Explora published a review of the Thypoch Eureka 50mm f/2 collapsible rangefinder lens for Leica M-mount. Here is their conclusion:
Pros:
- Collapsible design makes the lens super portable, especially when attached to a camera
- 50mm f/2 is a great focal length/aperture balance; it keeps the size and weight down while remaining versatile and fast
- Available in either Aluminum or Brass variants with a minimal difference in weight (<100g)
- Nice modern-ish rendering; image quality feels natural without being too clinical or too cloying with aberrations
- Machining and design elements feel solid and reliable. Also, a nice press-fit front lens cap
Cons:
- Infinity lock takes some getting used to when focusing at medium-long distances; I wish this could be overridden so the focus wouldn’t accidentally get locked when racking between infinity and other distance positions
- A36 filter size, while a nice nod to classic collapsible lens designs, is a relatively useless filter size. If wishing to use any filters besides the included UV one, you’ll need to source used ones or find a SOOGZ or similar adapter to use 39mm threaded filters. I wish the front ring was threaded rather than needing to use this clamp-on, tension-based filter attachment method
- Minimum focusing distance of just under 3’ (0.9m) isn’t quite the 0.7m standard of most rangefinder lenses; I wish I could focus a bit closer
