Saturday, June 19, 2010

Leupold RX-1000 TBR Rangefinder Review - Part 3: Accuracy

Leupold Review, RX-1000 Review, RX-1000 TBR Review, Range Finder Review, Leupold Rangefinder Review
So far I have covered the basic geometry of the Leupold RX-1000 TBR Rangefinder in Part 1 of this review.  In Part 2 I covered the rangefinder's functions and menus along with the optical quality.  In this part of the review (Part 3) I plan to cover the accuracy of the rangefinder and in Part 4 I will discuss some of this rangefinder's bullet drop compensation features.  Below in italics are some of Leupold's stated features that I covered in this review.  Throughout my review, all my measurements were made in yards.

> Min Range 10.0 yd / 9.1 m (Confirmed)
> Close Focus Distance 18.0 ft / 5.5 m (Confirmed but not for older eyes)
> Accuracy (per the Owners Manual page 7): +/- 1 yard/meter at distances less than 100 yards/meters (Confirmed)
> Angular Field of View (degrees) 6.0 (Confirmed)
> Linear Field of View (ft/1000 yd) 320 (Confirmed)
> Linear Field of View (m/1000 m) 97.5 (Seems low based on my numbers)
> Max Range (Deer) 500 yd / 457.2 m (No deer measured, but plenty of other stuff)
> Battery Life: At Least 2,000 measurements (Actual number unknown, but battery life is not an issue)

For the accuracy of the rangefinder, I compared the readings against the Leica Disto™ A3 which is accurate to +/- 10mm out to 328' (0.4 inches out to 109 yards).  For ranges less than 100 yards (really less than 50 yards which is the absolute maximum for most bow hunters), this should be more than sufficient for comparing accuracy since the Leupold RX-1000 TBR Rangefinder is only stated to be within +/- 1 yard out to 100 yards.

I started out with the rangefinder in LOS (line of sight) mode and only took the data below for distances less than 100 yards.  The first number represents the Leupold Rangefinder and the second number represents the Leica Disto™ A3.  The difference between the two rangefinders is calculated as shown below also.  Keep in mind that the resolution of the Leupold Rangefinder in this mode is to 1/2 yard and the Leica is less than an inch.  I'm not sure how Leupold rounds to the half yard but there can be anywhere between nearly 9" to 18" of error in their measurement compared to that of the Leica.  These measurements were made against my brick mailbox at about an hour before dark.

    #.  Leupold - Leica = Difference (yards)
  1. 10.0 - 10.8 = -0.8
  2. 12.0 - 12.5 = -0.5
  3. 18.0 - 18.1 = -0.1
  4. 20.0 - 20.2 = -0.2
  5. 23.5 - 24.5 = -1.0
  6. 25.5 - 26.0 = -0.5
  7. 28.5 - 28.7 = -0.2
  8. 32.5 - 32.4 = -0.9
  9. 40.0 - 40.3 = -0.3
  10. 51.0 - 51.3 = -0.3
  11. 61.0 - 61.3 = -0.3
  12. 78.5 - 78.9 = -0.3
  13. 84.0 - 84.1 = -0.1
  14. 91.5 - 91.3 = +0.2
  15. 102 - 102.0 = 0.0
I think this clearly shows that the Leupold RX-1000 TBR Rangefinder is accurate within +/- 1 yard within the 100 yard range.

As I was doing the close range measurements above, it was clear that my older eyes (yes, bifocals) can not achieve the minimum close focus distance with the focus ring adjusted to make the overlaid display also be in clear focus.  With both in clear focus it was about 60 feet (20 yards) for my bifocal eyesight, not the 18 feet listed.  If I adjusted the eyepiece and didn't care about having the display in focus, I was able to make the rangefinder focus on objects approximately 18 feet away.  I don't see this as an issue because I'm not overly worried about anything within 20 yards anyway and I can live with a little out of focus within this lesser range.

Next I checked the angular field of view of 6 degrees by measuring the distance to an object and having the object fill the entire field of view of the rangefinder.  I used a large circular plate that was 17.13" and it filled the field of view at 13' 3".  When you do the math, this comes up as 6.17 degrees.  Since there are some inaccuracies in my measurements, I believe that Leupold's advertised value of 6 degrees is correct.  Also since linear field of view is directly related to the angular field of view, I calculated the linear field of view and came up with 314" at 1000 yards.  That is close enough to Leupold's stated 320" for me to say the data is confirmed.  I was a little surprised that the linear field of view in meters value was not closer to Leupold's linear field of view value.  I came up with 105 meters at 1000 meters, where Leupold states 97.5 meters.  This is a 24' difference.  Personally I think something is hosed somewhere in Leupold's math or I don't understand the difference between how they measure feet versus meters.  In the end, none of this really matters because you are going to get what you get and I don't think you will be dissatisfied.

At this point I wanted to get a better understanding of how big the actual ranging area of the device was.  I went outside and placed a basketball on top of a boot so that the the ball was off the ground and the background of the ball was clearly at a much different distance than the ball.  As I tried to range the edge of the ball, what I found was that if the very center of the cross was not on the edge of the ball it gave me the background range.  In my mind, the Leupold rangefinder has a very precise ranging area.  I would love to find out how the actual ranging area works.

The center of the cross that forms the clear square seemed to be the ranging area.

After establishing the accuracy of the rangefinder out to ~100 yards, I decided to use it to help me determine the accuracy out to 500 yards.  To do this, I was able to range to specific wall sections of a very long building.  The distances between each wall section was less than 100 yards (about 67 yards).  It was a very convoluted method, but in the end, I was comfortable that the accuracy out to 500 yards was within 3 yards for all of my multiple measurement methods.  This ends up being +/- 1.5 yards.  Throughout this test, I was ranging on a 4' x 7' white electrical box at about 3 hours before dark.  Since Leupold does not state an accuracy of this rangefinder for greater than 100 yards, this is some good data.  As a second check I was able to see two reference points on Google Earth which were 492 yards per my measurements and also with Google Earth.

So far the longest object I have ranged was a white building at 697 yards.  For my purposes, I'm not really worried about anything out past 500 yards anyway and that is probably still a stretch.  At this point, my wife thinks I'm nuts and my neighbors probably think I'm a peeping Tom because I carry this on walks, drives, and the kids sports.  As I get more data, I will update the maximum yardage.

One thing I need to point out is that when you are ranging an object at the longer distances, you have the same issue you would have with aiming your rifle freehand.  You really need to hold still so you can get on target.  A deer out at 500 yards would be a struggle to range freehand, but not impossible.

Finally, I need to comment on battery life.  At this point I have no idea of the number of times I have ranged objects.  I'm sure it is well into the hundreds.  I have actually owned the rangefinder for about 4 months and cannot imagine battery life being an issue.  Leupold says "at least 2000 measurements".  I believe it, but a smart man would still toss a spare battery in his hunting pack and yet it will probably be a long time before it is needed.  I do wish they would have used a 123A battery instead of the CR2 battery.  I already carry spare 123A batteries for my flashlight.

You can see other parts of this review by going to the Leupold RX-1000 TBR Rangefinder Review Summary Page.


  1. I appreciate your review. I just bought one of these because I hope to get into load development and long-range shooting with a couple of semi-obsolete Mannlicher-Schoenauer calibers that I would like to think still have some utility in them. I probably wouldn't bother if I didn't think the rifles were so cool.

    I live over a coastal canyon in California that offers a lot of distant targets to range. The highest number I have seen displayed is 1007 yds, but I don't know what I was ranging because the number appeared after a button push while I was adjusting the instrument's position on my glasses.

    I can easily get a range reading on a wide spot on a hiking trail below my house. The display mostly gives me 576-578 as the distance, but I have seen as low as 570 (which may be an aimpoint problem, because I am doing this handheld and can't always be sure I am ranging the identical square foot every time in a patch that is about three feet wide and eight feet long on the ground). In low light levels I can range 775-783 at the top of the knoll at the end of that trail. I am surprised I can get a reading at all, because from my angle I can't see the path and am taking readings off a coastal sage scrub plant community, which can be pretty dark. A rock outcropping below the knoll and further forward gives me 830-835, but with a lot of failure measurements. From Google Earth photos I have determined that these are essentially accurate measurements. I credit the Leupold unit with accuracy at the one percent +/- level.

    I have had some rare freak readings, like 248 yds on a patch of dried grass that must be more than 500 yds away. Most of the time the longer distance is reported, but the incorrect short measurement shows up unpredictably.

    Battery: I probably have 500-700 measurements on the unit by now, and the battery indicator still shows full strength. But I agree one must have a spare available at all times.

    I agree with your overall assessment of this rangefinder as an excellent product.

  2. I'm glad to see you had the same positive assessment of the rangefinder. I use it all the time and am extrememly please.

    Thanks for the feedback!

  3. Great review and I really love this rangefinder and love it also because it is small and so portable. The clarity is unreal, looks better then my 10x25 power binoculars. Far clearer quality. Great tool. Thanks for the awesome review.