jacques_lamella Posted May 27, 2014 Share Posted May 27, 2014 <p>Hi All,<br /> <br /> So, turns out that the Sekor-c 50mm f/4.5 lens that came with the RB67 I just bought on yahoo auctions has some fungus in the rear element (see attached image). <br /> <br /> My first question, then, is whether or not it's even worth trying to clean it. Will it affect image quality? And even if it does, is it possible to remove it completely (I hear fungus can leave etching on the glass)?<br /> <br /> If it's worthwhile to clean, my next question is how do I remove and take apart the rear lens element?<br /> <br /> As far as I can tell from watching <a href=" video, it's not that hard to just remove. However, he doesn't actually take it apart after removing it, so I'm not sure how easy it is to do that particular task.<br /> <br /> Are there any repair wizards out there who happen to know how to take apart the rear element to clean the lenses? Anyone happen to have a service manual for this lens?<br /> <br /> Any help would be greatly appreciated.</p><div></div> Link to comment Share on other sites More sharing options...
joseph_dickerson Posted May 27, 2014 Share Posted May 27, 2014 <p>That looks like some pretty serious fungus. I'd send the lens to Mamiya, or an authorized repair facility for an estimate if possible. <br> I would also be contacting the seller re: a return or at least partial refund, unless the fungus was disclosed at the outset.<br> It will affect image quality and will only get worse. In fact, it may have already etched the glass beyond any chance of a mere cleaning.<br> A used lens from KEH and keeping your current one as a parts donor is another option.<br> JD</p> Link to comment Share on other sites More sharing options...
jacques_lamella Posted May 27, 2014 Author Share Posted May 27, 2014 <p>Hello Joseph, <br> Thanks for your response. In truth, the seller did mention there was fungus on the lens, however they also said that it would not affect image quality. So I wasn't expecting it to be covering such a large area (about a third of the rear element). Not sure if I have any recourse, but I did get the whole system for about 85 dollars, so I can't really complain too much. <br> I'm going to develop a roll of film and see how it looks. If it seems like there's a significant IQ loss then I guess I'll just bring it to Mamiya (I live in Japan and I'm actually quite close to their main service centre). Though I'm still thinking that if they say they will charge more than 100 dollars or so just to repair the lens, and there's a chance there will be permanent etching even after repairs, I might as well try fiddling with it myself ... if I can find out how to get at the rear element lens pieces. <br> Thanks again!</p> Link to comment Share on other sites More sharing options...
ondebanks Posted May 28, 2014 Share Posted May 28, 2014 <p>In leaf-shutter lenses like this, the most likely place for fungus to develop is on a glass surface facing the shutter & aperture unit - i.e. the back of the front lens cell or the front of the rear lens cell. These surfaces are well hidden but nevertheless exposed to air which can circulate in from outside the lens, carrying fungus spores and humidity.</p> <p>This is "good" (if lens fungus can ever be considered good!) because getting access to those lens surfaces is normally an easy DIY job - you just need a spanner wrench to unscrew the whole front or rear cell from the shutter threads. I've checked and cleaned several MF and LF lenses in this way. In only one case (a 50 year old Mamiya Press 90/3.5 lens covered in fungus) did I find that the fungus had etched the coatings on a surface.</p> <p>Of course, the outermost front and back surfaces of the lens are also vulnerable, but they are usually routinely cleaned by the owner. Other lens surfaces should be sealed within the lens cell, so they are much less likely to develop fungus. But if one does need to get access to them, opening up a lens cell can sometimes be rather difficult and one needs to pay close attention to the orientation, spacing and rotation of the elements in order to put it back together correctly. </p> <p> </p> Link to comment Share on other sites More sharing options...
joseph_dickerson Posted May 28, 2014 Share Posted May 28, 2014 <p>Darcy, <br> As the fungus was disclosed, albeit not very accurately, I guess you're stuck. Although for what you paid it's not a big problem.<br> I'm sure that Mamiya can give you an estimate before they start, but you might be able to do it yourself.<br> I think that Ray is probably correct, in that the fungus is not between elements but on the inner surface of the rear group. Shouldn't be too big a problem to get at it. Take lots of photos on the way in, and buy a good spanner wrench.<br> Good luck with it, let us know how it comes out.<br> JD</p> Link to comment Share on other sites More sharing options...
paul ron Posted May 28, 2014 Share Posted May 28, 2014 Take the rear cell out n clean it with denatured alchol. It wont get rid of it but will clean some of the dust in there. Keep an eye on keh for an ugly lens, or put out a WTB for a parts lens. Perhaps that fungus wont effect your pix but may contribute to flare under certain conditions. The more you say, the less people listen. Link to comment Share on other sites More sharing options...
jacques_lamella Posted May 28, 2014 Author Share Posted May 28, 2014 <p>Thank you everyone for your helpful advice. </p> <p>Yesterday I took the lens in to Mamiya's service centre in Tokyo and they were quite helpful. A technician sat down with me to test out all the lens functions (shutter speed, flash sync, etc.) and told me everything was in good working order. Then, he removed the rear element, and, unfortunately, determined that the fungus was <em>between</em> the lenses in the element. It would need to be sent out for disassembly and cleaning and that would cost around 160 dollars. Even he told me it probably wasn't worth it. He did however clean out the inside surface of the lens before reassembling it. </p> <p>I asked if I could just replace the rear element entirely with one from another lens if I found one for cheap, and he said that I could, but that there were spacer rings inside that were all slightly different for each lens, and that if I put in a different element the focusing would be slightly off. Does this make sense? </p> <p>He also told me that even though the fungus looks pretty bad, it won't affect image quality ... at least for the time being. I still haven't developed a roll so I'll have to wait and see if that's the case. I will post a follow-up when I do.</p> <p>Thanks again! </p> Link to comment Share on other sites More sharing options...
q.g._de_bakker Posted May 29, 2014 Share Posted May 29, 2014 If the fungus does indeed not have a noticeable impact on image quality, you could try to stop further growth of the fungus using an UV light to kill it.<br><br>It does indeed make sense that you cannot swap a lens group without having to callibrate and readjust the lens. There always are manufacturing tolerances, slight differences that have to worked around. Any required shimming may differ from one lens to another. The lens group should be centered properly too, making sure both that the group isn't put in skewed and that optical axis of the group and the rest of the lens are in line.<br><br>The price quoted doesn't sound too bad, considering that you then have a lens that should be good for many years. If this one turns out to be not usable as it is, it's a total write off and you'll have to spend money to get another one. That 'new' one also may need spending some money on it. So spending 160 dollars now may be the cheapest option. Link to comment Share on other sites More sharing options...
jacques_lamella Posted May 29, 2014 Author Share Posted May 29, 2014 <p>Q.G., I hadn't actually considered paying for the repair, but you make a good point. The 50mm is one of the most expensive lenses produced for the RB67. Buying another one in good condition would be almost twice the price of repairing the one I have. Anyway, something to consider for sure. I'm concerned however that even after a cleaning there will be some etching in the glass caused by the fungus. It would be very disappointing to pay 160 dollars and be left at the same point as I started in terms of image quality because the glass was permanently etched (assuming they don't just replace the lens entirely at that point; the price I was quoted was simply for repairs to older model lenses involving disassembly). I'm getting a test roll developed now so I'll post an update when I get the prints.</p> Link to comment Share on other sites More sharing options...
paul ron Posted May 29, 2014 Share Posted May 29, 2014 For $160 go buy 2 dead 50mm lenes! Yes there are shims but the difference is so slight, you'd need a machine to detect it. The more you say, the less people listen. Link to comment Share on other sites More sharing options...
q.g._de_bakker Posted May 30, 2014 Share Posted May 30, 2014 The difference is that slight that people were happy paying much, much more for those lenses, properly adjusted, than they would for lenses that were made going by the rule that "the difference is too sligh to bother, so let's not bother". Mamiya and their customers did not think it made no sense to put in shims to properly adjust these lenses.<br>You haven't paid the multi-K dollars price these lenses went for, just a tiny fraction of it, Darcy. Does that mean that you shouldn't expect to get the high quality Mamiya was known for from your Mamiya? Link to comment Share on other sites More sharing options...
paul ron Posted May 30, 2014 Share Posted May 30, 2014 Mamyia will only clean n adjust that lens and not replace the rear cell for $160! Your lens will still have the same fungus damage. The rear cell new if mamiya even has one in stock will cost you at least $200 or more just for the part plus $160 for the cla. So go buy another defunct lens n swap the cell. Shims n no shims makes no difference to the naked eye... Only has an impact on OCD photographers with fat wallets who bought the meatloaf n think they got the steak. Are you shooting professionaly or just joy riding? If the fungus doesnt effect your images.... Have fun just be mind full it may cause flare in certain light conditions. Buy extra film with the money you saved. . The more you say, the less people listen. Link to comment Share on other sites More sharing options...
q.g._de_bakker Posted May 30, 2014 Share Posted May 30, 2014 <i>"Mamyia will only clean n adjust that lens"</i><br>... so you end up with a clean and well adjusted lens. Link to comment Share on other sites More sharing options...
donbright Posted May 31, 2014 Share Posted May 31, 2014 <p>Just went through this with a Nikkor 55mm Micro. $60 to roll the dice as to whether or not etching became an issue. I lucked out, no etching! Thing is with these issues; How much future do we see in a piece of equipment? In the case of lenses, there are those that beg to be reborn in a CLA. So now I have my 55 Micro back, clean elements, smooth focusing collar, and the knowing light is being projected on the film plane the way it was intended. Not bad for a lens I've had for 30 years!</p> Link to comment Share on other sites More sharing options...
paul ron Posted May 31, 2014 Share Posted May 31, 2014 Q.G. de Bakker HeroFrequent poster, May 30, 2014; 07:25 p.m. "Mamyia will only clean n adjust that lens" ... so you end up with a clean and well adjusted lens. Hahahaha now I've heard it all! Did you read my entire reply? Please be my customer QG? I'd love to charge you $160 to CLA your lens n return it full of fungus.... But the icing on the cake is how pleased you are about being ripped off! After your responce, just for you QG..... I'd charge you double! In my 45 years of professionally repairing cameras this one proves the old saying there's a sucker born every minute! Priceless! You can't make this up! The more you say, the less people listen. Link to comment Share on other sites More sharing options...
q.g._de_bakker Posted June 1, 2014 Share Posted June 1, 2014 paul, so you are the type of repair person waiting for suckers to come along, promising to clean a lens and leave it full of fungus, and then charge double to boot. A repair person not caring about lenses being properly adjusted, because a bodge job is so much easier, not requiring expensive equipment, and all that. Doing that for 45 years already.... "professionally", once again a demonstration that this word only means "taking money for something".<br>paul, i read it all. Do you understand what you write? Good marketing strategy to tell us all! Darcy will now have no doubt who not to send the lens to.<br>:-)<br><br>paul, when you run out of arguments to support a bad proposition, it doesn't help to behave the way you do. Link to comment Share on other sites More sharing options...
paul ron Posted June 1, 2014 Share Posted June 1, 2014 Hahahaha yeah i see reading comprehension is your problem once again. Tff! You can't make this stuff up! The more you say, the less people listen. Link to comment Share on other sites More sharing options...
jacques_lamella Posted June 5, 2014 Author Share Posted June 5, 2014 <p>Hi everyone, </p> <p>So, I got my test roll back today, and to my relatively untrained eye it doesn't seem that the fungus is affecting the photos. There is some lack of sharpness which I wasn't expecting, and some vignetting, and distortion around the edges, but I'm not sure if that's the fugus' fault. What do you think? </p><div></div> Link to comment Share on other sites More sharing options...
jacques_lamella Posted June 5, 2014 Author Share Posted June 5, 2014 <p>And another ... </p><div></div> Link to comment Share on other sites More sharing options...
paul ron Posted June 5, 2014 Share Posted June 5, 2014 You're all set! Nice n sharp no ill effects. But just be aware you may get flare in certain lighting situations. Enjoy! The more you say, the less people listen. Link to comment Share on other sites More sharing options...
q.g._de_bakker Posted June 5, 2014 Share Posted June 5, 2014 I think it's worth it getting the fungus out of the lens (it will get worse, of course). For $ 160 a clean and well adjusted lens, on top of what you paid, still a bargain. Link to comment Share on other sites More sharing options...
mark_hubbard Posted July 5, 2014 Share Posted July 5, 2014 <p>QB:<br> You wrote, "If the fungus does indeed not have a noticeable impact on image quality, you could try to stop further growth of the fungus using a UV light to kill it." Just to clarify, this may work on the outside of the front and back elements, but it won't work on internal fungus, as the glass will effectively block almost all of the UV radiation. I own long-wave and short-wave UV lights for examining fluorescent minerals, including an $800 SW UV light. Even this big light doesn't penetrate glass, but after reading your post, I may try it on fungus to see if it helps. The inexpensive "black lights" you can buy at novelty stores are weak long-wave UV only, and are useful mainly for entertainment purposes, not sterilizing. I encourage anyone who is interested in learning more about the science and enjoyment of using UV lights to consider joining the Fluorescent Mineral Society.<br> With kind regards,<br> Mark H.</p> Link to comment Share on other sites More sharing options...
jacques_lamella Posted July 14, 2014 Author Share Posted July 14, 2014 <p>Thanks for the info, Mark. I guess that means UV filters are pretty much useless in that respect? Or do they manage to block certain wavelengths of UV that DO make it through the glass? <br> In any case, I've been shooting with the fungus-infected lens and, despite the large amount of visible fungus in the rear element (as you can see in the picture I uploaded), the image quality appears to be just fine. Here's an example if you're interested: https://www.flickr.com/gp/123858405@N08/32942P<br> Initially I was planning on getting the lens repaired, so I went back to Mamiya's service centre in Tokyo. However, it turns out the cost for repair (since the 50mm is quite a complicated lens with a floating element) would be about 260 dollars. I could probably find a good replacement on KEH for the same price, roughly. And besides I'm happy with the lens as it is at the moment. <br> Thanks!</p> Link to comment Share on other sites More sharing options...
mark_hubbard Posted July 25, 2014 Share Posted July 25, 2014 <p>Jacques,<br> Thank you for your response and especially for posting the link to your beautiful night photo of Hong Kong, which is sharp and clear across the frame. I would enjoy seeing other images you've made with this lens, especially any in bright sunlight. You mention that the Mamiya repair center told you the lens has a floating element which, if I understand correctly, might make it the "ULD" version. Is that the case? Currently the 50mm ULD fetches two to three times the price of the non-ULD versions on the used market. I'm wondering if the premium for the ULD floating element is worth it. <br> The use of UV filters has always been controversial among photographers. They do block UV light, as does window glass. Some people use them on all their lenses; I don't own any. If I'm going to photograph someone at the beach along our foggy and windy far-northern California coast and want to protect my lenses from salt spray, I prefer to use a warming filter. When it comes to whether or not to use UV filters at all, I politely refuse to argue the point.<br> This discussion has been useful to me, because I've had my eye on a couple of lenses for my RZ that are steeply discounted due to internal fungus or mild hazing, and I want to learn all I can about how these defects impact image quality, if at all. Any additional examples you can offer taken with your lens would be greatly appreciated.<br> With kind regards,<br> Mark H.</p> Link to comment Share on other sites More sharing options...
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