Dissasembly and Repair of Minolta Maxxum AF 50mm f/1.7 and f/1.4 Lenses Photo Gallery by Pete Ganzel at pbase.com

Dissasembly and Repair of Minolta Maxxum AF 50mm f/1.7 and f/1.4 Lenses

1.7 and 1.4 50mm lenses as well as the 35 and 28mm f/2.8 have nearly identical construction and these photos can be used as a guide for all.

The Minolta AF 50mm "normal" lenses are classic double Gauss designs and are similar to their MD/MC counterparts optically.

Advances in manufacturing allowed simplified more or less "sealed" plastic lens cells.

Cover.jpg	Pg1 Parts.jpg	Pg2 Parts.jpg	Rear Trim Plate.jpg	Lens Mount.jpg
Rear Element Group.jpg	Crutch Tip.jpg	Front Ring.jpg	Front Trim Ring.jpg	2nd Ring.jpg
FrontElement Group.jpg	Snap Ring Tool.jpg	Snap Ring.jpg	Iris Removal.jpg	Iris.jpg
Bad Solder.jpg	Plastic Front Element Group.jpg	Plastic Rear Element Group.jpg	Minolta 50mm ROM.jpg	ApertureSpring2486.jpg
GroundSpring2891.jpg	Toothpick Spring 2905.jpg	cover 1.4	50-1.4 3.jpg	50-1.4 5.jpg
50-1.4 9r	50-1.4 10r	50-1.4 12r	14 rear cell 1066.jpg	14 rear cell 1067.jpg
Hood Assembly 1069.jpg	Front retainer 1065.jpg	14 Front group 1070.jpg	14 Oily Iris 1071.jpg	Ultrasonic0012.jpg
14 mark 1074.jpg	14 Helicoid 1081.jpg	gallery: Maxxum 50mm Front Cell Disassembly	Iris Assembly 2850.jpg	Moving Plate 2857.jpg
Iris Tool 2858.jpg	Iris on Tool 2860.jpg	Inserting Iris 2862.jpg	Minolta AF 50s.GIF	Stop Screw 3451.jpg
Stop Screw 3457.jpg	Stop Screw.jpg	Ring Actuator 0009.jpg	Front Cell Compare 05.jpg	Rear Cell Compare 0010.jpg

comment |

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Kari		24-Feb-2016 00:30
My niece knocked my camera on the ground and now the focus ring is stuck. With much anxiety, I started to disassemble the lens to see if I could fix it. I am at the point in your instructions where the snap ring tool comes into play. The iris is fine, but I am not sure if I need to take the iris assembly out to reach the right component. It's very hard to describe exactly what happened, but it seems that the fall jammed the components down to the very last panel in the lens assembly. There is a noticeable slant on the lens, one side being higher than the other by a centimeter or two. Is the iris assembly crossthreaded into the back panel? If so, I need to remove it and try to screw it in correctly. Any insight you can give is appreciated very much.

Per		25-Jun-2014 20:54
I tried this once before on my 50/1.4 but obviously didn't read your instructions closely enough at the time. Gave it another try today but ran into one slight problem: I couldn't get the rear lens group out. It sits in there with a normal clock-wise thread, right? well, I couldn't get it to move so I suppose they put something in the threads to keep it there from the factory. Question is, what kind of solvent should I try using if this is caused by Minolta putting laquer in the threads during their assembly?

Louie		28-Nov-2013 12:55
Thanks for your excellent instructions! I was able to clean the iris on my 50mm 1.7 yesterday, although it came apart on me while I was removing it. It's really painful to put it back together because that iris is so fragile!

Tom		28-Sep-2012 16:39
I have a 1.4 that does not focus to infinity, but comes close. All else is fine. I have read through the comments so I have an idea of what to try but feel I may not need to dissassemble the entire lens. What do you recommend? Thank You!

Linda		22-Sep-2012 02:59
used a rubber glove over a baby bottle cover to remove trim ring! Used a infant medicine dropper to hold aperture assembly together. It still fell apart many times. That was the hard part was getting it back in there without the blades getting messed up. Whew!

Linda McDonald		22-Sep-2012 02:56
Thank you so much! I am doing the victory dance. Still can't believe that it works. I had trouble with a 'free' ring, I think it was under the front trim ring? And I think I wasn't supposed to move it. I am so happy! Saved $$$

David		15-Aug-2012 13:40
Nice guide and thanks for sharing it. My attempt failed with the front trim ring removal as is just won't unscrew no matter how hard I try.

atilla		23-May-2012 13:44
I need help to dissammebly of rear cell.How can I find page 3 in service manual.

Tom		13-May-2012 23:13
Thanks so much for this guide. I was just going to toss my 1.7 and I thought "What have I go to lose by trying?" It took about 2 hours of careful work, but it was nice reward when it worked properly. You saved a nice lens from the bin.

badt		04-Apr-2012 20:26
Thanks a lot for this guide!! But I have a problem. I can't take the snap ring tool. I don't have the dentist tool but I've tried with a lot of things and it doesn't work. When I read others messages, it seems to be not so hard! Can someone tell my the "tool" I could use to take the snap ring? Thanks!

Guest		05-Mar-2012 02:30
Just wanted to say thanks! The aperture blades on my lens were oily and sticking, and this was a very well put together guide to take care of the problem. I bought my 50 F1.7 several years ago, and after doing this cleaning it's working even better than when I first got it. I will say that I was unable to get the snap ring out, and so I removed the cylinder per Reiner's modified method in the comments below. As a warning to others who try it this way - i had to take it apart again to get the focus right, you have to make sure that the focus is set to infinity when inserting the cylinder, otherwise it will be off. Thanks again!

Miroslaw		12-Jan-2012 16:17
Your instruction how to take apart Minolta 5omm f1.7 lens are very clear and a was able to do it without any problems . My lens have back focus problem . Can you please explain how can I correct it.

SoapDude		27-Sep-2011 23:24
So I found it under 'front cell dissassembly. Thanks again so much! I actually cut the rear cell apart using an exacto knife and it went back together perfectly. This guide is incredible!

SoapDude		26-Sep-2011 11:32
Hello, thanks so much for this! It was a big help in disassembling my later model AF 50mm f/1.7. I have a question about splitting the rear/front cells. My rear cell appears to have a defect or some dirt/oil inside.. Is there any way to split the rear cell to get at it? Thanks again!

Jimmy		18-May-2011 13:47
When fixing a 1.7, I got some dust on the non-coated side of the rear element. I've tried and tried to get the dust off but feel like I am getting more on. I've used a couple of different solutions to whipe it off without success. Do you have any tips or tricks that I could use to get this element clean again? Thanks,

kadir		13-Apr-2011 13:00
Hi there, Thanks for this guide, but I got a question. Do you think the 50/1.8 is similarly build up ? Because the service in Germany quoted me 300€ on the repair (there is some dirt under the first glass and the iris is oiled !

Tony		09-Dec-2010 19:36
Pete, I have a Sony 50 1.4 lens that worked fine for about a year. Now: My first shot or 2 with this lens will be severely over exposed and then subsequent images will be fine (continuous drive shooting). After I stop and then start another series of shots, the same thing occurs(first shot or 2 severely over exposed).This will happen with with all shooting modes including M. Of course, this is not a problem when shooting at 1.4, only when at 1.7 and higher. When moving the aperture arm, it appears to snap back quickly and I see nothing visibly wrong with the blades. There are no blobs of oil or dust inside the lens. I also tried the lens on another A700 and the same thing happened. Any ideas?

Alex		26-Nov-2010 09:48
Thanks Pete, but that six screws was almost unmovable! I discovered that another thing was wrong: when I mounted the center helicoid fot he first time, i did it when the outer helicoid/focus ring wasn't in the infinite position. I unmounted and mounted it again, dointg it right, and the infinite focus is working again. Best regards, Alex.

Pete Ganzel		24-Nov-2010 05:54
Hi Alex: There is a ring with six screws once you remove the hood asssembly. This ring clamps the outer helicoid to the focus ring. If the screws have loosened, the focus scale will be off and the lens may not focus it's full range on either side. It can be adjusted so that when you focus on something (conveniently at three feet) it should agree with the scale. To adjust, loosen all six screws (they do not have to be removed) and then turn the focus ring with the helicoid stationary until the scale agrees with the focused distance on the screen, Then tighten the screws. Hope this helps, Pete

Alex		23-Nov-2010 02:09
Good Night Pete! Your articles are excellent! I have a Maxxum 50mm f/1.7, and its focus ring was jammed; i used your article as referecen and i could dissasembly and fix it! But now i have anoter problem: I don't know why, the scale and the real focus distance are not woking together: when the focus ring is at infinite, the focus in about less than 10feet (3m), no matter if it is on auto or manual focus. Could help me? Best Regards. Alex.

Juan		13-Aug-2010 03:23
A couple tips for anyone having trouble taking off the front cone if you dont have a crutch rubber thing then take a 20oz Gatorade bottle and take the cap off and with the mouth of the bottle put a rubber glove over it and it will come off very easy Second tip if your having trouble with the innner lock ring use a thumb tack and with a needle nose plyer bend the tip of the thumb tack and it should pop right off and make sure you scratch off the three nail polish glue points on the lock ring and just wanted to say thank you to the author of this tutorial followed it to the T and it works great thank you again. P.S. for people scared of taking the task trust me it is pretty easy just have to have a little patience Good Luck guys

C. Scott		07-Apr-2010 12:39
Pete, Thanks for your website! What a treasure trove of data for us that are brave (or crazy) enough to "fix" our camera equipment. I have a question about part no. 2550-0020. It's the part with the integral lens hood. I picked up a 7000 with a 50 1.7 on it for $20 in a pawn shop. The glass is perfect as is the aperature, however the lens hood doesn't work properly. I took it off only discover that the flange is broken and that there was a plastic coated wire that was "jammed" inside the hood assembly. Is the wire supposed to be in there? And is part 2550-0020 a part that can be fixed? Many Thanks! Chris

CHui		22-Feb-2010 05:58
Thanks for the guide, I couldn't have done it without you. My Maxxum 7000i's 50mm f/1.7 is working great. With some patience I cleaned the iris blades without removing the iris. Using an alcohol/water/detergent blend and many Q-tips I slowly removed the oil on exposed parts of the blades and waited for more oil to seep out. After three cycles the oil didn't return and the lens is working great now as a 75mm portrait lens on a Sony A300.

Chris		19-Dec-2009 20:16
This was pretty straight forward, thanks for the write-up. I would suggest taking the front trim ring off in the first step since it gave me a little trouble. Having the rear of the lens open and trying to get the ring out made me nervous.

Pete Ganzel		04-Nov-2009 06:45
Michael: The first section of the gallery shows assembly of the iris with the rear of the lens removed and just as you say with a cylindrical tool with the iris fully open. This is my preferred method. As for the ground spring, it is necessary for glitch free operation. A short piece of copper wire cut slightly long will substitute if you lost yours. No further adjustment should be necessary if you put everything back the way it was and did not disassemble the focus helicoid. If you did not mark the iris plate some adjustment may be necessary for the iris opening. Pete

Michael		03-Nov-2009 09:14
OK i finally fixed it. My solution was opening the iris blades up so it was fully open, sticking a cylindical object through (in my case a stick of glue). I also wasnt making sure the iris holder was sitting in its seat properly at first. I lost my ground spring... does this make any difference? If so where can i get another? Also how do i test that all is ok with the camera...are there any tests to do? Many thanks for the guide!

michael		02-Nov-2009 13:36
Please help. Im really struggling. All has gone fantastic until it has come to putting the iris back into the lens fitting. I am not using the tool suggested, i am using the crutch foot to rest the iris casing on, whiclt lowering the lens casing over it. I turn it over keeping pressure applied, remove the crutch foot so i have acces to be able to put the circular pin back in place...but everytime i have carried out this proceedur, the irs blades seem to get knocked out of the iris casing, causing the blades to come out of their 'rails' meaning i have to start over again. Its happening everytime, so wondering where i am going wrong?! How does the iris with the sticky tape have an adnatage over what i am doing? as i cant see how it can?

Matt Craig		29-Oct-2009 04:08
Thank you for the guide. While my experience was a little different, this really helped me a lot in taking apart, cleaning (oily iris), and reassembling my old Minolta 50mm f/1.4. It's great to have it working well. For the longest time I simply thought the old lens was incompatible with the new Sony DSLRs. By the way, I found pulling the blades off the iris and cleaning them individually to work well, and reassembly was easy. The Iris Assembly slide was very useful for this. I believe that tiny contact spring was what caused the most consternation. I didn't lose it, but it wasn't too keen to stay in place while putting the rear trim plate back on.

philipp		23-Oct-2009 21:13
Thanks a lot for your guide!

Wolfram		28-Jun-2009 11:58
Attempt with AF 50/1.7 RS Last night I tried to fix the oily blades of an AF 50/1.7 RS, thus the newer and "restyled" version. Unfortunatly, I did not succeed for two reasons. This first reason was up to my inability and lack of the right tools to remove the snap ring. Someone here suggested to use a safety pen instead of the depicted dental tool, but I am hesitant to sacrifice one of those at the moment. Thus, I could not remove the iris assembly completely, and I decided to clean the the whole inner helicoid as others did successfully according to their reports here. However, now the changed design of the RS version came into play. To clean the inner helicoid, one has to open the lens from the rear and to remove the rear lens assembly. According to the drawings and pictures here, the rear lens element is attached with three screws to the inner helicoid. But not in the RS version. Here, the rear lens assembly and the inner helicoid form one single plastic part. According to this finding, one really has to remove the snap ring in the RS version to get full access to the iris from both sides, and the shortcut of cleaning the whole inner helicoid incl. the still attached iris (but without the rear lens element) does not work any longer... :-( And one comment to the reassembly of the rear lens part: One really has to be careful to reassemble the lens in the right way such that the focus still works over the whole distance range (incl. its ADI interpretation by modern camera bodies). For this purpose, one has to insert the inner helicoid into the outer helicoid in exactly the right orientation before screwing it in again. Nevertheless, thank you very much for this detailed documentation. Maybe I will find the right tool to remove the snap ring. Wolfram

Brad		20-Apr-2009 13:51
I used this to repair the oily blades on my 50mm f1.7. I couldn't get the snap ring out, so I just put the whole tube with the iris and helicoid still in it into warm soapy water. I jiggled the iris open and shut quickly, and gently brushed it with an old lens brush when it was shut. Then I did the same thing in clean water to rinse it, then did it again in alcohol to dissolve the water and evaporate quickly. Then I used a hair drier on low to dry everything. I figured that at worst I would also strip the grease off the helicoid threads and have to re-grease that somehow, but because I didn't move it or scrub it with a brush doing what I did, the grease was still there. I figure that what I did may have actually removed a bit of the "excess" grease that caused the problem to begin with, if it removed any of the helicoil grease at all. I could see a definite film of grease on the threads before I reassembled, and the operation was smooth. If the focus stiffens up, I'll just take it back apart and re-grease the threads, but I don't think it will. It's been over a week now, and it still works perfectly. Thank you for the guide. It helped a lot. Darren and anyone else wondering about the screw size.... go to the hardware store and get a set of "jeweler's" screwdrivers. Use the largest one that will fit into the screw head and you shouldn't have any problem. None of the screws seem to be tight enough for you to destroy the head. The most likely things to destroy a screw head in my experience is cheap screws (the ones in this lens seem pretty good), a screw frozen in place by corrosion (not likely in properly cared for lenses... if it's there, you'd likely have other problems than just the iris), and using screwdrivers that are too small for the screw (they don't get the proper grip). Press down hard when you are turning hard to make sure the driver doesn't slip up in the slot. If it stays firmly in the bottom of the slot, you won't damage the screw.

Mark		10-Feb-2009 00:38
This this repair for an oily lens last night. What great information. My old 1.7 50mm lens works perfectly now! I used a safety pen adn bent the tip instead of using a dental tool. Worked with no problems at all!

Aaron		09-Nov-2008 22:45
I performed this repair (oily iris & oil drops on interior lens) on a Minolta 28mm 2.8f. It was almost identical with the following exceptions: the lens assemblies are screwed in and no retainer ring. Took me about 2 hours, most of which was reassembling the iris and getting it back in. One thing, to remove the front trim ring, I used two rubber bands under each thumb, pushing in opposite directions. Made my $40 ebay purchase a good-as-new lens. Thanks a bunch. Thanks, thanks, thanks.

Aaron		30-Oct-2008 16:02
I was curious, are any of you concerned about or taking any anti-dust measures?

Matt Staben		18-Sep-2008 07:32
Thank you Pete for your instructions, I was able to restore to perfect working condition a the f1.7 50mm. I have three suggestions: 1) use a ball of rubber bands for the crutch. If you collect (or save as it were) a set of rubber band balls, you will have different sized crutches. 2) Use fingernail polish to mark the position of the iris assembly retainer, it will stick around even if you clean out the inside of the barrel. 3) A plastic film canister with mailing tape wrapped around it backwards works well for holding the iris assembly as it is pushed up into the barrel. The film canister is small enough so that you will have room to hold in the iris assembly as the retaining ring is replaced.

darren		05-Aug-2008 15:20
great tutorial. could you give me an idea of the sizes of screwdriver required for a project like this, i dont want to fail at the first destroyed screwhead!! thanks.

Serban		30-Jun-2008 05:48
Excellent guide, wonderful website. My 50mm f/1.7 works better than ever after it had the aperture blades cleaned. Thank you!

Bob		01-Mar-2008 08:21
Pete Really useful site. I have a Maxxum 50mm f/1.7 which I ahve stripped as per your help. I now find that the middle helicoid has sufffered damage and needs replacing. Do you know of any suppliers who can provide spare parts? I'm in the UK but would appreciate names of any supplier worldwide. Regards Bob

Bob		01-Mar-2008 08:20
Pete Really useful site. I have a Maxxum 50mm f/1.7 which I ahve stripped as per your help. I now find that the middle helicoid has sufffered damage and needs replacing. Do you know of any suppliers who can provide spare parts? I'm in the UK but would appreciate names of any supplier worldwide. Regards Bob

Bob		01-Mar-2008 08:19
Pete Really useful site. I have a Maxxum 50mm f/1.7 which I ahve stripped as per your help. I now find that the middle helicoid has sufffered damage and needs replacing. Do you know of any suppliers who can provide spare parts? I'm in the UK but would appreciate names of any supplier worldwide. Regards Bob

Pete Ganzel		16-Feb-2008 18:22
John: My bet is you haven't really cleaned off all the oil from the blades. Alcohol will dissolve a bit but in my experience you need to emulsify with detergent and rinse with water...lots of it. The blades are steel and they can be magnetized by tools that are magnetized and they will also stick together a little for this reason. Pete

John Askham		15-Feb-2008 22:07
I have been through this process a couple of times now using alcohol to "de-grease" the blades. I'm not convinced it is oil that is stopping them but possibly water. I have noticed a couple of times after going from the cold outside to inside and not using the lens for a day has allowed the iris to stick. But on warming up the blades have freed themselves. Not saying that the original problem isn't oil/grease but if it gums up again I don't see where it has come from. Anyway these are just thoughts as I have no objective evidence to back these thoughts up.

Malcolm Turner		23-Sep-2007 23:34
Pete, many thanks for this very detailed guide. It seems to be such a common problem with this lens (50mm 1.7). Just like Reiner, I couldn't move the snap ring so removed the two guides and unscrewed the whole unit. Cleaned and dried it with a hairdryer and appears perfect. On a very quick test, focus seems o.k. and exposures seem consistent. It's the first time I've stripped down something this small and some of the smaller screws were great fun with my varifocal glasses!

Reiner from Switzerland		04-Jul-2007 22:28
Many thanks to Pete for this superb gallery. Took me 2 hours for my 50/1.4, I guess 30 mins will be sufficient for the next lens of this type. I think the job is less scary than it looks from the pictures. I tried a simplified, home-grown version of cleaning the iris: I did not go through the tricky step of removing the iris assembly from the inner tube (14 Mark 1074 and Snap Ring) but removed the two brackets that guide the inner tube (visible on 14 Helicoid 1081 and on Iris Removal). The aluminium tube with the iris installed may be screwed out to the front of the lens now. I cleaned the tube with the iris installed in a bath of dish liquid then clean water then drying with a hairdryer. Actuating the iris some minutes when bathing and drying did the job. Using alcohol will be even better. I'm wondering if this sub-perfect cleaning method will be a permanent solution or if the blades get stuck again or take on some rust... but the pictures of the removed iris didn't convince me the iris is easier to clean or to dry when removed from the tube. It would be fun doing it a second time anyway and I'm looking forward to the next challenge: an oily 24-85 !

Evil EMT		11-Apr-2007 03:27
I knew that flea-bay deal was too good to be true: "clean and oil free" indeed! My 50/1.7 now has a functioning iris finally. 2.5 hours start to finish - never even thought about what makes a lense work before; I'm handy but a complete novice. Thanks for the wonderful guide! May I suggest a few pictures showing the suggested markings for ease of reassembly? Now if I could just find some info on how to stop a Maxxum AF 100-200 f/4.5 from creeping out towards 200mm all the time thanks to gravity...

David Cram		01-Apr-2007 11:46
Thanks again for this guide. Just saved myself $100 on sending my KM 50mm f/1.4 off to get oily iris blades cleaned!

D Timoce		08-Feb-2007 23:37
Well, i've cleaned the oily blades of a 50mm 1.7 too, and thanks to your detailed step-by-step description of the process all went well. As for placing the iris in place, i've used a film box; works quite well. Thank you

Alexander Schrab		07-Feb-2007 06:00
Thanks for a good visual guide. I did manage to break my ground spring, but I am crossing my fingers it won't cause problems. Anyhow, a small tip would be posting detailed close ups on the correct rotation of the aperature blade ring and the actuator. The ring is not quite rotational symmetrical and the correct assembly could be shown with pictures.

Guest		01-Feb-2007 03:43
Thank you for posting this information. I have a twenty year old 50mm 1.7 that I bought with my Maxxum 7000 in 1987. The aperture blades wouldn't close down properly. The camera repair store said it would have to be sent to Sony to get it fixed and would cost over $200 (for a lens that isn't worth that much). I took it apart according to these instructions, cleaned the aperture blades and it is now functioning as good as new! I really like this lens and now I have it back. Thanks, Erik

Jeff		28-Dec-2006 03:11
Thanks for the great instructions, I fixed the oily blades on my 50 1.7. It turned a bad ebay deal into a great lens.

Markus		20-Dec-2006 02:37
Thanks! After finding this guide online I was encouraged to clean the aperture blades on a Minolta 35mm f/2.8 MC Rokkor HG that somebody sold me on ebay without mentioning the oily aperture blades. It took me about 4 hours to take the lens apart, clean the aperture blades and the rest of the lens, and put it back together. The hardest part was to get it to focus correctly again, but you can adjust that without disassembling the front of the lens again. Also, putting the spring that makes the aperture ring click back in was a major pain. The trick is focusing the lens at a short distance, and then putting the back of the lens on at a slight angle to squish the spring (when you take such a lens apart you'll know what I am talking about). I would definitely do this again!

briseyw		07-Aug-2006 13:00
Thanks Pete Although I wasn't brave enough to takle it myself, a very good friend followed your instructions to the letter and now my 'oily iris' is working perfectly.

Pete Ganzel		02-Jun-2006 02:46
Hello "guest" The only place that lubrication is used on the lens is on the helicoid and on the focus drive gear train. I wouldn't use lubrication of any kind on the aperture mechanism. Likely the spring is deformed or the little "arch" that it fits in is binding. You might try to bend that sheet metal a little. The "aperture spring 2486" photo shows this guide on the inside edge of the spring. Pete

Bj�rn Simonson		01-Jun-2006 19:11
Thanks for a great guide, it helped fix my 50/1.7. Now I might have a 50/1.4 RS with oily blades coming in, any difference picking that apart compared to the non-RS versions? Best Regards!

guest		01-Jun-2006 14:13
HI, thanks for the tutorial. I have a problem though, I think the aperture spring assembly is a bit jerky. Would it be an idea to spray some silicon spray in there??

Sam		13-May-2006 15:33
Many thanks for this guide. I managed to (just about) fix an oily 28mm f2.8 lens using these instructions. I think the iris could still be a bit snappier than it is and I did lose the ground spring, but at least it works! I got into a bit of a tangle with the focussing as I hadn't been careful enough about marking where things matched up. A bit of tinkering and it seems OK now. Cheers! Sam

Bob		13-May-2006 15:33
Had "the pleasure" to try this method because somebody sold me an oily 50 F/1.7 on ebay without mentioning it was an "out of order" one... Thank you to have taken time to post pictures and explain the "tricks" Do not be afraid to unmount the iris and take the blades apart. It is really easy to mount it again, do not worry... As I do not have a ultrasonic cleaner, I simply used 96% alcool and let the blades "take a bath" for about 15 minutes. Now I am looking forward to take some pictures with this nice lens !

Mal		01-May-2006 03:17
Absolutely the most informative site on Minolta lenses. I had tried to get to the iris but could not get the trim ring out. The crutch tip worked so well I couldn't believe it. With your guidance I removed the iris mechanism and placed it in a small plastic jar of alcohol. I closed its top and placed the whole jar into an ultrasonic cleaner. In that way the water in the ultrasinic fluid would not get to the steel blades of the iris - possibly resulting in rust at a later time. Then I also used Q tips to clean the oil that was all over the place. Thanks again for your devotion to detail.

Ruud v. Veen		02-Mar-2006 21:47
Thanks, Your wonderful description made it possible to succesfully clean the oily iris. You´ve made a stressful day in a beautiful one. :) Thanks

George		04-Jan-2006 20:04
Hey!Thanks big time! Glad you took the time to post this in such detail. I Just did my Minolta 28mm F2.8. The Iris was sticking loaded up with grease and the lens was useless. I did lose the iris blades and it did take some time to get them back in there place the right way but it was well worth it.All and all it was much easer then the 50mm 1.7 to do much less to have to take apart. If anyone out there has a 28mm F:2.8 they need to do all I can say is just do it! Also I found after doing it if you use two way tape on the end of a round spool the right size there is no need to take the back of the lens apart.Jus make sure you turn the lens over before you remove the iris. But what ever way you decide to do it it's easy.I also decided to place the lenses in the camera bag with the back face down this may buy a bit more time with keeping the iris grease free. Thanks Again! George in New Hampshire

Gene Nichols		13-Nov-2005 19:16
Awesome! I have a sticky aperture on my 50/2.8 macro. Using your instructions I'm going to give it a shot. Any major differences in the 50 and 50 macro? Thanks! Gene

Rich		15-Jun-2005 19:50
Great site! I was able to disassemble my Maxxum 28mm f/2.8 using the 50mm as a guide. Quite similar internally. I had an oily aperture that is now quite snappy. Thanks!

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