Hello. Nice tutorial. From the auction pages I have seen, I must remark that the fogging you have is quite a common problem, on the 100mm Macro Pentax lens. I don't have this lens, but quite a few others from Pentax from this era. As I have the "bad" habit of buying cheapo lenses with problems, in "as is" condition, haze is an issue I encountered many times. I highly doubt that fungus would insert itself between cemented elements. However, fungus comes with moisture. Apparently, it is the moisture that infiltrates, and degrades the cement used to make doublets. And many times, non-cleanable haze is within doublets, while occasional dirt elsewhere can be cleaned, without difficulty. Only a highly skilled tech would have the know-how and tooling to separate a damaged doublet and re-glue it properly. So, now, I would avoid shopping for hazy Pentax lenses, when I now there is a doublet somewhere in the optical formula. Cheers.
I have only run across fogy doublets, I think twice, which I guess is pretty good given how common they are. Most of the time I try to clean lenses that have had fungus on them so long it has etched the glass or the coatings. Either way the lens is crap. I would have thrown this one in the trash but the rest is in such nice condition. I tell myself I can use it for parts.
You can separate and re-cement doublets, and in fact any cemented group .You need the appropriate solvent, which is a controlled chemical, and very evaporative. The element group is then sat in this for about 24 hours ( use a sealed metal container), and when they separate, they are cleaned, and dried. Then a spot of modern uv cured optical cement in the centre (Edmund Optical, Norland Optical Adhesive-keep in the fridge-lasts longer!), carefully align the elements ( no more than two at once) and put under a nail-varnish UV light ( ebay, less than £10) on a level surface. Should take about 3 minutes max. Of course, until you separate the elements you have no way of knowing if the haze is in the cement or the glass-if the latter ( as in some samples of the Pentax 100mm bellows lens rear elements where the glass deteriorates). You just need to take care at all stages, and be very clean in how you do this. But I have done it a number of times successfully over the years.
Hi, thanks for sharing. Can you help me with some answers? I have this lens but the ring of focus is stucked - I think it's due to lack of lubrication. What can i do to clean and lubrificate that specific lens?
I also have one with fogging. If I understood Ravajaxa the fogging can't be dealt with. That would be a shame because the lens is in good condition otherwise.
I was able to separate the layers, clean and reglue the two pieces, I made a video of that also , here is the link ruclips.net/video/i8T6xE0lieU/видео.html , I only did it that one time but if you want to try, this is a place to start.
@@mrrcassidy I have not. i have a dozen projects at any given moment so nothing get done in a timely fashion. I hope to this spring, being the fair weather photographer that I am.
Hello. Nice tutorial.
From the auction pages I have seen, I must remark that the fogging you have is quite a common problem, on the 100mm Macro Pentax lens. I don't have this lens, but quite a few others from Pentax from this era. As I have the "bad" habit of buying cheapo lenses with problems, in "as is" condition, haze is an issue I encountered many times. I highly doubt that fungus would insert itself between cemented elements. However, fungus comes with moisture. Apparently, it is the moisture that infiltrates, and degrades the cement used to make doublets. And many times, non-cleanable haze is within doublets, while occasional dirt elsewhere can be cleaned, without difficulty. Only a highly skilled tech would have the know-how and tooling to separate a damaged doublet and re-glue it properly. So, now, I would avoid shopping for hazy Pentax lenses, when I now there is a doublet somewhere in the optical formula.
Cheers.
I have only run across fogy doublets, I think twice, which I guess is pretty good given how common they are. Most of the time I try to clean lenses that have had fungus on them so long it has etched the glass or the coatings. Either way the lens is crap. I would have thrown this one in the trash but the rest is in such nice condition. I tell myself I can use it for parts.
You can separate and re-cement doublets, and in fact any cemented group .You need the appropriate solvent, which is a controlled chemical, and very evaporative. The element group is then sat in this for about 24 hours ( use a sealed metal container), and when they separate, they are cleaned, and dried. Then a spot of modern uv cured optical cement in the centre (Edmund Optical, Norland Optical Adhesive-keep in the fridge-lasts longer!), carefully align the elements ( no more than two at once) and put under a nail-varnish UV light ( ebay, less than £10) on a level surface. Should take about 3 minutes max. Of course, until you separate the elements you have no way of knowing if the haze is in the cement or the glass-if the latter ( as in some samples of the Pentax 100mm bellows lens rear elements where the glass deteriorates). You just need to take care at all stages, and be very clean in how you do this. But I have done it a number of times successfully over the years.
Hi, thanks for sharing.
Can you help me with some answers?
I have this lens but the ring of focus is stucked - I think it's due to lack of lubrication. What can i do to clean and lubrificate that specific lens?
I also have one with fogging. If I understood Ravajaxa the fogging can't be dealt with. That would be a shame because the lens is in good condition otherwise.
I have had mixed luck with fog, it depends on what has caused it, and you dont know until its in your hand.
Came here to see how to dismantle mine to clean away the fungus. Mine is fogged/fungused in exactly the same place between the two bonded lenses.
I was able to separate the layers, clean and reglue the two pieces, I made a video of that also
, here is the link ruclips.net/video/i8T6xE0lieU/видео.html , I only did it that one time but if you want to try, this is a place to start.
@@tobroken1965 Didn't think that was even possible with bonded glass. Well done. Did you ever get to shoot with the reassembled lens?
@@mrrcassidy I have not. i have a dozen projects at any given moment so nothing get done in a timely fashion. I hope to this spring, being the fair weather photographer that I am.
Thank you most helpful