Tom, basically you didn't know the reflection theory. You believe the front
lens coating has no contribution to flare but that is wrong. I just argue
with you for this point but not talking about small coating defects. I
always believe small coating defect has no or very little influence on the
lens performance but you believe the front coating is just for good looking.
BTW, you never ware a uncoated glasses? If you have you should remember how
bad it was when in server backlight situation. The figures are nothing.
C.H.Ling
----- Original Message -----
From: "Tom Trottier"
> I'll have to fall back on a single argument: It's only a single lens
> surface. From http://www.photodo.com/art/Anti12.shtml
> "As the number of elements increases (for example 1, 2, 3, 4, 5, and
6)
> you get an increase in element reflection (1, 6, 15, 28, 45, and 66
> reflections respectively)"
>
> So coating loss on 1/10 of the front element of a 6-element lens would
> only contribute 1/10 x 1/66 of the total glare, or 1/660, times the
> increase in reflection, perhaps 8:1, so 1/82nd of total glare, or a
> very minor loss of contrast in the resulting picture. The proportion
> would be greater for a 4-element Tessar, less for a 16-element zoom.
>
> So some front coating loss won't ruin a lens, just add a little flare.
> There's a reason for those lens shades!
>
> And I do wear glasses -- coated ones...
>
> tOM
>
> On Wednesday, September 11, 2002 at 11:58, C.H.Ling
> <olympus@xxxxxxxxxxxxxxx>
> wrote re "Re: [OM] Fang! possibly two" saying:
>
> > I bet you don't wear glasses, in the old days when coated glasses is
> > still not so common, at backlight situation you will see the light
> > reflected on the front of the glasses with your eye behind. Reflection
> > on one surface will be seen from the other side. No one will put
> > coating on the front lens if just for good looking, coat a lens is
> > costly.
> >
> > Still not believe?
> >
> > check the following from photodo:
> >
> > "There were not only strong reflections between the different
> > elements, but also between the two surfaces of any single element."
> >
> > the link is:
> >
> > http://www.photodo.com/art/Anti12.shtml
> >
> > some more...:
> >
> > http://www.nikon.co.jp/main/eng/society/tec-rep/plastic_lens.htm
> >
> >
> > C.H.Ling
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