# How can I convert an orthographic camera to a perspective camera?

How can calculate perspective camera parameters from orthographic camera parameters (left, right, top, bottom, near, far)?

Specifically I don't know how calculate the FOV for a perspective camera from orthographic camera.

• You should create a question (or edit this one) that describes the feature that you need instead of asking about solution implementation. (XY problem) This way we could give you better answers. – Vaillancourt Jun 17 '16 at 15:19
• In theory, if your perspective FOV will be infinitely small, then said perspective matrix will kind of resemble orthographic matrix .. but I'm sure you need something less "extreme". – Kromster Jun 17 '16 at 15:34
• I need way to get data for creation perspective camera (fov ,aspect,near,far , matrix) if I have data for creation orthographic camera (left, right, top, bottom, near, far, matrix). – SomeGenericNameto_Display Jun 17 '16 at 15:46
• What are these matrices? The way to project stuff on screen is by using lots of matrices, so just saying 'matrix' adds some confusion... – Vaillancourt Jun 17 '16 at 16:17
• Matrix determine position of camera and direction of camera view. – SomeGenericNameto_Display Jun 17 '16 at 16:25

• Isn't there a hackish way to get the fov? Like 0.5f * (right - left) / (far - near) which would give us 0.5f * tan(fov) (which we can use to make perspective matrix given a ratio)? Though the view will be completely different from the ortho one ofc.. – Greffin28 Jun 17 '16 at 15:32