P3D Re: Red Button, K2 compared

["Dr. George A. Themelis" <DrT-3d@xxxxxxxxxxxxxxxxxxxxxxxxxxx>]

>From: Arthur Payson <APayson@xxxxxxxxxxxxxx>

>In all the recent discussions comparing viewer optics, I am surprised that
>no one has brought up the lack of contrast inherent in Red Button viewers.
>I have been using K2s for many years, and recently examined a number of Red
>Buttons.  In all cases the Red Button displayed a hazy image, with very low
>contrast and poor color saturation....  
>Dr. T attributes this "fogging" to the cement used when assembling the
>doublet lenses used in the Red Button, and has indicated that this problem
>is more pronounced in some viewers than in others.

This is a valid concern and I would like to point out the following:

This haziness (if present) is more pronounced when bright light is used.
In the 50s people were using No. 14 bulbs and carbon-zinc batteries.
No problem.  Today, some people are using halogen bulbs, alkaline batteries
and have their viewers tuned up with new reflectors, nice coat of paint,
etc.  ALL VIEWER PROBLEMS are magnified when extra bright light is used.

Even though there appears to be a problem is some red button viewers
WHEN USED UNDER VERY BRIGHT LIGHT, I would not conclude that this is
a problem for most of them.

I am not sure if the problem is in the cement or if the glass shows high
light dispersion.  (I guess it would be easy to verify by taking apart
one lens, examining the individual elements and then regluing it back...
I just have not done this)

>I think the sharper edge makes the Red Button a good viewer for checking
>stereo window placement, but for impressing your friends with a great
>stereo image, the K2s good contrast and color saturation delivers more of
>the "wow" factor.

I would not go that far!  One factor that makes the comparison between
the red button and the KII difficult is the non-matching of the light
intensity/colors.  In AC operation, the KII has a warm light.  Many
people are attracted to this, while the shouldn't (the viewer's purpose
is to show the image as-recorded... if the image needs warming this
should be done in the camera when recording and not in the viewer.)  
Even if both viewers are used with similar halogen bulb, a tuned up 
red button will be brighter than the KII, hence the comparison is 
unfair, IMO.

>From: Eric Goldstein <egoldste@xxxxxx>

>On an unrelated topic... I've worked up an excellent inexpensive means
>of filtering the ac lamps in K2s and Green Buttons to yield what appears
>to be a really nice daylight color temp instead of that horrid orange;
>to my eyes what appears to be as good or better a light than with
>halogens. Anyone interested can email me and I'll pass the info along...

How about passing this information into the list?

-- George Themelis


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