloudy:
ISO 200
f/5.6
SS 1/125
Then I'd start slowing down the shutter speed and stopping down the aperture to compensate...one click at a time
ISO 200
f/8
SS 1/60
(one more click)
ISO 200
f/11
SS 1/30
(One more click)
ISO 200
f/16
SS 1/15
(One more click)
ISO 200
f/22
SS 1/8
So you can see how to retain the same exposure while slowing the shutter down...every time the shutter opens a stop...the aperture must close a stop to keep things correct.
You can also see that when there is a fair amount of light..your shutter speed might be limited...as others have said..and ND filter (sunglasses for your lens) might be in order.
jerryc41 wrote:
I like that effect, but the flash would freeze the action in the background.
Not if that background or things behind the subject were far enough away so as not to be affected by the flash.
Keep in mind - flash power drops as it gets farther away.
Read about the inverse square law
HERE.
I once shot a whole wedding reception using the
drag shutter technique mentioned above (with Tri-X processed Dektol, a paper developer) for an art director I worked with.
I purposefully shook the camera during a longer shutter setting (1/15th or so) to get the blurred background and the flash froze the subjects.
The fact that the venue was dark helped a lot.
Unfortunately, I don't have any scanned images on the computer here at work to post.
Excited to try the technique. Quite the wealth of knowledge here!
I think you can use back button flash to create the background MOVEMENT blur, and the flash to capture your subject. Might be wrong.
djtravels wrote:
I think you can use back button flash to create the background MOVEMENT blur, and the flash to capture your subject. Might be wrong.
I think what you mean is
rear-curtain sync.
That would
still depend on the shutter setting, but may be something to consider if blur direction in important. :thumbup:
GoofyNewfie wrote:
I think what you mean is
rear-curtain sync.
That would
still depend on the shutter setting, but may be something to consider if blur direction in important. :thumbup:
Thanks for the correction. That's what I meant. If the flash goes off on the rear curtain any ambient light image blur is recorded first. Right?
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