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09-06-2014, 06:27 AM - 1 Like   #1
Junior Member

Join Date: Jun 2014
Posts: 36
sigma 28mm 2.8 mini wide II disassemble for problems

as I have described in this tread

I had some problems with my Sigma and since it is my only lens (unless I am lucky enough to win the 50 mm up for grabs... ) I have tried to solve and luckily I succeeded
I disassembled the lens because A mode don't work well, sometimes work with wrong minimum aperture value, sometimes its not working at all; contacts clean, the problem remained
my goal was to make it work in A mode, it was not important for me that it could work in manual
I search in PentaxForum for disassembly images, nothing... then I tried to repair it by myself

and as promised to the people who have helped me in my previous tread, here some images, which I hope will be of help...

thank's Paul!!!!, a friend of mine, who lent me a 50mm to take this shots

1. the lens with not Ricoh pin and the 3 screws to leave out
2. the lens with no screws
3. when you disassembled aperture ring take care: there is a ball bearing spring loaded for aperture clicks!!
4. the ball bearing in position
5. open the aperture mechanism
6. inside there are two spring wires...that can be thrown on the moon!! Attention please!
7. for my needs I circuited 'A' pin with the two metal part that make contact with the camera to read the values of aperture
doing so I always have 'A' mode setted...faultless!


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Last edited by teoprome; 09-06-2014 at 06:32 AM.
03-04-2016, 07:52 AM   #2
New Member

Join Date: Oct 2015
Location: Chemnitz, Germany
Posts: 7

Sorry for grave-digging, but I got the exact same problem and been trying to repair my lense too! I just don't know what you mean with point 7 in your list "(...) I circuited 'A' pin with the two metal part that make contact to the camera(...)"! What exactly did you do there?

Further, these two metal springs look a bit different in my copy of the sigma, is that of any matter?

Thanks much in advance and greetings from Germany
03-31-2017, 08:59 AM   #3
New Member

Join Date: Feb 2017
Posts: 2
Anyone fancy to disassemble a lens for me? Mine missing a crucial part, otherwise it's flawless. I need the diameter of the little pin (red circle on the picture).
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28mm 2.8 mini, aperture, ball, images, k-mount, lens, mini wide ii, mode, pentax lens, pin, sigma 28mm, slr lens, tread
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