Videomaker – Learn video production and editing, camera reviews › Forums › Technique › Miscellaneous Techniques › Why is movement exaggerated when zooming in?
October 26, 2008 at 6:57 PM #37399emomartianParticipant
If anyone else remembers, in the January 2008 edition of videomaker it stated on page 47 that movement is exaggereated greatly when zoomed in… 25mph to 50mph…
I’m doing a school-related science experiment that involves this fact, and I need to understand more about the topic. Does anyone know why it is so exaggereated? Or know of a website or article that describes this? A refrence link would be appriciated so i can put it into my citation.
October 27, 2008 at 4:20 AM #165811brandon0409Participant
Well you have to consider that it is the same principle as using a telescope to look at another planet or a star.
If you’ve ever done this, then you know how difficult it is to center the object in the lens.
It all has to do with angles. If you put your camera on a tri-pod and point it straight ahead toward an object 200yds away without zooming in, then move the camera 10 degrees to the left (or right), it doesn’t move much, but it does move. Right?
Now zoom in on that object and move your camera exactly 10 degrees again. You’ll notice it moves way out of sight of your view finder.
Now for the fun part; the experiment that will make this all make sense:
1. Put a protractor on the ground.
2. Line the bottom up with your camera lens.
3. Put a stick in the ground and tie a line of string to it. I would use a long wound ball of twine (it’s cheap).
4. Now pull that string to the object.
5. Once you get there, move your camera to the left (or right) 10 degrees (You’ll probably need a 2nd person).
6. You will now notice how far 10 degrees actually is once you get to a distance of 200yds.
7. The second spot is where your camera would be looking when it is turned.
Depending on the distance from the camera, you could move 20 yard or more to the left or right. Now if you don’t zoom in, you may be able to fit that into the viewfinder, but when you are zoomed it, it is dificult to keep things in view… just like with a telescope.
Now imagine that same thing while trying to look at Saturn through your telescope. You move 10 degrees in either direction and we are talking millions of miles.
If you were into astronomy, there is a formula you can use to actually figure out exactly how far the camera is from you. This is how scientists measure the distance of object in space from earth.
Hope this info helped you at least kind of understand the concept.
October 27, 2008 at 5:47 PM #165812EarlCMember
When you are zoomed in, you are effectively compressing space/distance, thus the object has to move a much shorter distance, making its movement appear faster since it has less distance to travel.
This is not the same thing, but…when you use your computer’s “mouse speed” settings, the “slow” setting seems to take forever to move your cursor from one point on your screen to the next – that, though a different thing, is still representative of a subject moving across your lens on wide or normal angle; set your mouse speed to “faster” or “fastest” and until you adjust to the difference you almost lose control of the cursor as it zips across the screen with the slightest movement of your mouse – that, though I will repeat being a different thing, is still representative of a subject moving across lens field of view on telephoto or “zoomed in.”
Different apples, same oranges.
October 27, 2008 at 6:52 PM #165813emomartianParticipant
Thanks so much! Earl, I like how you explained that you are compressing space and distance. That really helps me the most.
Brandon, your comparisson to astronemy was very cool and i’ll probaly be able to use that too
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