Fujifilm gf 500mm f 5 6 r lm ois wr vs fujifilm gf 250mm f 4 r lm ois wr?

Here is what the site says about that.

From Fujifilm GF 500mm f/5.6 R LM OIS WR: Fujifilm GF 500mm f/5.6 R LM OIS WR: A prime lens by Fujifilm for Medium format (44 x 33) cameras, 500mm f/5.6. The longest GF lens, about 400mm equivalent. Specs - Maker: Fujifilm - Focal length: 500mm (prime) - Maximum aperture: f/5.6 - Made for: Medium format (44 x 33) sensors - Mounts: Fujifilm G - Stabilised: yes - Autofocus: yes What it frames like - On Medium format (44 x 33) (Fujifilm G): like 395mm on full ...

From Fujifilm GF 250mm f/4 R LM OIS WR: Fujifilm GF 250mm f/4 R LM OIS WR: A prime lens by Fujifilm for Medium format (44 x 33) cameras, 250mm f/4. A stabilised telephoto prime, about 200mm equivalent. Specs - Maker: Fujifilm - Focal length: 250mm (prime) - Maximum aperture: f/4 - Made for: Medium format (44 x 33) sensors - Mounts: Fujifilm G - Stabilised: yes - Autofocus: yes What it frames like - On Medium format (44 x 33) (Fujifilm G): like 198mm on full ...

Quoted from this site's pages.