The Laowa 100mm f/2.8 is a manual focus macro lens for full-frame DSLR cameras. The optical design consists of 12 elements in 10 groups. The construction includes two Low Dispersion elements according to Loawa. The minimum focus is 9.7 inches and smallest possible aperture is f/22.
item 4 Canon EF 100mm f/2.8L MACRO IS USM AF Lens w/ Hood from Japan [Mint] Most relevant reviews. See all 36 reviews. 5 out of 5 stars. by pandries1 May 22, 2018.
At 100mm a good achromatic diopter (Raynox or Canon are the best two options) will get you more magnification much more quickly than extension tubes will: For example, 25mm of extension tubes will only get you to 1.25x over 1x. Extension tubes are better suited for f=50-60mm lenses.
The original Canon EF 100mm f/2.8L Macro lens was well known for being a versatile performer, offering 1:1 macro capabilities, sharp images, excellent image stabilization, and reliable autofocusR8SLW.