Dear all,
I mistakenly posted this to my personal (rather than work) account last week. Sorry for the long delay in replying to your follow up questions. I was out of town all week working and didn't check my personal account. Now I know why my work account has been so quiet!
I promise to try to respond more quickly from now on!
I often get calls concerning a laser range finder�s (LRF) accuracy, or lack thereof. 95 percent (or more) of the time, it�s a simple matter of yards vs meters, i.e., the user has a unit that he or she thinks is providing an incorrect distance (in yards) to a target, when in fact, it is either built (or programmed) to read meters. By the numbers, the quickest way to know is to ask yourself, is the unit reading approximately 10% shorter distance -than 1) you expect for a known distance or (in the case of a head to head comparison) 2) your spare (or your friend�s) rangefinder reads? If your rangefinder reads a 3D target as 36, but a measuring tape says 40 yards/120 feet, then your unit is telling you meters. The same goes for a target at a 100 yard berm coming up as 91. Likewise, if your spare (or your buddy�s) rangefinder says that a tree is 400 yards away, but the LRF in question says 360, again, it�s a meters vs. yards issue.
In the case of a Leica Rangefinder, one other quick check can tell you. Activate the unit by pressing the range button once. Do you see a red, square reticle? Or do you see a red, square reticle AND a decimal point next to it? If your reticle also has a decimal point next to it, your unit is built (or programmed) to range in meters.
The second most common cause of inaccurate readings I encounter is much less frequent. None-the-less, it can still vex the user. In this case, the problem is a misunderstanding of, or miss-alignment of, where the laser points versus the reticle. In other words, is the laser going where I think it is? Large reticles are always going to have this issue. The beam divergence of the laser will be nowhere near as big as the reticle. But, even on units with precision reticles, this can still be an issue. So, let�s figure out exactly where your laser beam is in relation to your reticle.
1) Ensure your LRF is working normally and the lenses are free from debris/obstructions.
2) Find a well-defined target with nothing behind it. This could be a STOP* sign on a hill at 50-100 yards or a bill board or water tower at 500-1000. The key is: the target's surrounding background must be clear blue sky.
3) From one side of the target or the other, but not on the target, begin ranging the sky and move progressively closer to the target in small increments** until you get a �hit�. You have just determined the outer edge of that side of your beam.
4) Repeat this process from the other side of the target and then from the top and the bottom.
*Traffic signs are not good for determining your LRF�s distance ranging capabilities. They are built to diffuse light, not to reflect it back at one place, such as a driver�s eyes.
**If your LRF is equipped with a scan mode, now is a great time to use it.
Knowing exactly where your beam is positioned in relationship to your reticle will make your rangefinding (especially at great distances) much more accurate and rewarding.
