Here's a post I did at Nikoncafe.com regarding the possibility of new lenses from Zeiss, designed to be used on Nikon F-mount cameras.
Noted Leica writer Erwin Puts reviews the "theory behind" the very new Zeiss ZM lens line's designs here http://www.imx.nl/photosite/comments/c015.htmland in a part 2 of a 3-part series on these lenses located at http://www.imx.nl/photosite/comments/c016.html He goes into some of the opto-mechanical aspects of three Biogon lenses, a 25mm,a 28mm,and a 35mm, then a 50mm f/2 Planar-T design which Puts says is as good as the Summicron lens,and a bit better in terms of curvature of field,which puts the 50/Planar in very good company. Read his conclusions,and the third part of the series, and you'll have little doubt that the Zeiss ZM lenses for Leica M-mount means the leaked ZF means F-mount. As far as metering compatibility,I have the D2x,so to me that means there's not an absolute NEED for CPU,or P-series manual focusing lenses from Zeiss for my own use. Still, MF lenses are not as attractive as AF lenses, and I don't think there's a LOT of market demand for manual focus AiS type lenses,like the beautifully-made Voigtlander SL series of F-mount primes like 40mm/2 Asph.,75mm/2.5,etc,etc and sold thru http://www.cameraquest.com/ in the US. I forget sometimes,to change the non-CPU Lens Data field on the x quite when mounting an AiS mount lens,so hey Zeiss, P-series those babies,pretty please! I would LOVE to see a Zeiss 110-mm ZF Macro, and would like to see a very small,very high quality 85mm of f/2 aperture which means a profile not much bigger than a 50mm 1.8 AF-D. The thing I miss most about the older manual focus Nikkors is the small profile,short overall lengths, and 52mm filter size from 20mm 3.5 to 50mm, 85mm to 200mm, all SMALL lenses. These current ZM lenses Erwin reviews sound like pretty danged good lens designs,and so I really hope there's a nice ZF line introduced soon; maybe, a ZF line would be fodder for the Lens Lust forum. Price might play a role in the success or failure of a ZF line. [end of my quoted post]
And now THE INTRO. Yes, we've seen the leaks. Zeiss has some ZF lenses coming. New,modern Zeiss lenses were introduced at Photokina 2004,and are on the market right now in Leica-M mount,and so the idea that Zeiss intends to test the waters of selling F-mount lenses is not a total surprise to me since I've been to the cameraquest.com web site a fair amount since 2001.Stop by cameraquest.com and take a peek at the beautiful lens lineup,which includes 21,25,28,and 35mm Biogon models, and the 50mm f/2 Planar model. http://www.cameraquest.com/ZM%20lenses.htm
Zeiss has some experience you might say,at lens design and assembly.Much of lens-making depends on mechanical design tolerances for the utmost in lens performance. Quality manufacture and assembly means better-performing lenses,but quality manufacture and assembly drives up COSTS.How much money are we talking? I think the current prices of the Voigtlander SL series lenses is about as high as the "mass market" as a whole is willing to go for manual focusing, AiS type lenses which lack a CPU for EXIF recording and for truly FULL and TOTAL integration with the Nikon system's better cameras of the last decade or so.The "specialty prime lens market" Nikon user might be persuaded to pony up as much as $800 for a single lens,especially if it's a really great performing lens.The current Zeiss Biogon series wides are commanding $800,and the 50mm Planar $600.The F-mount has no rangefinder coupling system, so F-mount lenses could be made less expensive than M-mount lenses I think. If you shoot a D2x,or a D1-series,D200,or other pro Nikon body, AiS lens mounts give you pretty good light metering and exposure control integration as far as the Ai-AiS mount can provide, BUT without a CPU in the lens there is no AUTOMATICALLY entered and reliably CORRECT EXIF reporting, and there's no chance for a D-series distance-aware signal either.Thus, the desire for a P-series lens,which has the Digital Goodeness factor and the ability to tell a New Nikon a lot of info about the lens mounted, it's f/stop,and its focused distance,as well as plugging into the 3D Color Matrix metering and into the i-TTL flash and T-TTL flash systems with the most info for the camera's metering systems.
The presence of a CPU determines if an AF lens can be designed as a G-series or not. And that brings up the first killer question: Would Zeiss consider making new ZF lenses for Nikon using the G-mount protocol? Quick Answer:No, they're not that stupid.The G-mount lacks an aperture ring on the lens itself, and requires basically the "NEW Nikons" with command dials in order to work well in more than two exposure modes. While I detest the G-mount because it breaks backward compatibility with the entire Nikon line, and because I LIKE to have an aperture RING control on every lens the G-series protocol might make it easier and lower-cost to produce than a lens with a traditional,mechanical,click-stopped aperture ring. BUT, and this is the big deal-breaker, G-series lenses are anathema to mechanical camera purists--G-series lenses are useless on the F-F2-FM-FM-2-FM3a cameras that appeal to MANY of the types of people who might want a Zeiss lens for their Nee-cone camera. No, a G-series lens gives up the all-important FULL-system comptibility that might assure Zeiss a second and third production run of these lenses.If Zeiss issues a G-series lens without absolutely killer AF performance and some simply excellent optics, these lenses will be very short lived.
If a company wishes to market a line of expensive, high-prestiege lenses for Nikon F-mount, if the lenses are manually focusing models, they had better have CPU's installed in them if Zeiss wishes to sell many of them. If the ZF lenses are autofocusing, they surely ought NOT to be G-series lenses; having the aperture ring on an AF lens is actually a key factor in that lens's overall,total usefulness as an F-mount optic,and a key ingredient in that lens's usefulness with the widest-possible range of F-mount bodies. A scrimped-on marketing department wrong choice in the ZF line could spell early exit from the F-mount market.
If they have done their homework, the folks at Zeiss will introduce a line of Zeiss ZF lenses which will work,as I said above, on the widest-possible range of F-mount bodies. Meaning a two-row aperture readout, with the smaller row of ADR f/stop numbers for the persiscope-reading 1970's-80's models, the Ai-S speed notch just for the heck of it (Nikon FA Owners Anonymous,anybody?) and the AI coupling ridge for every other AI-body, and a CPU in the lens to communicate with the "NEW Nikons", and screwdriver AF focusing. AF-S focusing probably would be the wrong choice I think,for maximum compatibility with the widest-possible range of F-mount bodies. It would be a nice thing to incorporate a half-decent A/M switch,like that found of the 80-400VR,for example. The 80-400VR's A/M switch was unique when it was introduced,and it's the lesser of all evils when one has to have an A/M selector switch within the relm of current House-of-Nikon designs. The forward-and-backward, sliding focusing ring implementation of Tokina and Tamron,for example, would be better than the shit designs Nikon has given its stamp of approval to in A/M switch designs. As I said, the 80-400 Nikkor's A/M switch, with LOCKABLE A and M settings, with two soft detents inside for A and M positions is a half-decent design, yet still in the so-19th Century engineering department. Tokina's push-pull sliding focusing clutch system has been imperfect in its shift point in two Tokina's I've owned,yet it was STILL a superior system to any A/M switch Nikon has ever done on a screwdriver focusing lens.The Tamron 90mm AF-SP Macro uses a similar system, with a push-pull design for shifting from Auto to Manual focusing, while maintaining the old-fashioned screwdriver focusing system that ALL Nikon AF bodies can use. Only the best of Nikon bodies can utilize AF-S focusing, and the original Nikon autofocus system AKA screwdriver focusing, is the most universal standard for Nikon autofocusing bodies.Screwdriver AF lenses from Zeiss would work quite well as manual focusing lenses on an FM-2 or an FM3a or an F3 or any of a zillion other Nikon bodies,and would not add the complexity and cost of an AF-S focusing motor,so my feeling is that IF,and it's a big IF, Zeiss makes a ZF AF line or model(s) of lenses that the regular,plain vanilla screwdriver AF will be the protocol they use. If they have a collective brain, they will use all the appropriate buzzwords in this age of vanity and shallowness. ED-glass, Aspherical,their old T* (pronounced T-star) moniker whenever possible,as well as some of the old and venerable Zeiss designs like the venerable Tessar,the wide-angle Biogons,the various Planar,Makro-Planar,Distagon,etc,etc. The NAMES of the old-line lenses from Leica and Zeiss are part of the lore,part of the allure,part of the pretentiousness,part of the clubbiness that makes expensive,luxury designed lenses so,so different from merely numerically named lenses from Japan; when you have a Planar lens design, well, you know it's a pretty good formula,but it also has a cool "name". (A name is important--look at the Lamborghini Countach;without such a cool name,would it have been in production for almost two decades? I think not.) I just do NOT expect a series of AF lenses designed to fit Nikon F-mount from Zeiss. I expect manual focusing lenses from the ZF series. If we're really lucky, the new Zeiss ZF lenses will be P-series manual focusing lenses,sort of like the Nikkor 45-P, but made better and costing more, but with that oh-so-handy little CPU in there. The P-series designation would allow D70 users and Fuji S2 and Fuji S3 users,as well as Nikon D100 users and D50 users to get good light metering with manual focusing lenses, and would also keep happy all the manual focusing purists who cling to their FM2's and FM3a's and such. And,to top it all of, why not include the "buckhorns",so that the owners of pre-AI Nikons can happily mount, rack to full-aperture, and later dismount at f/5.6 with their old Photomic heads and aging Nikomats and Nikkormats!
Bottom line, I don't see much widespread sales success coming from a Zeiss ZF line of manually focusing lenses introduced in 2006-2007, but I full expect the ZF lenses to be manually focusing, AiS lenses and not much more. I think the age of manual focusing cameras is mostly gone,and so manual focus lenses are no longer seen as desirable except among a small group of shooters whose numbers diminish every year. Still, the ratio of Nikon shootersto M-mount rangefinder camera users is probably at least 500 to 1,and probably more along the lines of 5,000 to 1.The sheer number of Nikon users world-wide is surely much,much larger than the number of M-mount users and if Zeiss can fairly easily enter the F-mount lens market by making a few small changes to its current ZM series of lenses, I can see that they might figure there's at least some opportunity there to establish some business, even if it's at the 600-800 US Dollar range,per lens.
Well,so much for my ramblings on the Zeiss ZF line of lenses for Nikon F-mount. Let's hope Zeiss can offer something really nice,really top-rate, which Nikon's not curently making. And with a CPU built into each lens!
I think short and medium telephoto lenses,as well as longer,wider-aperture manual focusing lenses work the best on crop-field D-SLR bodies,and are among the very easiest lenses to focus by hand and eye. With today's modern D-SLR's lacking both split image rangefinders and microprism doughnuts, todasy's manual focusing aids are the groundglass and the small green LED focus confirmation dot. Using the hand and eye and the focus confirmation dot, I think that lenses from 85 to 200mm and longer are reasonably easy to focus by hand and eye. I think that MAYBE Zeiss lenses will offer some type of optional focusing tabs,since improving the "hand" portion of hand and eye focusing could actually be of real benefit to some people. Frankly, I think the LED focus confirmation system is one are where a much more sophisticated display readout from Nikon would help people if it were actually researched,designed, and then put into cameras. I envision a system similar inh principle to todays, but larger and easier to see.An LED readout of focus distance would be nice, as well as some type of system which could show your focusing ring's needed travel amount,and direction, by means of a constantly updated bar graph display. Instant rangefinder readout in meters and feet from 1 to 100 feet, and a "progress bar" showing the focus ring's Travel Direction with BIG, and easy to SEE arrows! Not this dinky little crappy thing we have now,but something larger. Show the travel direction needed for ring focusing with arrow-shaped LED's, and show the target distance as a Green X, and the show under-run and over-travel on the focusing ring with a rapidly-response,rapidly updated yellow progress bar that runs right underneath the GREEN target distance. When the focus ring turning progress bar gets to the Green X or target distance, it would go to Green as well, and once the progress bar went past the target distance, the progress bar LED's would switch to Red arrows pointing the opposite direction,indicating back-focus conditionand showing you which direction to turn the focusing ring.ANd, in my Dream World, this system would compensate for the bass-ackwards focusing ring direction of third-partty lenses like Sigmas and Tamrons,which focus the wrong direction.With CPU-equipped lenses, designers could tailor a more-sophisticated,graphically-aided LED design that would make hand-and-eye focusing more like a video game,with a logical,simple system which I think would really HELP people by providing better mechanical engineering and better overall,total camera design. Focusing AIDS like a split image+microprism ring really help old-timers like me who know how to use a split image screen. And one focusing aid is sheer focal length--so c'mon Zeiss, bring us an 85mm lens. And a 110mm macro.And wait maybe 15 years for Nikon to implement a better MF aid system.