Home

Please support mflenses.com if you need any graphic related work order it from us, click on above banner to order!
SearchSearch MemberlistMemberlist RegisterRegister ProfileProfile Log in to check your private messagesLog in to check your private messages Log inLog in

Auto Sears 28/2.8 - How to remove front element?
Post new topic   Reply to topic
Home   Equipment Care and Repairs
View previous topic :: View next topic  


PostPosted: Tue Nov 27, 2012 5:07 pm    Post subject: Auto Sears 28/2.8 - How to remove front element? Reply with quote
Does anybody know how to remove front glass on Auto Sears 28/2.8 (possibly Ricoh)? The ring (nameplate) holding the glass doesn't have anything to grab onto to unscrew it from the barrel.

As you can see in the picture below, there might be some fungus going on inside or some dark paint in the glass corners coming off (one or the other, not sure what's going on here), so i need to open it up and clean it...



PostPosted: Tue Nov 27, 2012 7:13 pm    Post subject: Reply with quote
That's an interesting lens.

It's possible you might get some ideas if you sort through the material on this thread:

http://forum.mflenses.com/rubber-tools-t53739.html


PostPosted: Tue Nov 27, 2012 7:31 pm    Post subject: Reply with quote
guardian wrote:
That's an interesting lens.

It's possible you might get some ideas if you sort through the material on this thread:

http://forum.mflenses.com/rubber-tools-t53739.html


some interesting stuff in it. thank you Smile
i might try canister + rubber glove combo tonight Smile


PostPosted: Wed Nov 28, 2012 5:27 pm    Post subject: Reply with quote
canister + rubber glove trick worked. i was able to unscrew nameplate and removed front glass. the white spots (in the picture above) seem to be worn-out paint, which could have been caused by fungus eating the paint or it being too old and falling out??? dunno.

but right now, to fix the spots, i can either completely remove the old paint and kill fungi if there are any, or reapply black paint on those spots. in either case, i will need the black paint... any recommendations?


PostPosted: Wed Nov 28, 2012 9:56 pm    Post subject: Reply with quote
Jvg wrote:
canister + rubber glove trick worked. i was able to unscrew nameplate and removed front glass. the white spots (in the picture above) seem to be worn-out paint, which could have been caused by fungus eating the paint or it being too old and falling out??? dunno.

but right now, to fix the spots, i can either completely remove the old paint and kill fungi if there are any, or reapply black paint on those spots. in either case, i will need the black paint... any recommendations?


I have run into this sort of thing prior. No way to say for certain, but:

Doubt it's fungus. Probably just a case where paint adhesion finally failed owing to age of lens and old paint, or possibly due to corrosion.

After cleaning surface I would use a flat black acrylic enamel or flat black enamel. Be certain new paint is thoroughly dry before reassembling the lens. Thoroughly dry does not mean just dry to the touch. You don't want the new paint to outgas with the volatiles condensing on your individual lens elements inside a sealed lens. Since you cannot dry at elevated temperature without risking breakdown of your helicoid grease, you just need to let the paint dry for (at least) several days at room temperature. Alternatively, you could use a small fan if you're in a hurry, but be mindful of blowing dust into the lens.


PostPosted: Thu Nov 29, 2012 1:54 am    Post subject: Reply with quote
guardian wrote:

I have run into this sort of thing prior. No way to say for certain, but:

Doubt it's fungus. Probably just a case where paint adhesion finally failed owing to age of lens and old paint, or possibly due to corrosion.

After cleaning surface I would use a flat black acrylic enamel or flat black enamel. Be certain new paint is thoroughly dry before reassembling the lens. Thoroughly dry does not mean just dry to the touch. You don't want the new paint to outgas with the volatiles condensing on your individual lens elements inside a sealed lens. Since you cannot dry at elevated temperature without risking breakdown of your helicoid grease, you just need to let the paint dry for (at least) several days at room temperature. Alternatively, you could use a small fan if you're in a hurry, but be mindful of blowing dust into the lens.


thanks guardian,

you've provided me with much needed info. letting it dry out for few days - no problem. i'll let it dry for weeks if needed. no rush there Smile


PostPosted: Tue Dec 04, 2012 8:31 am    Post subject: Reply with quote
You'll never believe this, J, but the Auto Sears 28 that I picked up a few days ago looks pretty similar to yours through the front. Did you decide to clean inside for any specific reason? General tidiness or did you suspect a functional problem?

Alec


PostPosted: Tue Dec 04, 2012 3:50 pm    Post subject: Reply with quote
atabak wrote:
You'll never believe this, J, but the Auto Sears 28 that I picked up a few days ago looks pretty similar to yours through the front. Did you decide to clean inside for any specific reason? General tidiness or did you suspect a functional problem?

Alec


Hey Alec,

well, as you can see in the picture, my copy of sears had some white spotting going on inside. Didn't know if it was fungus, paint wearing off, inner tube discoloration, or etching. So, just to be safe, and avoid (in case of fungus) further contamination of my other lenses, i decided to clean it up. Not knowing how to get inside, i dis-assembled the entire unit, and only later (and thanks to Guardian) figured, that i could have just removed the nameplate and voila (duh Very Happy)... Fortunately it wasn't a fungi, just an old paint coming off of the side of the second element. I completely removed the old paint, bought myself a small pint of flat black acrylic enamel, and plan to apply new paint, then re-assemble it... Assembly will be a pain, there are way too many screws, parts, springs - and they all need to go to designated spaces, but i'm in no rush - and hope i can figure this out. Otherwise, i might sell everything for parts Smile..

as for the lens, it's pretty good, supposedly manufactured by ricoh (and looks very much like ricoh 28/2.8 too). i bought it, for very interesting aperture diaphragm...


PostPosted: Thu Dec 06, 2012 7:32 pm    Post subject: Reply with quote
Yes, it's a pretty wacky aperture diaphragm. My copy's wack beyond that, presumably due to a tilted or misaligned element cause by someone's dropping the lens with force enough to dent the filter threading. The effect is complex, but basically amounts to the middle and and the side of the image opposite the dent being focusable and sharpening in a normal way with aperture decrease and the side of the image corresponding to the dent being unfocusable—bizarrely so with subjects more than ten or so feet away. I have half a mind to try removing the name plate to see if I can reach the problem element, but am not sure the plate will come off…


PostPosted: Fri Dec 07, 2012 3:16 pm    Post subject: Reply with quote
Was the dent corrected? Are you able to screw and unscrew anything on it (hood, filters)?

Once you get the nameplate off, it's very easy and straightforward from there. The front group holds 2 elements, and both of them can be easily removed by unscrewing the rings that hold them inside. Very easy.
Post new topic   Reply to topic
Home   Equipment Care and Repairs
Page 1 of 1