My guess is that it will perform similarly to the Tamron SP 24-48/3.5-3.8 (which is pretty godd, minus the distortion). If you find out anything about the lens design you could compare them:
pdmphoto wrote:
My guess is that it will perform similarly to the Tamron SP 24-48/3.5-3.8 (which is pretty godd, minus the distortion). If you find out anything about the lens design you could compare them:
While the Tamron is a 10 elements in 9 groups design, the Zuiko is 11 in 8 and the diagrams look significantly different.
A quote from the patent description:
"As is understood from the foregoing descriptions and embodiments illustrated above, the present invention provides a very compact wide-angle zoom lens system wherein aberrations are favorably corrected in spite of a wide field angle of 84 [degrees] at its wide position, and the embodiments 1 and 2 [both 24-40mm f4 designs] are epoch-making compact wide-angle zoom lens systems which are usable with filters having a small diameter about 55mm."
hubsand wrote:
Nikon, Pentax and Minolta all had 24-50mm f4 designs: the compact Minolta in particular seems similar in spirit to the Zuiko.
None of the Pentax designs look anything like this Zuiko, but I was unable to find diagrams for the Nikkor(s) and Rokkor(s).
Another note of interest; This zoom is not an "S" Zuiko.
As I have read in various places "S Zuiko Zoom lenses are lenses targeted at the consumer market for economy prices. These include the 28-48mm/F4, 35-70mm/F3.5~4.5, 35-70mm/F3.5~4.8, 35-70mm/F4, 70-210mm/F4.5~5.6 and 100-200mm/F5."
Zooms not targeted to the economy consumer market:
- Zuiko AUTO Zoom 35-70mm f/3.6
- Zuiko AF AUTO Zoom 35-70mm f/4
- Zuiko AUTO Zoom 35-80mm f/2.8 ED (of course)
- Zuiko AUTO Zoom 35-105mm f/3.5 ~ f/4.5
- Zuiko AUTO zoom 50-250mm f/5.0
- Zuiko AUTO zoom 65-200mm f/4.0
- Zuiko AUTO Zoom 75-150mm f/4.0
- Zuiko AUTO Zoom 85-250mm f/5.0
- and, now, Zuiko AUTO Zoom 24-40mm f/4 (granted, this one was targeted to a pretty tiny market )
You could try calling tech support and asking them about the lens. I would be curious if they would turn you away if you requested servicing of the lens.
Or at least called to discuss servicing of the lens as if it were a standard Zuiko lens. Maybe the techs have some sort of info on it that the marketing guys don't have for some reason.
ewadler wrote:
You could try calling tech support and asking them about the lens. I would be curious if they would turn you away if you requested servicing of the lens.
Or at least called to discuss servicing of the lens as if it were a standard Zuiko lens. Maybe the techs have some sort of info on it that the marketing guys don't have for some reason.
Well, I did get those e-mails from support at Oly Japan, so I'm not sure what else I can do.
At this point I'm not all that concerned because I am putting the pieces together myself. My next step is to contact Nakagawa directly (if he is still alive).
I've considered the possibility of having it serviced, but I don't think I could bring myself to drop it off at a local shop, much less ship it half-way across the world (back where it came from).
If I assess the condition and decide that it needs work, I'll make it my lifelong project to restore it perfectly myself. The filter ring dent is a no-brainer. I already know the aperture functions. If there is haze/dust whatever, I'll clean it out. Worst-case-scenario is that the cemented elements have started to separate, but considering that it is a relatively young Zuiko, I do not expect this to be the case.
Oh, I thought you were conversing with a salesperson, or public relations person. Yep, I wouldn't part with it for service either. Impressive how much you have been able to gather so far. Good luck, continuing. I have been watching this thread since it started, it is like a great story unfolding, I always wonder what new tidbit you will post next.
Man, I feel like some weird freak that sits in his basement obsessed with great novels about mythical camera lenses that save the world and so on. I actually do have a life, but this is still a curious thread.
ewadler wrote:
Oh, I thought you were conversing with a salesperson, or public relations person. Yep, I wouldn't part with it for service either. Impressive how much you have been able to gather so far. Good luck, continuing. I have been watching this thread since it started, it is like a great story unfolding, I always wonder what new tidbit you will post next.
Man, I feel like some weird freak that sits in his basement obsessed with great novels about mythical camera lenses that save the world and so on. I actually do have a life, but this is still a curious thread....Show more →
Does it make you feel any better that I spent 1/2 hour last evening colouring the optical formula diagram with various colours of my daughters pencil crayons?
Maybe I'll scan it so you can all see the formula and my wonderful colouring ability
Why would anyone forge a lens and then smash the filter ring and sell it on an auction site as "junk" ?
Why would anyone forge a patent and somehow get it into google patents?
Stranger things have happened, but it would take an extremely odd person to come up with a plan so elaborate and simultaneously stupid.
Oh, and don't worry; one of the first things I'll be doing is taking a photo of the lens and posting a RAW for you all. Sort of difficult to fake a RAW.
I don't know, the shading in of the optical formula diagram looks suspicious to me. I am pretty sure that Olympus never colored d1 olive green (They always use forest green), and the stray line just outside of d18 is not the "mark" of a professional patent.
Just kidding, I like the coloring job. Waiting for the pictures from the thing is like a good suspense movie. Dang it! There I go again. There is more to my life than this thread, I swear.
See page 9, first paragraph of "Summary of the Invention", where it specifies a wide-end angle of field of 84 degrees, which equals 24mm. Extrapolating from that, it is possible it interpret the data on the diagrams.
Figures 5, 6 and 7, for instance, show the 3 key aberrations of "embodiment 1" (figure 1). In figures 5, 6, and 7, you'll see that that the design is indeed an f4 zoom at all focal lengths, as is "embodiment 2" (look under "spherical aberration").
Now look at the "Distortion" graphs. The scale is AOV, measured from centre to corner, so this value needs to be doubled to get the true, diagonal AOV. Simply plug the values into your favourite AOV->focal length convertor and voila! you discover that both embodiments 1 and 2 are 24-40mm f4 zooms.
Besides that, notice the good performance of the lens in all areas except distortion on the wide end (looks to be about 2.5%-3%). It looked "OK" to me when first viewing it, and then I started looking at a whole bunch of other Zuiko patents and this lens seems pretty good overall.
Based on my preliminary analysis and measurements, I can confirm with nearly 100% certainty that this lens is a prototype based on the design in the patent discussed earlier. In the patent, it states a filter size of "about 55mm". This lens has a 55mm filter diameter, which is simply one more piece of supporting evidence on top of what I discussed earlier.
Lens name: Zuiko MC AUTO-ZOOM 1:4 f=24-40mm
Lens type: Two-touch wide-normal-zoom design
Focal length: 24-40mm
Max. aperture: f4
Lens construction: 11 elements in 8 groups, Multi-coated
Picture angle: 84 degrees (f=24mm) – 57.4 (f=40mm)
Diaphragm: 6 blades, automatic, full aperture metering
Aperture scale: f/4 – f/22
Distance scale : Graduated in meters and feet from 0.6m to infinity (oo)
Focusing: Rotating helicoid system, by turning the focusing ring
Zooming: Rotating control via separate zooming ring
Filter size : 55mm (screw in type)
Lens hood: unknown
Weight: 410g
Min. length: 66mm (at 40mm setting, infinity)
Max. length: 82mm (at 24mm setting, close focus)
Max. diameter : 65mm
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Notes on condition:
- Good overall cosmetics, with the exception of the filter ring dent, slight cracking of the zoom ring rubber and some other signs of light use and age.
- Aperture stops are crisp and the blades are clean, oil-free and snappy.
- Zoom ring is stiff(ish), but smooth. Not difficult to turn but certainly stays put.
- Focus ring is smooth and well-damped. Not to loose or too tight (typical Zuiko) but towards the tight side.
- Mount shows a bit of wear.
- Exposed front and rear element surfaces are clean, scratch-free and the coatings look in perfect condition.
- The inner 2 or 3 elements of the first group have significant haze (significant enough to reduce contast quite heavily in photos).
- The mid and rear groups look pretty clear.
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Overall I am very pleased. The filter ring dent can be easily fixed and I am pretty sure I can go in through the front and clean up the haze in the first few elements. I have done this sort of thing before.
Here are some photos I took of the lens this morning. I've taken a variety so you can all get an idea of the size of this lens.
Anyone who wants a RAW for proof that I didn't sit and waste dozens of hours faking these photos will need to e-mail me and I'll send a link to download the RAW. I share bandwidth with other people, so I am not about to post the link here to a 12MB RAW file. Hope you understand. Just e-mail me and I'll happily send the link. If I see bandwidth getting out of hand, I'll have to remove the RAW.
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