Chasing bokeh: Fuji 50/2

TEAS wrote:

Does sterile mean it is sharp lacks distortion? I generally find that these vague, undefined words are meaningless in terms of scientific reality.

I’ve always found it to mean sharp without “magic”... in pixel peeper talk

Just Shoot Me wrote:

TEAS wrote:

I sold and extensive Leica collection to got o Fuji. The Fuji lenses are just as good as Leica.

You are completely wrong. Fuji lenses are very good but they are not Leica lenses.

When it comes to general photography ...they are right up there.

TEAS wrote:

Does sterile mean it is sharp lacks distortion? I generally find that these vague, undefined words are meaningless in terms of scientific reality.

Photography is not a science - it is an art. Of course one might argue that there are multiple aspects to photography but at the end of the day even in plain simple documentation - the more artistic the presentation the better the product.

And of course as an art form there are subjective descriptions which are used to describe the quality of an image. If you are not familiar with the language used to commonly describe the emotional context of art - then this might help.

https://www.words-to-use.com/words/art/

Sharpness of a lens is an engineering concept. Sharpness normally results from removal of aberrations of a finite aperture lens. However, it might just be some of those aberrations that generate interference in out of focus areas that result in what some call pleasing bokeh. In fact one of the most squeaky soft, fuzzy concept in photography is bokeh which is an important factor in the some consider when assessing the quality of a lens.

While bokeh is a concept that arises from interference relationships in out of focus areas and can be non-linear it be explained by non-linear Fourier optics.

http://www.phys.unm.edu/msbahae/Optics%20Lab/Fourier%20Optics.pdf

https://en.wikipedia.org/wiki/Fourier_optics

A lens can be be described as a Fourier transform operation on the incident light on the lens. This is the basis of optical signal processing which basis of such things as fiber optics communications and processing of ultra wideband signaling technologies.

That is the lens takes the Fourier transform onto the image plane. When a point source of light is incident on a lens with a finite aperture- the Airy disk that shows in the image plane the Fourier transform of the impulse conceived with the impulse. This results in the Airy Disk whose width is in a one to one relationship with the focal length of the lens and the size and shape of the aperture opening. Different shapes of aperture opening have different Airy Disk. This is known in photography as diffraction. What happens in front and behind the focal plane is different waves coming from different parts of the lens will have differing delays - depending on the abbreviations of the lens which can result in differencing rendering of the bokeh on the sensor plane (because of destructive interference) patterns.

Lens design is quite complex and today simplified ray tracking algorithms is what dominates lens design. Ray tracing fine. Ray tracking models the light through a lens systems as rays of light that are focused on a sensor plane. The object in the focal plane are in focus and the goal is to design the lens so that the resolution on the focal plane is maximized. This however, ray tracking is a very simplistic model for light and not an accurate model for what goes on in the out of focus areas. Although it requires the computerized design tools require massive compute resources to solve the equations of the interactions of the focal plane. The description is incomplete - in fact ray tracing does not predict the Airy Disk as part of the theory or interference patters in the out of focus areas. For that the more complete theory of Fourier optics is needed.

http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/raydiag.html

When it gets right down to it - unless you are designing a specialized copy lens - there are many aspects in the rendering of an image which become important. Out of focus rendering is not important for a copy lens - flat field is the prime consideration. You can turn an enlarger lens around, mount it on a bellows and it will become a fantastic copy lens. However, to express ones self there are many attributes of a lens that come into play that go into a pleasing rendering. What bothers one person or what one person might consider "harsh" or "sterile" another might not be bothered by it. Part of the quality in a lens is giving the photographer the ability to control the out of focus areas so the eye (and attention ) is not distracted away from the main theme of the composition. Bokeh is a fundamental element of composition.

https://www.thephoblographer.com/2013/06/01/the-basics-of-photography-b-for-bokeh/

https://www.imaging-resource.com/news/2013/09/11/understanding-bokeh-the-art-and-science-behind-the-beauty-of-blur-part-1

http://kurtmunger.com/bokeh_samplerid22.html

That may or may not be correlated with the resolution MTF and there can often be a trade off between out of focus control and in focus MTF.

Mind bogglingly complex, the Fourier articles, thanks. Complex as there are no live examples provided in the *.pdf.

Deed

Truman Prevatt wrote:

TEAS wrote:

Does sterile mean it is sharp lacks distortion? I generally find that these vague, undefined words are meaningless in terms of scientific reality.

Photography is not a science - it is an art.

Photography certainly is a science as well as an art. Look at the rest of what you wrote after this... its all science. Photography can be used to make art, but its origins are certainly a scientific discovery and has its roots in chemistry and physics.

Of course one might argue that there are multiple aspects to photography but at the end of the day even in plain simple documentation - the more artistic the presentation the better the product.

You cannot categorically say this...

And of course as an art form there are subjective descriptions which are used to describe the quality of an image. If you are not familiar with the language used to commonly describe the emotional context of art - then this might help.

Yes, to describe art...not lens attributes.  Only camera nerds go to a museum and talk about bokeh.

Part of the quality in a lens is giving the photographer the ability to control the out of focus areas so the eye (and attention ) is not distracted away from the main theme ...

It can be used this way, but bokeh is not a key compositional element... it is one type of isolation technique. An overused one... and many famous photographs do not rely on bokeh at all.

John Gellings wrote:

Truman Prevatt wrote:

TEAS wrote:

Does sterile mean it is sharp lacks distortion? I generally find that these vague, undefined words are meaningless in terms of scientific reality.

Photography is not a science - it is an art.

Photography certainly is a science as well as an art. Look at the rest of what you wrote after this... its all science. Photography can be used to make art, but its origins are certainly a scientific discovery and has its roots in chemistry and physics.

Photography like every other art has benefited from gains in scientific knowledge and technical innovation that might result - but so has painting, graphics arts, etc.  But that does not make painting a scientific discipline.  Most of the master painters worked with chemist of the time to get the paints they wanted.  Some like Michelangelo was among other things an architect so had to use science to design his architecture but his architecture is not known for his scientific knowledge but for it's beauty.

Then there was da Vinci.  He he a scientist, a mathematician (here I separate scientist and mathematicians because a mathematician is nor is scientist and visa versa).  But we all agree that da Vinci was a major figure in Renaissance art.  He was also was of one of the first artist to study the rendering of three dimensions on to a plane.  He published papers with Pacioli on perspective and published some of the first drawings illustrating perspective.  That give rise to the mathematical subject of projective geometry and what da Vinci showed in his drawings is the rendering of three dimension in two is all dependent where you put the "point at infinity."

But da Vinci's art work is not science.

Yes photography has benefitted from the discovery from physics if what happens when a photon interacts with a silver halide salt.  That discovery then led to the ability to detect that photon trap in a "spec" on the silver atom.  Chemical processes were developed to the exploit that to generate a photographic plate where an emulsion was made with suspended silver halide salts.  This is not different than new pigments and bases being developed for painters.  A photo detector used in digital sensors is simply a refinement where photons counted by their interaction with electrons of differers medium other than silver halides and circularity instead of chemical developers exploit it.

There is a technology that backs up photography and there is a technology that backs up painting - there is even a technology that concentrates on recreating the paints of older times so museums can restore art work.  Does that make painting science.

But to claim the use of such advances in science and technology in art is that art is science is like calling driving your car to the grocery science.

Of course one might argue that there are multiple aspects to photography but at the end of the day even in plain simple documentation - the more artistic the presentation the better the product.

You cannot categorically say this...

And of course as an art form there are subjective descriptions which are used to describe the quality of an image. If you are not familiar with the language used to commonly describe the emotional context of art - then this might help.

Yes, to describe art...not lens attributes. Only camera nerds go to a museum and talk about bokeh.

Part of the quality in a lens is giving the photographer the ability to control the out of focus areas so the eye (and attention ) is not distracted away from the main theme ...

It can be used this way, but bokeh is not a key compositional element... it is one type of isolation technique. An overused one... and many famous photographs do not rely on bokeh at all.

Sorabhs wrote:

deednets wrote:

Last night I read a blog/article about the rendering of a variety of lenses, comparing a few Zeiss, Voigtländer, Leica lenses. There was also an emphasis on bokeh rendering. Aperture blades were mentioned and how those were positioned and shaped e.g. rounded, but inward pointing, straight etc. Also the fact that sunstars work in a peculiar way, creating even numbers on lenses with an even count of aperture blades, but doubling the sunstars when an uneven number is picked.

The review(s) is/are of little importance to Fuji lens owners, but the blog made me re-visit some photos that I had taken lately with the 50/2. Hardly a contender for the royalties that were reviewed in that blog.

But then I thought: hang on, the 50/2 is a remarkable lens, incredible value with excellent bokeh even in scenarios where the background, straight lines etc can look a tad nervous on occasion, but the 50/2 I think gets away with a lot.

What's your take on this lens compared to the usual suspects?

Not a lot of distance between the bells and the wall

Again not a lot of space behind the Buddha

Not a flat surface behind the focal plane this time

Some transition and some flatness in the background

Another transition with more space between objects

Some straight lines typically hot contenders for a nervous bokeh

And the lot: foreground and background blur plus some straight lines

The last one is possibly the most challenging as it has strong foreground blur plus background blur and straight lines. But I think that the lens is doing remarkably well here.

And here is one as a little teaser, taken with the 75/1.8 Olympus. I found that I started looking at the nervous bokeh almost straight away, have plenty of examples but this one example will do. I found that when I had the 75/1.8 - a MUCH longer focal length compared with the 50/2 - I had to be far more careful when I chose the background.

The 50/2 is far more forgiving and possibly a true steal for the price!

Deed

Lovely pictures! I’m sure not just the 50mm but the photographer behind the lens both worked together to create a beautiful set of photographs.

I’m torn between getting either the 60mm f2.4 or the 50mm f2. I used to have a 50mm on my Nikon but I found the 75mm length a little impractical. Either too long or too short. The bokeh wasn’t as natural as the one Fuji produces though so I may need to reconsider.

Definitely don’t want to buy a 56mm as they’re just too heavy!

A couple of extras thrown in by Fuji here: 1. closest focusing distance is I believe 38cm, a tad longer than an A4 page 2. fast focusing: the 60/2.4 is slower, imho MUCH slower as I had this lens for a while.

The 50/2 also has 9 aperture blades and is one of the sharpest lenses in the Fuji selection:

https://www.lenstip.com/499.4-Lens_review-Fujifilm_Fujinon_XF_50_mm_f_2_R_WR_Image_resolution.html

Deed

hgercek wrote:

A few more 50mm f2 pictures... I am quite satisfied with the bokeh.

The cat shot is fabulous

Truman Prevatt wrote:

John Gellings wrote:

Truman Prevatt wrote:

TEAS wrote:

Does sterile mean it is sharp lacks distortion? I generally find that these vague, undefined words are meaningless in terms of scientific reality.

Photography is not a science - it is an art.

Photography certainly is a science as well as an art. Look at the rest of what you wrote after this... its all science. Photography can be used to make art, but its origins are certainly a scientific discovery and has its roots in chemistry and physics.

Photography like every other art has benefited from gains in scientific knowledge and technical innovation that might result - but so has painting, graphics arts, etc. But that does not make painting a scientific discipline. Most of the master painters worked with chemist of the time to get the paints they wanted. Some like Michelangelo was among other things an architect so had to use science to design his architecture but his architecture is not known for his scientific knowledge but for it's beauty.

Right, true... but photography goes a little deeper into science. Cavemen were not thinking of science when they painted on cave walls.

https://en.wikipedia.org/wiki/History_of_photography

deednets wrote:

Last night I read a blog/article about the rendering of a variety of lenses, comparing a few Zeiss, Voigtländer, Leica lenses. There was also an emphasis on bokeh rendering. Aperture blades were mentioned and how those were positioned and shaped e.g. rounded, but inward pointing, straight etc. Also the fact that sunstars work in a peculiar way, creating even numbers on lenses with an even count of aperture blades, but doubling the sunstars when an uneven number is picked.

The review(s) is/are of little importance to Fuji lens owners, but the blog made me re-visit some photos that I had taken lately with the 50/2. Hardly a contender for the royalties that were reviewed in that blog.

But then I thought: hang on, the 50/2 is a remarkable lens, incredible value with excellent bokeh even in scenarios where the background, straight lines etc can look a tad nervous on occasion, but the 50/2 I think gets away with a lot.

What's your take on this lens compared to the usual suspects?

Not a lot of distance between the bells and the wall

Again not a lot of space behind the Buddha

Not a flat surface behind the focal plane this time

Some transition and some flatness in the background

Another transition with more space between objects

Some straight lines typically hot contenders for a nervous bokeh

And the lot: foreground and background blur plus some straight lines

The last one is possibly the most challenging as it has strong foreground blur plus background blur and straight lines. But I think that the lens is doing remarkably well here.

And here is one as a little teaser, taken with the 75/1.8 Olympus. I found that I started looking at the nervous bokeh almost straight away, have plenty of examples but this one example will do. I found that when I had the 75/1.8 - a MUCH longer focal length compared with the 50/2 - I had to be far more careful when I chose the background.

The 50/2 is far more forgiving and possibly a true steal for the price!

Deed

In the one image where there is significant foreground, it's not doing well. But the background treatment seems natural and un-distracting in these photos. And I've seen other samples that don't fair as well and when the subject is closer and the background is thrown out of focus more extremely, it gets pretty nervous. So I think you've found it's sweet spot for background.