ovredal73 wrote:
..... the aperture is stuck wide open. ..... However I am (with Pauls generous advices through PMs) in the process of figuring out how to activate the aperture. It might be due to oily blades, or a bad spring or something else altogether. Will hopefully figure it out in a few days.
André/ovredal73, my aperture is stuck too. It's wide open now. I was too eager to do the mode when I finally found time to do it that I forgot to check if the aperture was working before the mod. SUPER Silly of me!!
Anyhow, it's stuck and was wondering if you managed to get your fixed. Any help to get mine working again will be wonderful.
BKue wrote:
News from Mr. Kim - and thanks to him:
He has updated his chart of Minolta MC 1.2/58mm Serial numbers and types. http://homepage1.nifty.com/~Kim/Camera/MC58_12-4.html
The columns denominated (1) to (4) are the different main types, as shown in photos when you click the link in the respective columnsL head. (4) is the rubber grip type without the "-PG".
I have a 277XXXX serial number. Since the web page is in Japanese (I think), can someone translate ot tell me what the note is saying about this version
G§CLASSIC CAMERA No.14uÁW@~m^@bR[`āv
I bought a 50mm 1.4 Rokkor that can't be converted so I just look at it and admire it . I was wondering on the steps the Cogi provides on Removing the Aperture Ring and Reduce the Aperture Ring Tab, Couldn't you just use a dremel with a cut off blade to remove the aperture tab and not have to take it off and deal with the ball bearing I think that would great best if you don't want to remove the aperture ring to remove and sand the tab. Just a thought.
khidhir wrote:
André/ovredal73, my aperture is stuck too. It's wide open now. I was too eager to do the mode when I finally found time to do it that I forgot to check if the aperture was working before the mod. SUPER Silly of me!!
Anyhow, it's stuck and was wondering if you managed to get your fixed. Any help to get mine working again will be wonderful.
Thanks all.
Dear Khidhir, I now have two rokkors, both came with stuck aperture blades, both are now fixed!
Of course I donīt know what the problem is with your copy, so check for springs or stuff like that out of place in the lens internals.
On my second copy, my blades were stuck due to too little use over the years, so simply moving around some pins down in the lens internals got this copy going again.
However my original copy (which is the one I use) had a ton of grease on the blades. They were covered in it, making the blades stick to eachother. I fixed it with isopropanol and a few cotton swabs. If you have this problem, you need to remove the rear group assembly to get all the way down to the aperture blades and then apply/wipe the blades with the isopropanol. Then I simply bent the tips of a few cotton swabs and did the same to the other side of the blades. And I also wiped off the isopropanol with dry cotton swabs as I went.
At the end I had to blow out and clean a bit, as the cotton swabs left some hairs around. But no big problem.
I guess you know how to remove the back of the lens - if not, refer to Paulīs (Cogitech) manual here.
Paul sent me this PM a few weeks ago, explaining how to remove the rear group assembly in case you have not done it before.
I hope he doesnīt mind me quoting it here
"One way to get to the blades and allow more room for you to work down inside is to remove the rear group assembly. Simply grab the metal cylinder which houses the rear group and turn it hard counter-clockwise. You may be able to do this by hand, but it may require a pair of "channel-locks" or large pliers. Try not to squeeze the cylinder too hard though. You do not want to crush or deform anything. I've done this with nearly every copy, in order to clean some of the internal elements, and I only had to use pliers on one of them. The rear group assembly is comprised of multiple cylinders, and sometimes they unscrew from each other instead of the whole assembly unscrewing from the base. If this happens, let me know and I will try to describe how I get around it."
Well, all this happened to me. Had to use plier, and all the sections unscrewed in different places every time. But no problem Just keep the air blower near.
I've just bought another Rokkor 58, #276XXXX, and I'm really convinced that the Rokkor 58 is one special lens.
I think this one is a later version.
it has a plastic focusing grip, and has "58mm" written in yellow. (or is it Orange?)
My only complain about this lens is that the aperture ring is too close to the camera body.
Thank you very much. I was really frustrated when I discovered that the blades were stuck. Your message in a way gives me hope, at least I know I am not alone. I have opened up a S-M-C Takumar 1.4/50 to clean up before, so I hope that experience will help with this one if I need to open it.
Anyway, I need to wait for more M42 adapters to come in, I screwed up my drilling on the one I was doing yesterday...NEVER do anything like this while watching the UEFA Football finals, never!
It seems that many has at least 2 copies of the lens. These Rokkors must be something special. Mine is the all metal early version - super heavy, a little less than the Viv 2.5/90.
Haha, glad to hear itīs televised in the US. I am very happy Spain won. It was their time now. And they were simply far superior anyway, so it was plain fair.
My two are metal ones as well. I bid on an ebay auction for the second one when the first one was not working properly. And yes I also screwed up the drilling, I only have 3 useable holes on the adapter, but it does not seem to matter. I will get around to drilling up a new adapter at some point, but I would rather spend my time shooting Good luck!
BKue wrote:
News from Mr. Kim - and thanks to him:
He has updated his chart of Minolta MC 1.2/58mm Serial numbers and types. http://homepage1.nifty.com/~Kim/Camera/MC58_12-4.html
The columns denominated (1) to (4) are the different main types, as shown in photos when you click the link in the respective columns?head. (4) is the rubber grip type without the "-PG".
I'm just curious...
Although I'm more than contented with 2 copies i have, does anyone know if certain version is the best performer?
For example, at wide open, the older version I have, #256XXXX, is little bit softer than the later version.
Is it possible that the later version had a better coating?
Maybe Paul, who has many of them, can share some thought on this.
Paul Yi wrote:
I'm just curious...
Although I'm more than contented with 2 copies i have, does anyone know if certain version is the best performer?
For example, at wide open, the older version I have, #256XXXX, is little bit softer than the later version.
Is it possible that the later version had a better coating?
Maybe Paul, who has many of them, can share some thought on this.
I haven't had any copies that I'd call bad, but the best performing one that I have used is the oldest one.
The newer ones likely do have better coatings and hence may have better flare control, and/or contrast, but I have not noticed it.
I don't have enough supporting evidence to draw any conclusions about which ones are "best".
ovredal73 wrote:
Haha, glad to hear itīs televised in the US. I am very happy Spain won. It was their time now. And they were simply far superior anyway, so it was plain fair.
My two are metal ones as well. I bid on an ebay auction for the second one when the first one was not working properly. And yes I also screwed up the drilling, I only have 3 useable holes on the adapter, but it does not seem to matter. I will get around to drilling up a new adapter at some point, but I would rather spend my time shooting Good luck!...Show more →
Let me guess; the larger drill bit chewed right through the hole when you where attempting to counter-sink it? Now the hole is too big? This is probably one of the more tricky parts of the conversion. I find using a dull bit on a slow drill works well.
cogitech wrote:
Let me guess; the larger drill bit chewed right through the hole when you where attempting to counter-sink it? Now the hole is too big? This is probably one of the more tricky parts of the conversion. I find using a dull bit on a slow drill works well.
YES. That is exactly what happened On the third counter-sink I was drilling - the one that goes on top of the mount. I donīt know exactly what happened, I was pressing sooo carefully on the drill trigger and somehow it slipped when the spinning drill touched the metal and it broke through. It is just a ten minute thing to do it again, but a serious issue to get around to.... You advised me to get two adapters for just this reason and the second one is now in the dentist waiting room
Exactly like what happened to me. Unfortunately, I only have 2 usable holes
I managed to open the rear assembly - in 2 parts. It was not difficult at all, just strong counter clockwise twist. But unfortunately I really don't know what to do next. I don't see the blades, (probably it's stuck inside). On the Takumar that I opened, I removed the cylinder that holds the blade cylinder/assembly. Just a matter of pulling it out (or tipping over). But on the Rokkor, I cannot figure out how to open it or should I not open it, or Here is the link to quick snaps of the lens with the rear assembly removed. What do I do next?
There are two pins sticking up down there. One is the aperture ring connector, the other one is a roundish pin "high up on the left side" if you hold the aperture pin rotated at the bottom in front of you.
If you wiggle this second pin on the left back and forth (with the aperture pin in right-most position, not to block the movement) it should open and close the aperture. Then you can see if you got any grease on there.
While you're in there, you might as well clean the inside element surface beyond the blades and any of the elements of the rear assembly that have been exposed. It is good to remember that you are not just removing the dust and debris that you have introduced to the lens, but also you have a chance to clean anything that has accumulated over time; including deposits from moisture and other fumes, oil, etc. that it may have been exposed to over the years. These are old lenses
And if you want to be a bit more thorough (although not completely) you can carefully remove the two front element retaining rings and pop out the front element. This allows you to thoroughly clean two more surfaces, which are particularly problematic with regards to dust, etc.
I always perform the above on any of the Rokkors that I've had, unless it didn't need it. There were only two that didn't.
It midnight here and after spending nearly an hour wiggling the pin, I managed to get the blades to open and close. Thanks guys. The blades were soaked with grease especially on the front side. I guess whether I like it or not, I have to open the front elements to get to the front side of the blades, unless there is another way to do it.
Do I use isopropanol/rubbing alcohol or lighter fluid to clean the lens? I have seen both being suggested somewhere on the internet. I don't have isopropanol, but I think I may have lighter fluid for my zippo somewhere in the apartment. I used to smoke, but has been off for almost 6 years.
I just bent the tip of some cotton swabs 90 degrees and soaked them in Isopropanol and closed the aperture half way and put the cotton swab through the hole and started rubbing the front of the blades with the bent swab tip. You have to clean with the aperture at various f-stops from f2 to f16
Also my blades were greasiest on the front, so same situation.
At first you feel you are going to destroy the whole thing, but being careful the blades can handle the treatment. I did touch the glass with the swab once or twice, but cleaned it off with a cloth and see no issues from that.
It takes a little while, being careful, but its worth it when you realize it works!
cogitech wrote:
And if you want to be a bit more thorough (although not completely) you can carefully remove the two front element retaining rings and pop out the front element.
Great, I didnīt realize this was possible ! Sounds (maybe) easier to clean the front of the blades this way.
My second rokkor had loads of spidery fungus on some of the glasses inside, and I cleaned that out as well with cotton swabs and various throw away cloths.
ovredal73 wrote:
Great, I didnīt realize this was possible ! Sounds (maybe) easier to clean the front of the blades this way.
My second rokkor had loads of spidery fungus on some of the glasses inside, and I cleaned that out as well with cotton swabs and various throw away cloths.
I could not reach the front of the blades with this method (did not need to clean the blades anyway) because there is another set of elements that need to be removed (after the front element) before you get to the aperture. I was never brave enough to dig that deep and cannot offer any advice on how to take that next step. This is why I specified "(although not completely)" in my post.
I just won one! Finally!
Been hunting E-bay since I saw this thread the first time. Missed two due to extremely bad luck. Tonight I got one off Austrian (!!) E-bay for ~$270.
MC Rokkor, serial# 2763994 I think.
I'm excited - but I also feel a great responsibility not to mess up this beautiful lens during the conversion.
Thank you Cogitech, for directing my attention to this lens and for all the great information. Much appreciated.
Don't worry. It is easy. Take your time. Read the howto twice before beginning.
Very soon I will be updating the howto, BTW, with some pointers I received from people who have the done conversions based on my howto. Some great ideas that would be worth waiting a week or so for.
. I was wondering on the steps the Cogi provides on Removing the Aperture Ring and Reduce the Aperture Ring Tab, Couldn't you just use a dremel with a cut off blade to remove the aperture tab and not have to take it off and deal with the ball bearing
I think that would great best if you don't want to remove the aperture ring to remove and sand the tab. Just a thought.