chaojesse Posted May 31, 2012 Share #1 Posted May 31, 2012 Advertisement (gone after registration) Hi everyone, I've recently picked up a used M-Rokkor 28mm f2.8 that seems like in good physical condition. The seller showed some decent pictures of the lens, but when I received it the second element is covered in dust and some other stuff that I can't quite make out. I've taken apart and cleaned some Pentax A lenses and a couple of M42 Helios before, so I am considering going at the M-Rokkor. My only hold-back is, this is a much more expensive lens than the ones I've tried. Also, I don't really know any good way to check the focus on a rangefinder lens like you can on an SLR (where you simply look through the lens). In the past, I've always had to tweak the focus of the lens upon re-assembly. Does anyone know if this can be cleaned? Any idea would be much appreciated! Link to post Share on other sites More sharing options...
Advertisement Posted May 31, 2012 Posted May 31, 2012 Hi chaojesse, Take a look here Minolta M-Rokkor dusty second element?. I'm sure you'll find what you were looking for!
jamesk8752 Posted June 1, 2012 Share #2 Posted June 1, 2012 I don't think that your lens suffers only from internal dust. I've read that this lens is notorious for the "white spots" which develop in many copies with time. Looks like you've got this problem. I've also read that the cause is partial delamination of the inner elements, and that repair is difficult/expensive. Google this lens for more info. Regards, Jim Link to post Share on other sites More sharing options...
jaques Posted June 1, 2012 Share #3 Posted June 1, 2012 That looks quite bad- but if anyone can service it it is Kamera Service in Holland. The cost for repairing what they call 'spotting corrosion' is 75 Euro... Will Van Manen specialises in these repairs. send him an email. here is what he said about this lens and the problems it has: "These M-Rokkors 28mm are notorious for 2 problems: 1. ‘Spotting corrosion’ The so called white spots are small spots on the lens surface caused by condensation between the sealed lens parts. Condensation moisture plus aluminium corrosion from the lens tube is acid. So, this corrosion will damage (etch) the glass surface eventually. The spotting corrosion can be helped for 75 Euros (shipping and 10 Euros handling per order will be added on the invoice). The end result depends on the extent of the decay. Normally the white spots will disappear for 95% without effecting lens quality or coating. More important, the process will be stopped. 2. ‘Schneideritis’ This is caused by loose paint particles of the black anti-reflection paint which is used on the side of a particular lens part. Schneideritis is a cosmetic problem and has no effect on the quality of the pictures. The Schneideritis can be helped for 75 Euros. We can also 6-bit code this lens for use on the Leica M8/M9. That will be, including modification for 28mm frame lines (necessary when coded), 100 Euros. We need 2 to 3 weeks for the job. When we send back the equipment, we will enclose an international invoice (IBAN/BIC) in the parcel. You can pay us (preferably via bank transfer) after receiving it back." I will be sending my own copy of this lens to him soon for the full treatment... Only thing that slowed me from doing it was getting a Nice Elmarit 2.8.. I have heard his repairs are very good. Kamera-Service Link to post Share on other sites More sharing options...
lars_bergquist Posted June 2, 2012 Share #4 Posted June 2, 2012 Will van Manen is an excellent person to do business with, and very competent. I recommend him. The old man from the Brass Age Link to post Share on other sites More sharing options...
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