https://gilwizen.com/laowa-25mm-ultra-macro-lens-review/

https://www.cameralabs.com/laowa-25mm-f2-8-2-5-5x-ultra-macro-review/

• Pros:
  – Lightweight, small size for a high-magnification macro lens
  – Highest magnification lens available for non-Canon users
  – Excellent sharpness and image quality
  – Consistent working distance
  – Narrow lens barrel makes it easy to find and track subject
  – Affordable

• Cons:
  – Manual, no auto aperture control
  – No filter thread (but still customizable with caution)
  – Dark viewfinder when closing aperture makes focusing difficult in poor light conditions
  – Magnification range is short 2.5-5x compared to the competition

Combining a Laowa 25mm 2.5x lens with a Kenko 12mm extension tube

To find the combined magnification when using a Laowa 25mm 2.5x lens with a 12mm Kenko extension tube, given the magnification of the lens itself, the extension tube length, and the combined setup, you can calculate the total magnification.

First, consider the magnification of the lens itself, which is 2.5x.

Then, to find the total magnification when the extension tube is attached, you can use the formula:

Total Magnification = Magnification of the Lens + (Magnification of the Lens * Extension Tube Length / Focal Length of the Lens)

In this case, the extension tube length is 12mm, and the focal length of the lens is 25mm. Using the values:

Total Magnification with 2.5x = 2.5 + (2.5 * 12 / 25) = 2.5 + (30 / 25) = 2.5 + 1.2 = 3.7x

Total Magnification with 5x    = 5 + (5 * 12 / 25)      = 5 + (60 / 25) = 5 + 2.4 = 7.4x