[photoptimist]

This thread has me thinking. Does the depth of field/circle of confusion aspects change because of the sharpness of a lens? It seems either a sharper lens will have a slighty bigger dof OR a less sharp lens would be more forgiving on critical focus.
If i am 1mm off will the sharper lens lose more focus than the less sharp? If so the sharper lens will also draw more attention away from the desired focus point.
This would mean under less than ideal conditions the less sharp lens might be preferred.

That's an interesting point. At the optical level, all the blurs from being slightly out-of-focus, from lens quality, and from diffraction add together.

How one assesses the overall depth of field depends on what one is looking for: resolution or perception,

A sharp lens will have a bigger DoF if you really insist on circle-of-confusion measure of image quality. Take a picture of a newspaper at an angle and the sharper lens will let you read more of the text. A softer lens will resolve less text almost as if it had shallower DoF.

But a softer lens will have a bigger DoF if you define DoF in a relative perceptual terms of how much of the image has the same minimized softness. A sharper lens will have more "pop" which could be distracting if the focus is slightly off.

[Sandy Hancock]

The second one is a keeper in my book - lighting, framing, focus, gesture, direction of view, sense of place, moment (yes, even if a less important one) - and I think it will grow on you over time.

Don't get me wrong; I really like it, but the less sharp one speaks to me on a different level.

And I should clarify that I consider lenses capable of excellent sharpness to be very important. I only have one lens which is truly soft. But just because a lens *can* be sharp doesn't mean that great images *must* be sharp.

[Theov39]

I notice that my lenses seem to have dual sharpness qualities. When I "nail" the photo I am appreciative for their degree of sharpness. When I don't nail (screw up?) the photo, then the lenses seem to have less than acceptable sharpness. It is an interesting phenomenon that Mr. Rockwell doesn't seem to address.

Indeed. You may wish to ask him to update the article.

[cyberjunkie]

There are times that I keep soft images because they are the best I have a particular moment or event, but if I have the choice, I somehow always choose the sharper image and delete the soft one.

This is your taste, and for sure many other people share your take on that. I can understand your point, but I think that in SOME circumstances excessive, surgical sharpness is just boring, and detracts from the esthetic value of the image.
Don't forget that 100 years ago, with sharp lenses like the Tessar readily available and not too expensive, professional portrait photographers could spend as much as the price of three Ford T cars to buy a best-of-the-breed soft focus lens. The reason was simple: their wealthy clients were willing to pay a premium for the beautiful, flattering portraits shot by those lenses. I'm not talking about faulty, out of focus, blurry images. I'm talking about sharp enough (but not too much), with a nice superimposed glow and a wonderful "roundness". Find some portraits of the early days of Hollywood and you'll see what I mean.
From my own experience I'd say that the esthetic taste of those who know nothing about objectives and technicalities hasn't changed much since then. If I shoot people with a modern expensive AF lens, and a carefully chosen vintage one, every time the subjects choose the pics shot with the latter.
Personally I'm perfectly aware of the difference between non excessive sharpness and technical errors like shake or wrong focusing. Usually I don't like "faulty" photos, but I've seen people, even those who shot those pics, who actually like the way they look. I don't agree, but I think I understand why.
As a matter of fact, of all my own pictures, the best portraits I've ever done were (carefully) shot with my 6x7 using a Pentax 120mm Soft Focus. That's a very soft lens around wide open! Though I like so much those photos!

I guess the main point is what we want.
If the purpose is documentation, art reproduction, photojournalism, surgical sharpness is perfectly fine.
If we are after creative fine art photography, or we just want to awake emotions in the viewer, beyond the documentation of reality, excessive sharpness can definitely get in the way.
To each its own.

Cheers

Paolo

[cyberjunkie]

Ken Rockwell aside, when Adams and Weston shot on large format, they had to focus accurately - there is no accurate infinity mark on a Linhof or similar. They also had the benefit of lens tilt to increase the sharp area in a photograph, something we mostly dream of unless your budget runs to tilt&shift lenses. Adams' photos were sharp, if you've seen any of his huge prints you'll know what I mean. He often shot on 6x6 and occasionally a 35mm Contax, but I digress...

IMHO their best pictures were shot quite early in their career. Almost always on 8x10", and with lenses that often didn't match the line/mm at the very center of the picture of a good Petzval (like Voigtlander's) built around 1850/60. The field curvature was terrible, and it was almost abandoned by the time Adams and Weston were shooting the pictures I refer to. Some very nice images were shot with a single cell of a Turner Reich Convertible, inferior to the Petzval in the center, and terribly unsharp by today's standards.
When Weston was in Mexico with Tina Modotti, he sold the good lens he had brought from the US, to pay for his stay, and bought a terrible one, a real Coke bottom... and with that lens he shot some of its best Mexican photos!
Also Adams shot some of his most iconic images with rather poor glasses.
The size of the film and the movements of the camera helped, and their technique was excellent, but the lenses they used at first weren't on par with a Trioplan from the fifties. Not even close. Though people buy archival prints (contact and enlarged) from the original negatives for good money, and find them beautiful and perfectly sharp.

Modern FF sensors should beat the best 8x10" chrome film, and be more or less comparable with recent B&W film.
Take your own conclusions...

Cheers

Paolo

[Rondec]

This is your taste, and for sure many other people share your take on that. I can understand your point, but I think that in SOME circumstances excessive, surgical sharpness is just boring, and detracts from the esthetic value of the image.
Don't forget that 100 years ago, with sharp lenses like the Tessar readily available and not too expensive, professional portrait photographers could spend as much as the price of three Ford T cars to buy a best-of-the-breed soft focus lens. The reason was simple: their wealthy clients were willing to pay a premium for the beautiful, flattering portraits shot by those lenses. I'm not talking about faulty, out of focus, blurry images. I'm talking about sharp enough (but not too much), with a nice superimposed glow and a wonderful "roundness". Find some portraits of the early days of Hollywood and you'll see what I mean.
From my own experience I'd say that the esthetic taste of those who know nothing about objectives and technicalities hasn't changed much since then. If I shoot people with a modern expensive AF lens, and a carefully chosen vintage one, every time the subjects choose the pics shot with the latter.
Personally I'm perfectly aware of the difference between non excessive sharpness and technical errors like shake or wrong focusing. Usually I don't like "faulty" photos, but I've seen people, even those who shot those pics, who actually like the way they look. I don't agree, but I think I understand why.
As a matter of fact, of all my own pictures, the best portraits I've ever done were (carefully) shot with my 6x7 using a Pentax 120mm Soft Focus. That's a very soft lens around wide open! Though I like so much those photos!

I guess the main point is what we want.
If the purpose is documentation, art reproduction, photojournalism, surgical sharpness is perfectly fine.
If we are after creative fine art photography, or we just want to awake emotions in the viewer, beyond the documentation of reality, excessive sharpness can definitely get in the way.
To each its own.

Cheers

Paolo

That's fine. It is also possible to shoot a sharp photo and soften it in post, if you desire. It is tough to go the other direction.

I guess I just don't see many images these days where someone says "I took a really sharp image here, but I really tried to soften it up in post..." The one exception is portraits, particularly of women, where for some reason they don't want defects magnified.

[acoufap]

This thread develops to an interesting one.

That's fine. It is also possible to shoot a sharp photo and soften it in post, if you desire.

Without doubt this is something I do quite often.

I guess I just don't see many images these days where someone says "I took a really sharp image here, but I really tried to soften it up in post..." The one exception is portraits, particularly of women, where for some reason they don't want defects magnified.

If I can support the mood like in the following picture I simply do it by using a minus value in Capture One's clarity tool. This also helps a lot if background looks too busy. Most of the time the really sharp parts of the image stay enough sharp respectively I soften the image only to the degree that it not turns out to be a problem.

K-1 • DFA28-105

In the following case I used the DA55-300PLM plus DA TC 1.4x through a not that clean window pane at the Zoo Hellabrunn, Munich. Focusing was quite hard to do but I made the shot. I remember I fiddled a bit around with Quick Shift since I thought AF was not spot on. In the end the image turned out to be a bit soft. But in post I even strengthend softness because I discovered that this gave me a soft lion to embrace.

K-1 • APSC mode • DA TC1.4x • DA55-300PLM@300

Another case ... the DFA28-105 and DA55-300PLM are very good lenses concerning sharpness and color rendering. Although the old Vivitar Series 1 2.8-4.0/70-210 Macro (I guess version 4) delivers significantly worse, in combination with the K-5 I got some nice pictures that hang on the walls. Low contrast was no problem in post and sharpness was simply sufficient for the print size.

---

Last edited by acoufap; 04-03-2018 at 08:41 AM.

[StiffLegged]

IMHO their best pictures were shot quite early in their career. Almost always on 8x10", and with lenses that often didn't match the line/mm at the very center of the picture of a good Petzval (like Voigtlander's) built around 1850/60. The field curvature was terrible, and it was almost abandoned by the time Adams and Weston were shooting the pictures I refer to. Some very nice images were shot with a single cell of a Turner Reich Convertible, inferior to the Petzval in the center, and terribly unsharp by today's standards.
When Weston was in Mexico with Tina Modotti, he sold the good lens he had brought from the US, to pay for his stay, and bought a terrible one, a real Coke bottom... and with that lens he shot some of its best Mexican photos!
Also Adams shot some of his most iconic images with rather poor glasses.
The size of the film and the movements of the camera helped, and their technique was excellent, but the lenses they used at first weren't on par with a Trioplan from the fifties. Not even close. Though people buy archival prints (contact and enlarged) from the original negatives for good money, and find them beautiful and perfectly sharp.

Modern FF sensors should beat the best 8x10" chrome film, and be more or less comparable with recent B&W film.
Take your own conclusions...

Cheers

Paolo

I don't understand this: how does one take soft film images from crappy antique glass and make gorgeous prints? I've seen original Adams prints at 36" (Mount Williamson from Manzanar) and 48" wide (Grand Tetons and the Snake River), sometimes larger (Aspens), and they don't look rubbish. You're pulling my leg, surely??

[wm_brant]

I don't understand this: how does one take soft film images from crappy antique glass and make gorgeous prints? I've seen original Adams prints at 36" (Mount Williamson from Manzanar) and 48" wide (Grand Tetons and the Snake River), sometimes larger (Aspens), and they don't look rubbish. You're pulling my leg, surely??

The Mount Williamson photo was taken with an 8x10 large format camera. Enlarging an 8x10 negative to a 36" wide print works out to a 3.6x enlargement of the information on the sensor (i.e., the 8x10 negative). A 3.6x enlargement of an image taken with a 24mm wide APS-C sensor would be only about (assuming my math is right) 3.4" wide. It would be hard to find a lens that could not produce a sharp looking 3.4" wide print from an APS-C sensor.

Key takeaways which are still relevant today:
1. Sensor size matters (a bigger sensor (or negative) requires less enlargement for a given final image size)
2. Degree of enlargement matters (enlarge *any* image enough and it will look bad - no matter what lens, no matter what camera, no matter if film or digital). Adams used 8x10 large format cameras because he wanted to make large prints - not because they were convenient to use!

Other factors which are also still relevant today:
1. Ansel Adams knew how to get the best out of his equipment. You can bet he wasn't shooting that 'crappy antique glass' wide open. He was stopped way down, which helps improve just about any lens' performance. His camera was on a substantial tripod and he took care to make sure his image was focused carefully. If necessary he would have used the movements of his view camera to help keep everything in focus. He would have used a cable release to trip the shutter
2. Ansel Adams knew how to get the best out of his images by optimizing and tightly controlling both his film exposure as well as his post processing of both film development and printing

-- Bill

[StiffLegged]

I know a bit about Adams' craftmanship: for years my own references were The Camera, The Negative and The Print while developing and printing my own B&W film. His images are still an inspiration, especially since I saw his original prints - even the best reproductions (I have several volumes) don't do them full justice. I just don't understand some of the nonsense talked about his work and his methods.

So I'm going to shut up now and go back to making my own images. It's more fun than squabbling about work that does stand on its own merits.

[mikesbike]

Don't get me wrong; I really like it, but the less sharp one speaks to me on a different level.

And I should clarify that I consider lenses capable of excellent sharpness to be very important. I only have one lens which is truly soft. But just because a lens *can* be sharp doesn't mean that great images *must* be sharp.

I definitely agree. And there is a difference between SHARP sharp and "acceptably sharp", which means ultra sharpness takes a back seat to getting a very good shot in putting across something. And my congrats as well, Sandy, to you and your family, regarding a matter which you did such a fine job of putting across with that excellent capture.

Photography is not just about one thing, but many things- from a studied composition, to capturing a moment in time with a certain fleeting expression or action, to telling a story. Sometimes time is of the essence in being able to act quickly enough, being more important over some perfection of exactitude.

[ffking]

The main advantage of very sharp lenses is that they can take very sharp images when that is required (either because of subject matter or level of enlargement needed), whereas a less sharp lens can only take acceptably sharp images. There are times, as people have said, where absolute sharpness is not only unnecessary to the image, but actually detrimental. Here it can be quite useful that all lenses are a tad softer at the extremes of wide open and stopped right down - also, with modern pentax, we have the option of using the AA simulator to take the absolute edge off sharpness if we want to

[Skodadriver]

I have extracted a couple of quotes from the in depth test of the SMC Pentax-FA 77mm F1.8, I hope this is not breaking any rules.
Ken Rockwell's argument may be very valid but maybe sharpness is one of the initial considerations in choosing a lens, after cost and focal length, followed by other considerations.


"Sharpness, or the ability to resolve small details, is an important measure of the performance of a lens. Sharp images let the viewer concentrate on the composition, color and light. On the other hand, soft images (except when looking that way on purpose) distract the viewer and decrease the perceived quality of the picture."

Read more at: SMC Pentax-FA 77mm F1.8 Limited Review - Sharpness | PentaxForums.com Reviews
"Summary

77mm is an optimal focal length for portraits and this lens is ideally suited for this purpose. Center sharpness is among the highest we have tested, being almost brutally sharp at medium apertures. The edges and corners are very soft wide open, and almost catch up by F8. Isolating the subject will be easy with the FA 77mm, but corner-to-corner sharpness won't be attainable at wide apertures."


Read more at: SMC Pentax-FA 77mm F1.8 Limited Review - Sharpness | PentaxForums.com Reviews

[cyberjunkie]

I don't understand this: how does one take soft film images from crappy antique glass and make gorgeous prints? I've seen original Adams prints at 36" (Mount Williamson from Manzanar) and 48" wide (Grand Tetons and the Snake River), sometimes larger (Aspens), and they don't look rubbish. You're pulling my leg, surely??

I thought it was absolutely clear that I meant the opposite.
Large film, excellent technique and first class wet darkroom wizardry allowed him to create incredible B/W prints, even when he used taking lenses that were quite poor by today's standards.
I know people who had the chance to actually see original prints, and I've been told they are outstanding.
I mentioned Adams and Weston because both were great photographers, and because I know that some of their early pictures were shot with a single element of a double anastigmat (when a long focal was deemed as absolutely necessary), a kind of optic that was considered rather unsharp even at that time.
If you read my previous message with no preconceptions, I'm sure you won't find a single sentence that suggests that they wanted to use unsharp lenses on purpose, or that they were after a pictorial effect.
Actually Adams was one of the founders of the F/64 Group, which was the answer to the second wave of the American Pictorialism, with a completely opposite idea of photography.

Actually i tried to make two points.
One. With a good technique you don't need the sharpest lens to produce pleasantly sharp pictures.
Two. Some kind of pictures actually benefit from the "character" of lenses that don't match the MTF charts of most modern premium zooms.
I find their rendition too surgical, non as pleasant to the eye. Of course it depends on the subject, but most of the times I don't go for the sharpest lens I can use, and when I submit portraits to non tech-savvy people, almost always they choose the shots taken with (good) vintage lenses.
Then there are terrible vintage lenses... I may collect some of them, but I've never suggested using them for general photography!
Having clarified the point (I hope), yes it's true, I like soft focus lenses, I think they have a place, of course they are not for everything, but some portraits come out gorgeous.
This has nothing to do with the previous points though. I mentioned SF lenses because the best ones aren't actually unsharp, cause they give a rather sharp image overlaid with a halo that's most visible in high contrast areas.
Pictures taken with bad lenses are usually ugly. Shaky, blurred, misfocused pictures are almost always ugly. You may dislike the esthetic, which is perfectly fine, but SF optics don't give ugly pictures (if properly used... but that's true for every lens!).

I'm asking myself if it's worth the effort. I mean, trying to express an opinion doing my best to elaborate and explain WHY, not just WHAT.
It seems that some people have their own ideas/preconceptions, and don't care to read and eventually criticize what I've written, not the complete opposite
Maybe quietly following the stream is the best recipe to avoid misunderstanding, but I guess I would be just boring... no safe exit, uff

Cheers

Paolo

[malcolmdavies]

I made the following general observation when testing my M 50 1.4 on a full frame K1:

At all apertures that when focused at far distance in the centre of the frame, the focal plane ('field') comes forwards significantly towards the borders.

I would expect the focal plane to be equidistant from the camera across the frame and therefore slightly curved, but the focus in the borders is far forward of an equidistant curve. I researched this further and the phenomenon is called Petzval Curvature, where the focal plane ('field curvature') is paraboloidal and worse at open apertures. I understand that is it possible to mitigate this in lens design and I haven't noticed it particularly on my other lenses (although I have only recently upgraded to full frame) but it is clearly significant in the M 50 1.4 lens on full frame a K1.

It is not something I have ever seen measured in a lens review test but I now think should be. It is a real issue.

I am surprised that this doesn't come up in Lens Sharpness discussions on Pentax Forums, including Ken Rockwell's Lens Sharpness missive.