heeshung
2011-02-20, 06:34 PM
I was asked why some of my panning shots were soft near the nose or tail of the airplanes. Here is my explanation.
While the airplane is always on the same track and in the same direction, to the camera it is rotating about its central axis. As a result, if you think about an object rotating about its central axis, then the outer extremities in the axis it is rotating in will change the most.
Another note, the rate of change of the perspective also varies with distance from the object. As you can see in the winglet shot comparison, the winglet is closer to my camera, and thus changes perspective faster than the fuselage. The photos shown of Southwest were taken about 1/3 second apart.
http://horriblephotography.com/albums/Misc/panningexplanation.jpg
Here's a good example:
ISO100 1/125
http://horriblephotography.com/albums/JFK%2011-14-10/IMG_9328ps2.jpg
Notice how towards the middle of the fuselage the 747 is tack sharp, including the gear. But, as you go towards the nose, there is a noticeable gradual decrease in sharpness.
Here's another great example:
ISO100 1/13
http://horriblephotography.com/albums/Misc/IMG_5830tut.jpg
Sure, some of the blur is due to low shutter speed and natural hand movement, but it is mostly from the tram's movement.
The tracking point is pretty sharp, but you'll see that the further away from the tracking point in the x-axis you are, the softer the image gets.
While the airplane is always on the same track and in the same direction, to the camera it is rotating about its central axis. As a result, if you think about an object rotating about its central axis, then the outer extremities in the axis it is rotating in will change the most.
Another note, the rate of change of the perspective also varies with distance from the object. As you can see in the winglet shot comparison, the winglet is closer to my camera, and thus changes perspective faster than the fuselage. The photos shown of Southwest were taken about 1/3 second apart.
http://horriblephotography.com/albums/Misc/panningexplanation.jpg
Here's a good example:
ISO100 1/125
http://horriblephotography.com/albums/JFK%2011-14-10/IMG_9328ps2.jpg
Notice how towards the middle of the fuselage the 747 is tack sharp, including the gear. But, as you go towards the nose, there is a noticeable gradual decrease in sharpness.
Here's another great example:
ISO100 1/13
http://horriblephotography.com/albums/Misc/IMG_5830tut.jpg
Sure, some of the blur is due to low shutter speed and natural hand movement, but it is mostly from the tram's movement.
The tracking point is pretty sharp, but you'll see that the further away from the tracking point in the x-axis you are, the softer the image gets.