Panning - Not Quite Right

R

r0b53

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Edit My Images
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Hi,

Have spent the day practicing my panning technique and although the keeper images were reasonably sharp on the focus spot (in the example below the centre of the car) they appear to suffer from blur at the front and rear, can anyone give any suggestions on how this could be improved to enable me to get the whole of the car reasonably sharp
The camera settings were as follows:
Nikon D300 17-55 2.8 dx
f/6.3
Shutter 1/60
Continuous AF focus

Any help or suggestions would be welcome
A day at the races... by rbullingham, on Flickr
 
I did think about a higher f stop but car was parallel to me and when I took a static test shot the DOF was OK
Cheers

Rob
 
What you're seeing with the front and back ends is what happens when you pan with subjects that are doing something other than moving perpendicular to the camera sensor. You've tracked the middle of the nearest side of the car accurately but the other parts are moving in a slightly different manner so you start to lose them to motion blur.

Here's an extreme example of this, I tracked around the middle of the car and everything gets progressively blurrier the further it is from that point. Another, less extremely blurred, example where the door is sharp and everything else less so.

If you want a sharp car from front to back you'd need a higher shutter speed at the same location, or you could use the same shutter speed at a location where the whole car is moving at an angle closer to perpendicular to the sensor (e.g. a perfect straight).

For example, this one is close to perpendicular so the car is sharp from front to back but even so far side of the car is still slightly soft.

Don't feel that every bit of the car always has to be sharp though. Trading bits of car for more background blur or a more interesting photo is worth considering.
 
Last edited:
What Darren said (y)

Imagine panning with the front carriage of a train, which moves 1 carriage length while your shutter is open. (Assuming infinite DOF for the purposes here)

HT70u2z.png


Each carriage moves the same distance (as they're connected), during this time.

You need to rotate Fº in this time to keep the front carriage sharp, howerver you need to rotate Mº to keep the middle carriage sharp, and Bº to keep the rear sharp.

Front angle is clearly greater than the middle and much greater than rear.

obviously you can only rotate (pan) at one speed, so only one area can be sharp.

i think slightly blurred parts add to the sense of speed, you just need to make sure the focus point is where you want it.
 
Now it all makes sense, thank you both for your time and your detailed explanations, much appreciated :)

Rob
 
Nearly there with the comments above. The problem (more of a characteristic) is caused by the relative rotation of the vehicle in relationship to the sensor during the exposure.


The point on the sensor which most closely matches the rotation of the car will be the sharpest, wherever that point may be – front, centre or back. If you think of it like two cogs making contact on one of the teeth, and the rest of the teeth “effectively moving” in relationship to each other, and you sort of get the idea.


The points furthest away from that “pivot point” will be the most blurred. The phenomenon is exaggerated on the outside of the corner, and happens the least when you are at the centre of the radius of the inside of the corner, because the view of the car doesn’t change at all whilst the image is being cast on the sensor, when stood at that point.


We are running a seminar in the near future that goes over all this sort of thing if anyone is interested in finding out a bit more.
 
Thanks for the explanation, I guess if its a characteristic you need to learn to work with it, I originally thought that it was something wrong with my tecnique
 
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