- Extech LT45 LED Light Meter

Easy to use and seems to be accurate.

User friendly

Meter appears to work fine, however there appears to be an error in the instruction manual that came with it. On p6 the L2 to L4 colours appear to wrong. I went on-line and the e-version of the manual I found had what I believe are the correct colours L2 Red, L3 Yellow, L4 Green. My data made a lot more sense after I applied these. It took a long time to sort out though. Otherwise OK.

Very easy to use and compact. Without a back light it is hard to read at night.

A distinguishing feature of the LT45 is its claimed ability to measure specific colors of LED lighting. This is not quite false, but is rather misleading. First, the meter has no ability to filter the color of light it sees. It has neither physical filters, nor does it have multiple sensors for different wavelengths, as you might have expected given the priced differential. The entire color-specificity revolves around this: The single sensor, unsurprisingly, has a sensitivity profile -- more sensitivity at some range of wavelengths, tapering to less at other wavelengths. To compensate for this, the meter can be set to invoke a multiplication constant to increase or decrease the reading according to where the color of interest falls in the sensitivity graph. That's it. Compounding this disappointment is that the menu for "selecting the color" (ie: picking the multiplier) requires picking a menu item number from L0 to L9, not by color name. The display does show the multiplier value, but you have to look in the manual to find which one corresponds to which color. And then you discover that the paper manual (v1.8 6/16 version) doesn't agree with the currently available online PDF version (v1.4 9/13) as to which L number is for which color. Further, while the paper v1.8 manual doesn't show the multipliers, the v1.4 PDF manual does, and they don't agree with the values actually in the meter, by a wide margin. So who knows which setting is which, or if any of them are useful. So effectively, the color feature, even if working, is unsophisticated, clumsy to use, and rendered useless by the discrepancies in between the manuals and between the manuals and the meter. Bottom line: if you are looking for a meter that can actually give you measurements of different colors of light that you can have confidence in, this is not the meter.

This same product is available from other sellers with NIST calibration certification for a higher price . If your work product is going to be evaluated by an insurer, or in court, you need the NIST calibration certification.

The only lihgt meter with all that we we're looking for. We love the options and different light bulb settings that are programmed into this meter.