WR refers to something in photography.

Fa 100 3.5 is rare. Common ones are fa 100 2.8 which looks like a big bottle, and common ones are fa 100 f4.

This fa 100 3.5, like 100 f4, can only achieve a macro of 0.5 times. It can't reach the macro of 1: 1 as fa 100 2.8 and dfa 100 2.8 (with or without wr). For shooting very small objects, the magnification of 1 is definitely better, but in some professional fields such as criminal investigation and criminal investigation.

Now I want to buy a Pentax macro lens. In fact, it is the most cost-effective to buy dfa 100 2.8 wr, and the new one is less than 3,000. It is waterproof, digitally optimized, all-metal, fashionable and, most importantly, not heavy or light.