Enlarger f-stop sweet spot

I recently asked the question about sweet spots for Cameras and Enlarger on the
MF site. I received so very good information on camera lens and learned about
diffraction. My question is "are the problems the same with enlarger lens?"
Since the projection is on to a two dimensional field does this change the
quality of the print.
Is there an optiimum f-stop?
Thanks.

The problem is the same with enlarger lens, there's a sweet spot.
Usually, 2 stops less than maximum aperture.

Jorge

ojunk (ATIPPETT) wrote in
:

I recently asked the question about sweet spots for Cameras and
Enlarger on the MF site. I received so very good information on
camera lens and learned about diffraction. My question is "are the
problems the same with enlarger lens?" Since the projection is on to a
two dimensional field does this change the quality of the print.
Is there an optiimum f-stop?
Thanks.

I've read a number of times that, in general, APO's are at their
sharpest one stop from wide open and others at 2 stops. This has been
true in my own experience and with my own equipment. Naturally,
alignments and focus accuracy become extra critical at these settings
as you lose the forgiveness of expanded depth of field at these wider
settings. I've also found that until you get into 11X14 and up
(medium format) and 8X10 (35mm), these differences are extremely hard
to discern. This assumes good, solid, high grade equipment that is in
proper adjustment.

On 12 Jun 2004 18:46:36 GMT, ojunk (ATIPPETT) wrote:

I recently asked the question about sweet spots for Cameras and Enlarger on the
MF site. I received so very good information on camera lens and learned about
diffraction. My question is "are the problems the same with enlarger lens?"
Since the projection is on to a two dimensional field does this change the
quality of the print.
Is there an optiimum f-stop?
Thanks.

Hi

A perfect enlarger lens using a cold light would have the following center
resolutions in lines per millmeter.

f-stop resolution

f-1 2000
f-2 1000
f-4 500
f-8 250
f-16 125

A typical Nikon 50mm 2.8 lens might do

f-2.8 100
f-4 400
f-8 250
f-16 125

A typical Nikon 50mm f4 might do

f-4 200
f-8 250
f-16 125

Larry

"ATIPPETT" wrote in message
...
I recently asked the question about sweet spots for Cameras and Enlarger
on the
MF site. I received so very good information on camera lens and learned
about
diffraction. My question is "are the problems the same with enlarger
lens?"
Since the projection is on to a two dimensional field does this change the
quality of the print.
Is there an optiimum f-stop?
Thanks.

If you go to the Schneider web site I provided on the MF newsgroup, you will
see the MTF charts for each enlarging lens and see where the sweet spot is.
Not all apertures are tested, but you can get the idea.

Note that there are multiple factors to consider such center sharpness, edge
sharpness, light fall-off, distortion (probably not important unless your
photos have a lot of straight lines near the edge).

Also note that measurements differ according to the enlargement factor in
addition to the aperture. This is because enlarging lenses are optimized for
a certain enlarging factor (just like camera lenses are optimized for
distances close to infinity).

ojunk (ATIPPETT) wrote in message ...
I recently asked the question about sweet spots for Cameras and Enlarger on the
MF site. I received so very good information on camera lens and learned about
diffraction. My question is "are the problems the same with enlarger lens?"
Since the projection is on to a two dimensional field does this change the
quality of the print.
Is there an optiimum f-stop?
Thanks.

Yes. The better the lens, the earlier this will be attained. With the
better 50mm lenses, the optimum is about f/5,6-f/8.

"ATIPPETT" wrote in message
...
I recently asked the question about sweet spots for Cameras and Enlarger
on the
MF site. I received so very good information on camera lens and learned
about
diffraction. My question is "are the problems the same with enlarger
lens?"
Since the projection is on to a two dimensional field does this change the
quality of the print.
Is there an optiimum f-stop?
Thanks.

Yes. Around f/5.6 or f/8 for faster or slower lenses respectively.

Yes. Around f/5.6 or f/8 for faster or slower lenses respectively.



To get reasonable printing times of 8s or so, I have to print at f11 or f16.
Anybody know if they sell ND filters for enlargers?

"Mike" wrote in message
m...

Yes. Around f/5.6 or f/8 for faster or slower lenses respectively.



To get reasonable printing times of 8s or so, I have to print at f11 or
f16.
Anybody know if they sell ND filters for enlargers?

Despite what some have said, f/11 has just as good resolution (even with
diffraction limitation) as f8 on many lenses.

But check with B&H Photo. You should be able to find a large unmounted
filter that you can cut down to size.

Mark A wrote:
"Mike" wrote in message
m...

Yes. Around f/5.6 or f/8 for faster or slower lenses respectively.



To get reasonable printing times of 8s or so, I have to print at f11 or

f16.

Anybody know if they sell ND filters for enlargers?


Despite what some have said, f/11 has just as good resolution (even with
diffraction limitation) as f8 on many lenses.

But check with B&H Photo. You should be able to find a large unmounted
filter that you can cut down to size.



A piece of drafting mylar cut to size is neutral in color and has a
transmission density of about .15. Ask for a sheet of 5 mil drafting film,
single sided. Double sided will work as well but single sided is less
expensive. You can find this in any art store where the
drafting supplies are.

You can cut it with scissors. If one piece is not enough then add a second
one. You want to buy an 8-1/2 x 11 sheet. Place the piece you cut in the
filter drawer.

Bert