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I was trying a DOF experiment: Will Maxwell properly follow the camera's interest interactively as the center of the DOF? Yes, it does! I focus first on the closest object, then the farthest, then the middle object. But I notice that when I then zoomed in on objects, the exposure seemed to change: it got darker. Zooming out again caused the image to brighten back up. I've checked it frame-by-frame and there's no question that the image gets darker with the zoom.

DOF/Focal Length Test -1 MB


So I'm left with 2 questions:

• 1) Is this what happens with real cameras (my personal experience says no.)
  
  2) During the zoom in/out, should there be motion blur in the direction of the zoom? I'm not sure about this one, but my gut says no. It's difficult to test in this particular animation, because during the zoom in/out, the actual interest is moving as well. That, in combination with the DOF makes an analysis of Zoom blur nearly impossible.

Thoughts?

_Mike

Hi Mike,

Besides moving the camera, camera maxwell will do motion blur when you modifies the fstop, the focal length or the focal distance.

If your camera is moving at the same velocity that the target you are focussing then no motion blur effect will be noticeable.

I hopes it helps you.

Best regards.

Wow, now this is a cool feature!

And a really great demo tehre, mverta! Thanks!

hi guys

there will be motion blur with real cameras (when zooming in or out), it mainly depends on shutter-speed i think.
you all know those long-exposure-blurred-car-rear-light-trail-pics.
maybe it doesn't matter if the car itself is moving or you're zooming.
it's all a matter of exposure. or am i completely wrong on this?

greez
ale

Well, there's a difference between moving and zooming. Moving is moving, and of course there'll be motion blur. But zooming with a static camera is what I was curious about. I think Oscar was saying that a focal length zoom, where the camera is stationary, also produces motion blur, but I'm going to test this specifically to be sure.

_Mike

Mike,
Zooming is technically being achieved by moving the lens in aperture.
Thus, every piece of change falling on the film will make blur teorically.
We're very happy to see your Maxwell Renderings here, keep em

Yeah, makes sense, Tom... it'll be nice to have some reference animations of that...

Best,

_Mike

i just took a foto with my slr-digi-cam (canon 20D) with zooming out.
so there will be 'motion blur'.

Well that answers that! Thanks! Though has anyone noticed that the image gets darker on the zooms?

_Mike

i think the darkening (this only should occur while zooming IN) is a physical phenomenon that occurs because of the optics (lenses). there's less light
that passes the lenses. So when fully zoomed back the pic should be brighter as the viewfield is larger and there's more light that passes the optics.

greez
ale

mverta wrote:Though has anyone noticed that the image gets darker on the zooms?

_Mike

I've seen the darkening effect happen with video cameras quite a lot.