From: Jack Fulton (jefulton1@home.com)
Date: 03/13/01-10:50:42 AM Z
Oh, yes Bob . . . I just mentioned how lenses are made, or perhaps better
put, why they are made. If one has a good camera lens you can make small
enlargements and perhaps not notice a difference in the print.
But, going back to lenses . . the 'process' lens is symmetrical. This means
the various lenses in the front of the aperture are the same as behind the
aperture. All one is doing is copying the flat item in front and enlarging
to paper or film.
A 'macro,' lens is designed to obtain closer focusing and you will notice
the largest aperture is often not more than 3.5. These lenses are 50 mm
lenses but the optical design allows one to focus closely, say, on the face
of a person, and not have the nose become extended or distorted.
We have, where I teach, a class in mural creation. many students use 35 mm
to blow up very large. We purchased a special Rodenstock lens to allow
enlargements much beyond the normal 5 to 15 times enlargement. This lens
does, indeed, make a profound difference in quality. However, since the
students use it for that purpose, I am quite sure that very few, if any,
even know what they are using.
For sure, I am in no way even close to being an expert on lens design, but
these basic principles give you an idea of special qualities configured for
specific lenses.
Jack
> With what you said in mind, I have a question....
> If we use both eyes to view dimension and depth, how can
> a lens (essentially "one eye") interpret "our world" in anything
> but two dimensions? Shouldn't I be able to use, say for instance,
> a typical 35 mm "normal" camera lens (i.e. 50 mm, give or take),
> and use it as an enlarger lens, and still get the "flat plane" type of
> performance as you would from a specifically designed enlarger lens?
> Especially if I stopped the lens down, and did not use it at full, or near
> full apertures?
>
> Just a thought.
>
> Thanks for your comments, and time.
>
> Bob Mazzullo
>> -----Original Message-----
>> From: Jack Fulton [mailto:jefulton1@home.com]
>> Sent: Monday, March 12, 2001 10:18 AM
>> To: alt-photo-process-l@skyway.usask.ca
>> Subject: Camera lens as enlarger lens
>>
>>
>> When I first started making photographs, I was very poor but
>> clever and used
>> my camera lens as the enlarger lens. I created a stiff cardboard
>> cut out and
>> 'implanted' my camera lens there.
>> Don't quote me on this, but a 'good' enlarger lens is almost a symmetrical
>> one whereas the idea of a camera lens is different. The camera lens is
>> designed to bring a 3 dimensional world to a 2 dimensional flat plane. The
>> enlarger lens brings 2 dimensional flat plane to another 2
>> dimensional flat
>> plane. Due to this, similarities to a process lens will be found in an
>> enlarging lens.
>> However, most of the lenses made are pretty darned good and in
>> making small
>> enlargements, one may well not even notice the difference.
>> Jack Fulton
>>
>
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