Selective Motion Blur/Depth of Field?

[DestinationAlan]

Hi everyone,

I just registered for this forum today so I apologise in advance if this question has been asked again but there are a couple of shots I want to try with my shutter speed:

1. One subject in a crowd walking on a footpath being blurred out due to motion blur but the crowd remains focused
2. The opposite where the crowd is blurred out but the subject is focused
3. In sports (especially athletics) where theres two runners who are focused but one runner is blurred out. A bit similar to the iconic shot of Usain Bolt smiling at the 2016 Olympics.

I am just trying different experimentations as I've been thrown into the deep-end and given a photography assignment for the student magazine next week!

[Mike Buckley]

Welcome to the forum, Alan!

Please define what you mean by "blurred out," as that definition can affect the answers you receive. I'll hold off on responding until I learn that.

[Stagecoach]

Hi everyone,

I just registered for this forum today so I apologise in advance if this question has been asked again but there are a couple of shots I want to try with my shutter speed:

Welcome to CiC.

I'm a bit confused by the title but here's some thoughts......................

1. One subject in a crowd walking on a footpath being blurred out due to motion blur but the crowd remains focused

For the subject on the footpath to be blurred due to motion blur obtained by using a slow shutter speed the crowd would have to be almost if not completely still to be in sharp focus?

2. The opposite where the crowd is blurred out but the subject is focused

For this one the subject walking on the footpath could be panned but the degree of blurring of the crowd caused by the camera movement would depend upon their movements directions.

3. In sports (especially athletics) where theres two runners who are focused but one runner is blurred out. A bit similar to the iconic shot of Usain Bolt smiling at the 2016 Olympics.

The iconic shot of Usain Bolt you refer to I suspect is the one where he is looking inwards to the runners just behind him, there is motion blur in the runners but his face is spot on sharp.

This shot was a pan using a slow shutter speed and there was some luck involved, possibly a burst as well. Bolts head would have been pretty steady with motion in mainly the forward direction.

I am just trying different experimentations as I've been thrown into the deep-end and given a photography assignment for the student magazine next week!

You mention DoF in the title but this will only be of any use where you can guarantee separation by depth of your subject to background (crowd).

[DestinationAlan]

Hi Mike,

Sorry for not being more specific but I found some photo samples of what I am trying to do!



In the first picture, the band are focused but the crowd behind them are blurred out. I want to know how to do this and the opposite: Instead of the crowd being blurred out, its the subject instead.



Here's another example:

http://pasteboard.co/yz7iru93f.png

So crowd over the two people in the foreground being focused.

I hope that clarifies things for you!

[DestinationAlan]

Apologies I do not know why I wrote in depth of field. So basically I would just have to experiment a lot?

[Stagecoach]

Apologies I do not know why I wrote in depth of field. So basically I would just have to experiment a lot?

Alan

For the two examples shown in your post No4 and the one linked to your subjects are still and the crowd behind/around them moving. To achieve this just shoot with a long shutter speed. Some experimentation will be necessary but try 1 or 2 seconds to start with.

For the shot where you want "Instead of the crowd being blurred out, its the subject instead." I can only think of two ways to achieve that;

a) The crowd being still and the subjects moving (slow shutter speed again).
b) The crowd all moving in the same direction (?), your subjects still, and you pan the crowd. But I suspect not achieveable.

[Dave Humphries]

Hi Alan, welcome to the forums from me.

The two example shots you provide both show (to me), the same thing, not opposites.

In both, the subject is sharp and the people that are not the subject, are blurred because the shutter speed used was significantly long in relation to their speed of movement across the frame. e.g. 1/4s to 1s, probably 0.5.

The technique is also reliant on your subject(s) keeping perfectly still during the exposure and you keeping the camera still too, e.g. by use of tripod. We can see this was achieved because the backgrounds are sharp.

In the first example, none of the five has apparently stayed still enough as they are softer than the road below their feet
The chap in the second example pulled it off though

Cheers, Dave

[DestinationAlan]

Hi everyone! Thank you for your helpful replies and welcomes (I will do a proper hello in the new members thread). I will definitely need to get a tripod over the couple of days and experiment as I only recently started learning about photography. Hopefully some of the results will make its way up here on to the forums

[Mike Buckley]

In addition to the helpful information you've already received...

The reason I asked what you mean by "blurred out" is that you may not be aware that it is possible to photograph a scene with a moving object in which that object becomes invisible. I wondered if that is what you were referring to. As an example, when photographing a building using a long enough shutter speed and when a moving car goes in front of that building moving from right to left at a sufficient speed, it is possible that the photograph will display only the building and not the car. So, rather than calling the people who are moving in your example photos "blurred out," I would describe that characteristic as "blurred motion" or "motion blur" because the people are displayed both blurred and in motion.

You will most likely need to do a lot of trial-by-error shooting to figure out how slow your shutter speed has to be in various situations to achieve the results you desire. As an example, when people are moving from right to left, the shutter speed doesn't have to be as slow to record blurred motion as when people are moving toward or away from you. Consider that the amount of blur will be affected by a combination of how fast the people are moving, the direction relative to the camera they are moving, how slow the shutter speed is, and how much blur you hope to achieve.

The one characteristic that is common to all three example photos you provided is the quality of light; the light is diffuse in all three cases. Diffuse light creates soft shadows (shadows with soft, poorly defined edges) rather than hard shadows (shadows with hard, well defined edges). Hard shadows would probably be a distraction unless cleverly used to appealing effect, so consider looking for scenes to photograph where the shadows are very soft.

[dem]

You will need a tripod to hold the camera steady and a Neutral Density filter to slow the shutter speed down to 1 sec or so. Might be the easiest to get a variable ND filter...or shoot late in the evening when it is getting dark.

[DavidPavlich]

Or you could get a blurring plugin. I did this in Analog Efex Pro 2 using the Motion Blur option in Classic Camera. I was just playing around with it. That's my son trying out a new lens and those are seagulls being sucked into the vortex. :-)



David