From this <http://en.wikipedia.org/wiki/Ross_%28optics%29> it appears
that Ross was fairly well along in lens design for the time. I suspect
that the good performance shown by Jim's lens is due to long focal
length (200mm), moderate max aperture (f/8) and especially much smaller
image format than the lens was designed for. I tried looking up the
history of apochromats but couldn't find when the first was designed.
Actually, the trick was not the design effort but having glass of
suitable index of refraction.
Chuck Norcutt
On 1/3/2011 2:48 PM, Jim Nichols wrote:
> Jan,
>
> In reviewing all of the images, I found one that I liked in color. It is
> linked below:
> http://gallery.leica-users.org/v/OldNick/Mocking+Bird.jpg.html
>
> I have not searched it critically, but the colors and bokeh look pretty good
> for a 19th Century design.
>
> Jim Nichols
> Tullahoma, TN USA
> ----- Original Message -----
> From: "Jan Steinman"<Jan@xxxxxxxxxxxxxx>
> To:<olympus@xxxxxxxxxxxxxxxxx>
> Sent: Monday, January 03, 2011 12:44 PM
> Subject: Re: [OM] IMG: My Ross Lens Project
>
>
>>> From: "Jim Nichols"<jhnichols@xxxxxxxxxxxxx>
>>>
>>> The best example is shown below, showing battle flags at a local
>>> Confederate Cemetery. This was made at ISO 200, 1/400 at f/16, RAW,
>>> converted to B&W using a PhotoPlugins converter.
>>> http://gallery.leica-users.org/v/OldNick/Flags+BW.jpg.html
>>
>> That looks promising, but I'm wondering about colour, and why you chose to
>> convert to B&W.
>>
>> Old lenses that predate colour film (certainly 1890) are generally not
>> corrected for colour.
>>
>> On the colour images, do you see any evidence of fringing or CA? It would
>> probably be most prevalent in the corners, where spectral dispersion would
>> be expected to be greatest.
>>
>> ----------------
>> Every now and then go away, have a little relaxation, for when you come
>> back to your work your judgment will be surer. Go some distance away
>> because then the work appears smaller and more of it can be taken in at a
>> glance and a lack of harmony and proportion is more readily seen. --
>> Leonardo da Vinci
>> :::: Jan Steinman, EcoReality Co-op ::::
>>
>> --
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>>
>>
>
>
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