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Just picked up: MC MTO-11CA 10/1000 and MC 3M-5CA 8/500
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PostPosted: Sat Nov 05, 2011 7:52 am    Post subject: Just picked up: MC MTO-11CA 10/1000 and MC 3M-5CA 8/500 Reply with quote

well im really excited i got these two beauties for 50$ in our local flea market


i also grabbed a good sturdy tripod from the old days.
and i shot a few pictures with those lenses now, they are pretty good and sharp actually the 1000mm is sharper than the 500... and there isnt anything interesting to take pictures of right now, but ill post samples as soon as i manage to take a walk with those.


the only problem i have now is that those lenses have good amount of fungus on the glass, both of them ...
apparently the previous owner had them lying in a storage room or somewhere

i wanted to ask about disassembling those mirror lenses, is there something unusual about it, because i've cleaned a few lenses from
fungi but never a mirror lens. any tips? or maybe tips bout removing the fungi? i use 70% alcohol.. is it ok?


PostPosted: Sat Nov 05, 2011 5:19 pm    Post subject: Reply with quote

Congrats! That's quite a handful!

I'd avoid touching the mirrors, some of them are extremely delicate and you can damage the silvering with a touch.


PostPosted: Sat Nov 05, 2011 5:32 pm    Post subject: Reply with quote

Congrats!
Excellent deal!
Where is that flea market?


PostPosted: Sat Nov 05, 2011 6:25 pm    Post subject: Reply with quote

That 1000mm looks awesome!

Whilst I do not have experience of these particular lenses, it is usually possible to unscrew the helicoid of a mirror lens so the front and rear sections of the lens come apart. Of course, the ring with the stops that limit the focusing rotation has to be loosened and/or removed first. As you unscrew the helicoid be careful to note the position at which it disengages so you can screw it back on in the correct orientation to get the correct focus range. Making other marks to note min and max focus distance is a good idea as well.

With the two halves apart, you should be able to clean the fungus off the inside of the front lens without further disassembly.

Whether cleaning the mirror will damage it depends on whether it is first or second surface coated. Mirror lenses like the Tamron are second surface coated so the coating is on the back and it cannot be damaged. If it is first surface coated, I would avoid anything other than the gentlest of cleaning with e.g. a lens tissue moistened in methanol.

I would avoid complete disassembly of a mirror lens as alignment (collimation) is critical. But just unscrewing the two halves cannot disturb the alignment. Clean what you can that way.

Good luck

Mark


PostPosted: Sat Nov 05, 2011 6:41 pm    Post subject: Reply with quote

I had 500mm it's quality more less same than Tamron SP 500mm f8 which is excellent, I can't imagine usage of 1000mm . Congrats!


PostPosted: Sat Nov 05, 2011 11:02 pm    Post subject: Reply with quote

thanks for the tips, well ive cleaned all the fungus on the 500mm, its squeeky clean right now Smile
the mirrors on this lens are pretty gentle especially the round one on the front element, but is nothing special if you're careful
you can easily clean them.
yet i couldnt open the 1000mm its like a beer barrel , huge, i have no idea how i will open it, the upper ring that should unscrew is so big
and nothing would move it. so im pretty much stuck.

about usefulness of these, the 500 is really hard to handle on a crop sensor dslr, maybe tele wildlife.. on a full frame film\dslr the 500 would be pretty useful sharpness is good and overall wieght and size worth it.
the 1000mm i guess ss just for play. or star gazing Razz


PostPosted: Sat Nov 05, 2011 11:13 pm    Post subject: Reply with quote

Smoli4 wrote:
about usefulness of these, the 500 is really hard to handle on a crop sensor dslr, maybe tele wildlife.. on a full frame film\dslr the 500 would be pretty useful sharpness is good and overall wieght and size worth it.
the 1000mm i guess ss just for play. or star gazing Razz


I've got the 500/8. It's relatively compact, so with a little practice I don't mind shooting it handheld... at least on a sunny day Razz

My tripod is too flimsy, but I've had good luck with a beanbag, in my case a plastic freezer bag full of dried beans from the pantry.


PostPosted: Tue Apr 10, 2012 2:30 pm    Post subject: Reply with quote

Just picked up the MTO-1000 and wondered if anyone managed to open it. Having similar problems with dust inside the lens, rather than fungus, but it needs a clean! Any tips? Many thanks!


PostPosted: Sun Feb 24, 2013 2:53 am    Post subject: Mto 11 Reply with quote

I need help too, I just bought the 1000mm and the focus ring seems stuck. What can I do?


PostPosted: Tue Jul 16, 2013 12:24 am    Post subject: Reply with quote

I had a MTO 10/1000 a few years ago and I am just trying to remember how I took it apart. I did loosen the small scrws on the focusing grip and unscrewed it in the middle and as was mentioned make alignment marks to use when realigning the two halves.
I used nutrile gloves when cleaning it because the oil on my hands was getting onto the glass.

The mirror coating was on the back of the rear mirror on mine so it was relitively safe to clean the front surface. In mine the black cone stuck to the rear mirror was a simple finger pressure press fit and was easy to remove and replace. You will need something to blast dust particles out of the lens like a large rubber hand bellows or similar. I found that the cans of compressed air sold for this prupose left a liquid on the lens that evaporated but left a mark.
Both the MTO lenses are beautifuly simple in their design but the 3M-5A does have its mirror silver on the exposed side as was mentioned so that requires carefull cleaning.I just used reading glasses cleaning liquid and a glasses cleaning cloth.

Here is a link to a image of a cockatoo I took with the 10/1000. The lens needs plenty of light and a sunny summers day in australia can be ideal.
http://www.flickr.com/photos/98915894@N06/9297281202/


PostPosted: Sun Feb 17, 2019 8:32 am    Post subject: Reply with quote

Hello,
I had just got my hands on one copy of MC MTO - 11CA 1000mm. Came with its original box, filters, caps, well preserved apart from the fact there is fungus inside. Fungus is present on the front glass element (not very dramatic) and on the main mirror element - which looks a bit irritating but again - ive seen worse, although not on mirror lenses (this is my first one). I did only a few tests and i dont see image degradation, but i really have no means to compare. Im based in Serbia, have a few options to service lenses in general - am unsure if anyone will take up to do this with a mirror lens. Taking it outside the country is out of option, the expense of exporting it alone would be huge.
My questions are -
1) I have committed it to the sun, and plan to leave it for the day. I would expect this will stop the growth however, im unsure if i need to repeat the process? Can anyone advise me on this?
2) In the case i could clean the lens locally, i probably would not do it right away (that is why im interested to stop the infestation for now / cannot afford some massive expense on cleaning right now). Is it, in the current state as seen on the images, even worth of cleaning it - i.e. would someone be able to tell me if the degradation of the image is dramatic - or am i looking at something that is not really an issue. Images of the main mirror and the glass element are included in the post.

Many many thanks to anyone with a hint, answer or complete solution Smile
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PostPosted: Sun Feb 17, 2019 1:47 pm    Post subject: Reply with quote

Hello nuclear panda and welcome.

I have cleaned tamron mirrors. The post by SXR_Mark above covers it but I'l reiterate: because mirrors are structurally relatively simple with no internal zoom or aperture mechanisms, if you can separate the helicoid that is IMO the best way to proceed. You then have the lens in two halves and can access the mirror and the rear side of the objective. Don't forget to mark the separation point. You will also be able to relube the helicoid - often desirable on ex USSR lenses, the grease gets sticky with age.
On the tamrons this is acomplished by releasing the focus distance scale ring, 3 screws. You'll have to figure out how the russian mirrors are put together. Oh one more point. On the tamrons there is no concern about damaging the reflective coating because they are back silvered - the front of the mirror is just glass. I don't know if that's the case with your lenses. If not - take great care.