I had recently bought a Tasco OS 54. I appreciate your article and the precision of the binocular. I developed some "thumb rules" that would be interesting to other peoples.

As example : I may get any distance simply dividing the "height of the sighted object" by reticle's numeral (*) and multiplying for 60 (sixty). This result is 5% over the actual distance. In case you need accuracy you just reduce the obtained value in 5%.

The advantage is that all the calculus you may perform mentally.

(*) As alternative, multiply by 300 if you count the minor reticle's division (each numeral groups 5).