If you’ve ever looked to buy a gaming mouse today, chances are you’ve been smacked in the face with obfuscating numbers, e-Sports gamer promotion and generally unhelpful terminology when aiming to buy a mouse. For gamers who simply want the best mouse tracking experience, the choice between Optical mouse and Laser mouse is the question most often asked, and the answer has a few variables that speak to each sensor’s strengths and weaknesses.
Sensors: Fire The Laser
Most often you’ll hear Optical is generally superior to Laser based mouse, and it’s almost been elevated to a rule of thumb, even though the latter is newer technology. Although I cannot go into the intricacies of mouse sensor tracking, the differences in actual sensor technology are only in name, since both actually use optical sensors and mostly use the same principle to function.They both shoot light at a surface, capture the reflected light into their CMOS sensor and analyse it using a DSP, or Digital Signal Processor, much like how a camera takes pictures. Although instead of one picture, these sensors are taking thousands of pictures a second, and analysing the differences between them in order to determine direction and movement.
The core difference is the way they illuminate the surface they track on. A laser mouse uses a *gasp* Laser or Vertical Cavity Self Emitting Laser (VCSEL) for illumination, while older and cheaper Optical mice use red LED, while newer “gaming” sensors use infrared LED.
These differences between an optical and laser mouse come down to the different wavelengths of light for illumination. A laser light is more sensitive towards capturing the entire structure of the surface it’s travelling over, generating a “deeper” illumination, picking up the peaks and valleys in a surface. A normal LED in an optical mouse focuses on surface illumination, mostly picking up the tops of the surface they move over.
These different methods of tracking over surfaces introduce differences in sensor accuracy. Since a laser does “deep” illumination, it’s picking up a lot of information about the surface it’s tracking over, and thus it can track over a large range of surfaces generally easily. In fact, one of the original selling points for the first Laser mice were their wide range of tracking surfaces you could use it on, as opposed to Optical mice at the time, which stumbled on reflective surfaces or glass surfaces. People mistakenly (through marketing no doubt) conflated this wide-surface tracking capability to sensor superiority itself. On the contrary, even though a Laser sensor is capable of tracking over many more surfaces than an optical sensor, it does not make them more accurate by that measure alone.
When a surface is non-uniform and rough (i.e lots of peaks and valleys) the Laser sensor is sensitive to that structure and is picking up far too much useless information. This causes discrepancies in tracking accuracy, especially at slower speeds, something I definitely picked up while using the Avago ADNS 9800 powered G.Skill MX 780 on a cloth based mouse pad.
Deep tracking, shallow accuracy
This change in accuracy across different speeds is what most people commonly refer to as acceleration; but the more technical term would be “resolution error versus speed”. The issue here is not that the mouse sensor itself has built in positive or negative acceleration, but that laser sensors pick up too much “noise” or useless information in determining direction and movement. This noise affects overall movement by adding “counts of movement”. For instance, when you move your mouse horizontally, noise may add counts of movement vertically (up or down) or in the opposite direction, thus losing some accuracy or “1:1” hand/cursor movement.
So now that movement across the screen at a slower speed will not match the one at a faster speed, not because of built in acceleration, but because the sensor’s interaction with the surface it’s on can cause discrepancies in accuracy at different speeds. This phenomenon is generally understood as “acceleration”, but it doesn’t quite describe everything that’s going on; clearly the type of mouse pad plays a heavy role in that.
The type and weave of a surface is integral to Laser mouse accuracy. Even though older optical mice could not track or had issues tracking on glossy, reflective and white surfaces, newer sensors using infrared light are able to bypass most of those issues; white surfaces are still a no-go though! A Laser mouse sensor is much more finicky when it comes to mouse pads, often producing anywhere from 5-6% variation is tracking of the “acceleration” variety. Generally speaking, laser sensors perform poorer on softer cloth based mouse pads because its sensor is more prone to pick up the non-uniform cloth structure and cause erratic movements and acceleration issues. This is why a harder, more uniformly rigid, mouse pad is recommended with a Laser mouse. In contrast, an optical mouse performs “more predictably” on a number of soft or hard mouse pads, although generally the feeling is softer mouse pads are preferred for optical mice. With gaming optical sensors tracking accuracy is much better as a result, having less than 1% variation, with some of the best (Logitech G900 Chaos Spectrum using the excellent Optical PMW3366 sensor) having less than 0.1%.
So if Optical is more accurate, why Laser?
Good question, right? Although objectively true, there are some reasons to consider a laser mouse, even if the reason is somewhat passable. First off, the reality is that most gamers do not need as close to perfect precision — not everyone can buy the nearly R2500 Logitech G900 Chaos Spectrum when they just want to jam some chilled indie games. For games where it really counts, i.e, FPS and maybe 3rd person shooters, the accuracy argument has pluck; but 1:1 accuracy in minesweeper, although l33t as hell, is not useful. For those who would care, most laser mice usually have higher DPI over similarly priced Optical, although it’s achieved by using interpolation which negatively impacts accuracy and can increase mouse latency.
Another important consideration would be more ergonomically based—a mouse can have the best sensor, but if its shape, weight and button configuration is not to your liking, accuracy will reflect your hand comfort rather than the sensor’s capabilities. Lastly, just because a mouse has the same sensor, even an optical one, doesn’t mean they perform the same way; the manufacturer firmware and implementation introduces very different results. For example, take the ASUS Gladius(right) which shares the same S3988 Optical sensor with the Corsair Scimitar (left). Looking at the different results, the Scimitar shows poorer performance as DPI increases.
So, if you can help it, make sure you at least start off looking for and researching an Optical mouse before you buy. See if there are any Optical based sensors in your price range, which sensor version they use, which you can most likely find out a forum post on Overclockers.net with a list that gets updated frequently. Then gather what the general review consensus is and whether or not it will suit your grip, feature and software requirements. If nothing there suits your needs, then move over to comparable Laser mouse options and do the same sort of research. If anything, a cheaper optical mouse might still not have some of the features you would need in a similarly priced Laser mouse.
Last Updated: November 8, 2016