Magic of Fresnel

Now and then, photographic industry comes out with a product designed to make our lives, as a working photographers, easier,  while also providing us with new ways to approach the image capture process. Newly introduced Nikon AF-S Nikkor 300mm f:/4 E PF ED VR lens (Yes, product names are getting ridiculously long, while the lens itself got shorter) is certainly a product with a potential to be such.


First I have to give some credit to the people behind most of the recent Nikkor releases. It seems they have really adopted the feel for true needs within the realm of photographic artistry, while remaining reasonable price and spec-wise. Their f:/1.8 line of prime lenses is a fine example of such product philosophy. And here enters the new AF-S 300mm lens with f:/4 aperture and abbreviation PF which stands for PHASE FRESNEL, a technology making this lens relatively small and at 755g also quite light.

Land Ahoy!

The basic idea behind Fresnel lens was to achieve similar effects with less mass and volume of material (glass) required. The invention was credited to Augustin-Jean Fresnel, a French physicist, who was aware of waveform characteristics of light and a diffraction phenomenon. In the year 1823 photography was just about to be born and photographers almost nonexistent, but there were plenty of sailors exposed to the dangers of seafaring. Therefore Fresnel lens got its first implementation as a compact lighthouse optical system. Light beam shining from the first such example could be seen at a distance of more than 30 kilometers. Consequently sea travel became safer and Fresnel’s contraption ready for a new task, to shine on the stars themselves. Of course we are talking about theater and movie stars of the world. Fresnel lens equipped lights are being used to this day on movie sets, stages and photographic studios, where they illuminate spaces with their characteristic evenly lit focused beam. Prime examples of such application in photography can be observed in the works of George Hurrell and his classic Hollywood portraits.

Image above: A rough blueprint representation of Diffractive Optics by Canon with exagerated proportions. In reality gratings are much smaller in size and require tools with ultimate precision to manufacture.

Canon was the first

It took almost two centuries of advances in the field of manufacturing precision optical elements. In 2001 Canon corporation finally introduced their first main (focusing screens and some lighting products were already using similar micro-prisms) general image taking product with fresnel lens properties. Canon EF 400mm f:/4 DO IS lens was painted with a green, instead of a usual red decorative ring, along with the inscription: DIFFRACTIVE OPTICS (abbr. DO.)

The lens itself was 36% lighter and 26% shorter than a hypothetical conventionally designed one would have been. In 2009 it was time for another first, a compact zoom lens featuring a DO lens element constructed with three layers. EF 70-300/4,5-5,6 DO IS lens measured a mere 10cm when not extended and weighted 720g, while still being constructed up to professional standards.

Canon’s DO was introduced 14 years ago and lot of things have changed since. Film emulsion is now almost completely replaced by a plethora of high resolution imaging sensors. Lenses, once considered to be flawless, are beginning to appear dated. Canon realized that fact and replaced their 400mm DO lens with an updated version in 2014. Diffractive optical element is, in this latest iteration, better than ever and uses a new gapless design that leaves nothing to be desired quality wise.

Image above: Current state of the art lens with diffractive optics by Canon corporation of Japan is this 2.1kg “light” EF 400mm DO IS II lens.

Nikon enters the stage with Phase Fresnel

But why is this Nikon’s 300mm PF lens so special, if Canon has been doing it for more than a decade, you might ask. It must be said that there is absolutely nothing wrong with a current crop of Canon DO lenses. The problem is not that Canon couldn’t do the same or better, but that they didn’t. Their latest 400mm DO lens weighs almost insignificant 300g less than, at 2.4 kg already light for its class, EF 300mm 2.8 L IS II lens, with latter offering more flexible pairings with extenders. Similar dilemma is forced upon the user of a relatively expensive EF 70-300mm DO IS lens. Lower weight advantage is not impressive and difference in bulk is only significant when this lens is ready to be packed in a bag. And let’s not forget that these two great companies are now in competition with a couple of promising mirrorless systems.

Image above: Nikon AF-S 300mm f:/4E PF ED VR lens. Phase Fresnel lens in a size comparison with its conventionaly built sibling.

Nikon has chosen the middle path and struck a sweet spot between aperture, focal length and portability. The resulting lens weighs approximately half of its conventional sibling, while being significantly shorter. I’m sure this lens will find its usage in hands of various types of photographers, while expanding their visual language in locations previously unthought of or in situations before unpractical. Be it on a mountain top or in a scarcely lit bride’s room, a photographic product is a success only when it becomes more than just a demonstration of technology. Good job, Nikon!

© 2015 The Unpublished Journal by Peter Mlekuž, All Rights Reserved; Source files of the featured product images and graphics are © Canon corp. and  © Nikon corp.