Solmeta GMAX-EOS review

Original Solmeta GMAX-EOS

I purchased a Solmeta GMAX-EOS in September 2017. It arrived September 17th - 3 days after I ordered, very efficient! Previously I had a Canon GPS, but as I don't use Windows I could not use the full facilities (I use a RISC OS computer). The Solmeta allowed me full access to its log files which work properly with the RISC OS mapping program RiscOSM. When plugged into a computer the device behaves like a USB stick allowing full access to the log files.


Initially everything was fine: the GMAX-EOS talked to the Canon EOS-70D via its hot-shoe and shots were properly stamped with full GPS information, including direction.


However the instructions, being in Chinglish, did not make much sense in places and the GMAX-EOS has a lot of features in its menu which are clearly there because the chipset that it uses (MTK3339) is not designed for camera use, but rather for vehicular use. These extra features do tend to confuse things, so it was sometimes difficult to work out whether the feature actually did work and I did not understand the instructions or whether the feature simply didn't work. I am a technical author so this was an annoyance. That said - the instructions were a lot better than many Chinese instructions and did adequately cover most of the things I wanted to use.

There were certain things in the instructions which simply did not work.

The above list could go on: testing every feature is quite a labour! The point is that the GMAX-EOS and the instructions do not agree with each other. However, even considering this, the instructions are not at all bad, especially considering their Chinese origin. But the device deserves good instructions.


The GMAX contains its own internal lithium battery, charged from a USB connector via the lead supplied with the device.

The GMAX menu includes an option to look at the current battery voltage. However the instructions make no mention of what this voltage should be or what the minimum recharge voltage is or how to use the information.

The display, when the GMAX is plugged into a USB, shows the fact that the GMAX is charging, but gives poor indication that charging is complete. There is a battery indicator on the display which shows 1, 2 or 3 small bars to display charge state, but it is tiny and very easy to miss. When charging all 3 bars change 1-2-3, 1-2-3 etc to indicate charging. But there is no way of telling how far charging has gone until eventually they stop at 3 bars. If you unplug the charging lead and switch on, then the display will change to show 1, 2 or 3 bars. Care must be taken when using the GMAX that the battery does not run out. If you are lucky, unplugging the charging lead and reconnecting will trigger this display, but this tends to lock up the software until the charger is unplugged.

However most lithium cells are 3.7/4.2v - nominally 3.7v but 4.2v at first when fully charged. The battery voltage, read via the menu, seeds to be 4.15 fully charged, rising to 4.18 when the charger is connected. But this cannot be relied on as plugging in the charger when the device is ON freezes the software!


Solmeta did release an upgrade to the software but as I do not use Windows and the program for upgrading (supplied by STMicroelectronics) only works on Windows this was no help. Upgrading the software, provide you use Windows, appears to be simple enough using STM's own programming software, available from Solmeta's www site.

Log Files

The log files are in NMEA format. The computer system I use - RISC OS - has a very good mapping program - RiscOSM - which, at that time, was relatively new and did not at accept these log files. So I suggested to Solmeta that a proper description of the format of the log files should be made available. Surely someone in their organisation had that? - Again no response!

However between myself and the mapping program's author (with help from the internet) we worked out the format and the program's author altered the program to accept NMEA format logs. I wrote up the Solmeta log file format for my www site.


Solmeta guarantee the device for two years. Of course returning such a device to China is not quick, nor inexpensive. I had reason to test their guarantee when my device failed to reliably communicate with my Canon EOS-70D after some 19 months.


The device seemed to be good and Solmeta appeared to be a good company who I wished well. But oh the instructions... Although good by comparison with lots of other companies there are many Chinglishisms and there are points which are not explained well and some that don't work. I had many email communications with Solmeta offering to edit the instructions and check them, but this offer was eventually refused.

However this does demonstrate that their support is, by modern standards, good. With many products it is simply impossible to get manufacturer's support. Solmeta are good - especially considering that there is probably only one English speaker there, who is not an engineer and is not always available. Translating a chinese speaking engineer's comments so that an English speaking customer can understand is not easy! However Solmeta are quite capable of ignoring questions they do not wish to answer!

Service and bad communication between GMAX-EOS and camera

As I said above, the Solmeta GMAX-EOS worked faultlessly for 19 months. Then it refused to talk to the EOS-70d camera via the hot shoe. Connection via the cable worked - some of the time, but about 30% of the shots failed to have added any metadata to the photo. I sent several emails asking about this, without response (the English-speaking lady was out of the office!). Eventually I got a response and it was agreed I should return the device for service.

Solmeta supply a form to fill in: on this I said Does not connect via hot shoe. Connection via cable is erratic (~50%) and I added Display may be failing: at switch on centre top of display is feint.

It takes a few days to get through Chinese customs (they prefer to export rather than import!) but once Solmeta received it it wasn't long before they returned it. The display had been replaced, but there was absolutely no change in the connection problem.

There was no paperwork in the return, so no engineer's report. I therefore had no idea what tests had been done. Admittedly there are significant problems in arranging a Chinese-speaking engineer to convey useful details to an English customer, but if no fault can be found then surely they should say so.

More emails. Solmeta suspected a faulty cable, but as this would not affect hot shoe connection, I did not think this was the trouble so they sent a replacement. This malfunctioned exactly as did the original.

I therefore took the camera, GMAX-EOS and all to a camera repair expert (Advanced Camera Services of Watton) who tested the GMAX-EOS on my EOS-70D and also on an EOS-7D. The device behaved the same on both.

There are, on the internet, reports from other people with problems of non-communication between GMAX-EOS and camera so it seems this is a tricky area - one which possibly may have been solved with the GMAX-EOS2.

Eventually Solmeta kindly suggested I should return camera and both devices to them for attention. The story of Solmeta's service department is another page.

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Page first published: 24th of September, 2019
Last modified: Wed, 01 Jun 2022 08:55:15 BST
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