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I am very curious to know what the breakdown is for lens production costs. This information is hard to come by, and I am unable to find any reliable sources. Obviously, I can't just email Canon to send me their financials, but I was hoping that someone here who has worked in the field of lens design/engineering might offer up a rough estimate based on their experience. Just to take a classic design, maybe a 50mm f/1.8 or a 70-200 2.8 lens (any make).

I was thinking of a breakdown like so:

  • Raw Materials
  • Polishing/Processing/Coating/etc.
  • Assembly
  • Packaging
  • R&D
  • Marketing
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    "PS Can someone please add a "lens-manufacturing" tag. I don't have rep". Not needed. We have lens-design, which is for: "of and related to the specifics of lens construction and manfacture." Combined with "manufacturing", I don't see a need for a new tag. – scottbb Nov 30 '18 at 20:13
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    Are you asking because you're trying to spec out what it would cost to create one or...? These values are likely to be very different between the big names and the knock-offs. – Hueco Nov 30 '18 at 20:59
  • Agreed! It's a question borne out of my own curiosity than anything else. – Automaton Nov 30 '18 at 21:19
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    "Where can I find...?" generally doesn't make a good question. This site should be a primary source of answers, not a substitute for Google. Your question body reflects this — I suggest adjusting the title to match. – mattdm Nov 30 '18 at 23:53
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    @mattdm Thanks for the suggestion. I altered the title.. – Automaton Dec 1 '18 at 0:39
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Price of materials

Optical glass and glass-like materials is priced according to a fairly unique model. The most ubiquitous glass, Borosilicate Crown glass is used as a base price and other materials are priced as a multiple of this. N-BK7 is the name for this material from Schott, or S-BSL7 from Ohara. It is about $10/lb. Common glasses have "cost factors" of 1-5x. Low-dispersion glasses are closer to 10x, and anomalous partial dispersion or high index materials reach as high as 30x.

For a large element, such as the front element of a 70-200mm lens, three quarters of a pound of material may be needed to block, grind, and polish the finished lens. For a smaller element, such as the front element of a 50/1.4, the weight may be as low as an eighth of a pound.

Per-element, you can then estimate that the price is anywhere from ~$1-225 per element.

However, the modern process chain, especially in volume, strives to minimize the number of hours needed to produce the finished optic. This means manufactures often work with the glass vendors to deliver "preforms" which may require no grinding at all, and are immediately suitable for polishing. These will have extra cost, but when the volume reaches 6-7 figures, I imagine the cost increase is not more than, say, 10%. But I do not know any specifics.

Processing

Each element must be cut from the slab glass, ground, and polished. The cutting is essentially free -- diamond saws and coring tools are not expensive enough to make it onto a costing spreadsheet. Grinding will be done either on a spindle (~$15,000) with a highly skilled optician, or on a CNC machine (~$200,000) with a differently/less skilled technician. The spindle may be able to grind up to 36 lenses at once if they are small, CNC machines only process one element at a time but are ~4x faster per cycle; the greater control allows a more aggressive process. Grinding may take anywhere from 1 - 100 hours depending how far from the final shape you begin. With a 5-year machine amortization at 120 hours a week, this works out to 30,000 hours per machine, or $6.66/hr in the CNC case. After electricity, you are looking at more like $7/hr. The technician price is heavily dependent on how many machines they run, but assume at volume it's something like one tech per 5 machines, at $50/hr after overhead - so $17/hr. Polishing machines cost about the same, and depending on the grade of surface you are producing and how good it started, it may take 1 to 100 hours as well. The better you grind, the less you have to polish.

If we assume a mean processing time of 50 hours in the cut-from-slab glass case, the cost is $850 per element in processing for CNC. In the spindle case, it is more like one tech per spindle, and the spindle will be amortized over 10 years (simple machines wear slowly and last forever). So the spindle itself is $0.25/hr, plus a tech at $50/hr overhead. This produces, in effect, up to 9x as many lenses per hour as CNC, so we would cost at a mean of 50/9 => 5.5 hours per optic. This works to $276 per element in processing.

A reasonable range would be $170 - $1700 per element in CNC, and $50 - $550 in spindle.

Now, if you got preforms, grinding may only take a few minutes to touch up the shape, and polishing just a few hours (say, 3) to make things shiny. This brings the cost estimate to more like $50 to process in CNC, and $5 to process in spindle.

Assembly

At scale, assembly may require a cumulative 2 technician hours. So $100.

R&D

Developing a lens will require 1000 or so engineering hours, at an overhead of $100/hr. So $100,000 for design. Small scale prototype production is best estimated at $15,000 per artifact. If 10 variants are produced before finalizing design at 2 units each, another $300,000. At scale, a pilot run of the full line will be done, producing say 1000 artifacts at the nominal production cost. Worst case (destroy them when complete, as done with cell phones) this represents a loss of up to some millions of dollars. If they are sold (SN001, baby!) there is a net profit, but the initial scrap rate will be high.

If a new manufacturing process must be developed or specialty equipment procured (say, aspheric polishing and testing) ~$2M must be added to the budget. An aspheric CNC machine starts at $200,000 and the price goes up with workpiece size.

Coating, Packaging, Marketing

I do not know much about any of these, but I would not assume more than, say, $5 per artifact in packaging.

These numbers seem really high

Yes, this is why lenses are expensive! These are US labor rates, in developing nation they are about one tenth of this. These are also new machine prices - if a company has a bunch of 20 or 30 year old spindles they still run and maintain, costs are lower there too. If a company does precision glass molding, or uses optical plastics, in volume the price is essentially that of the volume of material consumed per element which has nearly no waste. This will reduce element cost to more like $1-$10.

Not everything is moldable, and molding parts parts with optical precision is really hard. This is why Canon made their own autonomous production line. I'm sure it has an extreme capital cost, but also very low operating cost and high repeatability.

  • You mention the amount of glass for a 70-200mm. What about something like a 14-24? That element has some pretty extreme curvature, so I imagine the blank before being cut/ ground must be a substantial amount of glass... – scottbb Dec 8 '18 at 18:19
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I have had glassware made according to my specifications for a couple of industrial applications.

I have had f-theta scan lens assemblies, flat mirrors, and prisms manufactured and various stock lenses taken off-the-shelf for experiments.

Your application will determine costs due to the limitations imposed by your system. Are you limited by wavelength, physical size, image quality, environmental extremes, etc.

One strives to use stock parts whenever possible. Optical suppliers have a variety of parts that when assembled can achieve the desired effect; but, not always in the available package space.

Large optical fabricators have staff-engineers to help you and access to heavy-duty computational power if your resources aren't up to the task.

Start with a catalog from one of the optical companies such as CVI/Melles-Griot. The front of their catalog breaks down the process and includes a short course in optics.
Here's a scanned copy of the tutorial [front] part of their catalog suitable as a basic text that I have found handy.

After you get the light path right (by breadboard experiment after design and ray-tracing done computationally) you're ready to machine a housing for the assembly and assemble a prototype for experiment and testing.

There are schools for optical design where you can make further enquiries such as University of Rochester and others.

There are books with optical formulas such as Elements of Modern Optical Design, Modern Optical Engineering, and Lens Design Fundamentals which have become some of the primers in the subject.

Your question is very broad and covers many aspects of design, development, manufacturing and marketing usually covered by specialty interest groups that meet at optical conventions. Optical Society of America, SPIE (formally Society of Photographic Instrumentation Engineers, SMPTE Society of Motion Picture and Television Engineers, and others.

There are studies, budgets, estimates, industry polls, and guidelines in various technical papers published by the industry

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    The O.P. seems to be concerned with complete lens assemblies offered on the retail market for Canon cameras, not custom fabricated pieces for use in industrial photography. – Michael C Dec 1 '18 at 3:55
  • @MichaelClark Correct. This answer is irrelevant to production consumer lenses. – Eric Shain Dec 1 '18 at 16:01
  • @Stan thank you for your thoughtful and detailed response. I will try and read up a bit more about the SPIE. Michael is correct, I was more interested in the breakdown costs for consumer lenses. – Automaton Dec 3 '18 at 19:26

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