Magnifing Glass? Best Way to Aproach it?

Looking into doing something like a magnifying glass but ran in to a huge basic question.

Is there a way to retrieve the render as a texture?

If I am to use a SceneCapture2D and then draw the material on the hud, is there a way to draw a material with a round shape, like draw a circle and fill it with the texture?

Last idea would be to use a materialinstanceconstant and pass it the coordinate values to stretch the texture and pan it, but wouldnt this be performance heavy? and how could you know the limits, I mean if I stretch the texture 10 times, would the render area be 0.1? so to render the center I would have to pan it 0.45 on both ends?

Any input is welcomed.