ImperialStormTrooper

This follows up my previous post on wing mirrors.

It turns out that I have two options for a driver's side wide-angle wing mirror:

1. Convex auto-dimming non-tinted glass
2. Aspherical auto-dimming blue tinted glass

Does anyone know what the advantages/disadvantages of the two mirrors are?

2legit

ever see those side mirrors that have a little circle mirror attached to them...thats an aspherical mirror...has more of a concave shape IIRC and lets you see more of the road and the side of your car.

Truck drivers use these all the time.

Stoney

called "spherical" and "convex"?

2legit

i know a lot of cameras use aspherical lenses...maybe mirrors use shpherical lenses...

either way...its the opposite of the convex mirror...

ImperialStormTrooper

I'm not sure I'm following the back and forth here.

If I understand things, both the (spherical) convex mirror and the aspherical mirror are "wide-angle" mirrors. On the passenger side mirror, there is standardly a convex mirror. An aspherical mirror, since it does not have a constrant curvature, like a spherical mirror, can have wide and wider angles, and so would be more effective.

Stoney

"Convex." A concave mirror is either a magnifying mirror or an inverting one, depending on radius. Only other choice is... flat.

Stoney

I'm still waking up. ;^)

meq123

They are more-or-less plain convex over the inner 80% of the mirror, then the outer 20% (or-so) bends 'out' at a more extreme angle, giving a wider view at the edge. Some manufacturers use a mirror that has an actual break line between the two areas (making the change obvious, but distracting IMHO), others (Audi?) just change the curvature. Kinda like the difference between bifocal glasses and those newer ones without the line (forget what they're called).

Stoney

Thanks!

ImperialStormTrooper

I found the following study on the web comparing planar, spherical and asperical driver's side mirrors, all of which are permissible by European regulations. Not too surprisingly, the study says there is a trade-off between elimination of blind spot vs. image size reduction leading to mis-judging whether there is enough space to change lanes.

My own experience is the former is a clear advantage, as one quickly adjusts one's judgement of the gap, given the size of the image in the mirror, just as one does with a spherical passanger side mirror.<ul><li><a href="http://www-nrd.nhtsa.dot.gov/PDF/nrd-12/TNOmirrorfinalrept.pdf">http://www-nrd.nhtsa.dot.gov/PDF/nrd-12/TNOmirrorfinalrept.pdf</a</li></ul>