Surface Team talks about the new Surface Pro 3 Pen / Digitizer

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I’ve been anxiously waiting for details about the new pen technology. The Pen has been for me, the distinguishing feature of the Tablet PC that has kept me coming back for a decade. And it’s been pretty much unchanged for that long. The Pen in the Surface Pro 3 is different.

The promise of much higher accuracy especially at the edges is exciting, but I was concerned about the lower specification for pressure sensitivity. I wanted to know more and I found it here on Reddit  – I’ve added some formatting for readability. I intend to use this as reference.
We are Panos Panay and the Surface team at Microsoft. We proudly introduced Surface Pro 3 last week. Ask us anything!

Hi.. this is StevieB. I anticipated the pen digitizer question.. so I have been thinking about how to talk about it over the weekend. I hope you and other folks find it useful. I will try to answer the rest of your questions preceding. Below is about your Wacom and Pressure question.

There are 3 main types of pen digitizer technologies: Electromagnetic, passive capacitive (those conductive rubber tipped pens that trick the digitizer into looking like a finger), and active capacitive.

Electromagnetic works by putting a printed circuit board across the entire device, typically situated underneath the display and its backlight. This is a completely separate system from the touch digitizer that typically goes in front of the display. The circuit board has a bunch of planar coils that emit an electromagnetic field (like one side of a transformer). The Other side of the transformer is located in the pen itself. As the pen approaches these fields and coils it couples the EM signal and adds a load. This load is picked up across multiple coils and the position of the stylus is then interpolated. These field lines can emit 15mm or so above the display, and thus the mechanism for hover. Data is transmitted from the pen to the device (pressure and button data), by modifying the frequency content of the load. To get orientation there is typically a secondary coil/circuit.. and simple trig can extrapolate the orientation of the pen.. this is important for later to remove mechanical parallax. Among the three this technique has been around the longest.

Passive stylus, works by simply acting as an extension of your finger, by being a conductor to passively couple with the electrostatic signal from the transmit and receive rows and columns of the digitizer. This technique uses the same transparent conductive lines in front of the display to do both the finger and “fake” finger/stylus.

Finally, active capacitive solutions started coming into fruition in the early 2000s. Their mode of operation is to use the same transparent conductive lines as passive stylus does above, but rather the pen tip injects an electrostatic signal which is picked up by these touch capacitive lines. Think of the pen is a mini radio and the sensing lines in front of the display the device are little antennas. The junction(s) (where the rows and columns of the transparent conducting lines cross) which receives the strongest signal is correlated to the position of the pen. To do this, the pen typically needs a battery, but the pen can emit all kinds of signals from buttons, pressure, and other. We purchased a really fantastic active capacitive pen and touch technology a couple years ago: you may remember the company that did the CNN election boards.. Perceptive Pixel. This is no doubt the most fantastic pen technology around for large non-mobile screens. Active capacitive field is defiantly showing a lot of activity by a number of different touch makers.. cause it is a natural extension of touch technology and its integration with the touch solution.

Now let’s go into what makes a great stylus from a hardware perceptive :

1) Precision is king. The more accurate and consistent the pen tip is to the actual ink of the display the more natural and more accurate you as an artist and user are able to execute. a. The Precision problem is broken down into 3 categories:

i. Visual Parallax: from pen tip to ink on screen. This is where you think the pen tip is.

ii. Electronic parallax: from pen tip to digitizer and where the digester thinks the pen tip actually is.

iii. Digitizer precision and linearity across the entire screen.

2) Feel and sound: should sound and feel like writing on paper.

3) Pen weight, feel, and ergonomics.

4) Consistent and accurate pressure sensitivity

5) Buttons for switching modes (erase, selection, and other commands)

6) Latency: the lag of ink behind the pen tip (highly app dependent)… good developers can keep this number to a minimum.

7) Palm detection so the computer can reject false touches. 8) Device Integration: how it fits, and the industrial design requirements.

Now that we have a bit of a background of the different popular pen digitizer options and the hardware characteristics of what makes a good pen. Let’s go into a brief pros and cons of each of these (I am gonna skip passive stylus as it is still offers an obvious compromise in experience for our current applications [for now]). But before we begin, please let me say first none of these 3 options are generally more superior than one another. It all depends on the application and even more importantly the implementation/execution of technology. The performance of any one of these technologies is highly dependent on how thoughtful, careful, the engineering put into by the device makers to integrate the digitizer system. I have seen some really poor implementations of all 3 of these solutions above by various device makers. Using the brand of technology does not guarantee performance in the least bit.

Electromagnetic Stylus:

1) Precision: This can be very good for electromagnetics but it is highly dependent on implementation. To get the corners working well, and avoid non-linearity, the digitizer sitting behind the display must extend slightly beyond the display. Also metal objects or magnetics objects near the digitizer or in front of even in the device greatly effect noise and performance. This highly constraints the device maker from having a certain boarder size, and also the types of materials they use on the device and in the pen. Because magnetic fields shift with the environment, you will see drift and offsets… The device maker must do a really good job of calibrating the device.. and if the user puts something in front of the device (say a case that has metal in it), then they must be able to do the same level of calibration. Outside of these constraints, EM pen can give very good results.

2) Visual Parallax: this just depends on thickness the cover glass is… and none of the technologies really have an advantage of disadvantage here.

3) Electronic parallax: because the EM digitizer is buried behind the display and the coils are not located the tip of the pen, the digitizer must calculate the orientation of the pen and translate position from that… this is really never perfect and will often be dependent on where you are on the display.. so it is not a single mathematical transform for all points on the display.. it can be highly complex.. most of the time, the simple route is what is taken.

4) Digitizer precision and linearity across the entire screen: best way to test this.. is take ruler and draw straight diagonal lines across the display. Note how the lines are never really straight… this is very hard to do.

5) Feel and sound: Typically today we work with various materials to change the coefficient of static and dynamic friction of the tip on glass.. but there are other techniques we are working on to make this even better no matter what pen technology is used.

6) Pen weight, feel, and ergonomics. Because it is magnetic based the pen cannot be made out of metal. EM stylus has all kinds of shapes and sizes… from really thin and uncomfortable (but can be docked) to ones that feel like a pen. The pro here is that the pen does not need batteries.

7) Consistent and accurate pressure sensitivity: generally known to do a great job. This is much more about how the pressure curve looks like than the number of bits… I will explain below.

8) Buttons for switching modes (erase, selection, and other commands): because the pen and modify the signals actively (powered by the coils).. it can communicate buttons and pressure information.

9) Latency: the lag of ink behind the pen tip (highly app dependent)… good developers can keep this number to a minimum.

10) Palm detection so the computer can reject false touches: does not really have advantage of active capacitive.. but over passive stylus it does.

11) Device Integration: how it fits, and the industrial design requirements: because the pen digitizer is a separate digitizer from the touch, this solution will add anywhere between 0.4-1mm in thickness, a few mm around the bezel of the device, and a few 10’s of grams of weight. It is a bit harder to integrate into the device cause of the constraints around materials and mechanics.

Active Capacitive Stylus:

1) Precision: in the past I have seen some not so good implementations here, but I am so pumped to see our current results in Pro3. We really did move the mark here. The Pen is really much more precise, linear, and linear across the entire device. The first comment I hear from artists when they use the device, is how precise the pen is.

2) Visual Parallax: this just depends on thickness the cover glass is… and none of the technologies really have an advantage of disadvantage here. In Pro 3 we have dropped the optical parallax to .75mm.. this one of the lowest parallax I have seen anywhere for inking tablets. This means as you move your head around your pen tip, the pen tip stays closer to the ink.

3) Electronic parallax: because the antenna lines are just behind the cover glass (for us that is .55mm thick!) the electronic parallax is further reduced.. and this is one of the reasons our pen feels more accurate.

4) Digitizer precision and linearity across the entire screen: do the ruler test!

5) Feel and sound: We are using new materials to change the dynamic and static friction of the pen tip. The result is a more paper like feel. As an industry we can do better.. but it is going to have to go to a different mechanism.. more on that later 

6) Pen weight, feel, and ergonomics. Because the signal emits from the tip of the pen, metal objects in the body do not effect performance.. this is why we were able to do a beautiful anodized aluminum pen, that feels like a high quality pen in hand. Now we do need a battery, but the advantage of a battery is that one can emit a more powerful signal for other functions.. like click note: click the top of the pen once and OneNote automatically gets pulled open (even over the lock screen [secured]).. and double click and you get the acetate layer for clipping out portions of the screen into OneNote… pretty neat!.. and you can hold the pen about 3-5 feet away to do that… and you cannot do such an experience if you did not have a battery.

7) Consistent and accurate pressure sensitivity: just as good as our previous implementations.. as good as they come in my opinion. More on that below.

8) Buttons for switching modes (erase, selection, and other commands): because the pen is powered it can emit all kinds of commands via its emitted signals (buttons, pressure information, click note).

9) Latency: the lag of ink behind the pen tip (highly app dependent)… good developers can keep this number to a minimum. We have one caveat during hover.. while our latency is still best in class when you are inking, you may notice a bit of a lag during hover.. but only during hover mode..

10) Palm detection so the computer can reject false touches: about the same as EM. 11) Device Integration: Active capacitive digitizer are integrated into the touch controller, and use the same touch sensing lines. This is a fantastic form of integration, which makes for a thinner and lighter device. Also there are less restriction on materials.. for example our Type Keyboard clicks into the bottom portion of the device bezels via magnetics.. this would really be a bad thing for an EM digitizer.


Pressure I have heard a few folks worry about the 256 pressure levels vs. 1024…

One can claim absurd amounts of resolution 10,12,14,16 bits.. whatever.. but in the end even though system is spitting out a 10 or 16 bit number does not mean there is a 10 or 16 bits worth of useful information there.. just like an overspeced digital camera.. the sensor is 20 megapixels.. does not mean the resultant image is 20 megapixels worth of information. You can do this experiment yourself.. I did it over the weekend to try to prove a point to my friends: I took the best known a EM based device I know of and compared it to Pro 3. I started by first downloading and installing a Microsoft PowerTool software called “digiInfo”.. this allows you to record and see Windows messages… I set the software to record pressure on both device. And then a built a small rig to hold the stylus above the digitizer with a about 50 grams downward pressure. Recorded the data of the static pressure.. imported to excel and did some statistics.. here is what I saw: the 1024 pressure tip static-pressure-number had a standard deviation 3 times greater than that of the 256 pressure tip. In end, the performance was the same.. even though one had 2 bits less reported info. This makes a lot of sense.. let me put it another way. The Pro 3 pen measures from 10grams-400 grams of pressure and maps 256 levels to that… the mapping is nonlinear.. cause the human hand force activation is non-linear… but one can approximate about 1-1.8 grams per level. The 10 bit pen.. goes from 10-500 grams.. and supposedly does about ~0.4 grams. Think about both those numbers and that is both super super sensitive.. the best weight scale I have can do .1 gram increments…. The only reason it works is cause it averages the heck out of the numbers which adds a considerable amount of lag.. this lag one cannot do on a stylus.. so you are stuck with a nosier signal comparatively in a stylus. With any new stylus there is a difference in the force curve that you have to get used to… and that is likely what people will notice.. not the difference in bit resolution. We are going to make that easier for you by later giving you a piece of software that allows you to map your own force curve! I encourage you to get one of those scales and try to control it to the .1 grams.. will shed some light on the topic. The feedback from artists I have heard.. is that they do not see a difference.. and that is cause really the resultant info is not different.

WinTab: yes we have wintab driver support. See the link below to download and install it for pro3. In the future I hope apps start using the more modern APIs.. Wintab is old and outdated.. adds latency, and inserts itself in the pen path.. select the windows 8.1 option.

DPI You are right for higher DPI screens a number of the older desktop applications are not DPI aware. Things are getting better though. Windows 8.1 supports different scalars nor for different simultaneous monitors.

Retina: Anywhere between 190-300 dpi is a good place to be for tablets.. people hold them closer and you really want to avoid seeing jaggy lines.. but over specing the screen here can be dangerous and we are already seeing people going beyond 300 DPI.. there is not much benefit at all.. and in the end if not done right can cause more harm….I love our screen 100% SRGB and high contrast.. combined with great DPI. Balanced approach.

Home Button Heard some feedback on people pressing by mistake.. we are definitely looking into it.

Custom Keyboard.. Good feedback.. I agree.

Hope you find this helpful.. sorry it was a bit long 🙂 StevieB
Here is a link to the original Reddit Ask Me Anything

Surface Pro 3: Battery Life Core i3, i5, i7

I’m considering getting the Surface Pro 3 Core i7 just to experience the difference. I had some concern that making the step up would cost me in terms of battery life. Here’s what we learned from the Surface Team today.

Will there be much of a battery trade off for performance in the i7 SP3? Also, what is the overall performance gain for the i7 version over the i5?

Answer from the Surface Team

The battery performance is the same across the i3, i5, and i7. The i7 will see benchmark scores appx. 15-20% better than the SP3 i5.


We are Panos Panay and the Surface team at Microsoft. We proudly introduced Surface Pro 3 last week. Ask us anything!

And if you really want to delve into the differences between the processors offered check out:

Microsoft Surface Pro 3 CPUs Compared: Intel Core i7-4650U vs i5-4300U vs i3-4020Y

The three red bars are the CPUs offered in the Surface Pro 3.

Intel Core i7-4650U vs i5-4300U vs i3-4020Y Benchmark

Surface Pro 3: Is this the One?

It’s May 20th and the big news is the Surface 3. Bigger, lighter, faster, longer battery life, better ergonomics (multiple position stand). Of course, I want one. And I scoured the Microsoft Store for the Order Now button.

And now, front and centre, finally, the pen.


It looks like Microsoft is embracing the Pen as the strategic advantage of the Surface Pro platform. I’ve often thought that the Pen was misunderstood and under-sold as an alternative to the mouse. It is so much more than that. And this message is coming out loud and clear in the images of the new Surface Pro 3 at


I’ll no longer have to use make-shift devices to put the Surface at a great angle for writing.


I’m very excited about the 12” Surface Pro 3 and this is a much easier decision for me, than to be trying to figure out how to fit a Surface Mini into my life.

I need the full capabilities of a laptop in my portable life and having a little more screen real estate is going to be a big help. If you were to translate the new 3:2 aspect ratio (2160 x 1440) to the Surface Pro 2 (1920 x 1080)   – at 3:2 this would be 1920 x 1280. Now that  is something to which I can relate because that extra height in landscape mode is something I can really use for documents and in development tools like Visual Studio.

It looks like the rest is all there too. Lighter, longer battery life, faster, ergonomics. As a potential desktop replacement, I’m looking at the 256 GB Intel Core i7. The August 31st delivery date can’t come soon enough for me. But I’m willing to wait even though the i5 models look like they’ll be available sooner in some markets.

7 Things I Want in a Surface Mini

While we’re waiting to find out what Microsoft has in store for Surface on May 20th I thought we could have a little fun musing about what I’d like to see in a Surface Mini.

1. Pen with Active Digitizer

If it comes with a Pen with an Active Digitizer I’m 90% there. People who have not lived with an Pen with an Active Digitizer have a hard time understanding just how much more you can do with a device with this capability.

Eleven years ago I was completely taken with the Tablet PC with the Active Digitizer.  With that came the ability to write and sketch as easily as I could on paper. Size, weight, and battery life all conspired against the brilliance of this concept but as the hardware improved, it led to Surface Pro and Pro 2.

2. Make it Light

Certainly no more than 0.75 pound (341 grams). People are constantly asking about my devices and why I use them. Please let me not have to rationalize the weight compared to other devices that are the same size.  Besides I want to be able to use it anywhere, set it up on lecterns, music stands or prop it up in places never intended or imagined for a device like this.

I also want to fearlessly hand this to others, typically to read something on the screen. I don’t want to see it tumble from their hands because they were surprised at the weight.

Weight matters.

3. Battery Life

Give me at least the battery life of a Surface 2.  I want battery management to be the last thing on my mind as I’m using it. And while I’m at it, please let me charge it up through via USB Port or my existing Surface AC power supplies.

Minimum: 10 hours

4. Windows – Both Flavours Please

I’d really like the choice of operating systems, and I want two versions of Surface Mini with support for Windows x86 and Windows on ARM.  For me I’d give up an hour or two of battery life to be able to run the same software as I can on my Surface Pro 2. I may not need that all the time but often enough that it’s critical.

5. Ports and Expansion

Give me a full sized USB port – USB 3 would be nice. I want to use all my USB devices without having to buy an extra adapter. And a Micro SD slot would be great.

6. 4G LTE

I’m in an urban area where Wi-Fi is everywhere and it is only once or twice a week that I have to tether my Surface to my Windows phone. I understand that most people are not so lucky. And now that I think of it, if it were available I’d get it with 4G LTE.

7. Office 2013

I’d really like to see Office bundled with the Surface Mini. Couple this with the Pen and I can be really productive in places where it’s just not appropriate to flip open a keyboard. I mark up documents all the time. The Pen is so much better than a keyboard for this, so give me a Surface Mini that I can write on, that I can use in any position or posture, with or without a place to put it.

I’d be okay without this if there is full support for the Pen in versions of Office.

I started off with only 5 things but you know how it goes.

Tick tock, tick tock. May 20th is coming up fast. I can’t wait to see what’s next for Surface.

Two Surfaces for Presentations

Have you ever done a presentation and wished that you had two computers: One to share with the audience, and one for you? Well, I do it all the time with my two Surface Pros. One is the original Surface Pro and the other is a Surface Pro 2. There’s no reason not to use two identical machines. I’m  using what I’ve got.

I used to do this with a Surface and a Surface Pro.  That works fine when I don’t need to connect the two machines in any way. Most of the time I like to share a mouse and keyboard across both machines. I use Mouse without Borders to do that with the Surface Pros.

I frequently do live demos or a lab session with a very dense screen like you find in Visual Studio. It’s tough to have a screen resolution suitable for an audience viewing on a projector and still have it workable for me. I set up two Surface Pros side-by-side and it solves all those issues for me. Here’s how I do it.


Presentation Machine (right) Surface Pro 2

I usually have the Surface Pro 2 on the right and display it on the projector.  Sometimes I do that hard-wired but most of the time I use Skype. See: Surface Pro 2: Using Skype for Presentations for details.

I keep this machine on the right because I frequently draw sketches or live mind maps during my presentations. I do this with the Surface Pro 2 pen of course.

I like to wander away from the lectern while I’m presenting. It’s easy to take the Surface Pro 2 with me when I’m using Skype. I found a case that works really well for that. I leave the Type Cover 2 attached to the other Surface Pro.

Notes Machine (left) Surface Pro


On the Surface Pro that I am not sharing with the audience (the notes machine) I have my notes, code that I will copy/paste to the other Surface Pro (the presentation machine), and other support materials like sketches and mind maps. In practice it feels as though I have a virtual desktop that is the width of two Surface Pros. When I need a snippet of code I can copy it from the notes machine to the presentation machine. This is so much better than people having to watch me type while I talk.  I use the Type Cover 2 on the notes machine and move the mouse across both screens. Wherever the mouse is, the keyboard is active.

What makes this all work is Mouse without Borders, a great Microsoft Garage project from Truong Do.


Mouse Without Borders

Mouse Without Borders – The Desktop version.

Mouse without Borders is a product that makes you the captain of your computer fleet by allowing you to control up to four computers from a single mouse and keyboard. This means that with Mouse without Borders you can copy text or drag and drop files across computers.
Mouse without Borders

I use Mouse without Borders all the time in my desktop setup too. That might be with the two Surface Pros if I’m borrowing a desk somewhere, but I also use it back at the office across my  desktop machines. Even though Mouse without Borders supports dragging files from one machine to another I don’t need to do this very often now that I’m using OneDrive for almost everything. But this feature can be handy especially when I’ve got the machines logged in as different users. See why I use Separate User Account for Presentations.

This is not nearly as complicated as it sounds. Once you’ve done it a couple of times you’ll find that you can be set up and ready to go in about as long as it takes to fire up the machines and have them find a network. And in case you are wondering, in a pinch you can even tether them together using Internet Connection Sharing on your phone.

Here’s a list of related articles and references:

Surface Touch & Type Cover Keyboard Shortcuts

The Touch and Type Covers are brilliant at bringing the full keyboard experience of a laptop to the table. They protect the screen when in transit, and flip out of the way when they’re not needed.

I like the Touch Cover 2 with it’s backlighting and enhanced responsiveness and accuracy because it’s slim, light, and it’s resistant to liquids and well, the weird stuff that ends up on tables at coffee shops. It’s also pretty much silent except for the light drumming of your fingers.

The Type Cover 2 is great when I’ve got to do full-on production typing, both for office work and development. And the backlighting is a nice touch in the dark.

And now to the main focus of this note: Here are keyboard shortcuts to make you even more productive with your Surface


From the Surface Blog 

  Fn + Caps:

Locks F1-F12 into being function keys. Do it again and you get the charms, volume, Home, End, etc. if you are in the function lock mode, you can get the inverse options by pressing the Fn key, naturally

  Fn + <spacebar>:

Print Screen

  Fn + <spacebar> + Alt:

Print Screen for the in-focus App only

  Fn + Del:

Brightness Up

  Fn + Backspace:

Brightness Down

  Fn + <left>:


  Fn + <right>:


  Fn + <up>:

Page Up

  Fn + <down>:

Page Down

Be sure to check out this related article: Left-Click and Drag on Surface Type and Touch Covers: Thank You!