View Full Version : M-Rokkor 28/2.8: Spots, Schneideritis, Haze - How can I decide, what's what?
krötenblender
02-06-2011, 00:50
Hello
I've read the threads about that lens and now got one included in a full CLE equipment (CLE, 90, 40, 28, Flash, some Filters, Bag...) in a good condition for a very reasonable price.
However, the 28 M-Rokkor has at least two different kinds of white spots. I guess, the bigger ones at the edge of the lens is what is called Schneideritis and only a cosmetic problem. But the smaller spots in the center I can not relate to either haze or the "famous" white-spot-problem of the 28mm.
Has anyone here experience with these spots and knows what's what?
I like to give the lens to a repair-service and like to know in advance with what I'm dealing here. I like to use it on my R-D1 (and on my CL and my new CLE, of course) and have not seen any problems with the images so far. But since the R-D1 has not that much of resolution and high dynamic output, it might be acceptable there, but simply unusable on a film-camera.
Thanks for any input.
http://www.mempool.net/galleries/misc/M-Rokkor-2828-Spots.jpg
Yours lens have already been opened - there are two cuts on the front ring in order to unscrew the front element. And the spots are still there so I guess that it is not possible to remove them:/
rollerbraun
02-08-2011, 05:16
Hello,
my M-Rokkor 28 mm f/2,8 also two cuts in the ring holding the front lens but there is not a sign of white spots on the inside of the lens. However there is a kind of stitched collar around the inside of the front lens. I think this lens has been refurbished at Minolta, USA some time ago. I bought it from a dealer in the US a year ago. Some years ago I had another such lens but it was full of white spots, all of them in different sizes. That lens had no collar inside. I had to sell it to a very reduced prize.
krötenblender
02-08-2011, 07:47
Until now, I can't really tell the difference, but I'm pretty sure, that the big spots at the border are coming from Schneideritis. I don't care about that, since it's only a cosmetical problem, and I do not want to sell the lens, but use it. - For now, it doesn't seem cause any visible artifacts on my R-D1.
But I do care about the small spots in the center. I will try to find a camera-repair-service who knows, if this can be fixed. I wrote a mail to a service in the Netherlands and got a quick reply, but they are closed from next week for some weeks. If I find one here in Germany and get it fixed, I will show the results here.
Anyway, if someone can tell, what the spots in the center are, I would appreciate that.
errorlogin
02-09-2011, 11:15
If I find one here in Germany and get it fixed, I will show the results here.
Hallo,
that would be very kind. I have a 28mm Rokkor here as well, which is starting to develop these white spots....when i bought it like 3 years ago, there was no single spot.:bang:
I would like to bring it so service, before the spots are goinig in the middle destroying the coating.
In the last repair shop, I had this lens, they told me, that this is unrepairable, because the elements are cemented together. But I don't believe them. I think it can be fixed.
Thanks and kind regards,
Jan.
hexiplex
02-24-2011, 05:50
In another thread, there is a link to Will Van Manen camera service in The Netherlands, it seems he performs cleaning of Schneideritis/Haze for relatively reasonable prices, I am sending the 28 Rokkor I bought for 170 EUR to him when I get the money, I think he charges 75 EUR excluding postage, that to me makes it worth it even though it's just a cosmetic problem.
http://www.kamera-service.info/
krötenblender
02-24-2011, 09:28
In another thread, there is a link to Will Van Manen camera service in The Netherlands, it seems he performs cleaning of Schneideritis/Haze for relatively reasonable prices, I am sending the 28 Rokkor I bought for 170 EUR to him when I get the money, I think he charges 75 EUR excluding postage, that to me makes it worth it even though it's just a cosmetic problem.
http://www.kamera-service.info/
Yes, I found them in the other thread, too. I'm already in contact with them and will send them mine, too.
goodtimes
02-24-2011, 09:42
Since it's been opened anyway and is willing to be opened a second time, why don't you open it yourself ? I would with no hesitation, when I observe this condition.
jsrockit
02-24-2011, 09:58
Before you do anything, I'd use it as is and see what you get... :)
krötenblender
02-24-2011, 10:59
Before you do anything, I'd use it as is and see what you get... :)
Well, I do use it and I like it despite it's condition. It's very nice on the R-D1 and on film. But on the E-P2 it seems to give odd results.
I send it in, because I have enough other lenses I like, so I can live without it for some time. And if they can really fix it, it's worth the money.
I also opened it, but the backside of the front lens is unreachable nevertheless. It' glued into some kind of tube with some other lenses. I guess, with my tools I cannot reach the spotted side without breaking the thing.
hexiplex
02-24-2011, 15:38
When you get it back, please share the results!
krötenblender
02-24-2011, 20:38
When you get it back, please share the results!
Promised .
m.galimathias
03-13-2011, 11:17
Are there some news?
krötenblender
03-16-2011, 14:10
Are there some news?
Not yet. I was very busy... I hope to send the lens on friday or saturday.
Update 20/3/2011: The lens is on it's way to www.kamera-service.info (http://www.kamera-service.info).
Update 25/3/2011: It's there... Now I'm getting nervous... ;)
krötenblender
03-28-2011, 07:54
It's back:
http://www.mempool.net/galleries/misc/M-Rokkor-2828-NoSpots.jpg
I'm impressed... Decide yourself, if it's worth the money, I have to pay 200 Euros. But for me it's worth it, since I really like the lens. The dust in the picture is not in the lens, but on the lens... My fault.
Kavenzmann
03-28-2011, 08:58
Same lens, same problem - same repair-service, same money
I'm also impressed. Looks like new!
krötenblender
03-28-2011, 09:12
Same lens, same problem - same repair-service, same money
...and same day. :eek: - I hope, they did not switch our lenses... :D
First Images with R-D1 and E-P2 look very promising. No faults to see. I really love that lens, especially on my CLE. I'm really looking forward to the first roll with the 28 and Ektar 100.
jsrockit
03-28-2011, 09:31
Is there a huge difference from before?
This is very impressive. I may do the same.
krötenblender
03-28-2011, 11:29
This is very impressive. I may do the same.
Yes, and it also a very nice lens on your new toy, the E-P2.
Yes, and it also a very nice lens on your new toy, the E-P2.
This is also my thought. It would be a sharp 56mm 2.8 lens.
I need someone located in the USA to do the cleaning.
krötenblender
03-28-2011, 11:50
Is there a huge difference from before?
Not sure, if the difference is 200 Euros big, but there is a difference. I think, I will try to make some tests on the weekend to see, how contrast improved.
At least a visible foggy spot in the center of images is gone. I don't know, if this is simply caused by cleaning the lens or by the spot-repair.
I was happy with the image-quality of the lens before, though, but a little bit unsure.
hexiplex
04-03-2011, 10:54
That looks great, I haven't seen any ill effects in the rolls I've shot with the lens thus far, except maybe some strange smudgelike flares in the bottom when shooting against the light. And ofcourse some pretty low contrast. But I will be sending in my lens as soon as I get the money to do it, very nice results from the service. Do you know if the white spots have a tendency to return after service?
Thank you for remembering to share your experiences by the way!
back alley
04-03-2011, 11:41
big difference in the looks of the lens...very curious to see what the difference in images might be like.
krötenblender
04-03-2011, 11:42
Do you know if the white spots have a tendency to return after service?
No, can't say anything about that. But if they return, I will post.
Thank you for remembering to share your experiences by the way!
I promised...
krötenblender
04-03-2011, 11:49
big difference in the looks of the lens...very curious to see what the difference in images might be like.
Well, it's not that much of a difference. As I wrote before, I had a small foggy spot in the center of the image, which is gone now. But the lens was good before, so I expect only small differences, like improved contrast and less flares. Since I really like that lens, I think, it was worth the money.
back alley
04-03-2011, 12:14
the rokkor 28 is a great lens...i sometimes think of looking for a good copy so i might have a faster 28 than the cv 3.5 but one that is still just as small.
krötenblender
04-21-2011, 08:57
just curious, but did he also change the mount of the lens so that the right framelines come up on a M?
Of course not. It's the same lens as before.
Got this week my CLE with 28/2.8 back from Will van Manen.
CLE got CLA; new light seals, "flickering LED syndrome" repair...
Rokkor: white spots removed; mount changed to bring up the 28mm frame at the M
http://www.kv-page.com/rokkor.jpg
Unfortunately, a previous owner clean the coating off the frontlens...:)
kermaier
09-16-2011, 05:48
I had the spots in mine repaired by John Van Stelten at FocalPoint in the USA. It was great for a while, but then the lens developed haze in the front element group. DAG was not able to completely clean it out (but he did modify the mounting flange to bring up 28/90 frame lines on a Leica M camera, as well as mill 6-bit coding into it). The haze results in flare when pointed toward the sun, and maybe a bit lower contrast overall.
I don't really use the lens anymore since buying an Elmarit-M Aspherical 28/2.8, but in some ways I liked the M-Rokkor better.
::Ari
micromoogman
07-02-2012, 11:50
Anyone knows where these bubbles develop? Is it between a glued lens group or just on the surface of one element? If it's not in between it might be worth trying doing it yourself. Got one for $300 5 min ago and I must do something even if pics come out good...
Palaeoboy
07-02-2012, 18:43
Anyone knows where these bubbles develop? Is it between a glued lens group or just on the surface of one element? If it's not in between it might be worth trying doing it yourself. Got one for $300 5 min ago and I must do something even if pics come out good...
The front glass of the Rokkor 28 is a single element so its not a glue or separation problem. The white spots are crystals that leech out of the black paint that coats the side rim of the element painted on to reduce internal reflections. Thats why the appear as a perfect circle around the lens when you look at it straight on. The process is accelerated by heat. The crystals can continue to form until they break off and find their way onto the inner surface of the front element whereby they can etch into the lens coating itself. Not all go that far. Most never get past the rim which has little effect as its not in the optical path. Its fixable but the hard part is that the front element is difficult to remove from the element tube. It may be more than a do it yourself job.
I had the spots in mine repaired by John Van Stelten at FocalPoint in the USA. It was great for a while, but then the lens developed haze in the front element group. DAG was not able to completely clean it out (but he did modify the mounting flange to bring up 28/90 frame lines on a Leica M camera, as well as mill 6-bit coding into it). The haze results in flare when pointed toward the sun, and maybe a bit lower contrast overall.
I don't really use the lens anymore since buying an Elmarit-M Aspherical 28/2.8, but in some ways I liked the M-Rokkor better.
::Ari
Ari: Wasn't your lens without the white spots at first?
kermaier
07-02-2012, 20:33
Ari: Wasn't your lens without the white spots at first?
It had a variation on the white spots theme: translucent spots in a similar uniform pattern. John at FocalPoint said the cause is the same -- condensation interacting with metallic compounds in the coatings to produce crystalline bubbles.
I'm still planning to send it back to John to see if he can get rid of the garden-variety haze it currently has. Then I'll have to decide which of the M-Rokkor and the Elmarit-M stays and which goes....
Cheers,
Ari
micromoogman
07-03-2012, 02:55
It so strange that this phenomena doesn't affect the image. Are these spots visible if you let the light come through the lens and get focused on a white paper? They must be visible at some point of focusing distance...not necessarily within the range in the camera. Also worse with small aperture?
Might it be possible to keep the front glass in the barrel and clean it from the inside? Dismantle aperture blades and the other lens groups. Just thoughts...
Might it be possible to keep the front glass in the barrel and clean it from the inside? Dismantle aperture blades and the other lens groups. Just thoughts...
I thought of doing that but it looked easier to cut the front element out.
Palaeoboy
07-03-2012, 07:03
It so strange that this phenomena doesn't affect the image. Are these spots visible if you let the light come through the lens and get focused on a white paper? They must be visible at some point of focusing distance...not necessarily within the range in the camera. Also worse with small aperture?
Might it be possible to keep the front glass in the barrel and clean it from the inside? Dismantle aperture blades and the other lens groups. Just thoughts...
I think your misunderstanding where the spots are in the early stages. They are not on the optical front and rear of the element, they are on the side of the element which is painted black to prevent internal reflections. They are visible because of the way the sides are angled that permits you to see them as a ring. But in the early stages its not on the optical path and therefore doesnt have any impact on image quality. In the later stages however the crystals break off and then find there way onto the rear surface of the front element. Its at this point it does affect lens performance and can etch into the multicoatings of that element. For some reason only a few get to this later stage. Maybe the paint where the crystals leech from was applied thinner so there isnt enough to create large enough crystals to get to the damaging phase. The phenomenon is not unique to this lens. I have photos of Schnider, Zeiss Hologon and Elmarit lenses that have had the same problem, its just the instances with the Rokkor are more frequent.
micromoogman
07-03-2012, 07:44
Thanks for clarification. I have those bubbles on a Zuiko 50/1.4 too, but those are clearly limited to the outer region of the lens element/group, these are all over. These also look more like micro spots than transparent bubbles.
Shouldn't every "bubble" create a lens in itself, changing the path of the rays of light?
http://img.tradera.com/mega/034/146245034_3.jpg
My Rokkor has very few white spots. In fact, I sold the lens at RFF as not having any white spots, but the buyer sent the lens back because he found white spots. I am a very happy dude that I got my lens back. On the EP-2, it is a normal lens with 2.8 max aperture.
I had one I had bought new, accidentally -- it was shipped in a 40mm box, and my local shop gave it to me for the price of the normal lens with the CL kit I was buying.
I had it for years, and as I recall, the white spots appeared in a much reduced form.
I was told it was not repairable, and sold it on at a reduced price to a happy dealer, I probably should have tested the performance, but we are kind of hard wired to see any defect in a lens to be, perhaps, more important than the subject and the guy behind the camera.
At shows, people always want lenses and bodies to be pristine in looks, even above function.
My local shop knew I was looking for an M2 user, and took one in trade with scratches on the body and a hazy lens, they did not even ask, just shipped it to me for the trade in price,-- they did not want in in the shop-- new customer wanted to trade.
I got the lens cleaned, turned out to be a simple job, and found the camera had been CLA'd and had the M4 frames installed, all for a highly reduced price mostly because the PO had scratched up the top mainly from installing and removing the meter. Yeah, it has a few "experience" marks and a slight ding.
If I pull one out to use, this is a good choice.
I'll make up a different story if I put it up for sale.
And, now, I would not have sold the 28mm Rokkor, more hind sight?
-- OTOH, got a good deal on the CV 28, some wear showing, so got it right, with adapters and M8 UV filter--
BTW, Looks like a nice cleaning job, nice of you to keep things posted on the long term.
Raid, glad you got it worked out right.
Regards, John
vBulletin® v3.6.8, Copyright ©2000-2013, Jelsoft Enterprises Ltd.