Hi C.H.Ling,
Your pictures are perfect for showing this type
of chromatic aberration. This is normal because this
isn´t a fluorite special glass and you cannot solve this
problem with coatting or making groups of elements.
I think that everybody has this problem, and Olympus gave
us a terribly heavy solution. Zuiko 180/2
Of course that other Zuiko lenses should have this
problems, even my CAMEDIA that takes a very high quality
zoom lens has this problem, due to the lack of ED glass.
Olympus with the new 35-140 f2-2,4 will be again in the
first line!!!
Finally I´m with you that you won´t reduce chromatic
aberration, stopping down. Never!!!
Dave
"C.H.Ling" wrote:
>
> Hi Richard,
>
> Okay! there is one possibility - you have got the latest version Zuiko
> 180/2.8 that has the problem corrected.
>
> I was not the first one to post the chromatic aberration of Zuiko 180/2.8.
> Before I brought my 180, I have already heard at least two mailing list
> member said that there were problem with their 180. If my memory serve one
> have mentioned that his 200/4 did not have this problem.
>
> Now David also posted this problem, but looking back to David's photos I
> found the problem seems a bit too much. I just search some of my slides,
> found two of my shots that I can identify the problem. I have check them
> with a Peak 10x 4 elements achromatic loupe (No. 1983), a Leica projector
> with Leica colorplan P2. Follow is the scan with my poor quality Nikon
> LS2000. Both shots are hand held, it may not reflect the true quality of the
> lenses.
>
> They are posted at:
>
> http://www.glink.net.hk/~olympus/180TEST.htm
>
> Cropped areas were scan with 2700dpi.
>
> Please note that we also have other lenses, problem will not only happen on
> the 180 if it was the problem of our slide projector, loupe or scanner. I
> have a slide shooting with 85-250, which also has some bright water
> reflections, it does not have the same problem like the 180.
>
> At last I want to amend two things:
>
> 1. I Just check with some other shots taken with my 180/2.8+1.4xA, where my
> wife wore white clothes under bright sun light, they were the tests shot
> used for checking of my new 1.4xA. There is no obvious color fringes. Where
> there is no over exposure of the clothes, so I expected the problem only
> appeared on over exposed white area.
>
> 2. I have not formally test the 180/2.8 at different apertures, since I
> found the problem with my shot at F5.6 so I expected it was not due to wide
> open. And then I made the assumption that "Stop down the lens does not seems
> to improve the situation."
>
> C.H.Ling
>
> -----Original Message-----
> From: Richard Schaetzl <Richard.Schaetzl@xxxxxxxxxxxxxxxxxxxx>
> To: olympus@xxxxxxxxxxxxxxx <olympus@xxxxxxxxxxxxxxx>
> Date: Sunday, September 03, 2000 1:02 AM
> Subject: Re: [OM] Zuiko 180 TEST !!!
>
> >Holla David,
> >
> > ................
> >I couldn't see coloured fringes in the images with the 90mm lens at
> >aprox. 30x enlargement. At aprox. 45x enlargement with the 60mm
> >lens... oh s##t, some coloured fringes are visible when looking very
> >close at the screen! Hmm, crosschecking with an b/w slide. Again
> >coloured fringes, on a b/w slide! So it must be the projecting lens.
> >End of test, the limiting factor seems not to be the 180mm lens.
> >
> >So if someone asks why do you use that crapy US$350 lens (new price in
> >1992), I'll answer: Because it's an excellent projecting lens used
> >within the specs it was designed for, there is no superior
> >alternative.
> >
> >Under that viewing condition, I was able to see chromatic aberration,
> >I would have other problems than coloured fringes, seeing the whole
> >picture would have been impossible at that distance.
> >
> >I had an 50mm projecting lens because I like the big picture. I sold
> >it because regardless how hard I tried I was not able to have an sharp
> >projection, corner to corner. Limiting factor was not the lens but the
> >slide not lying flat in the projector. I tried hard, tested all
> >available slide mounts, no avail.
> >Only solution was looking at the picture from a bigger distance or
> >using a lower enlargement, longer focal length.
> >My conclusion is 60mm is the shortest focal length one can use for
> >standard projection conditions. Those shorter lenses are made for rear
> >projection and moderate enlargement.
> >
> >C.H.Ling wrote:
> >
> >"Stop down the the lens does not seems to improve the situation."
> >
> >Conventional wisdom would indicates that the colour error of lenses is
> >less noticeable with smaller apertures (only to grow again if an
> >optimum aperture has passed).
> >
> >Did you check that nowhere else in the chain of reproduction has been
> >made an error?
> >
> >I don't care about the performance of my lenses as long as they are
> >not the limiting factor.
> >
> >Anyway it's not possible to cheat the laws of nature. Newton stated,
> >it's not possible to eliminate the wavelength (colour) depending
> >focusing error. One can only try to reduce it to an usable amount. If
> >one tries hard enough, one might reveil the chromatic error of every
> >lens.
> >
> >
> >Best regards
> >
> >Richard
> >
> >
> >*an cheap 10x loupe and an 50mm Zuiko.
> >
> >**No that aren't el cheapo plastic lenses, both are PC (perspective
> >corrections, shift) lenses with full metal lens barrel and multicoated
> >lens elements. Those lenses are AFAIK not made by Kodak but either by
> >Schneider or more probably by Docter Optic, both have identically
> >looking lenses with identical specifications for offer (save the
> >writing on the lens barrel). Docter Optic is now owned by Leica and
> >"surprise" two similar looking lenses are now available for Leica
> >projectors under the name PC Elmarit-P 60mm/2.8 and 90mm/2.8.
> >
> >
> >< This message was delivered via the Olympus Mailing List >
> >< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
> >< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
> >
> >
>
> < This message was delivered via the Olympus Mailing List >
> < For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
> < Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
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