Why does Ultrasound Vision have different modifiers dependent upon how much light is present

Full Darkness -3
Partial Light -1
Glare 0

Ultrasound Vision not relying on light should have the same modifier in all Light Condition?

because (AFAICT) it is negating half of the penalties for lowered visibility. it isn't as good as your natural eyes because you are much more practised with your natural eyes. you still rely on them to some extent, and no ultrasound image is going to fully compensate for them, IMO.

ok if you are using 2 type of visions and you have all 4 types then could you not use a alt vision with ultrasound to lower the mods...ie ultrasound and thermographic in full darkness. or ultrasound and low light to remove the med on light fog....

that that being said ultrasound says it a laid over (or replaces) of the user normal visual sensory input pg 324. so can use only ultrasound what would the mod be at that level also.

this is odd also that you can not install the ultrasound into an eye. if you have the capacity for it why can't i add it to eye cyberware being as it is a vision add-on. what is see is there something missing??

Ultrasound was originaly eyeware. I suppose they are saying that you can put it into any limb, not just the eye.

In SR3, ultrasound vision reduced vision penalties by half, round up, and the penalties in the chart were based on normal vision- you got even lower penalties with thermo. I suspect they kept the chart while forgetting what the chart represented when they converted it to 4th.

As it stands, that total darkness penalty also applies to spotting invisible people with ultrasound, or whenever you use ultrasound ONLY to see things.