Crop Factor and Stabilization

sfoster

sfoster

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Hopefully this question isn't too stupid.. but here we go..

A moving, handheld 10mm lens is going to produce a more stabilized image than a 30mm lens.. lower the focal length, more perceived stability.

If we're dealing with a crop factor of 3x then the 10mm will have a a smaller field of view.. a field of view that matches the 30mm.

Will it have the same handheld look as a 30mm as well?

The only confusion I have here is that if I took a huge super hd image from a full frame 10mm lens and cropped out the middle, in this digital post-production crop it would have the field of view of a 30mm but the stabilization of a 10mm.. does crop factor in-camera work the same way, or is it truly identical to filming with a 30mm lens and full frame sensor?
 
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I ended up on Academic Physics and Optics websites when trying to sort all this stuff out in my head. Don't feel bad, there are a lot of folks who are really close and have functional explanations that miss the finer points, but still get you to your goal. Full understanding requires you to think about the size of the individual pixel, the size of the photons and the path they have to traverse to get from the light source to the capture device. There's a lot involved there.

Focus is a point in space X distance from the lens… everything else is out of focus to varying degrees. Circles of confusion (real term to describe some complex bit about how out of focus something is based on many factors Trig and Geometry stuff) combine with the optics of the camera to create "Bokeh" (the style and shape of the out of focus bits)… I understand it all down to the photon, but explaining it is difficult… which is why so many sites have incomplete data… most'll get you the results you want, just not necessarily in a completely accurate fashion.
 
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sfoster said:
A moving, handheld 10mm lens is going to produce a more stabilized image than a 30mm lens.. lower the focal length, more perceived stability.

If we're dealing with a crop factor of 3x then the 10mm will have a a smaller field of view.. a field of view that matches the 30mm.

Will it have the same handheld look as a 30mm as well?
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(Not speaking from experience) Yes, it will have the same bounciness as the 30mm.

Cropping a 10mm to the 30mm equivalent will also have the look of the 30mm.

The reason in both cases is because when you magnify it (either by having a smaller sensor or by cropping the image which in turn magnifies it), you also magnify the perceived stability (or rather, the lack of stability). Small bounces will become medium, and medium will become noticeable.

You can do a very simple test which I'm certain will verify this for you. Shoot 10 seconds of a distant object in the center, handheld, with a wider lens. Bring it into your NLE and view it and pat yourself on the back at how stable it is. Then crop it to the center where the object is, and view it again and see just how bouncy it looks.
 
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