I bought a canon rebel XT with a 28/300mm Lens to take pictures of my kid playing softball.

The season has started and I do not like the angles I have to shoot at . I either have to get in the dugout or shoot thru the fence.

I found this Phoenix 500MM lens f/8 with a 2x converter and I thought I could go to the outfield and get better angles.

Has anyone ever used this brand of cheap lens?

Also can I do the converter on my sigma lens?

Do they work ?

Thanks for the help

Mike