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03/07/2019

How to Calibrate a DISTO

By bwauters

DISTO Family US

calibration certificate

Maybe you dropped your DISTO. Maybe you've had your DISTO for a while and are wondering if it is still accurate. Maybe you are just amazed at how it works and you are a little skeptical that it is really that accurate.

Whatever your motivation, the first thing you need is a reference. The best source is the calibration certificate that came with your DISTO from the factory.

Each and every DISTO, regardless if it is a €1,399 S910 or a €159 D110, is tested and the deviation for a series of reference measurements is recorded on a certificate that is included in the box. 

If you no longer have your calibration certificate, you can go by the Typical Accuracy, which you can find in the user manual. Or, if you have a current model, in the spec table on the product page.

Distance Measurement Calibration: Determining Typical Accuracy for Your Device

Optional: Download our calibration aid spreadsheet and let us do the math.

  1. Establish a constant baseline. Pick something easy to get to, like a window frame or the length of a room, that is between 1 and 10 meters away. Determine the length of your baseline with an accurate steel tape. If you are an ISO certified user and are performing this calibration to certify a DISTO to ISO standards, the tape must be traceable to a national standard (a class I or II steel tape with Roman stamp is sufficient). Be careful that the hook at the end of the tape does not introduce any errors. 
  2. Take at least 10 measurements from a fixed point. A tripod or some other method of making sure the DISTO doesn't move between shots is highly recommended.
  3. Average the measured values and use the average to determine the systemic deviation from your baseline value. Systemic deviation is the absolute value of (average value - baseline value).
  4. Calculate the Standard Deviation Using the individual measurements (Xi), the average and the number of measurements (n).
    standard deviation
  5. Calculate the Typical Accuracy by adding the systemic deviation to 2x the standard deviation.

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Jeffrey Mantz (not verified) Mon, 10/07/2019 Permalink

When measuring at a distance of 10 feet the laser dot is small but as the distance grows the dot is completely out of proportion and many times fails. I bought it 2nd hand however, I had noticed this issue. When measuring up to 50 feet, many times it gives an error. Do you have any suggestions? The serial #1032251902

Hi Jefferey:

A laser is a focused beam of light. The more powerful the laser, the more focused it remains at longer distances.

Distos are a Class 2 laser, so not very powerful (which makes them safe to use around a crowded job site). As you've seen, the "dot" can get pretty big at long distances -- like the size of a plate when you get out to the maximum range.

The accuracy of a disto at long distances has more to do with the technology we have developed to measure the return signal of the laser than with the strength of the laser itself. An accurate measurement can be ascertained from a relatively weak return signal.

At longer distances, how reflective your target is will impact your ability to get a reading from that big laser dot. For example, if the 358 sign in this video were black instead of white, we probably would have gotten a 255 error.

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