What is the biggest, perfectly sharp format you can get from your sharpest negatives?

JBrunner

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Uhh... my prints don't have pixels.
 

Thomas Bertilsson

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holmburgers

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The pixel analogy can just as easily be applied to analog....
 

eskyone

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I dont know about anyone else, but as I get older the closer I get to a print the more out of focus it looks. I have to stand back anyways so it's all good at my distance.
 

RalphLambrecht

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JBrunner said:
Uhh... my prints don't have pixels.
Click to expand...

Not to worry, it's the same for us.

It's commonly agreed that the minimum visual angle at which a line is perceived within a pattern of three bars, separated by spaces of equal width, is about 1 minute of arc (0°01'00"). Beyond these studies, empirical tests have shown that common detail and distinct texture are still visible down to about 20 seconds of arc (0°00'20"), a value that must be considered for critical observation. However, let's not forget that other factors, such as image contrast and ambient illumination, significantly influence the minimum visual angle.
 

MattKing

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RalphLambrecht said:
One photo out of focus is a mistake,
ten photos out of focus are an experimentation,
one hundred photos out of focus are a style.

author unknown
Click to expand...

And a thousand out of focus photos ....

is that Lomography?
 

removed account4

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Q.G. said:
Learn to ski and you can have loads of fun on the slopes!


(I.e.: there's nothing inherently worng with that slope, as long as you master it.)
Click to expand...

lol

i DO ski, ( and for years i used to ski competitively ) ..
i agree, there is nothing wrong with the slippery slope of
sharp, very sharp, wicked sharp, uber sharp if there is a point ..
but often times it just seems to be a futile exercise ..
( at least it was with the friends i have witnessed slide down this slope ) ..
they just ended up with lots of "test images" and a drained bank account.

but if it what makes'em happy THAT is the important thing ...
 
OP
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A49

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Allen Friday said:
A49,

I recommend the book The Edge of Darkness, by Barry Thorton. The book deals with many of the issues raised in this and your other post.
Click to expand...

I ´ve heard a lot (good things) about this book in many discussions that dealt with high res and high sharpness photography. I´ve already read "Image Clarity" by Williams which I liked because it goes very deep into this subject. Those who have read "Edge" and "Clarity", is it really worth also to read "Edge" in addition? In Germany this book is not easy to fetch.

Best regards,
Andreas
 

JBrunner

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holmburgers said:
The pixel analogy can just as easily be applied to analog....
Click to expand...

I beg to differ, there are many more factors than "dots" involved in the apparent sharpness of an analog print. Note the word "apparent". It's a big player too. Analog sharpness is a perception based on many variables. It can't be put in a box all nice and neat, as much as a "pixel peeper" would like to.

Basically if you want insane sharpness learn to shoot 8x10 with a good sharp lens and then learn how to contact print, because that is where the standard is set, and has been set for decades. I don't believe any process will even come near, either. Not because it couldn't be done, but because there isn't much of a need for it. A good contact print is many times sharper than it needs to be, and strangely enough doesn't have to have any "dots". (this assumes sharpness as an intention).
 
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A49

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For those who don´t like theoretical stuff, please skip this explanation.

I calculate DoF for those who want to have their nose near the print and therefore want to achieve something in the region of 50 lpm in LF not only in the focused distance but also in the DoF. You and others who have tested LF lenses with low grain films say that 50 lpm is a reasonable number. At least if you do not close the aperture more than to f/22.

To get 50 lpm I assume a maximum CoC of 0,02 mm.(One line at 50 lpm is 0,01 mm wide and therefore a maximum of 0,02 mm for the CoC is acceptable to resolve a black and a white line distinct from each other. Hope I interpreted the chart at page 133 WBM ed. 2011 correctly.)

If a calculate with the DoF formula and this CoC of 0,02 mm I get following DoF for a 210 mm normal lens of a 5x7 inch camera at f/22:

focused distance (just as an example): 5,0 meters
DoF: 4,77 meters to 5,25 meters

At f/22! Very short. You can be happy if you focuses well enough so that your object you like to shot is within DoF at all. I you close the aperture farther to get some more DoF you will reduce your resolution to something around 40 lpm at f/32 and to about 30 lpm at f/45.

I think this example shows the antagonism between the pursue of resolution and DoF in LF. The more the negative format grows, the longer the lenses become and the smaller your DoF becomes.

If you shoot with 5x7 inch wide angle, say 120 mm at f/22 then your DoF for 50 lpm becomes significantly more comfortable:

focused distance: 5,0 meters
DoF: 4,35 meters to 5,88 meters

Still not much, but much more than with the 210 mm lens.

I hope that I´m calculated correctly, but I don´t mind if someone tells me the contrary.

Best regards,
Andreas
 

2F/2F

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A49, QUIT BREATHIN' ON MY PRINTS!
 
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A49

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2F/2F said:
A49, QUIT BREATHIN' ON MY PRINTS!
Click to expand...

Why you did not varnish them?

If I´m through this bigger prints and more resolution purgatory I will convert and make unsharp contact prints from small negatives. Or even shoot pinhole with thick FB paper negatives and print through them to get the positive picture.

Kind regards,
Andreas
 

JBrunner

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You could always throw in a swing or a tilt. I read somewhere that can help.
 

Diapositivo

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A49, if we abstract from tilt & shift, what you say is that there is more depth of field with a smaller negative. This is not really true although we all are more or less used to think it is.

Let's compare 6x6 and 24x36. If you use a 80mm on 6x6 and a 45mm on 24x36, and you fill the frame with the same composition, you might think you have more depth of field, but basically you have not (there are differences in the distribution of the DoF in front and behind the focal plane, though).

It is very well explained here:
http://www.cambridgeincolour.com/tutorials/depth-of-field.htm

Note that I did not mention focal length as influencing depth of field. Even though telephoto lenses appear to create a much shallower depth of field, this is mainly because they are often used to make the subject appear bigger when one is unable to get closer. If the subject occupies the same fraction of the image (constant magnification) for both a telephoto and a wide angle lens, the total depth of field is virtually* constant with focal length! This would of course require you to either get much closer with a wide angle lens or much further with a telephoto lens[...]

It is totally counter-intuitive because we are always inclined to think wide-angle lenses as having more DoF than tele lenses, and we think so because we seldom actually go far enough backward to take, with a tele, the same composition we were examining with the wide angle. So if we compare two different compositions, we are comparing apples and oranges. The normal experience we have is that wide angle lenses appear to have more DoF because we compare them to tele lenses from the same capture point, with different fields of view.

In your case, as we are discussing where is the maximum theoretical sharpness, I suppose you would like to know where is the theoretical maximum sharpness considering that if we increase the negative size, we increase the sharpness on the focal plane but we loose DoF in front and behind it (not considering "movements") and so there should be somewhere an "ideal" format where the two factors play for maximum combined sharpness.

We should rather think in terms of composition first. Given a certain composition, which is the format which guarantees the maximum sharpness? Supposing we are completely free to walk backward, the answer to the question is: the format which guarantees the maximum sharpness is the maximum format at our disposition. If we keep the composition constant, the DoF will be the same for every format. With shorter focal lenses, we will have to get nearer to the subject, and "nearer" means in a region of the focusing scale where we lose the "advantage" in DoF that the shorter focal length seemed to have given us at first. So the DoF factor "cancels out" and the larger surface of the larger negative remains the only factor which plays a role.

Fabrizio
 

Ed Sukach

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What is FAR more difficult to determine is "Why does one image work and another fails." I've been chewing on that one for many moons, now, and I am convinced I'm further from the answer than when I started.

I've seen many technically excellent photographs: "sharp", tiny grain, a complete range of tones, brilliant whites with lots of detail, deep blacks, again with lots of detail ... in short, meeting all possible "technical excellence" criteria - that were lifeless, dull... mindlessy boring copies - devoid of "soul" - something like a "formula" TV comedy.

I've also seen "technical disasters" that were absolutely brilliant - even with "baseball" sized grain and "blown highlights".

I usually rate the work I experience, involuntarily, to one of three categories:

1 . Work the I do not understand. By no means "bad work" ... I just do not share the vision of its creator - we do not "see" the same way. This requires a lot of study; If I can transcend my limits and appreciate the other artist's vision, I will expand my perception of the world.

2. Technically excellent work. Stuff you would hang in your living room Pleasant (usually), peaceful, non-controversial.

3. The Fascination Category. I find myself drawn involuntarily to it. I'll re-visit it many times in a gallery. I'll close my eyes - and it will STILL be there.

Needless to say, the last category - "Fascination" is where I choose to - MUST!! work. I've succeeded a few times in producing work like that --- HOW - I don't have a clue - and the longer I go, the more I convince myself that I don't WANT to know.
If, by some miracle, I could attain that divine understanding ... all of the mystery, all of the breathtaking surprises, Ansel Adam's "fortunate accidents", would be gone, and this entire game will have been reduced to lifeless drudgery.

Photography can be frustrating as hell. One can produce work the does not "work" repeatedly. When we succeed and an image DOES work ... all of the past frustrations are wiped out, tenfold.
 

phaedrus

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Existing Light said:
Step 1: Get a large format camera
Step 2: Contact Print
Step 3: Stop worrying about sharpness. You wont have to deal with loss of sharpness and big grain if you contact print big negs

Click to expand...

I can only second that. Plus, as were officially with our noses to the print in this thread, I'd like to call attention to another sharpness effect in large format contact prints. Detail resolution in contact prints can go to a smaller scale than the materiality of the paper surface. So, for example, if you do a palladium-platinum print on Kozo paper, single fibers can show more than one tone. An effect I really like.
By the way, this kind of myopic examination of prints is nothing new. People used to appreciate Daguerrotypes with loupes.
 

Mark Crabtree

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Is this sharp enough?

These scans (full image as printed, then a detail from it) are from an old enlargement that I always thought of as sharp enough. I know some people could have shot it with an 8x10 camera, but I'm not one of them.
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RalphLambrecht

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Ed Sukach said:
What is FAR more difficult to determine is "Why does one image work and another fails." I've been chewing on that one for many moons, now, and I am convinced I'm further from the answer than when I started. ...
Click to expand...

You may want to get a copy of 'The Command to Look' ©1967 by William Mortensen. It's the best source I know of to specifically answer that question. Well, it answered it for me. But be careful, this little gem of a book usually sells around $600!
 
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A49

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Interesting way to look at it. Keeping the magnification factor constant...

Diapositivo said:
It is totally counter-intuitive...
Click to expand...

Yes it is. And these constant magnification factor DoF thoughts are really true and practical for only one case: If you shoot reproduction of flat objects, there the only thing that matters is the magnification factor. There the DoF is only important in relation to possible focusing errors or the misalignements of the ground glass and the sheet holders.

If you photograph real (3D) scenery, then the composition can only be kept "constant" if you don´t leave the point from which you shoot. If you step backwards, then you change the size relations between foreground objects and farther distanced objects and therefore the perspective changes.

So back to my example with the 210 mm in the 5x7 inch format. If you stand with this setup at one point and you want to shoot the same framing of the scenery with 35mm film then you have to use a 42 mm lens. The DoF in this case is (Again at 5 meters, because the distance to the objects must NOT be changed, if you want the same frame. And also again at f/22 and for 50 lpm):

DoF: 2,7 meters to 38,8 meters

This difference is what we all experienced if we ever worked with different negative formats.

Best,
Andreas
 

hpulley

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RalphLambrecht said:
Absolutely. It also explains the extended DoF of miniature digital cameras. Small image area > short focal length, > extended DoF.
Click to expand...

Sub-35mm film too of course, 110, Disc, Minox, same effect and was another reason for the adoption of such small film formats for fixed focus snapshot cameras. With a wide angle lens and a small fixed aperture (e.g. f/11) they could make fixed focus cameras which were hyperfocal from 3 feet to infinity.
 

Diapositivo

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Mark Crabtree said:
These scans (full image as printed, then a detail from it) are from an old enlargement that I always thought of as sharp enough. I know some people could have shot it with an 8x10 camera, but I'm not one of them.
Click to expand...

Ahem, yes, that seems sharp enough :w00t:

Is this 135? Something like Kodak Technical pan? With a very good lens (which lens?).

Fabrizio
 

Q.G.

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Quite true.
But it does show that the format thingy is a red herring.
Compose equal compositions in two diferent formats, say 35 mm and 8x10 (which of course involves same distance to subject, but proportionally different focal lengths), and people will - wrongly -say that the 35 mm negative has more DoF.
But enlarge both to the same size print, and you will have not only achieved equal magnification, but also equal DoF.

Focal length too is not a factor, except as part of what 'makes' magnification.

So the best (as in easiest to deal with, and also most correct) way of dealing with DoF is by remembering that it depends on two fatcros only: f-stop and magnification.


There is a catch, though.
Smaller formats run out of steam sooner when being enlarged. The resolution recorded on film is less than that captured in the higher magnification image on larger formats.
DoF being the invisble difference between sharp and unsharp, an image that is less sharp to begin with will appear to have less difference between that 'sharp' bit and the really unsharp bits, so apparently has more DoF.
Conversely, really sharp lenses and sharp films will show less DoF than less good lenses and films, now because of a greater, and therefore more obvious, difference between what's really sharp and what's plain and simple unsharp.
 

RalphLambrecht

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Q.G. said:
... But enlarge both to the same size print, and you will have not only achieved equal magnification, but also equal DoF. ...
Click to expand...

Equal magnification, yes, equal DoF, no.

Enlarging a negative changes final print resolution but not the depth of field, which is already locked into the negative. A brief look at the DoF equation shows that, aperture and subject distance being equal, focal length and CoC are the controlling factors. The CoC difference between formats is compensating for by the different magnification needs, but the focal length advantage of shorter lenses remains.
 
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