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yuri_ch
Participating Frequently
April 17, 2019
Question

Photoshop: Shows wrong horizontal FOV in 3D in a rectangle canvas size

  • April 17, 2019
  • 1 reply
  • 1484 views

When you create a 3D layer Photoshop says wrong horizontal field of view if the canvas is not a square. The simple formula to calculate the field of view is 2 tan-1 (w/2d) where W - the width of the image and D is the distance to the center of projection, it is for the horizontal field of view and the same is for the vertical but instead W you just put here H (height) of the image. Try to check it in PS and you'll see that it doesn't shows the results of the horizontal FOV in the menu "field of fiev" correctly when the canvas is for example 5000x2000 px.The similar problem is when you use the vanishing point filter. When you determine a group of parallel lines in the image and after try to back a 3D layer, the FOV calculations are always wrong, so the perspective of the image and created 3D layer doesn't match. Wherein no matter what type of the canvas the image is: square or rectangle.

I've seen it some years ago but still there is the same problem in here.

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1 reply

JJMack
Community Expert
JJMackCommunity Expert
Community Expert
April 18, 2019

I would think field of view would be a camera setting like a lens focal length. Where the canvas size is more or less like a camera sensor Aspect Ratio.  If you change a camera lens focal length the image capture will have a different field of view. the Image captures aspect ratio and number of pixels  does not change the Image captured contents change because of the lens different field of view. The is focused on the cameras Aspect Ratio sensor.  I do not use Photoshop's 3D feature that much and IMO Photoshop is not really a 3d Application. You may want to look at a real 3d Application the may have a FOV feature or button that may change to 3d projection  perspective onto a different aspect ratio displayed image. Field-of-View Button | 3ds Max 2016 | Autodesk Knowledge Network

As I wrote I do not use Photoshop 3D feature much so I do not know how many controls you have when it come to Photoshop 3D feature 3D Camera. Are the FOV options and settings?

JJMack
Y
yuri_chAuthor
Participating Frequently
April 18, 2019

1. I don't say that 3D in PS can be compared with, e.g. with 3ds Max or others applications. But there are some cases for me when it is comfortable to use 3D in PS. If I'd like to put perfect shadows from the objects which initially haven't them I can do it with the 3D instead of drawing it by myself. Of course, before I have to determine the perspective of the image in order everything to look realistic. It's just one of exampe how I do use it in my projects.

2. So I just want to say that PS calculates horizontal field of view wrong, IT'S A BUG!!! See the proof. As you see PS says us that in this canvas size we've got a horizontal FOV like 75 and vertical 30. But it's a mistake. The real Horizontal FOV must be 67.6

The simple formula proves it

canvas width w = 5000 pixels

canvas height h = 2000 pixels

d = 3732,73 (distance to the center of projection)

Horizontal FOV 2 tan-1 ( w / 2d ) = 67.6

Vertical FOV 2 tan-1 ( h / 2d ) = 30

So if you try to save an image from PS and then create the same canvas size in Adobe Dimension CC or in any other proper application and use the saved image from PS as a background, then will put camera FOV 75 degrees you will certainly see that perspective of this cube will not match. But if you put in FOV the value like we've got in the formula above (67.6 degrees) the perspective will fully match because it's correct, it's simple trigonometry.

3. Photoshop can't determine the real perspective camera parametres frome the image. There is simply no any accurate tool. The vanishing point filter has problems with the FOV too. Just to try to create in PS some 3d layer and then use VP filter to reconstruct camera parametres just created)) You will see the wrong FOV. Basically that means that Adobe users haven't opportunity to add something to a real photo using any of ADOBE applications. How can it be in 2019? Comparing with the Sketchup I can determine an image perspective in minutes but if in Photoshop I must do it manually, using knowleges of geometry, of course if I want to get accurate results.

davescm
Community Expert
davescmCommunity Expert
Community Expert
April 18, 2019

Hi

I just checked it and I agree the FOV is reported incorrectly (75 degrees in your example instead of the calculated 67.6 degrees).

I suggest raising it at the link below, which is monitored by the Adobe developers.

Photoshop Family Customer Community

Dave

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