Why is HDRI backgroud so big?

Hi

I bought this hdri from cg-source Furnished apartment HDRi - CG-Source.
As you can see it’s a good hdri with a fair size i think…
my problem is wen i use it to light and reflections in my back ground all i get is what you see below in the image… why? is it scale, units? i am working in millimeters.

Greetings.

I have several HDRI’s that do the same thnig, but others that don’t. You might have to match the camera they used.

thanks for the tip! unfortunately this hdri doesn’t have any info on camera on its properties

It’s a sphere environment background so you don’t need to match the camera. What you see is normal. Depending on the camera lens you use in the viewport it’s either this big or smaller. But in any case HDRI sphere shots can’t be rendered as backgrounds if you’re even a little bit serious about the quality of the render output. They just have too much distortion (what you can see in your preview). You need a backplate which is a classical background photo. Show this in the render. HDRI sphere you can use “only” for reflections.

I have several HDRI’s that I am able to use for lighting, reflection, and environment. The are exterior HDRI’s and I love them!

Exactly, it’s only a matter of resolution. I also have a number of environment HDRIs that are 15,000-pixel wide and they can be used perfectly as backgrounds on large-resolution renders. Anything below 10,000 pixels, however, tends to become pixellated or blurred when used as background.

Keep in Mind this is highly FOV dependent. And easy to calc. If you have a FOV of 90 for example you will hit a max of 1/4th of the HDRs resolution. So with 10k you can do a max of 2500px wide without sizing up the BG unintentionally. Also bear in mind that most HDRs are not as sharp as normal Fotos for various reasons (depending a lot on the procedure used to create them).

Thanks every one for the tips!

Greetings
Orlando Nóbrega