Stopping Down Enlarger Lens Focus Question Newbie

I'm a beginner. So go easy. I'm printing B&W (first prints done this week in
fact). When I stop down my enlarger lens (exposure around 20secs. at f22)
does focusing becoming less critical, ie. is it similar to a camera in that
I'm increasing depth of field therefore I can be out a bit? What are the
advantages to stopping down as opposed to using lower f-stop values (f5.6).
Am I losing contrast or sharpness in the print? Any grain issues? Does
leaving the light on that long change any of the characteristics of tone
distribution? Thx.

On 4/17/2004 12:10 PM SofaKing spake thus:

I'm a beginner. So go easy.

OK.

I'm printing B&W (first prints done this week in fact). When I stop down my
enlarger lens (exposure around 20secs. at f22) does focusing becoming less
critical, ie. is it similar to a camera in that I'm increasing depth of
field therefore I can be out a bit?

Yes; it increases the depth of field of the projected image in exactly the
same way as with a camera taking a picture. Smaller aperture = greater depth
of field = more latitude in misfocusing.

What are the advantages to stopping down as opposed to using lower f-stop
values (f5.6).

Just what was described above: increased overall sharpness.

Am I losing contrast or sharpness in the print?

Nope.

Any grain issues?

Only that what grain is visible will be more sharply in focus. That could be
good or bad, depending.

Does leaving the light on that long change any of the characteristics of
tone distribution?

Nope; you're apparently thinking of reciprocity failure characteristics. I
don't think this becomes a problem with photo paper until your exposures are
into the range of several minutes or more.


--
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imagined, some new and unspeakable form of sexual debauchery practised
by young persons of dubious morality, but a way of providing news
articles to the cybernetic publishing moguls of the World Wide Wait so
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- Cynical shop talk from comp.publish.prepress

So maybe other than being slower to print no real disadvantages mostly
advantages, good. I also like stopping down because it's a little bit more
forgiving when I want to increase or descrease exposure too. Thx.


"David Nebenzahl" wrote in message
...
On 4/17/2004 12:10 PM SofaKing spake thus:

I'm a beginner. So go easy.

OK.

I'm printing B&W (first prints done this week in fact). When I stop
down my
enlarger lens (exposure around 20secs. at f22) does focusing becoming
less
critical, ie. is it similar to a camera in that I'm increasing depth of
field therefore I can be out a bit?

Yes; it increases the depth of field of the projected image in exactly the
same way as with a camera taking a picture. Smaller aperture = greater
depth
of field = more latitude in misfocusing.

What are the advantages to stopping down as opposed to using lower
f-stop
values (f5.6).

Just what was described above: increased overall sharpness.

Am I losing contrast or sharpness in the print?

Nope.

Any grain issues?

Only that what grain is visible will be more sharply in focus. That could
be
good or bad, depending.

Does leaving the light on that long change any of the characteristics
of
tone distribution?

Nope; you're apparently thinking of reciprocity failure characteristics. I
don't think this becomes a problem with photo paper until your exposures
are
into the range of several minutes or more.


--
I was quickly apprised that an "RSS feed" was not, as I had naively
imagined, some new and unspeakable form of sexual debauchery practised
by young persons of dubious morality, but a way of providing news
articles to the cybernetic publishing moguls of the World Wide Wait so
they can fill the airwaves with even more useless drivel.

- Cynical shop talk from comp.publish.prepress

When I stop down my enlarger lens (exposure around 20secs. at f22)
does focusing becoming less critical,

No, all the image focus is in the negative, your enlarger will not make focus
where there is none. Oft time a grain focuser is used to focus on the grain of
the negative which has nothing to do with image focus. If you missed focus at
the camera stage you will not get it back of come close at the printing stage.
In the darkroom all you can do focuse the negative to sharpness and let the
image fall where it will.

What are the advantages to stopping down as opposed to using lower f-stop
values (f5.6).

Every lens has a "sweet spot". It is usually mid way between max and min
apature, maybe 5.6 or 8. Enlarging lenses are flat focus lenses in that they
project a flat negative image onto a flat piece of paper, unlike camera
lenses.. All the DOF the image has in in the negative, closing the apature
will not increase image DOF. It will lengthen exposure time which is a good
thing. I personally like exposures of more than 30 seconds and if burning or
dodging is involved I will stop down as much as possible to insure enough time
for burning or dodging.


_________________
Ready, Fire, AIM.
Bruce
Brooklyn, N.Y.

In article , David Nebenzahl
wrote:

Just what was described above: increased overall sharpness.

Am I losing contrast or sharpness in the print?

Nope.

Any grain issues?

Only that what grain is visible will be more sharply in focus. That could be
good or bad, depending.

With my 35mm printing (on a focomat), stopping down to F22 decreases
sharpness and blurs grain.

On 4/17/2004 4:05 PM Bruce spake thus:

When I stop down my enlarger lens (exposure around 20secs. at f22)
does focusing becoming less critical,

No, all the image focus is in the negative, your enlarger will not make focus
where there is none. Oft time a grain focuser is used to focus on the grain of
the negative which has nothing to do with image focus. If you missed focus at
the camera stage you will not get it back of come close at the printing stage.
In the darkroom all you can do focuse the negative to sharpness and let the
image fall where it will.

You missed my point, or maybe I didn't state it clearly enough: I'm not
claiming that greater depth-of-field at the enlargement state can make up for
poor focus in the picture-taking stage. (That would be quite a feat, with
metaphysical and quantum-mechanics implications.) What I meant is that
stopping down an enlarging lens gives greater depth of field so far as the
negative being projected is concerned, and will allow more focusing errors to
still result in a sharp image of the negative (which may well be out of focus,
but that's another story).


--
I was quickly apprised that an "RSS feed" was not, as I had naively
imagined, some new and unspeakable form of sexual debauchery practised
by young persons of dubious morality, but a way of providing news
articles to the cybernetic publishing moguls of the World Wide Wait so
they can fill the airwaves with even more useless drivel.

- Cynical shop talk from comp.publish.prepress

On 4/17/2004 4:38 PM David Nebenzahl spake thus:

On 4/17/2004 4:05 PM Bruce spake thus:

When I stop down my enlarger lens (exposure around 20secs. at f22)
does focusing becoming less critical,

No, all the image focus is in the negative, your enlarger will not make focus
where there is none. Oft time a grain focuser is used to focus on the grain of
the negative which has nothing to do with image focus. If you missed focus at
the camera stage you will not get it back of come close at the printing stage.
In the darkroom all you can do focuse the negative to sharpness and let the
image fall where it will.

You missed my point, or maybe I didn't state it clearly enough: I'm not
claiming that greater depth-of-field at the enlargement state can make up for
poor focus in the picture-taking stage.

Whoops: realized too late that you weren't replying to *my* reply. But the
point remains, since I don't believe the O.P. was asking whether stopping down
an enlarging lens could increase depth of field *in the original negative*.
(At least I hope they weren't.) In other words, when he asked "does focusing
become less critical?", he was referring to focusing the enlarging lens, not
the camera lens.


--
I was quickly apprised that an "RSS feed" was not, as I had naively
imagined, some new and unspeakable form of sexual debauchery practised
by young persons of dubious morality, but a way of providing news
articles to the cybernetic publishing moguls of the World Wide Wait so
they can fill the airwaves with even more useless drivel.

- Cynical shop talk from comp.publish.prepress

On 4/17/2004 4:23 PM jjs spake thus:

In article , David Nebenzahl
wrote:

Just what was described above: increased overall sharpness.

Am I losing contrast or sharpness in the print?

Nope.

Any grain issues?

Only that what grain is visible will be more sharply in focus. That could be
good or bad, depending.

With my 35mm printing (on a focomat), stopping down to F22 decreases
sharpness and blurs grain.

So you're encountering diffraction effects, right? Or focus shift, one.


--
I was quickly apprised that an "RSS feed" was not, as I had naively
imagined, some new and unspeakable form of sexual debauchery practised
by young persons of dubious morality, but a way of providing news
articles to the cybernetic publishing moguls of the World Wide Wait so
they can fill the airwaves with even more useless drivel.

- Cynical shop talk from comp.publish.prepress

"SofaKing" wrote in message
news:Tifgc.147080$Pk3.126052@pd7tw1no...
I'm a beginner. So go easy. I'm printing B&W (first prints done this week
in
fact).

Your questions are very good. Some of the replies are not.

When I stop down my enlarger lens (exposure around 20secs. at f22)
does focusing becoming less critical, ie. is it similar to a camera in
that
I'm increasing depth of field therefore I can be out a bit?

Small aperature will increase depth of field, but not enough to overcome
poor initial focus.

What are the
advantages to stopping down as opposed to using lower f-stop values
(f5.6).

None, as to the resulting image.

Am I losing contrast or sharpness in the print?

You are loosing sharpness because of optical defraction when you use your
lens much below f8.0. This a matter of light itself, not lens design or
construction. The only way a close comparision would not clearly show this
for you would be if you were using a very low quality lens or were out of
focus.

Any grain issues?

No.

Does leaving the light on that long change any of the characteristics of
tone
distribution?

No. If you want longer print times, which can be useful, use a lower output
bulb or insert neutral density filtration above the negative, and [assuming
35mm printing with a 50mm lens] keep the lens aperature in the 5.6 - 8.0
range.

In article , David Nebenzahl
wrote:

On 4/17/2004 4:23 PM jjs spake thus:

With my 35mm printing (on a focomat), stopping down to F22 decreases
sharpness and blurs grain.

So you're encountering diffraction effects, right? Or focus shift, one.

Yes, diffraction. I can watch the grain go soft through the focusing
scope. Refocusing has no effect. So I always print stopped down two from
wide open. If the exposure is too short to comfortably dodge and burn, I
use an ND filter.