"Rendering" vs Sharpness

[FA Limited]

With digital, it seems like the number one focus for reviews is pixel peeping and sharpness.

When the Nikon 58mm came out most people ridiculed it for its price and the fact that Nikon has added yet another normal option. With the initial scientific reviews showing not such stellar results (relative to the price), the lens rendering comes under some closer examination. Some nice samples here by Joe Marquez.

How important is sharpness versus rendering? and what price premium would you pay for a lens that renders better than another? how much sharpness would you sacrifice for that look?

 

[BlackXList]

Just reading through that thread, I'm amused that some people think it's just not sharp enough wide open for them.

I haven't clicked through to see anyone's work but if that's the case then they must be formidable photographers haha.

I think it's a very good question though, and something I've been wrestling with with compacts recently, I have enough that have "sharp enough" lenses, I'm just working my way through which lens rendering suits what.

 

[Ansel]

Pixel peeping is nonsense. Its because people don't print their images anymore. If they did they would soon realise that sharpness is a non-issue.

 

[Scrambler]

For me the lens is about rendering. A painter uses different brushes, not all of them "sharp." Even spray cans can be used to make art! So the sharpness of the lens is only one attribute.

The excellent Zeiss discussion on "bokeh" (http://www.zeiss.com.au/C12567A8003B8B6F/EmbedTitelIntern/CLN_35_Bokeh_EN/$File/CLN35_Bokeh_en.pdf) makes it clear that sharpness and attractive out-of-focus blur are fundamentally opposed optical phenomena. Decisions need to be made about the rendering and sharpness. As one example, the Summitar was designed to be sharp (for the time) and the out-of-focus characteristics are ... interesting.

There are other characteristics as well (colour rendition, contrast etc) which affect the "character" of the lens.

 

[Pioneer]

IMO people are way too concerned with sharpness nowdays. The sharpness of today's lenses is a slave to technique. Unfortunately most people do not use proper technique so there is no way they are enjoying the sharpness they paid so much for.

Since I started printing instead of enlarging my pictures to 100% of a computer screen I have found that there are all kinds of lenses that are perfect for me, and a lot of them are very inexpensive. As an example, an Elmar 50/3.5 is a surprisingly good lens when you aren't worried about the enlargement on the computer screen. 🙂

 

[noisycheese]

Pixel peeping is nonsense. Its because people don't print their images anymore. If they did they would soon realise that sharpness is a non-issue.

Agreed. Zack Arias wrote in his book Photography Q&A (pg. 195):

Any image can look good on an iPad. The truth comes out when you print it.

I think the man has a point there.

Given the caliber of images that are prevalent today, it's no wonder most people don't print their images.

For me the lens is about rendering. A painter uses different brushes, not all of them "sharp." Even spray cans can be used to make art! So the sharpness of the lens is only one attribute...

...There are other characteristics as well (colour rendition, contrast etc) which affect the "character" of the lens.

Two more excellent points about sharpness vs. rendering (AKA the "fingerprint" of a lens).

JMHO but the otherworldly hyper-sharpness of the megadollar digital cameras looks unnatural. The homogenized, uniformly glass smooth rendering of digital sensors looks bland and weird. Neither are my cup of tea.

A lot of people don't object to this look though. Beyond that point, I suspect that image attributes like image quality, rendering, visual texture, contrast, color balance, etc. are non-issues for the masses. As time goes by, people seem to be becoming more and more daft, visually speaking.

 

[gavinlg]

If I were a nikon user I would be all over that 58mm.

 

[tbhv55]

Pixel peeping is nonsense.

I agree - in fact, I'm a "reformed" sharpener! Some years ago, I would enthusiastically read about sharper lenses, and about techniques for sharpening in processing, and what-have-you... yada yada, and yet I never seemed to be satisfied with the resulting pictures. Eventually I realised that I was not really looking at my photographs, but concentrating on the sharpness. Once the penny had dropped, I removed - (almost) completely - sharpening from my post-processing, and I much prefer all my recent output when I compare with images that I took, say, five years ago.

Over-sharpened images now have a tendency to make me cringe a little (sometimes more than a little! 😱).

 

[FA Limited]

i agree, printing is a whole new level of skill. i acquired a printer last year and still coming to grips with making the most of printing.

but as much as i disdain pixel peeping, i find myself doing it all the time. at first it was a function of me not handholding the camera and to check photos. i still have a tendency to go 100% all the time. however, i definitely appreciate more sharpness and resolution and makes the prints all the more clearer. as well sharpness is much easier beginners to grasp rather than contrasts like "micro-contrast" "glow" "bokeh" or "tonality"

i must say i do like the look of the 58mm so far from the limited set of photos so far, it seems very smooooth.

 

[Ko.Fe.]

My 50L is sharp and renders OK. Not so expensive comparing to FF DSLR price. Works nicely with film EOS cameras.
My Summitar renders amazingly and it is sharp. Not so expensive comparing to my budgetary RFs.
My CS 35 2.5P is crazy sharp, but absolutely "no name" in rendering department. It is my most expensive RF lens...

 

[tunalegs]

It's much easier to see differences in rendering than it is to see differences in sharpness, so it's natural that rendering becomes a major point of discussion about lenses.

Most lenses are "sharp enough" for most people, because few people make really big prints from small negatives. I will say though that having uniform sharpness (or softness) is preferable than having a lens which is sharp in the center but soft in the corners. If the frame is not uniformly sharp (however sharp that may be), then the soft areas become more noticeable/distracting.

 

[Sid836]

For me it depends on the medium I use. On film I like things to look more natural than perfect. On digital, I'd like to have the best I can get due to pixels messing things up in the most unwanted areas (especially when others look just the details in your photos).

 

[pgk]

'Sharpness' is overrated IMHO. There is far more to a lens than its ability to extract the maximum detail from a scene.

My pet hate is flat horizons (such as the sea) which curve when near a frame edge - de-distorting in software solves the problem but makes rather a mockery of using an extremely 'sharp' lens - I'd rather have a low distortion lens myself......

 

[Mcary]

Personally I pixel peep pretty much every frame I shoot as I find that its an excellent method to check for critical focus and to determine the widest usable aperture on lens. Example with my Sigma 30mm F1.4 on my Canon 7D that would be F 2.0. As far a sharpness goes well I've never had an image that was in focus not be sharp enough. Now as silly as it sounds I really think a lot of people, maybe not here but on other websites, seem to confuse focus with sharpness. These are the people that are constantly complaining about how this or that lens isn't sharp, and then provided example that clearly show poor focusing techniques.

 

[Erik van Straten]

de-distorting in software solves the problem but makes rather a mockery of using an extremely 'sharp' lens - I'd rather have a low distortion lens myself......

The Nokton-M 50mm f/1.5 has a really low distortion for such a fast lens.

Leica M2, Nokton-M 50mm f/1.5, Tmax400.

Erik.

 

[kiss-o-matic]

Example with my Sigma 30mm F1.4 on my Canon 7D that would be F 2.0. As far a sharpness goes well I've never had an image that was in focus not be sharp enough. Now as silly as it sounds I really think a lot of people, maybe not here but on other websites, seem to confuse focus with sharpness.

I believe differentiating lack of sharpness and poor focusing on a Sigma lens is Einstein's definition of insanity.

 

[Dez]

I see a great deal of discussion on RFF about different aspects of the rendering of a particular lens, of the particular character of a lens, and various adjectives that tend to be associated with a lens, things like "Zeiss pop" or "Leica glow". But all that stuff appears to be very ill-defined and subjective. Is there anyone on the list who could help to rationalize these rather fuzzy attributes in terms of the actual physical properties of different lens designs?

A lens is after all an assembly of glass bits, designed to bend light in such a way as to form an image on a sensing surface, whether film or a digital device. It will have certain physical properties in terms of resolution, contrast, flare susceptibility, aberrations, Out-of-focus properties, field flatness, consistency of focus etc. All the rather subjective attributes of lenses have to have come from these physical properties in some way. What are the actual physical properties that make a Sonnar a Sonnar, a Planar a Planar, a Tessar a Tessar, and all the rest?

I don't believe I am a Philistine for asking this question. There are overall perceptual differences in the final print depending on the lens used. There are many list members who spend thousands for multiple lenses of the same focal length in order to have available these different "renderings". At the end of the day, this perception of the print is what matters, but I see value in understanding the underlying optical properties that cause those differences to be there. Sadly the multiple-thousands-on-the-same-focal-length option is not available to me, so I need to be able to choose wisely based on a good understanding of what makes the lenses what they are. And yes, as is obvious, I am an engineer.

So, any good references out there to objective physical properties, and their perceptual results?

Cheers,
Dez

 

[redisburning]

there are plenty of sharp lenses with good rendering, so why use a not-sharp lens?

btw, what if the rendering you like comes from high contrast in the high frequencies? I love the 50MP, some people call it clinical. I disliked the ZM 50P, some people say that is the one. contrast in the frequencies towards extinction is generally what is referred to as sharpness, anyway.

 

[mfogiel]

In the "about" normal focal length, there are a few things that I care about most.
1- effective fl
2- speed
3- bokeh and hence the roundness of aperture blades, background blur, foreground blur and specular highlights/contrasty edges rendering
4- sharpness
5- contrast/midtone gradation
6- microcontrast
7- flare resistance
8- focus shift

This is quite enough characteristics to differentiate the lenses apart. I am only talking about B&W here, because you could also add issues like colour reproduction, and if (god forbid) you use some digital contraption, then a can of worms would open about the colour fringing, corner vignetting/colouring, etc.
My ideal lens would be a long normal (55-60mm), capable of a dof equivalent to a 240mm/f4.5 lens on a 5x7 camera, (that would be precisely a 58mm/f1.4), with at least 9 rounded aperture blades, and a sharpness wide open as good as the Summilux 50 ASPH, possibly medium contrast, good flare resistance and great bokeh. It goes without saying, that it should have no focus shift, as this would make stopping down problematic.
What would I do with such a lens?
Take a look at the work of photographers like Avedon, Sander, Newton, HCB, Penn, Giacomelli, Doisenau, Erwitt,etc, etc. Most of their best photographs has been done with lenses that were close, but not as good as this one. Could the 58/1.4 Nikkor be a solution for life?

 

[DominikDUK]

Both have their place for scientific photography and a few other fields like repro I want the sharpest lens there is. For all other fields rendering is more important to me than sharpness. The old lens designers thought so as well. Just look at the names they gave their lens design Plasmat says it all Plastic look was the design goal not ultimate sharpness. The Planar on the other hand was designed to be the most highly corrected lens . Plane no to little field curvature etc... Contrast wasn't all that important it was mostly used indoors. The Heliar was another design for plastic look the tessar was designed for economy in production and ultimate sharpness meaning in this case high contrast. Correction of optical faults was not the main goal of the design.

Dez the look is mostly created by accepting certain let's say acceptable faults in lens design that enabled the lens designer to reach his ultimate goal in case of the Sonnar speed in case of the Tessar high contrast and lower costs. Each compromise results in a different look. Portrait photographer wanted a rounded, plastic look and speed so lens designers created lenses like the Heliar and the Plasmat these designs incorporated certain optical faults that gave them the look they wanted. The position of the iris diaphragm and how many blades it had played a roles as well.
For certain uses like pure portrait lenses like the Universal Heliar those optical faults could be enhanced by the photographer to give him the look he desired.
To give you an example the Petzval design had one goal and one goal alone ultimate speed in order to achieve this goal the designer Petzval accepted some amount of coma, significant amount of field curvature and vignetting these faults gave the Petzval lens the look that so many photographers seem to price. Very good center sharpness and swirly bokeh when the lens does not fully cover the plate/film format resulting in 3d like look