Marrex MX-G20 Professional Geotagger GPS System

Just received the Marrox MX-G20. After an initial charge of the LI-ion battery, I easily installed the unit on my camera (Nikon D7100), took a few photos and imported them into iPhoto. The unit works very well and I was amazed to see how accurately the GPS operates. Within a foot or two, according to iPhoto map! That's better than my Garmin. True, unlike the more expensive G20M model, the G20 doesn't have a digital panel on which, in addition to the lat/long, you can read the elevation (third dimension) and the direction of motion. But lat/long is all you need for identifying the location of your photos in iPhoto. This unit will save me hours of data entry by hand, plus it's a lot more accurate. I can always carry a magnetic compass for direction if need be, and I don't see what use I would have for the elevation. Like all GPS devices, to operate the unit must receive GPS signals from satellites. It does not work inside buildings. The cables are very sturdy and the unit is well built. It fits snugly into the hot shoe. The kit includes a necessary re-charging cable, which can be connected to the USB port on your iPhone AC adapter or similar. The unit and connecting cable together weigh 2.7 oz. The kit also comes with a very handy remote shutter release cable that connects to a port on the GPS unit.

I had been very interested in purchasing a Nikon body with built-in GPS; however, after reading negative review after review, I decided against it and dropped money on the D7200 instead. I then began looking for an external GPS offering and quickly realized Nikon's was a pass. Unfortunately, there are little options out there (why can't I just use my iPhone's A-GPS via Bluetooth Nikon?!) so I narrowed my selection to this unit since it wasn't too great of a loss if it didn't work out. Besides, with Amazon's excellent return policy, I wasn't too concerned.Upon delivery, I opened the unit and quickly charged it. The documentation is vague in regards to its charged state upon arrival so I was glad that I did indeed charge it since it was pretty much shipped dead. After it was full of battery goodness, I mounted it to the flash shoe and plugged in the USB-mini to Nikon proprietary connection. I pressed the on button and nothing happened. I pressed it again and heard a beep and then I pressed it once more. Bingo, a red light appeared and then a flashing green light. Within a minute, the green LED went solid indicating it had locked into GPS. I took a picture and viewed the EXIF information. Yup, there were my coordinates!After a month of use, here's what I've found:1) Turning it on and off is tricky. You need to press the button quickly, and then hold and press until you see some short of flashing light to indicate is powering up or down. The same goes with charging.2) The documentation is pretty much useless.3) The rubber USB cover broke off within four weeks.4) In clear-sight (i.e. outside in clear skies) the GPS acquired VERY quickly (under 30 seconds.)5) GPS does not engage within most buildings though homes may from time to time. As a workaround, enable the device outside and then walk into the building as the last known coordinates are written to the EXIF.6) Listen closely to the faint beep upon pressing the button to know to let go and then press again to perform the needed action.7) Enable the GPS after the camera is on.8) Take a test picture after each time you power on the device as in some cases, it does not write to the EXIF. Power-cycling the camera and or reseating the cable to the camera corrects this issue. (Note, this issue does not happen often.)Overall, I am happy with this unit. I saved $20 not getting the one with LCD; however, if you want to be sure of connection and the status of your battery, then it can be helpful. After you learn the trick to powering it on and off, it really isn't needed. Solid green means you have GPS and flashing means you don't. Pretty simple. Battery life is very good as I never had it die on me after a full day of use. Charging is also quick charging a dead unit in about two hours and a top-off only taking about 30 minutes.I would like for this to be smaller and the long cord made smaller. Better power cycling method would be nice as well. Press button, power on. Press button, power off. Simple.At the end of the day, my pictures know where they were taken and it does what Nikon couldn't internally or by accessory. A sad statement to one of the most amazing camera manufacturers in the world, but thankfully Marrex is able to handle it.

DO NOT BUY THIS ITEM. I purchased two of them. The first one had the decency to fail within one week-- well within Amazon's 30-day return period. The second, unfortunately, lasted almost four months, then (like the first) failed completely. The problem appears to be with the internal LI battery/recharger, which, even with careful monitoring, can very easily be over-charged. Once that happens, the unit starts to send random trigger signals to the camera shutter (in a matter of an hour, I got quite few pictures of the floor and people's behinds); this is followed very shortly by battery coma and death.While it works, the Marrex is quite good-- but based on a useful life of 10 to 120 days, it is hardly a bargain, even compared to the price of a Nikon GPS.Final note: when I tried to locate the return policy/address for the seller (Movo Photo) on Amazon's "Online Returns" page, none was listed (despite Amazon's statement that this is a requirement for its 3rd party sellers). I guess the return policy is "You're SOL."

I purchased this item to use with my Nikon D750 to geo tag my photos while I traveled around Europe. It works as advertised and I was able to get the unit to lock on a GPS signal usually within 30 seconds at each new destination and kept it on all day without loosing the signal. When viewing my photos I was able to see exactly where the the shot was taken and it seemed accurate. It was a bit tricky turning the unit on and off. It worked best with I pushed the button twice and held it on the second push. I had to remove it to use the built in flash, but most of my photos were outside and this wasn't a big problem as I could still keep the unit attached. Overall I was satisfied with my purchase.

Records location correctly but the direction of view (or "heading") was off, at times by close to 180 degrees. Yes, I had it mounted correctly on the hot shoe and not near metal objects (except the camera). There is no calibration button/procedure for the built-in electronic compass as is normal with GPS devices I've used in the past. FYI, I had also ordered the model MX-G20M (the one with LCD panel on the back) at the same time. It worked better and was accurate, but died after a day of use (see separate review, but note I never received a reply from Marrex customer service when I contacted them through their website). These look good and seem well-made on the outside, but given the other bad reviews and my own experiences, I cannot recommend the Marrex brand. I am now going to try Solmeta's two similar devices, I would like to have the direction of view recorded to my photos for a project.