p.1 #1 · Zeiss ZF 18 mm f/3.5 cut open to reveal mechanics
I was at the Salon de la Photo in Paris yesterday, where I saw a great deal of junk but also a lot of interesting gear.
The Zeiss lenses were on display, including the latest 35 mm f/1.4 (confirmed: way too big). They had also sliced open an 18 mm ZF for display. The mechanics, which accommodate a floating element, are pretty impressive:
Metal everywhere. I've lusted after the 18 mm ZF for a long time. This isn't helping!
By the way, is this technically a cross-section, cutaway, or something else? I thought I'd label it accurately to help Google searchers, but wasn't sure what to call this.
p.1 #2 · Zeiss ZF 18 mm f/3.5 cut open to reveal mechanics
Specularist wrote:
By the way, is this technically a cross-section, cutaway, or something else? I thought I'd label it accurately to help Google searchers, but wasn't sure what to call this.
Olympus seems to enjoy chopping up their better lenses too; many examples out there for a few years now. I'd call it a sagittal cross section, as opposed to a cutaway which might just remove a wedge from something.
BTW, it looks like Zeiss tilted the 18mm's rearmost element... I'm guessing it doesn't perform very well in that condition!
p.1 #4 · Zeiss ZF 18 mm f/3.5 cut open to reveal mechanics
I'd love to see the saw that cuts that kind of product - that's a lot of glass - I can see linear marks - diamond impregnate abrasive - they polished the glass after the cut, though I don't see polishing on the metal - check out the brass parts, higher wear areas - quite the precision.
p.1 #5 · Zeiss ZF 18 mm f/3.5 cut open to reveal mechanics
mMontag wrote:
I'd love to see the saw that cuts that kind of product - that's a lot of glass - I can see linear marks - diamond impregnate abrasive - they polished the glass after the cut, though I don't see polishing on the metal - check out the brass parts, higher wear areas - quite the precision.
I doubt they simply cut through an assembled lens - too many parts could tip and tilt and jam the cutter, and, as you mention, the radically different properties of the materials in the lens would surely cause issues.
If it were me, I'd assemble a lens, sans glass, but being careful to provide correct spacing for its later presence, gluing lightly as I went. I'd then cut it in half on a bandsaw and lap the cut faces. Finally I'd drop in half elements prepared separately.
I might consider filling a lens with fluid, solidifying it, and then taking my time abrading through the whole kit and caboodle, though. Water, plaster, or various thermoplastics could be used, so long as suitable solvents are available to clean up later.
p.1 #6 · Zeiss ZF 18 mm f/3.5 cut open to reveal mechanics
All of the element holders are threaded sockets with threaded retaining ring type sub-assemblies - probably aluminum except for the brass - they're all lathe spun machined parts - a few connections might be adhesive welds. I'm counting approximately 30 parts plus 10 glass elements.
OK - lenses are cheap for what goes into them! No wonder I like them so much - and I though it was for the photography. Zooms with AF and IS must be a modern mechanical miracle - or maybe I'm just easily amused.
p.1 #7 · Zeiss ZF 18 mm f/3.5 cut open to reveal mechanics
It does look like they just cut through an assembled lens. Look at all the swarf and shavings embedded in the various nooks and crannies. they least they could have done was blow it out with compressed air.
Various diamond saws could do what we see here, w/o much trouble. with a big enough blade, there's little jam potential, really.
p.1 #9 · Zeiss ZF 18 mm f/3.5 cut open to reveal mechanics
Ed Sawyer wrote:
It does look like they just cut through an assembled lens. Look at all the swarf and shavings embedded in the various nooks and crannies. they least they could have done was blow it out with compressed air.
Various diamond saws could do what we see here, w/o much trouble. with a big enough blade, there's little jam potential, really.
p.1 #11 · Zeiss ZF 18 mm f/3.5 cut open to reveal mechanics
carstenw wrote:
I am a bit surprised how sloppily they cut this lens. It really doesn't fit with the company's image of high-quality photographic equipment.
p.1 #12 · Zeiss ZF 18 mm f/3.5 cut open to reveal mechanics
I noticed the tilted rear element, olyacme; and the torn aperture blade too!
In a strange twist I ended up back at the Salon de la Photo today, which allowed me to take some more photos; this time with an SLR. I think I got a better pic of the Zeiss ZF 18 mm f/3.5:
The Tamron looks clearly different from the Zeiss and Leica: more plastic, less metal, and a simpler method of holding the elements in place (glue?). It's probably representative of "consumer" lenses from Canon and Nikon too, though they'd charge more than Tamron do for the same thing, I'm sure.
All of them are impressive in their own ways. Samyang also had some cut lenses on display, but I flunked the photos badly enough that I'd be embarrassed to post them here (far too little light at their booth).
p.1 #13 · Zeiss ZF 18 mm f/3.5 cut open to reveal mechanics
Specularist - thanks for posting these - very enlightening.
The Zeiss and Leica are using the same/similar construction design - a lot more brass on the Leica - completely different construction on the Tamron - very interesting.
One would have to think if they are indeed "sawing" these in half that a liquid coolant would be necessary to evacuate the (cut) waist and cool the glass - thought dry diamond cutting is possible - but hot. A lot of what we see as debris on the first one is partly reflection from being top lit.
Very cool - I wonder what they did with the other halves?
p.1 #18 · Zeiss ZF 18 mm f/3.5 cut open to reveal mechanics
Maybe they only use lenses with some (optical) defects. It's also possible that they don't use special (optical) glass, put only polycarbonate, or normal window glass.
p.1 #19 · Zeiss ZF 18 mm f/3.5 cut open to reveal mechanics
It's undoubtedly a real lens with real glass. It would cost more to tool up to create fake elements than it would to just write off a couple of real lenses.
