Doubt about panning

Dear friends, I've been testing some panning shots with an ATR and I was in doubt about the result. I'd say the front section looks "okay," however it's noticeable a gradient blur from the mid section to the end of the fuselage. Until then, I had not realized that such a "technical artifact" could occur, even in f / 16. And I wonder if such a result would be acceptable here on the website. Thank you very much for your attention.

Attached photos:

Let`s say you are shooting with a prime lens and you are around the middle of the runway. When the plane starts to accelerate, you have a 3/4ish view of the aircraft, and it is small in the frame. As it moves through the runway, you see how it changes the view from 3/4 to lateral and it gets bigger in the frame, the aircraft stretches, the distance in the frame between nose and tail increases. If you are following the nose with slow shutter speed, when you release the shutter, the nose is in the point A, and the tail in the point B, and when the sutter closes, the nose is still in the point A (remember you were following the nose), but the aircraft "stretched" and the tail moved further, to point C. The picture will show the movement of the tail from B to C.

This "problem" is less obvious when the aircraft is in a perfect lateral view, it doesn't stretches anymore, but after that, as the plane goes away, it starts to contract and the "problem" returns.

Many thanks, Manuel, for the excellent explanation! It is very interesting to see what happens if you click at a time when the object's axis of motion is not perpendicular to the sensor. Great lesson! But, after all, does such a result condemn the chances of accepting such an image here on the website? Or should I try?

It all dependes on the screener opinion... You can increase your chances by cropping the picture to hide some of the blurred parts, reducing the size of the picture, or just telling the screeer that it is impossible to get the whole plane sharp in that kind of pannings. For example, crop the second picture just behind the wheels, it will hide the blur on the registration and the windows around it. There will be some blur, but much less noticeable.

Cheers.

Thanks Manual, I finally understand how the difference in sharpness occurs!