Some years ago, I liked playing *Counterstrike* (at last 1.6) professionally. The people who know what I’m talking about, also know that mouse/sensitivity/resolution configuration is crucial for success. These days, friends and me from time to time play *Day of Defeat: Source* and *Team Fortress 2*. In these games, I’ve lost a huge amount of skill im comparison with *Counterstrike* in earlier days. That’s okay, because I did not play for years and I do not know **how** to play DoD/TF2 as well as *Counterstrike* formerly. But unnecessarily one annoying thing results in an even bigger loss of skill: setting the same mouse sensitivity in CS 1.6 (*“Halflife 1”*) and DoD:S/TF2 (*“Halflife 2”*) **does not result in the same distance-of-mouse-movement to distance-of-crosshair-movement-on-the-screen ratio**, when using wide screen aspect ratio. Now, I’ve spent some time to analyze this issue more deeply.

#### Method

I’ve modified my mouse pad with some steering elements, so that I can make the same mouse movement with only right/left component with always the same **distance-of-mouse-movement**. It’s quite accurate.

Ingame I stand right in front of a wall and shoot to mark a point on this wall. I then go “some steps” backwards, stand still and aim at this marked point on the wall. This guarantees that I really look straightforward (and not a bit up/down). Starting at this marked point, I perform the special right/left movement of a certain distance. Then I simply measure the distance **D** between the crosshair position and the marked point directly on the screen using a ruler. The result of this measurement is the quantity **D [cm] ** I base my conclusions on: I take this value under certain different conditions and compare them.

Of course this method brings along a measurement error of about some millimeters, but it’s negligible in comparison with the distances I’m measuring **and** with the differences of the distances I’m comparing.

#### Experiment, results and discussion

The following table shows the relevant configuration that is valid throughout the whole test:

##### General configuration

mouse | MX 518 |

mouse dpi setting | lowest |

Windows mouse speed |
6/11 |

Okay, now let’s see the results of the tests with Counterstrike 1.6

##### Counterstrike 1.6

resolution | 1600 x 1200 (4/3) |

sensitivity | 1.0 |

others | launch options: -noforcemspd -noforcemaccel -noforcemparms |

D |
19 cm |

`D=19 cm`

. This was measured at least 20 times on different maps and on different positions. Now I’ve changed the resolution (and the aspect ratio):

resolution | 1920 x 1200 (16/10) |

sensitivity | 1.0 |

others | launch options: -noforcemspd -noforcemaccel -noforcemparms |

D |
19 cm |

`19 cm`

, again. I somehow remembered that changing the aspect ratio in *Halflife 1* results in another real sensitivity while keeping the same *sensitivity* setting. I’ve just measured that I remembered wrong: **In Counterstrike 1.6, the real sensitivity is independent of the aspect ratio (while keeping the same sensitivity setting)!**

Now let’s see what’s up with *Day of Defeat: Source*.

##### Day of Defeat: Source

Regarding *Halflife 2* / the *Source* engine, I only consider DoD:S — I think the results should be the same as for TF2; at least I hope :-)

resolution | 1600 x 1200 (4/3) |

sensitivity | 1.0 |

others | m_pitch “0.022”, m_side “0.8”, m_yaw “0.022”, m_filter “0”, m_forward “1”, m_customaccel “0”, m_customaccel_scale “0”, m_customaccel_max “0”, m_customaccel_exponent “1”, m_mouseaccel1 “0”, m_mouseaccel2 “0”, m_mousespeed “1”, |

D |
19 cm |

**Again D = 19 cm**. It seems that you can keep the same *sensitivity* setting in *Hl1* and *Hl2* without any worry; at least for a 4/3 aspect ratio in *Hl2*. Let’s change the aspect ratio here, too.

resolution | 1920 x 1200 (16/10) |

sensitivity | 1.0 |

others | m_pitch “0.022”, m_side “0.8”, m_yaw “0.022”, m_filter “0”, m_forward “1”, m_customaccel “0”, m_customaccel_scale “0”, m_customaccel_max “0”, m_customaccel_exponent “1”, m_mouseaccel1 “0”, m_mouseaccel2 “0”, m_mousespeed “1”, |

D |
16 cm |

Err.. okay now we’ve seen an essential difference between *Halflife 1* and *Halflife 2* based games: **In DoD:S the real sensitivity depends on the aspect ratio!** And what now? You ***want*** to have the same real sensitivity as in *Hl1/Counterstrike 1.6*? I tried to calculate it, assuming linearity:

s1/s2 = a1/a2 s1=1.0, a1=1600/1200, a2=1920/1200 s2=1.2

Let’s see:

resolution | 1920 x 1200 (16/10) |

sensitivity | 1.2 |

others | m_pitch “0.022”, m_side “0.8”, m_yaw “0.022”, m_filter “0”, m_forward “1”, m_customaccel “0”, m_customaccel_scale “0”, m_customaccel_max “0”, m_customaccel_exponent “1”, m_mouseaccel1 “0”, m_mouseaccel2 “0”, m_mousespeed “1”, |

D |
21 cm |

`D=19 cm`

would have been desired, but I got `21 cm`

. When we assume linearity and calculate `16 cm*1.2=19.2 cm`

and compare that to the result `D=21 cm`

, we see that the assumption of linearity is wrong.

There is a nonlinearity between the *sensitivity* setting and the *distance-of-crosshair-movement-on-the-screen*. I did not expect this nonlinearity and I don’t think that it makes any sense. It means that when you change your *sensitivity* setting from 1 to 2, you won’t get double speed! In this case, you will get more!

The dumb thing now is that we don’t know and I don’t want to do many measurements to find out the almost-exact form of this nonlinearity. Hence, **because of this nonlinearity, we cannot calculate the sensitivity setting for DoD:S in widescreen mode to get exactly the same real sensitivty as in 4/3 mode of DoD:S or as in widescreen/normal mode of Counterstrike 1.6**. Since it is a matter of fact that we cannot set it more exactly than to one digit (DoD rounds it then), an exact calculation would even not help much in many cases.

**With this widescreen aspect ratio, you’re simply not able to get the same real sensitivity as in CS 1.6 or as in DoD:S 4/3 screen mode :-(**

#### Conclusion

*Counterstrike 1.6*, which is based on *Halflife 1*, produces the same real sensitivity for normal or widescreen aspect ratios, while keeping the same *sensitivity* setting. *Day of Defeat: Source*, which is based on *Halflife 2*, produces the same real sensitivity as *Counterstrike 1.6*, while keeping the same *sensitivity* setting **and** playing in 4/3 aspect ratio mode.

If you play *Day of Defeat: Source* in widescreen mode, you have to adjust your *sensitivity* setting to get the same real sensitivity as in 4/3 mode of DoD:S or as on widescreen/normal mode of *Counterstrike 1.6*. **But**:

- it cannot be calculated easily, because of an unknown nonlinear relation
- if you find it out by “trying”, you often cannot set it exactly, because only one digit is allowed

**I want to have the same real sensitivity on both, Counterstrike 1.6 and DoD:S. Hence, I have to play DoD:S in a 4/3 mode on a wide screen. Urks.**

If you have more information about this problem, then please let me know. Any feedback is appreciated.