First of all, you are not doing a zoom, you are moving the camera. It's properly called a dolly shot. There are also tracking shots (where you move with your subject) and trucking shots (where you move paralel to your subject). Moving the camera in Z space past objects distributed on the Z axis is a dolly shot.
That's normal behavior for real cameras and for AE's camera. The farther away an object is from the viewer the slower the apparent rate of the change in size. Think about driving toward the mountains from western Kansas. As you approach Denver you slowly start to see the mountains increase in size. By the time you are 50 miles away they occupy something like 20% of the horizon. At 20 miles they occupy 25% of the horizon, but by the time you get 10 miles away they occupy 50% of the horizon. At 5 miles the mountains fill most of the sky. As long as you are moving around in 3D space these same rules apply. It's just the basic rules of perspective and parallax.
If you want a smooth zoom then animate the zoom value of the camera or animate the scale of the layers. Personally I think the exponential size changes you get with camera movement are more pleasing because it's what happens when we move around in our environment.
I understand you and that's totally correct but that is not what I meant.
Maybe a simple drawing will help
Let's say I've used over 200 tree images and created a road by placing them in lines on the left and the right side of the street.
If you look at the TOP view in AE and then look at my drawing example below ( .. would represent the camera and the _ would represent some of the tree images)
the camera .. is moving backwards by using the Z position but after a while (and I get closer to my 30 sec of footage I need) the camera seems to be moving a lot slower then in the beginning when I started
at Z position: 0
I've also checked the keyframe interpolation but its all on linear.
_ .. _
In the real world when you move a camera backward by using the same speed, the speed wouldn't increase after a longer distance.
Not sure what you mean. The farther away you get, the smaller the differences from frame to frame will be in terms of how the visible pixels change, resulting in a perceived "slowness" due to barely any changes being visible. That's no different from a real camera. No matter how far away you are, the distant trees will never completely disappear. Simple math and physics (though of course in the real world atmospheric haze and Earth curvature would come into play as well and the trees eventually disappear). Unless I'm completely misunderstanding waht you are trying to do, this sounds perfectly normal.
It's not completely clear whether you're talking about the perceived speed as the camera gets farther away from cards or the speed at which it's passing "new" cards just as they enter the fov.
A good rule of thumb is to always parent the camera to a null and move that instead. What's not very intuitive but very important is the "point of interest" does not follow the camera's position. Even when your camera's 700000 pixels away, it's still looking at the original poi unless you move both with a null. This may or may not be the cause of your problem, but I'd create a null rig either way.
I mean the new cards that are passing the camera are getting slower after a while.
The point of interest is not moving (haven't keyframed that)
But I'm noticing in the top view now my cards seems to be farther away from each other then in the beginning of the comp and maybe this is the problem.
I'll fix this and let you know.
Found it, the solution was to make sure to keep the same distance in the top view in AE and make sure you've got the same scale as the rest of the objects you use in 3D space.
Because some objects that needed to look big were too big I needed to resize them and visa versa.
This gave the illusion of NEW objects that were passing by the camera were actually not so close as it seems to be.
- I needed to make sure to have the right scale before going into AE
- Look if the distance between the objects is the same.
Thanks for the help!