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Author Topic: Turntable issues.  (Read 2574 times)

RossFranks

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Turntable issues.
« on: March 21, 2016, 07:23:37 AM »
Hi there we're having weird results using a turn table and I'm sure we're missing a simple step and thought you guys might be able to help us.

We seem to get good results when photographing a subject when walking around it, but when it comes to a turntable subject all the cameras seem to align from one direction (we're using a Canon 6D) rather than in a circular direction, see below (we tried on a turn table and also turning the subject on a tripod with a red screen to use as a mask to see if the mask would help).

We've turned GPS off on the camera, and have markers rotating with the subject, but can't think why else this would be happening.

Any ideas?

Thanks in advance.
« Last Edit: March 21, 2016, 07:33:36 AM by RossFranks »

Kjellis85

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Re: Turntable issues.
« Reply #1 on: March 21, 2016, 11:16:38 AM »
How are you masking the object? Having a mono-coloured background is not enough as far as masking is conserned, you need to either generate masks manually or from backgroundimages.

One thing I can say is that you are not filling the frame very well, loosing a lot of potential resolution. Go as close as possible, even tilt the camera as to get more of the object in frame and less of the background. Another thing to consider is the object in itself. A plush animal is not optimal as it has a very little features to detect (not enough texture), making matching difficult. Try with something a little more "dirty" or something highly textured.

JMR

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Re: Turntable issues.
« Reply #2 on: March 21, 2016, 02:15:11 PM »
Turntables are acceptable as they can actually emulate a moving camera changing its position with respect to object. This means that in each frame all objects should change accordingly to the camera movement emulation. If your rotary stage and background are starring the scene and are actually steady, then you will not get the program fooled into thinking that it is the camera that has moved.
So you need to mask every thing but the object to allow this "confusion".
Get closer to the object to fill the frame as much as posible... and better if you try with a texture rich subject. why the hell most people want to plushes end plastic toys? pick up a rough stone

RossFranks

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Re: Turntable issues.
« Reply #3 on: March 22, 2016, 01:56:19 AM »
Hehe thanks guys, the plush toy was just a test piece, we'll eventually be looking to do food shots for a client, ie see the banana below that was shot by walking around the banana (mind you that was only with 30 photos, so it was a rough test). The client wants about 400 food shots done, which we're now thinking a QTVR approach might be better for time's sake.

But for the future, masking and filling the frame should fix the software's camera positioning issues?