Extra lenses with enlarger - why?

Hello,

As a former teacher, I must object There are no "dumb" questions,
for all questions seek an answer and that how's we learn. Of course,
there might be wrong questions but that's another keetle of fish which
would be best not to enter.

Anyway, it wasn't a dumb question, You see, you learned something which
validates the posing of the question.

OK, outta the classroom....

Cheers,
Bogdan

Gabriel wrote:

ahhhh..... of course. Told you it was a dumb question. :-]

Thanks,


Gabriel

"Bob Salomon" wrote in message
...

In article ,
"Mike King" wrote:


You could use the 75mm for both 35mm and 6x6 but the 55mm lens will give
greater magnification with 35mm negatives for any given enlarger height.
Unfortunately the 55mm lens will not "cover" the entire 6x6 image so you
can't use it to make bigger prints from the 6x6.

You would also find it very difficult, if not impossible, to make larger
then an 8x10 and possibly even an 8x10 on the base board with the 75mm
from a 35mm neg.

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--
__________________________________________________ ________________
Bogdan Karasek
Montr‚al, Qu‚bec e-mail:
Canada

"Wovon man nicht sprechen kann, dar�ber muss man schweigen"
"What we cannot speak about we must pass over in silence"
Ludwig Wittgenstein
__________________________________________________ ______________

Hi all,

The diagonal of a 35mm neg (24mmx36mm) gives you 43mm whereas the usual
enlarging lens for 35mm negs is a 50mm. Is this significant in terms of
results? I have a 25mm for half-frame but I seem to remember that
someone, somewhere, made a 45mm enlarging lens for 35mm negs? (I'm not
talking about the the wide-angle enlarger lenses). Maybe it's my
imagination?

Cheers,
Bogdan

Joe Makowiec wrote:

On 19 Mar 2006 in rec.photo.darkroom, Gabriel wrote:


ahhhh..... of course. Told you it was a dumb question. :-]


Rule of thumb is that 'normal' enlarger lens for a given negative size is
roughly the same as 'normal' taking lens, or roughly the diagonal of the
negative.


--
__________________________________________________ ________________
Bogdan Karasek
Montr‚al, Qu‚bec e-mail:
Canada

"Wovon man nicht sprechen kann, dar�ber muss man schweigen"
"What we cannot speak about we must pass over in silence"
Ludwig Wittgenstein
__________________________________________________ ______________

Dennis

The 55mm has coverage to cover a nomimal 35mm exposure. 24mm x 36mm
nominal. The 75 will probably cover 60mm x 60mm nominal. The
magnification will be greater for the 55mm than the 75mm.

Bob AZ

Bogdan Karasek spake thus:

As a former teacher, I must object There are no "dumb" questions,

[...]

I thought you were supposed to say "the only dumb questions are the ones
you don't ask".


--
Second, Scientologists are like computers trying to run an emulation
of another computer. It can be done, but the performance is awful.
Scientologists are trying to run a bad copy of LRH.

- Keith Henson, from alt.religion.scientology

On Sun, 19 Mar 2006 21:43:02 -0500, Dennis
wrote:

This is my guess ... (correct me if I am wrong):

The 75mm has the correct focal length to magnify the 35mm film size to a
usable projector height and the coverage (field of view to cover the size
of the negative).

The 55mm lens has a wider coverage to take into account the larger size of
the negative and also magnify the film to the similar projector heitht of
the enlarger.

Backwards. Focal length and angle of projection aren't necessarily
locked together. Just look at the Super Symmar XL's as an example.
Anyway, the 75mm covers 6X6 and the 55 is the "normal" lens for 35mm.


==
John S. Douglas
Photographer & Webmaster
www.legacy-photo,com
www.xs750.net

Hi all,

Is this a 5x7 Elwood? You need a 218mm lens, no? I have one and am
putting an APO Nikkor 210/9.0. That should do it but 135??? Have to
try it it with my 135 Componon-S

Cheers,
Bogdan

John wrote:

On Sun, 19 Mar 2006 15:56:05 -0800, David Nebenzahl
wrote:


To expand on this just a little, another rule (rule of pinky?) is that
while you shouldn't use a lens with a shorter focal length than what is
"normal" for the format, you can use a lens that's longer; in fact, some
folks even recommend this, as it eliminates any concerns about lens
coverage of the negative. *However*, if you do, you'll find that this
limits the size of enlargements you can make.


Which I have to wonder as to how valid this is for the current lenses
on the market as I found that putting a 135 El-Nikkor into the Elwood
allowed me to make enrgments that seem identical to those made with
the 180mm Coponon-S. Of course I'm only making 2X enlargements ;)

==
John S. Douglas
Photographer & Webmaster
www.legacy-photo,com
www.xs750.net


--
__________________________________________________ ________________
Bogdan Karasek
Montréal, Québec e-mail:
Canada

"Wovon man nicht sprechen kann, darüber muss man schweigen"
"What we cannot speak about we must pass over in silence"
Ludwig Wittgenstein
__________________________________________________ ______________

Hi,

I certainly would very much appreciate that kind of information as it
would help me to optimize my lens selection for the size of the print,
8x10, 11x14, 16x20 and formats ranging from 35mm, 6x6, 6x9, 3x4in, 4x5
and 5x7. What's best for the desired result and do I have the lens for it?

Cheers,
Bogdan

John wrote:

On Sun, 19 Mar 2006 19:25:06 -0500, Bob Salomon
wrote:


To expand on this just a little, another rule (rule of pinky?) is that
while you shouldn't use a lens with a shorter focal length than what is
"normal" for the format

Unless you are going to use a wide angle enlarging lens to allow you to
make very high quality prints 30% larger then a normal focal length
enlarging lens at the same negative to baseboard distance.


Bob,

Would you take the time to share with the group the optimizations for
the different focal length lenses ? As I remember from our
conversation a couple of years ago, most enlarging lenses are
optimized for 6~10X.

==
John S. Douglas
Photographer & Webmaster
www.legacy-photo,com
www.xs750.net

--
__________________________________________________ ________________
Bogdan Karasek
Montréal, Québec e-mail:
Canada

"Wovon man nicht sprechen kann, darüber muss man schweigen"
"What we cannot speak about we must pass over in silence"
Ludwig Wittgenstein
__________________________________________________ ______________

John wrote:

Which I have to wonder as to how valid this is for the current lenses
on the market as I found that putting a 135 El-Nikkor into the Elwood
allowed me to make enrgments that seem identical to those made with
the 180mm Coponon-S. Of course I'm only making 2X enlargements ;)

Idle point: When you make a 2x enlargement with the 135mm lens,
the bellows extension is actually 135 * (1 + 1/2) = 202.5mm, which is
a lot larger than the film diagonal. Even for a 4x enlargement the
extension is 169mm. On the other hand, making an 8x10 from
35mm means an 8x enlargement, so the 50mm lens is used at
an extension of 56mm. That is, lenses for smaller formats tend to
be used at larger enlargements and so need more margin of
lens f.l. film diagonal.

It's the same reason that lenses cover a larger circle when used
in the macro range.

In article ,
Dennis wrote:

This is my guess ... (correct me if I am wrong):

The 75mm has the correct focal length to magnify the 35mm film size to a
usable projector height and the coverage (field of view to cover the size
of the negative).

The 55mm lens has a wider coverage to take into account the larger size of
the negative and also magnify the film to the similar projector heitht of
the enlarger.



Gabriel wrote:


Okay - this might sound like a dumb question - the "new" enlarger I just
picked up (1960s vintage Opemus III) has two lenses, with the numbers
4.5/55 and 4.5/75 on them. 4.5 is the maximum aperture, of course, and I
presume the 55 and 75 refer to focal lengths. Why would I want this choice
of lenses, and under what circumstances might I prefer one over the other?


Thanks,

Gabriel

Wrong.

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To reply no_ HPMarketing Corp.

In article ,
John wrote:

On Sun, 19 Mar 2006 19:25:06 -0500, Bob Salomon
wrote:

To expand on this just a little, another rule (rule of pinky?) is that
while you shouldn't use a lens with a shorter focal length than what is
"normal" for the format

Unless you are going to use a wide angle enlarging lens to allow you to
make very high quality prints 30% larger then a normal focal length
enlarging lens at the same negative to baseboard distance.

Bob,

Would you take the time to share with the group the optimizations for
the different focal length lenses ? As I remember from our
conversation a couple of years ago, most enlarging lenses are
optimized for 6~10X.

==
John S. Douglas
Photographer & Webmaster
www.legacy-photo,com
www.xs750.net

See:
http://www.linos.com/en/prod/obj_vergroesserung.html

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To reply no_ HPMarketing Corp.