How to properly setup a camera on top of a vertical image?

Question

I have a vertical image, so I want to rotated my camera to fit the composition, but I am running into a lot of issues. My first problem is, after rotating the camera vertically every time I press 0 the view port also rotates. I end up looking at my composition in this really weird horizontal angle. I don't want this, I want the camera to keep the vertical perspective, but rotating the view by 90 degrees. See my problem below.

My second problem is, I want the camera to cover the entire image, so I can accurately place models into the scene with respect to the composition. I thought about placing the camera using orthographic mode to cover the entire image, but the camera bounding box disappears. I am now sure how to do this.

Does anyone know how to solve these two issues?

Answer 1

If I understand properly, you want your camera orientation to be 'portrait' and not 'paysage', right?

If you want to do that, you shouldn't have rotated the camera but change your render's dimensions instead.

Just think about it as a real world camera, if you rotate your camera you'll end up with a tilted image (unless your camera has a gyroscope or a system that makes it detect its rotation automatically).

If you have something like this :

Rotating the camera will give you this (90° on y axis):

And I think it's not what you want so just undo what you've done and look at the dimensions of the image. Mine is 512*1024 which is an aspect ratio of 1:2 so I can just change my render dimensions to exactly 512*1024 (or anything with 1:2 aspect ratio will do):

After that, I just have to adjust the position of the camera to fit the image :

Notice that the camera is still upright as indicated by the arrow that is on top of it and that means the image will be upright too.

There are tools like fspy which allows you to align exactly your camera to an image (dimensions, focal lenght, perspective..). You may want to try it as well.