The Steam Forums have an update from Professor Pew, spokesperson for 4A Games, and esteemed doctor of pew-pew, who explains the situation regarding the locked field of view in Metro: Last Light, their new shooter sequel (thanks Strategy Informer). It turns out the problem is that allowing adjustable FOV would conflict with their 3D HUD (which arguably means the HUD should have been reworked, rather than FOV locked). They are contemplating their options for a long term fix, and in the meantime are planning a game update "in the next few days" to allow players to adjust the FOV by directly editing CFG files, though this will indeed mess with the HUD. Here's word:

We're aware the community have been asking for a 'Field of View' slider for Metro: Last Light. Unfortunately, this was not as simple a thing to implement as it might appear!

The main reason for maintaining a fixed FOV is because we have 3D elements like the watch and weapon ammo that need to remain visible.

In addition, all the game's first-person cut scenes and cinematics and each and every animation involving Artyom's hands - idle weapon animations, reloads, ladder climbing, melee attacks etc, - were created assuming the same, fixed field of view.

Changing the FOV would break all the cut-scenes and animations - you would be able to see inside Artyom's arms, or they would appear to float in the air in front of you. Or worse.

We had considered offering three FOV pre-sets, but this would still require significant work to re-do every animation, adjust the HUD and UI and other seemingly small but incredibly time consuming tasks.

Even with a wider but still fixed field of view, Artyom's hands would look too far away. We know - we tried.

Game performance is also tied to FOV - the amount of geometric detail we put in each scene has been partly determined by this set FOV, and setting a wider FOV would have a performance impact.

We understand this issue is important to many people, and we have been looking at possible solutions.

In the immediate term - the next title update, due in the next few days will allow you to directly change the FOV in the .cfg files.

This may well trigger a number of issues listed above - you have been warned!