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- เผยแพร่เมื่อ 9 ต.ค. 2024
- There was A LOT Fungus in this Canon EF 28 70mm 1:2.8 L USM, the problem was, to come in to the inner lens system there is part of the aperture system. you REALLY HAVE to disassemble the hole lens.
The inner lens group is NOT ment to be disassemble, but it's not a problem do it, use a little screwdriver to get the edge away so you can come into the 2 lenses. You have to glue the edge of the plastic thing where the lens group is sitting in, when you put them back again.
To assemble the lens again just take care of wich ring comes first on, (FOCUS RING, next ZOOM RING.) well, i did it wrong in this movie :-(.
I could not take away the Fungus even with clean gasolin, because the Fungus has damage the inner lens toooo much :-(...
Hi, Thank you for your video. It was very useful. I have the same problem as yours, but I do believe it is glue separation in the doublet of the unit, which is a very common problem for this lens. Yours could be a compound problem with fungus and glue separation. Here is what I did to fix the lens. First remove the plastic clip/ring around the triplet of the inner lens group with an exacto knife; you will have to destroy the clip. remove the triplet from the housing and then the plastic airgap ring, then take out the doublet. Ususally it is the doublet that is causing the problem. Next, soak the doublet in methylene chloride (i got it from the chemistry department at the university, some paint thinner may contain the ingredient, but not very effective. You can improve the activity of methylene chloride by adding ammonia, but I did not.) It took couple of weeks with intermittant agitation and physical shear force and prying with finger nails to get them apart. Next clean the glue with methylene chloride in a well ventilated area. After cleaning the glasses, glue them back. I used Canadian Balsam, since it is easy to get apart if I make a mistake. I let the glue to cure over a month (the Canadian cold weather here makes it longer for the glue to cure.) Once glue is cured, clean off the excess with acetone or nail polish, then put it back into the house and re-assemble. The lens is working very well now. There is a guy in Taiwan who can do this job for 150 USD if you ship him the inner group. I could not justify the cost, so instead I spent over 10 hours on this job myself. Hope you can fix yours too.
Thank you very much! This was very helpful for assembling mine again :D
Hi Mikeno, first of all, thanks for all your videos. They are very helpful.
I have a 28-70mm 1:2.8L lens, but its taking pictures very soft loosing the sharpness. So I took it to a repair shop who told me that its the optical that is coming loose and it can't be fixed because there are no parts available. Would you please know what i can do in order to repair it properly bringing it back to a good usable condition?
I thank you in advance for your help!
Hi Omega
I'm actually right now working with a Canon 28-70mm 1:2.8L that have some loose lens elements in the middle of the lens, so I will make a film of that process and post it later.... It will great :-)
Hello Mike,
First thanks for the video. I have the same lens and the mounting screws broke free. I was lucky to find parts online. I did do a bone head move, when removing the aperture ring the blades came out. Do you remember which way the blades face when closed at f22?
Thanks
Carlos
Hi, very nice video.
Are you sure that it was fungus and not a cement deterioration over time ? It seams to be a pretty common problem with this lens sadly.
BTW, having your lens elements back in place without calibrating each must have resulted in a big loss in the image result of your 28-70, no ?
Yes it was absolutly fungus, i look in my microscope and i could see that it has damage the lens with grooves in the surface of the lens element, because the lens has been stored in a basement, that was a bit too wet, in too long time :-(.
All the lens element i took out, can ONLY sit in one position, there is no adjustment. If one have to micro adjust the lens, it will be the back element group or at the bajonet, with some very thin spacers, to get the right distance to the sensor.
mikeno62
mikeno62
Hi, thanks for the information. In fact, it seams that canon introduced some ways to calibrate the lens : I saw that the rings you have for the element between the focusing group and the lenses that are stuck between the 2 diaphragms are in plastic (4mins in your video). Both of my 28-70 L uses metal rings that you can use to calibrate your lens.
Second, the 3 screws holding the rear element have a huge impact on the focus plane : by adjusting this I had a huge difference in image quality.
And last of course, you can turn the front element to have it closer or further from the focusing element.
All those 3 changes makes a big difference in my own point of view.
And about the fungus effect, that is a shame... if it was only hazes it was perhaps possible to remove it completely... But with fungus, I have no tips for you. Sorry...
mikeno62 Ho... and one last thing : it is WAY easier to include the element you add in the barrel at 4mins... before :) You should put them in it before you include the inner barrel : it is safer
Lyze Kiel
Many thanks for the information about that lens, next time it will be way to easy' to dismantle and assemble.
Normaly i remove haze in lenses with clean gasolin, but in this lens, the fungud has damage the lens element tooo much :-(. During the years i have clean many many lenses with clean gasolin, with very good result and only few i could not save, because they was in a very bad condition.
Where are you located? I have three Canon lenses with fungus that need repair, 24-70, 100mm, and 20mm. I am tempted to do it myself but I think I'll mess up. What would this cost? What do you recommend I do. I am located in Key West, FL.
Hi, interesting and useful video.
I have a problem with one of the lenses sizing is unclear, your video is not shown as it is removed and replaced, it is by the bayonet. I want to do it. Say it will be difficult to replace, or is it more complicated than what you have done in your video? Sorry for bad english, interpreter translated Google.
Thank's, well, without seeing the lens, as I understand you, I would guess you want to change the back lens group, but there is a problem because you need to adjust the lens correct, after the assemble so focus is correct.
This clip helps me a lot.
Can you tell me why may Canon 28-70 f2,8 L, after changing focusing unit, is working in bad condition? focuses in small steps, sounds like is hitting something inside, and the focus goes to one direction only, from macro to infinity. Never came back! The seller of the focusing unit told me that the focusing unit was working just fine.
Please check your cables connection on the circuit board.
What is the name of the first lens element to be shown in the vid? I was told by the repair man that there are two lenses housed together and can't be separated. We are looking for a replacement part. However, it appears in the vid (if it is the same part) that you reassembled the "problemed" component which has successfully cleaned. Any suggestions or clarification would be welcomed.
f2mel2 It's correct that the first lens I show in this film, is the most inner lens group which is 2 lens element put together in a plastic ring with a tight fit. It is possible to take it apart, but VERY gently and just on the edge on one side ONLY of the plastic ring. Have no idea what's the name of that lens group is, and the part is the one which originally was in the lens.
Read also the "about".
Cheers
Kenneth
Hi, I bought on ebay this lens Canon EF 28 70mm 1:2.8 L USM and it is broken, the screws were ripped and the flexcable with six pins which makes the contact with the camera was torn and the other flexcable on the left from the previous flexcable is also cout. I want you to please tell me what does this second flexcable do, and where could i find parts to fix my lens, because it is old and i didnt find parts anywhere. Thank you for answering me and i wish you could help me with indications to fix my lens.
The 6-pin is from the aperture/diaphragm i believe. Very hard to get a hold on since its not being made anymore, like most parts from this lens. (Part number YG2-0173-000)
The one which also breaks is probably the one from the USM assembly, which does the focal lenght data.
Hi Ciprian
That's a shame to hear that some people send completely broken spare parts to other's, but I found a part's list for your lens and many other Canon lenses. There is also a Lens test chart: www.f20c.com/stuff/canon/
You can take a look on those site's, they maybe have the spare part's or know where to get them..
www.dhcameras.com/search.php?search_query=Canon+EF+28-70mm+f%2F2.8L+USM&x=0&y=0
www.procamerarepair.com/search.asp?keyword=Canon+EF+28-70mm&search.x=0&search.y=0
Cheers
Kenneth
Hi I would like to know the first part, the element you shined your little LED torch through just before you connected the aperture ring, it look to me like there was a light foggy haze in the element, you see I have this particular lens and I indeed took it apart because the same part was foggy only mildly tho, (the element) was wondering how to actually take this element apart so I can deal with the foggy crap... part is a pain to find online etc..
Hi Ross , the inner lens group is NOT ment to be disassemble, but it's not a problem do it, use a little screwdriver to get the thin plastic edge away (it lock's the one lens...), that ONLY hold the one lens, so you can come into the 2 lenses. You have to glue the edge of the plastic thing where the lens group is sitting in, when you put them back again.
To assemble the lens again just take care of wich ring comes first on, (FOCUS RING, next ZOOM RING.) well, i did it wrong in this movie :-(.
I could not take away the Fungus even with clean gasolin, because the Fungus has damage the inner lens toooo much :-(...
Hope it make sense.
Cheers
Kenneth
When taking apart the two lenses, I'm having a lot of difficulty getting the glue to separate from the other parts, any tips or tricks?
Around the edge of one side of the lens group they have fold a little edge of plastic, to keep the lens in place. With a small wire cutter you can gently unfold the edge and take out the lens.
Be aware of how the lens is faced, or make a small arrow on one side of the lens so you remember how the lens should sit correct.
Cheers
Kenneth
what size and type screwdrivers were needed thanks
Can I pay you to fix this lens for me? If so, how much?
Hi any tip about stuck focus in this lens. Sometimes it stucks... if i turn lens up side down it helps unstuck...
Thank you for this video! I need your help! i have a canon 28-70mm 1:2.8 ultrasonic lens. in your video marker 16:40 the green circuit board ring, i have but i do not have the black piece that is sitting on that piece. Do you have this part for this lens? I would appreciate any suggestions or help you can offer. Thank You!
+sharon bedingfield Sorry, I have no spareparts, it's real problem in this repair business, but do as I do, try to find a broken lens for spareparts.
Cheers
Kenneth
Yeah this is really messed up! I bought this lens used from a supposed reputable camera store...and according to canon the year i bought it they no longer had spare parts! The store went out of business here in Chicago...it's like buying a car, paying a lot of money for it...find out its a lemon! And then to top it off, there are no parts to fix it! I did not drop it it just came apart! It does not seem right the money i paid...they even sold me insurance for a year after I bought it! If there are no parts what good the insurance help!? Anyhow...thank you very much for responding...if by chance you run into this part...much appreciate your help...Thanks again! 😉
hi, did you recieve my message about my broken lense Canon EF 28 70mm 1:2.8 L USM?
Hi ciprian
No I haven't received your message, you could send it again...
Hi Ciprian
I'm not sure what second flex cable you mean, but I found a webshop where they maybe have the sparepart you need for this or other lenses.
www.procamerarepair.com/product_index.asp?page=5
Hope it will help you :-)
Hello, my 24-70 after the fall ceased to work well auto focus. Sometimes works well and sometimes doesn't work at all. But more often it doesn't work on zoom.
What could be ?
Jack Daniels Well, it can be many things that go's wrong but it could be some of the screws, that came loose in the zoom section, I have made a film about loose lens elements in a 24-70 L, which you can see here and maybe can give you an idea what to look after. Take a closer look on all the screws in the grooves, some of them can be loose and make the problems you describe.
th-cam.com/video/2cwCIZFtyIo/w-d-xo.html
Cheers
Kenneth