Motion blur background?

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AndyG123

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Hi guys... I've seen images of say a person running, or a car driving past. And the object is sharp, obviously shot at a high shutter speed to freeze motion... But the background is blurred.
I know this can be achieved with photoshop very easily, but can this shot be achieved without processing? Is there some obvious technique I can't fathom?
 
Sharp car and blurred background => panning with a slow shutter speed.

Sharp runner and blurred background => some other technique. You can't pan on a running person without their arms and legs exhibiting motion blur. To freeze the motion and get the runner sharp you'd need a fast shutter speed, probably 1/250th at least, and then the background wouldn't be blurred. Of course you could blur the background using a wide aperture and a shallow depth of field, but that's a different type of blue and I assume that's not what you're after.
 
AndyG123 said:
Is there some obvious technique I can't fathom?
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Clearly ;)

The technique is called panning. The blurred background is created with the slow shutter speed. The sharp subject is created by keeping the subject in exactly the same part of the frame throughout that long exposure.

It takes a lot of practice, but it’s a simple enough principle.
 
StewartR said:
Sharp car and blurred background => panning with a slow shutter speed.

Sharp runner and blurred background => some other technique. You can't pan on a running person without their arms and legs exhibiting motion blur. To freeze the motion and get the runner sharp you'd need a fast shutter speed, probably 1/250th at least, and then the background wouldn't be blurred. Of course you could blur the background using a wide aperture and a shallow depth of field, but that's a different type of blue and I assume that's not what you're after.
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Scratching head....???

Think I have seen such runner pictures where panning shot with 2nd curtain flash was used. Was it also called "dragging the shutter" or am I mixing up two old memories of different techniques?
 
Box Brownie said:
Scratching head....???

Think I have seen such runner pictures where panning shot with 2nd curtain flash was used. Was it also called "dragging the shutter" or am I mixing up two old memories of different techniques?
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Scratching head because you're thinking about the technique, or scratching your head because you're not sure about what I wrote? I hope it's the former!

You might be mixing up memories, but only partly. Dragging the shutter refers to using flash with a slow shutter speed, so you get a mix of ambient and flash lighting. Second curtain flash is a variant of this, and what you'd use for moving subjects, but for static subjects you can drag the shutter with first curtain flash. So second curtain flash is dragging the shutter, but dragging the shutter need not necessarily involve second curtain flash.

(To the OP / @AndyG123 - if this is all double Dutch to you, here is a very good explanation if dragging the shutter, and here is a very good explanation of second curtain flash.)

The trouble with using this technique for runners though, is that if you're outdoors the ambient light can be too bright to permit a slow shutter speed, and the runner may well be too far away for the flash to be effective. I'm not saying it can't be done, but I think the circumstances often won't be suitable.
 
Thinking about this whole issue further, of course it is possible to get runners sort-of-sharp and the background sort-of-blurred just by panning.

There's a very famous photo of Usain Bolt at the Rio Olympics, where he's looking over his shoulder and grinning. Bolt's head is sharp-ish - not sharp in the way it would be for a static photo, but good enough for this sort of thing - and everything else is blurred.

Here's the story of how it was taken:
http://time.com/4452585/usain-bolt-2016-rio-olympics/

And here's the photo:
gettyimages-589521390.jpg
 
What hasn't been mentioned is the distance your panning from to the moving subject.This can make a huge difference to the final picture.
 
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StewartR said:
Scratching head because you're thinking about the technique, or scratching your head because you're not sure about what I wrote? I hope it's the former!

You might be mixing up memories, but only partly. Dragging the shutter refers to using flash with a slow shutter speed, so you get a mix of ambient and flash lighting. Second curtain flash is a variant of this, and what you'd use for moving subjects, but for static subjects you can drag the shutter with first curtain flash. So second curtain flash is dragging the shutter, but dragging the shutter need not necessarily involve second curtain flash.

(To the OP / @AndyG123 - if this is all double Dutch to you, here is a very good explanation if dragging the shutter, and here is a very good explanation of second curtain flash.)

The trouble with using this technique for runners though, is that if you're outdoors the ambient light can be too bright to permit a slow shutter speed, and the runner may well be too far away for the flash to be effective. I'm not saying it can't be done, but I think the circumstances often won't be suitable.
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Scratching head because I was trying to recall the possible technique(s) to achieve the desired result ;)
 
Be aware that when second-curtain sync is enabled, it doesn't switch in until the shutter speed drops to 1/30sec, and it's not really visually effective until longer speeds than that like 1/8sec.

Also, when panning with longer shutter speeds, like that great shot of Usain Bolt, arms and legs obviously get blurred but heads and bodies can bob around unpredictably too. In other words, shoots lots :)
 
As others have said it's not a post processing technique, it's using a relatively slow shutter while moving your lens to follow the subject (aka panning). Done right you should get a sharp subject and blurred background. It takes a bit of practice and your keeper rate is generally quite closely related to your shutter speed. The slower your shutter the more shots you'll end up binning so take lots. This was taken at 120mm and 1/80th, the car is probably travelling at around 100mph at this point. Having a lens or camera with IS helps a lot too.

Blancpain Endurance Cup, Silverstone 2017 by Richard Crawford, on Flickr
 
HoppyUK said:
Also, when panning with longer shutter speeds, like that great shot of Usain Bolt, arms and legs obviously get blurred but heads and bodies can bob around unpredictably too. In other words, shoots lots :)
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Yeah, I know that's what happens, but it bothers me, because the OP said this (with my emphasis):
AndyG123 said:
I've seen images of say a person running, or a car driving past. And the object is sharp, obviously shot at a high shutter speed to freeze motion... But the background is blurred.
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I can't think of any technique that's usable in the field to get a runner sharp and the background blurred. I wonder whether it has to be post processed?

@AndyG123 - Can you point to any examples of this you've seen?
 
StewartR said:
Yeah, I know that's what happens, but it bothers me, because the OP said this (with my emphasis):

I can't think of any technique that's usable in the field to get a runner sharp and the background blurred. I wonder whether it has to be post processed?

@AndyG123 - Can you point to any examples of this you've seen?
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I think you're reading too much detail into a general question. The way it reads to me, panning is the answer.

You could quite easily get a 100% sharp shot of a runner with blurred background by using slow-sync flash, though there would be also some blurring/shadow around the subject from the ambient light that would be more or less obvious depending on how dark/bright the background was. Second-curtain sync is a way of managing that, rather than eliminating it.
 
With no disrespect to the OP, it is after all a beginner's level question (I discern that from the way he asks if such a shot - even one featuring a car - can only be acheived in post), and I think the OP would be hard pressed to provide an example picture of a runner who's body is entirely sharp against a blurred background: many people taking a casual look at the Bolt picture above would say he appears sharp against a blurred background, because his head/upper torso more or less are, which are essentially the primary subjects of the shot.

Would be nice to hear from the OP though :)
 
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AndyG123 said:
Hi guys sorry been a bit busy the last few days had chance to get on here on my evenings really.
An. Example image is http://www.rialbike.com/magicpower/wp-content/uploads/2013/04/photodownloader.php_.jpeg

The guy seems quite sharp in places, obviously motion on his feet but the background is massively blurred. I do think panning is what is used after reading your posts..
Thanks guys. Some of the car shots are awesome.
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Another thing you can do is check the Exif data if it is still included in the image. Sites like Flickr generally show it anyway, but if you download an image to your PC, right click on the file and click Properties, the Details tab will then give you the Exif data, including what software the photo was edited with and all camera settings. Doesn't work for all images but it's a good way to learn how to achieve the look you are going for.
 
RichardC27 said:
Another thing you can do is check the Exif data if it is still included in the image.
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This is a good idea, with one caveat: when panning, shutter speed is dependant on the subject motion speed, you might need 1/15 for the same amount of blur on a cyclist as 1/100 would give on a F1 car on a straight.
 
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