Again, I am amazed at the complete lack of CA. The resolution is not to shabby, either. You can see the effects of the haze in these shots. I can't wait to clean it out and try it more.
After the cleaning I suppose the next test will be examples of how it looks next to some primes in the same range. It looks pretty good now, I can't wait to see how well it performs after its checkup.
Paul
I don't think it was one of their high end lenses, because they have codes printed on the back that tell the factory and date of manufacture. The results look pretty good stopped down to f8-11, but I've found a lot of zooms that do well in that range. How are the result at f4?
PeaktoPeek wrote:
After the cleaning I suppose the next test will be examples of how it looks next to some primes in the same range. It looks pretty good now, I can't wait to see how well it performs after its checkup.
Paul
I plan to do just that. I know my Zuiko primes well enough by now to know that this lens performs very well.
I'm actually considering having it professionally serviced by the best.
adamM wrote:
I wonder if they didn't actively peruse manufacture of this lens due to cost? Or because it might cannibalize their prime offerings?
Such a tantalizing mystery.
I tend to think along these lines. It is obvious to me that this is a prototype (Oly Japan has no record that they ever produced this lens, much less in any significant volume). The possible reasons for not producing the lens in volume are many, and the reasons you mentioned here are two of the most likely reasons. I already know the reason not because it is a stinker lens.
Edited by cogitech on Mar 31, 2008 at 06:16 PM GMT
pdmphoto wrote:
I don't think it was one of their high end lenses, because they have codes printed on the back that tell the factory and date of manufacture. The results look pretty good stopped down to f8-11, but I've found a lot of zooms that do well in that range. How are the result at f4?
While some people may have many and varied reasons why they might not want this to be a high-end lens, the evidence speaks for itself.
I've already explained that the low-end Zuikos all have the "S-Zuiko" designation, which is a commonly known fact.
OM experts agree that the lens in question resembles the 35-70/3.6 the most. The 35-70 is one of the most desirable Zuiko zooms and is not an "S-Zuiko."
There is evidence of rare earth (radioactive) element(s) in this lens (very mild yellowing, see last photo of lens on page 2 of this thread and also the cast in the snow in the crops) which are (were) put into lenses to make them perform better, not worse. Just look at the optical diagram of the Zuiko 35-80/2.8 ED. All the pink is rare earth:
The "factory and date of manufacture" codes are missing, obviously, because it is a prototype. The only reason to mark codes would be for reference when lenses are returned for service. It would only be something they would mark on lenses that actually had production runs.
Finally, the initial impression (despite the haze and obvious calibration issues) is that it is a very good lens. I don't expect my Zuiko primes to be incredible wide open, so I don't expect the zoom to be. I tested at f8 and f11 because those are the settings that any wide Zuiko prime needs to be used at for great performance.
Regarding f4 performance, I can say (borrowing hubsands terms) that zones A and B are excellent to very good (as above), zone c is on the softer side, and then the extreme corners are a little "smeary". Sound familiar? It sounds a lot like my wide Zuiko primes. Still no CA in sight, which I cannot say for some of the Zuikos I own or have owned.
On another note, I've just been looking very carefully at light beams coming through the lens from the rear, which concentrates bright little circles of light onto the internal haze of the front few elements. Based on what I saw, I can conclude with 100% certainty that this lens is the one on the patent. By tilting the lens slightly or moving the light source, I could easily see the shape of the inner side of the first element. That element is shaped exactly like the one in the patent diagram(s). Furthermore, I can watch the placement of the lens groups while zooming and I can confirm that it works as described in the patent.
I have also been able to determine that it is the inside surface of the first element and the front face of the second element (at least) that has the haze issue. Seems like a simple fix, but I have been warned that I'm going to have a ball-bearing nightmare on my hands when I open it, if it is anything like the 35-70/3.6.
cogitech wrotebut I have been warned that I'm going to have a ball-bearing nightmare on my hands when I open it, if it is anything like the 35-70/3.6.
If you shake it, does it rattle? I don't know about the 35-70/3.6, but the 65-116 auto tube audibly warns of legion tiny balls ready to seek their freedom.
I'm perplexed how the bearings could be related to or have anything to do with the 2 front elements. I've removed the front elements of several lenses and it is very difficult to imagine bearings having any function in the front group. In the focus ring? Yes. In the zoom action? Yes. Between the first and second element? No.
There will be a bearing on a spring tensioned inside a drilled hole to provide the click-click of the aperture ring and if there are any other slide-switches that click as you operate them (e.g. auto-manual) then you'll likely find one there as well. Other than that I can't think of where they'd want to use one.
You might contact John Hermanson <[email protected]> for advice in how to open and repair this lens.
cogitech wrote:
On another note, I've just been looking very carefully at light beams coming through the lens from the rear, which concentrates bright little circles of light onto the internal haze of the front few elements. Based on what I saw, I can conclude with 100% certainty that this lens is the one on the patent. By tilting the lens slightly or moving the light source, I could easily see the shape of the inner side of the first element. That element is shaped exactly like the one in the patent diagram(s). Furthermore, I can watch the placement of the lens groups while zooming and I can confirm that it works as described in the patent.
I have also been able to determine that it is the inside surface of the first element and the front face of the second element (at least) that has the haze issue. Seems like a simple fix, but I have been warned that I'm going to have a ball-bearing nightmare on my hands when I open it, if it is anything like the 35-70/3.6....Show more →
foxbat wrote:
There will be a bearing on a spring tensioned inside a drilled hole to provide the click-click of the aperture ring and if there are any other slide-switches that click as you operate them (e.g. auto-manual) then you'll likely find one there as well. Other than that I can't think of where they'd want to use one.
I've been warned that this lens most resembles (of all the Zuiko zooms) the 35-70/3.6 in size, weight, zoom action (extending while zooming wider), etc. The 35-70/3.6 has two runs of 180 (or so) 1mm ball-bearings that have a habit of spilling out on unsuspecting "technicians." Apparently this aspect of the design is responsible for the excellent zoom and focus action of the 35-70/3.6. Everything about the 24-40/4 indicates that it is made to the same standard, so I take this warning seriously.
On the other hand, I doubt if removing the front element would result in spillage.
you2 wrote:
You might contact John Hermanson <[email protected]> for advice in how to open and repair this lens.
Thanks.
We've connected already through the OM mailing list. I do not intend to seek his advice for free. If I do not have the balls to open it myself and I decide to seek his help, I will send the lens to him and pay him accordingly. I am sure he would do 10 times better work than I, and I imagine he (or any OM expert) would truly love the opportunity to work on this lens.
I do, however, have a bit of a Gollum/Ring complex with the lens. "My precious!"
