Right here’s why the intriguing design of a quick new Voigtländer 50mm f/1.0 lens – to not point out a extra reasonably priced value – has bought common AP contributor, Professor Bob Newman, excited
Not too long ago my eye has been caught by the looks of a brand new lens, which appears to be fairly a departure from the norm. The lens is the Voigtländer 50mm f/1.0 Nokton Aspherical, to offer it it’s full title.
Optically the design of this lens follows well- established patterns for such a quick lens. The entrance of the lens is a six-element double-gauss design, which might have been present in any quick regular lens because the Fifties – with one exception, of which we are going to speak later. Constructed into the rear of the lens is what has turn into misleadingly generally known as a ‘pace booster’ with three components in two teams.
The entrance lens may have been designed with an extended focal size than the 50mm marked on the lens whereas the again half reduces that focal size to 50mm thereby lowering the f-number to f/1.0. This can be a related design to the 1966 Zeiss Planar 50mm f/0.7 famously utilized by Stanley Kubrick in his movie Barry Lyndon, although not as formidable, at the very least as far as the f-number is worried. So, the essential configuration will not be novel.
What’s so particular about this Voigtländer 50mm lens?
It’s the entrance factor that’s notable, as its entrance floor is aspherical. However the common manufacturing processes for aspheric lens surfaces should not appropriate to be used on this uncovered location in a lens. Aspheric surfaces are a lens designer’s dream. At a stroke they will overcome spherical aberrations that may take many conventional spherical surfaces to appropriate. Nonetheless, manufacturing them in amount has at all times been very costly, till just lately.
Two processes have been developed to beat this downside. The primary is ‘hybrid aspheres’. Right here a resin (plastic) veneer is moulded with one face spherical, to match a glass lens, and the opposite aspherical. When this veneer is bonded to a glass lens the result’s a lens with an aspherical floor. The second approach is precision glass moulding, the place a glass lens is pressed from an actual mould with the required surfaces.
Each these methods have issues for low quantity lenses, on condition that the set-up prices for the precision mould may be very excessive. By way of their utility as a entrance floor, the issue is the fabric used. Neither optical resin, nor the particular glasses needed for precision moulding, have the sturdiness required.
Therefore the Voigtländer lens’s entrance factor is floor and polished identical to a standard spherical floor. This manufacturing methodology has up to now been so prohibitively costly that it has been restricted to solely probably the most esoteric, high-price lenses.
A breakthrough in affordability
The Voigtländer will not be low cost at $1,799 / £1,650, however even this value is a breakthrough in affordability. Leica makes its aspherical surfaces this fashion. It will probably accomplish that due to the costs charged for its merchandise. Leica’s nearest equal lens is the 50mm f/0.95 Noctilux with a value of greater than 5 instances that of the Nokton. Grinding spherical surfaces is low price due to easy geometry.
The one surfaces that match collectively precisely as they transfer in relation to one another are spheres, thus if a chunk of glass is floor in opposition to a compliant instrument the 2 will adapt to one another because the grinding proceeds and the result’s a spherical floor. Grinding an asphere requires very shut management of the grinding instrument to get precisely the floor required. This may be performed utilizing specialised computer-controlled instruments, however till just lately the outcomes had been not statistically predictable sufficient for mass manufacturing.
Clearly Cosina, producer of the Voigtländer lenses, has mastered this piece of manufacturing engineering sufficiently nicely to permit the constructing of this lens.
By the way in which, from the few check experiences I’ve seen, the Voigtländer lens performs at the very least in addition to, and possibly even higher than the Leica.
Bob Newman is presently Professor of Laptop Science on the College of Wolverhampton. He has been working with the design and growth of high-technology tools for 35 years and two of his merchandise have gained innovation awards. Bob can also be a digicam nut and a eager newbie photographer.
The views expressed on this column should not essentially these of Novice Photographer journal or Kelsey Media Restricted. You probably have an opinion you’d wish to share on this matter, or some other pictures associated topic, e-mail: [email protected].
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