Can't realise how Shadow Catcher works in Corona Render with Alpha channel

[Goha]

Hello. I am testing Corona and stuck with the Shadow Catcher Material... There is a scene, with an object (cylinder), two Corona Light sources and a disc with a Shadow Catcher Material for the next compositing in Photoshop (Alpha mode = For compositing). Why the disc with the shadow catcher is illuminated by light sources and because of this I can see the whole disc in the Alpha channel, not just the cylinder shadow? I tried to exclude the disc in the lights Excludes but it didn't help. What am I missed? There are screenshots with Shadow Catcher material and Alpha channel of the render.

[Beanzvision]

Can you share your scene file?

[Goha]

Can you share your scene file?

Sure.

[Goha]

Looks like I should use Corona Sky as Environment for Shadow Catcher and with Corona Sun, then Alpha channel is fine but Shadow Catcher still catch Sun rays too if I set 90º Angle and I have hard shadows with the Sun. Still misunderstood the logic of Shadow Catcher material (it should not catch the lights at all — just shadows). :(

[houska]

Did you watch the Shadowcatcher tutorial?

[Goha]

Did you watch the Shadowcatcher tutorial?

Yeah, I did. There are not so many options to make a mistake. Looks like I forgot to hide an object which cast the huge shadow at shadow catcher. My bad, sorry.