Author Topic: Shift, only auto works?  (Read 2103 times)

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Offline andy.engelkemier

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Shift, only auto works?
« on: January 14, 2016, 06:12:26 am »
Shift is a great addition to keyshot. The "estimate vertical shift" button works and make the vertical lines actually vertical. Lets say it puts you at -.14 to be perfectly vertical. Great. But I wanted it to just look less extreme. You'd think you could just cut that in half to -.07? But all that does is shift your whole seen instead of moving what should be the camera back. It doesn't seem to be changing the perspective.

This is also quite useful, but not what I expected for this particular tool. Is there a way to adjust the shift like it does when you hit the estimate button?

Offline richardfunnell

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Re: Shift, only auto works?
« Reply #1 on: January 14, 2016, 07:01:55 am »
Hi Andy,

Vertical shift doesn't adjust the amount of perspective, it's vertically shifting the lens to adjust for perspective distortion. You can find more information about about how it works here: https://en.wikipedia.org/wiki/Perspective_control_lens

Those sliders are independent of each other. You can adjust perspective using the Perspective / Focal Length slider after enabling the Shift lens, and use the Vertical Shift slider to adjust the shift amount (basically use it instead of panning the camera.

Does that help, or just make it more confusing? :)


Offline andy.engelkemier

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Re: Shift, only auto works?
« Reply #2 on: January 14, 2016, 07:08:39 am »
no, that's what I want it to do. But it's not working.
When you hit the "guess" button, it does exactly what it should.
But if you undo that, then manually type in the same number, you get a different result. Instead of shifting the lens it appears to just be shifting the entire camera. So the vertical/horizontal perspective doesn't actually change.

I didn't want to assume it was just broken, but it seems that it is.

Offline richardfunnell

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Re: Shift, only auto works?
« Reply #3 on: January 14, 2016, 07:26:12 am »
I don't think that it's broken, but it is dependent on you using the "Estimate Vertical Shift" button in order for the calculations to take place. The amount of vertical shift is dependent on the Absolute XYZ camera position, so if you change that when working with your camera, you'll need to recalculate the shift.

It may not be the most straightforward feature to use (I certainly have never used a physical camera to create this effect), but using the Geometry View to visualize the camera position helps me see what the camera is actually doing.

Offline andy.engelkemier

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Re: Shift, only auto works?
« Reply #4 on: January 14, 2016, 08:23:03 am »
Shoot. You know what, I was thinking about tilting the camera back instead of shifting the lens, which is Way easier to control.

Tilting the camera back inverse of the lens means you don't have to move your camera. If you shift the lens your whole image shifts, so you have to move the camera closer to a zero inclination.
Well, hopefully you guys add tilting the camera back soon. That's the feature I would want.

If you wanted to play with that, you can use a physical camera in 3dsMax. If you have an older version, you'd need to have vray installed and use a vray camera instead. I tried to find a video of it, but it wasn't really coming up easily. I'm sure one of you guys has it though.

I'm guessing people are using the shift options here mostly just to keep their perspective relatively the same, but shift the focus a bit, helpful if you like the perspective, but you need your subject to be more in frame.