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BTW, The other two lenses that came with the kit are fine.
Comment by ynnek posted on Repair manual for Pentax - A 645 Lens at 06/12/2018 - 17:46
Kim C wrote:
But looking at the 120 macro, It will be difficult to remove the groups. On the 35mm lens, it is usually relatively easy the remove the rear baffle and then unscrew the rear froup without dismantling the mount. In a similar way, It is usually easy to remove the trim at the front to remove the front group. But floating elements are a problem. Also there is very little room around the rear mount and no baffle so the whole mount might have to come off.
JAK & Kim thanks for the responses. And no JAK, I have never attempted to disassemble a lens. I am though a machinist, so I understand the complexity of the issue. But I look at it this way, If it works good. If not, then all I lost was a compromised lens.JAK wrote:
I'd be careful using fungus infected lenses. You wouldn't want the spores jumping ship to wreck another lens.
Someone on the USA forum has described how to deal with an A 50mm F1.7 lens here. I'd presume the process would be comparable for your 120. I gather the 120 has 9 elements in 7 groups (with floating elements.)
Maybe Kim may offer further guidance. At least it isn't an FA one. Are you used to dealing with lens disassembly? In any event good luck if you attempt it.
The A series lenses are very easy the clean. 2 problems. There are many types of fungus. It's not so much a problem of the spores jumping ship. They are all around us all the time. But they won't germinate unless they have the right conditions. It is more the type of fungus. A few of them produce acid as a by product of their growth. This acid attacks glass and etches it. If this has happened the lens is a write off. The cost of having the elements re polished is far more than the lens is worth. If it is a more normal fungus, Once clean you do need to kill anything left using alcohol or something else.I'd be careful using fungus infected lenses. You wouldn't want the spores jumping ship to wreck another lens.
Someone on the USA forum has described how to deal with an A 50mm F1.7 lens here. I'd presume the process would be comparable for your 120. I gather the 120 has 9 elements in 7 groups (with floating elements.)
Maybe Kim may offer further guidance. At least it isn't an FA one. Are you used to dealing with lens disassembly? In any event good luck if you attempt it.
But looking at the 120 macro, It will be difficult to remove the groups. On the 35mm lens, it is usually relatively easy the remove the rear baffle and then unscrew the rear froup without dismantling the mount. In a similar way, It is usually easy to remove the trim at the front to remove the front group. But floating elements are a problem. Also there is very little room around the rear mount and no baffle so the whole mount might have to come off.
Comment by ynnek posted on Repair manual for Pentax - A 645 Lens at 06/12/2018 - 17:45
Hello all. Not a whole lot to tell. I have currently own 4 Pentax cameras. Pentax 645 (mk1) - 2 - lensesinclude 200mm f4, 120mm f4 Macro, & 75mm f2.8. Also a K1000 w/ 50mm f2, & a Spotmatic with 50mm f1.4. I am a member of the facebook group "Pentaxians". I mostly shoot digital. Canon 70D, but I do dabble in film. My other cameras include mamiya C220, Mamiya RB67 Pro S, Graflex Speed Graphic, Rolleicord, Rolleiflex, Minolta Autocord, Yashica MAT 124 G. Kodak Retina iia, Zeiss Contaflex, Polaroid SX-70 Sonar, Canon AE-1 Progam, plus many many more.
Taken with my Pentax 645 in Mishawaka, Indiana, the negative was scanned using my Canon 70D & 100mm f2.8 USM Macro lens, Edited in Lightroom.
FirstUnitedMethodistChurch-MishawakaIN by Kenneth Martin, on Flickr
Taken with my Pentax 645 in Mishawaka, Indiana, the negative was scanned using my Canon 70D & 100mm f2.8 USM Macro lens, Edited in Lightroom.
FirstUnitedMethodistChurch-MishawakaIN by Kenneth Martin, on Flickr
Comment by ynnek posted on Hello From Memphis, TN at 06/12/2018 - 13:05
My apologies, the correct lens is a Pentax - A 645 120mm f4 Macro. I cannot send it back. It was bought with a kit. I am waiting to get my film back. I shot a roll with it to see how it affects the image. Thanks form all of the replies.
Comment by ynnek posted on Repair manual for Pentax - A 645 Lens at 06/12/2018 - 12:52
I acquired a Pentax - A 645 100mm f4 Macro has fungus. Does anyone here have a service manual or other resource about the disassembly of these lenses? Or should I wing it?
Comment by ynnek posted on Repair manual for Pentax - A 645 Lens at 05/12/2018 - 15:59
