Gear Reviews

Epson SF-810 review – GPS sports watch & wrist mounted optical heart sensor

Epson doesn’t only make printers, among their catalogue of electronics they also have the RunSense sport watches and PulseSense activity monitors. Here I look at their top of the line RunSense watch, featuring their latest, home grown, optic heart rate sensor, in the Epson RunSense SF-810 Review

Epson SF-810 review – RunSense GPS Watch

Epson at the end of 2014 decided that they were going to get into the fitness/running watch market. Many companies would start off by testing the waters, and releasing a single unit, such as the way FitBit initially came to market, and building from there.

Not Epson, who as an initial offering launched not one device, but a fully fledged series of four running watches, under the RunSense banner, AND two activity monitors under the PulseSense banner.

epson runsense sf-810 review

RunSense – The new kid on the block

At the top of the RunSense range, sits the SF-810 which is Epson’s top spec watch comprising:

  • GPS
  • Accelerometer
  • Vibration Alerts
  • And most interesting of all is the Optical heart rate monitor

Dont join them, beat them!

When receiving the review unit, I was particularly interested in testing the optic HR sensor found on the Epson SF-810. Whilst there is currently several different watches that use optical HR sensors, they all use a sensor from one of either two manufacturers – Valencell or Mio. Although its more likely that you’ll have used the Mio sensor in the past, as this covers the majority of the Big Boys – TomTom, Mio (well they made it, makes sense they’d use it!) and Garmin.

Epson have really decided to flex their technological expertise with the SF-810 by developing their own optical HR. Which is an almost Apple approach to controlling the whole product end to end, I’ve even been told they developed their own extremely small GPS sensor, which is one of the reasons the SF-810 can pack so much technology into such as small form factor.

However when you compare the hulking Fenix 3 to the SF-810, there doesnt seem much to choose between them in terms of size. However the 85g of the Fenix 3, really makes it feel the heavier watch compared to Epson’s svelte 52g. Certainly you dont feel it on your wrist the same way as you do the Fenix 3

epson runsense sf-810 review

Fenix 3 vs Sf-810

The Device

Another interesting feature of the watch is the charger – no wait, I’m not that boring!! Ok, the charger is a mildly interesting feature. The point being, when you first open the packaging, you are struck by the massive block of plastic that dwarves the watch. Frankly it looks rather old school, and a little at odds with some of the other sports watch chargers. Heck the Polar M400 merely has a micro USB port, making it the smallest charger

epson runsense sf-810 review

Clever charger

When I compared it to my Fenix 3 charger, I initially thought that Epson must have made the choice to go with the massive charger as a way of making savings having developed their own chips and sensors for the watch. Then I used the charger for the first time and was very pleasantly surprised.

epson runsense sf-810 review

Thats a form factor design for you!

Sure the Fenix 3 charger takes up very little space on its own, but it’s a bit of a fiddly blighter to attach the watch to. Plus when you finally get the watch charging, the watch sits flat, and splayed out, so the combined units take up quite a bit of space on the desk, or bedside table.

By comparison, the Epson charger is so simple. The Epson RunSense sf-810 review model pushes snuggly into the boxy charger with a reassuring *click*, there is no messing around trying to slot the watch into the charger, a simple push and you are away. When plugged in, the watch/charger combo stands proud, allowing the watch to wrap round it, taking up much less space – All in all a very well designed charger.

Using the SF-810

Lets look at the elephant on the back of the watch, the optical heart rate sensor.

Optical Heart Rate sensor

In so many ways the presence of the optical heart rate sensor makes this an awesome watch

epson runsense sf-810 review

Optical HR

The mainstay of  watches sports watches utilise a heart rate sensor. Over recent years companies like Garmin with the 920XT utilising the – Garmin HR-Run and the Wahoo TICKR have successfully levered  further functionality from the heart rate sense, such as measuring cadence data. The Epson SF-810 has done away with the need for a separate HR monitor, but doesn’t lose a beat in terms of functionality.

Running Data

Like the new Garmin Fenix 3, the Epson SF-810 is able to calculate cadence – which Epson terms pitch – using the internal accelerometer within the watch. The SF-810 is also able to calculate stride length, more sensibly termed stride – which can be used in conjunction with cadence to help improve running efficiency, and potentially help address issues such as infra-patella pain

In terms of activity tracking, the SF-810 will also count the number of steps taken during a run. Although this is ONLY recorded in the run setting. If you have accidentally forgetten to swap from Bike mode, the data isn’t recorded

epson runsense sf-810 review

RunSense Dashboard running data

The optical heart rate monitor, and the including running data does make the SF-810 a very complete, single package running watch. The simple ability just to grab the watch and go running, without any need to go draw diving to find a chest strap, and remember where your heart rate monitor pod was out at the end of the last run is very freeing.

Optical Heart Rate monitoring growing pains

But this is Epson’s first generation optical heart rate monitor, and as such its not completely 100% perfect. Maybe 95%. But the few niggles I had with it are common to all optical sensors at the moment.

The most notable issue – the sensor doesn’t like it when I’m cold. Or should I say it doesn’t like it if I havnt had a good warm up. I’m a relatively slight chap, and if its chilly it seems that the blood decides not to go below my elbows – my GF can attest that during winter my hands have a temperature suggesting they are stored in the freezer over night!

epson runsense sf-810 review

Optical HR doesnt like the cold

The point being, when doing a chilly morning run, it has taken the optical HR about a minute, or in this case kilometre or so after I’ve started running to actually for the watch to pick up my pulse.

I also found that occasionally the watch would simply lose my heart rate completely. Initially I thought that this was related to my pace, as I flailed my arms around running down the road, but as you can see from red line on the below graph, as I move to a sprint the heart rate tracks up nicely. The drop outs – green gaps – seems to occur randomly, but turned out to be related to the watches position

epson runsense sf-810 review

Heart rate dropouts


One of the ways I have found to improve the heart rate pick up, is to have the watch seated slightly higher up my wrist – 3 finger breadths – up from my wrist. This moves the watch away from the prominent ulna styloid of the wrist, giving the watch a flatter surface to interface with your skin.

epson runsense sf-810 review

Positioning of the watch is vital to good HR data

Having a good contact patch with an optical HR sensor is relatively important, as it means the watch sits flatter and thus reduces the amount of stray light that is able to hit the sensor. As stray light, is the enemy of optical heart rate sensors. Opitcal sensors are a little bit like  vampires, but ones that can tolerate  just a little sun light, but any more than a little, and they just cant concentrate on your pulse!

Was you can see from the top graph, moving the watch three fingers up the wrist gives an excellent heart trace, which corresponded nicely will the data from my TICKR

Going running

Using the core functions of the watch is sooo simple. Want to run, press “Start”, find the GPS, and hit “Start” again to run, want to check your pulse, hit the “HR” button. It’s just that ridiculously simple.

epson runsense sf-810 review

Simple function buttons

You can off set the finicky nature of the optical HR when setting off in the cold, as the watch does have a slight lag in GPS acquisition of maybe 30secs or so, but really this is a proper first world problem! You merely start the GPS search whilst putting on your trainers – you can also pre-cache satellite data from the phone app – although as this data is only valid for 2 hours, I found you were better off waiting for the satellites to be found by the watch anyway. This is quite a large departure from the Fenix 3, where the satelltie data can be stored 7 days, and is actually very effective at ensuring fast satellite lock – maybe something for Epson to look at in an update?


Epson has a very effective set of running screens outside of the box, but changing them on the watch is basically not going to happen. Initially the whole setup of the watch seemed astonishingly difficult, then I realised you are not supposed to do it on the watch, but on the Epson RunSense companion app instead.

epson runsense sf-810 review

Watch fields in the phone app

If you’ve ever tried to set up the device screens on a Garmin…well lets just say that I could have almost wept for joy seeing this interface. Thats not exaggeration. Setting up screens on the phone and having those settings beamed over the to watch is so much easier than the Garmin user interface!

Now the Epson Sf-810 screen is NOT as pixel perfect as the Garmin Fenix, but the screen estate is just as well used, if not better. Certainly its easier to see exactly where you are on the Epson’s runnings screens

epson runsense sf-810 review

Pixel perfect vs usability

Batteries, what batteries.

Oh and lets not forget a major boost that is having one device as the whole running package, You just have to recharge, one device, and not worry about the battery life in different parts of it. Discard the run pod, chuck the heart rate strap, one charged Epson SF-810 and you are on your way

Getting the data off the watch

You need to first to create your RunSense account

This is vital to the best part of using the Epson SF-810, as without the RunSense account, and crucially the app, you can’t wireless upload of your data. With technology today, especially sports technology, if the device needs to interact with wires with the computer, it really looks old hat – thankfully Epson has that covered. Auto upload via WiFi, such as with the Garmin’s would be a nicer trick, but given that does lock you into using Garmin Connect, I’m happy to press a button to get the upload started!

epson runsense sf-810 review

RunSense site

Within RunSense you can easily navigate around everything you need to do with your activities from the home page.

I’ll be honest I really like my Garmin Fenix. However Garmin can keep their Garmin Connect. I think there is a good reason why people, especially Garmin users, flocked to Strava – because the user interface is great. Epson has clearly seen the weakness in Garmin’s offering here as RunSense is just excellent.

Its intuitive, it has everything you need in one straight forward screen.

On this one screen you can see when you ran, the distances on that day that you ran, the week distance summaries.

This is how to set up a site for everyone using your device. I you want to dig deeply into your data, you can. Its there. If you just want to keep an eye on things, and see what you did. Its all on the front page.

Ultimately RunSense is a very elegant, and ultimately user friendly system. I deal with many different software systems working between hospitals and GP practice. I can’t tell you how great it is to find a system designed to display potentially complex data in an effect way. A system that is designed to be used by a human being, not someone with a degree in IT!


I’ll be honest, the uploading from the watch to the smart phone app was surprisingly slow. Even when the run had uploaded, some of the data still had not fully sync up. Which necessitated plugging the watch into the laptop to upload that data. This isn’t really the end the world, as i’ve already said the charger is very nice, and you also get a top up charge whilst doing so. But it does flag up that there is some work still to do on the firmware side of things with the SF-810

Data Analysis

Even digging a little deeper into an activity, need one click, and the results are straight in front of you. The graphs are simply elegance personified. Click the data and it populates! This is probably the best of sports analysis I’ve seen from a user interface perspective

epson runsense sf-810 review

Elegant data presentation

The best part is that this data isn’t locked onto the web. The smart phone app contains about 95% of this simple, elegant data approach. Yes you are limited to space, but the data certainly is eminently accessible.


I’ll be completely honest. I didnt warm to the EPSON SF-810 initially. That took me about 2-3 days of using it, finding out how the optical HR sensor worked, and then discovering the app. Certainly its grown on me since then, all the more because of its ease of use. It just works! I could go on much more for a conclusion but I think thats all I really need to say.

The optical HR data matches up with my classic heart rate monitor. The data from the watch is easily uploaded. Perhaps the ONLY thing to prevent it getting a full 5/5 is that the screen technology is a little dated when you compare it to the colour offering from the Fenix 3, or the crystal sharp display of the Polar M400. But then this is a sports watch i’m talking about. I’d hope that you were running fast enough that as long as you can see the numbers clearly you’d be happy!

Any comments or questions about this first rate, yet first generation watch, drop them below!



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  4. I have been using this as my everyday watch for a month now and even gone open water swimming in it (HR tracked 100% and surprisingly the GPS tracked about 90% on a short test).
    The battery life is great and it’s tracked everything I’ve done, run, bike or swim.
    I have had Garmin and Suunto watches before (Bulkier & without optical HR) so this is really the full package and very compact compared to 90% of the competition.
    Yes, the Android syncing software could be better but that will be addressed as the products develop.
    As for analytical data, I have it set to automatically share with Strava and just use that, even though the Epson website is very good indeed.
    As for cost? Well i got it from Goldsmiths Boutique using 3 to 1 Tesco Clubcard vouchers – cost me £65 in vouchers 🙂


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