Quote:
Originally Posted by johndallman
Low-Tech p42 has rules for scanning with optics.
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Huh.
I certainly didn't expect to see such a rule
there. But it is and it should work fine.
In short, optic Bulk penalises scanning, which can be reduced or eliminated by Taking Extra Time. Optic Bulk does not affect focusing on a single target and will thus usually be irrelevant for riflescopes and most uses of spotting scopes. It mostly only matters for binoculars used to
find targets.
Now I simply have to assign TL8 optics Bulk values, on the assumption that a 4 lbs. pirate spyglass with 4x magnification has Bulk -2.
I'm inclined to believe that a binocular design is better than a monocular one for rapid scanning, so I'd reduce the Bulk penalty by 1 for scanning purposes (not Holdout, however, where binoculars are obviously harder to conceal for the same weight).
Base Bulk would match level of magnification, but optics that are smaller and handier than TL4 spyglasses should get a bonus of 1-2 levels of functional Bulk. It's possible that fancy gewgaws having to do with focusing and stabilising would do the same.
Stabilising a light pair of binoculars is mostly a matter of having adequate Trained ST to hold them steady for long periods, experience and one of the many things that go into DX in GURPS. At a human scale, it means that very light, low magnification optics can be stabilised with a firm two handed grip, the use of low-tech aids like a strap or at worst, against an object, analogous to how firearm are Braced (use the same rules).
Depending on strength and skill level, normal people (Trained ST 10) can adequately stabilise up to 8x or 10x magnification binoculars of not much over 2 lbs. using nothing more than both hands and possibly a neck strap. Higher magnification usually requires assuming a stable position or bracing against an object. Heavier binoculars require higher Trained ST, using the relative skill level of such skills as Observation, Soldier, Survival or Hobby Skill (Birdwatching).
Inadequately stabilised optics will at best give the benefit of
half their actual magnification, at worst be useless in game terms.
Bracing or other forms of stabilisation makes it possible to get any benefit from higher magnification, but most methods of stabilisation beyond a firm two handed grip
do make it slower to scan the entire front arc. Add -1 or even -2 for very stable positions (making it hard to move the optic fast) to effective Bulk unless watching only that part of the forward arc within a few degrees each way of the field of view of the optic. Only tripods designed for easy and fast handling avoid this penalty.
Mounting an optic on a weapon will probably raise MinST and possibly also penalise effective Bulk. I don't think I'd count the full Weight of a rifle + optic to calculate MinST as if it were binoculars, as unless the rifle is terribly balanced, it isn't really held in the same way as binoculars and each added pound matters less. I'd probably add anywhere from +1/4 to +1/2 of the weapon Weight to the optic weight when calculating MinST. Optics other than low magnification, wide field of view dedicated tactical optics would also take a -1 penalty to Bulk for being mounted on typical CQC Bulk -4 weapons and -2 penalty to Bulk for being mounted on especially unwieldy sniper weapons.
Now, what real world optics should I think of as the benchmark for different Bulk levels?
Bulk 0:
Tiny pocket opera glasses in 3x25, 4x21 or other ultra compact designs. (Holdout +1)
Bushnell Powerview Extra Wide 4x30? (Holdout -1)
Bulk -0.5 (not sure whether to give 0 or -1):
Leica 8x20 BCR Ultravid Compact? (Holdout +1)
Other very compact 6x to 8x binoculars (Holdout +1 to 0)
Bulk -0.75 (not sure whether -1 or 0):
Compact 8x and 10x binoculars (Holdout 0 to -1)
Zeiss 10x25 Terra ED Compact? (Holdout -1)
Fujinon M24 7x28? (Holdout -1)
Typical 8x30 or 8x32 binoculars (Holdout -2)
Bulk -1:
Most 8x and some 10x binoculars (Holdout -2)
Fujinon/Kama-Tech/Steiner M22 7x50 (Holdout -3)
Other heavy or clumsy 7x50 binoculars (Holdout -3)
Vortex Optics Viper HD 10x42? (Holdout -2)
Riflescopes or other monocular devices in up to 4x magnification?
Bulk -2
Largest and bulkiest 8x to 10x binoculars (Holdout -3)
High magnification (12-24x) binoculars (Holdout -2 to -3)
Heavier, clumsier, older or narrow field of view monocular optics of up to 4x
Common TL8 riflescopes or other light monocular devices in 5-8 magnification?
Very light 11-15x spotting scopes on good, smoothly traversing tripods
Bulk -3
Heaviest and clumsiest high magnification (12-24x) binoculars (Holdout -3 or worse)
Extremely high magnification (25-39x) binoculars (Holdout -3 or worse)
Riflescopes or other light monocular devices in 8-12x magnification?
Most 10-15x spotting scopes stabilised?
Bulk -4
Ultra high magnification (40-60x) binoculars (Holdout -3 or worse)
Riflescopes or other monocular devices in 11-15x magnification
16-24x spotting scopes stabilised?
Bulk -5
Riflescopes or other monocular devices in 16-24x magnification
25-39x spotting scopes stabilised?
Bulk -6
Riflescopes or other monocular devices in 25-39x magnification
40-60x spotting scopes stabilised?
Bulk -7
Riflescopes or other monocular devices in 40-60x magnification
61-90x spotting scopes stabilised
Bulk -8
Riflescopesor other monocular devices in 61-90x magnification
91-135x spotting scopes stabilised
Bulk -9
Riflescopes or other monocular devices in 91-135x magnification
136-200x spotting scopes stabilised
Bulk -10
Riflescopes or other monocular devices in 136-200x magnification