You asked
Best telephoto lens for the panasonic lumix s1 iie?
Here is what the site says about that.
From Panasonic Lumix S1 IIE: Panasonic Lumix S1 IIE: A mirrorless camera by Panasonic with a 24.2-megapixel full frame sensor, announced in 2025. The S1 II body with a simpler 24-megapixel sensor, for less money. Specs - Maker: Panasonic - Mount: L-Mount - Sensor: Full frame, 36 x 24mm, crop factor 1.0 - Resolution: 24.2 megapixels - Stabilisation: in the body - Announced: 2025 - Type: mirrorless camera Focal lengths on it Full frame is the reference size: lenses ...
From Sensor sizes: What it costs you: - Size, weight and price, especially of the lenses. A full-frame telephoto is much larger than its APS-C or Micro Four Thirds equivalent. - Less depth of field when you want more of it, for macro or landscape.
Quoted from this site's pages.