Focus problems in Canon zoom lens EFS 17-85mm 1:4 - 5.6 IS USM (focus hunting) PART 1
HTML-код
- Опубликовано: 4 окт 2024
- This Canon zoom lens EFS 17-85mm 1:4 - 5.6 IS USM have problem with the focus hunting, so I try to fix it, but could not.
Here are some link's to different repair tool's and lubricating stuff:
"ORBIT" HEPA Blower:
photosol.com/p...
You can buy it here:
www.adorama.co...
"Liqui-Moly" LM 50 Litho HT:
www.amazon.co....
"Liqui-Moly" LM47 MoS2 grease with Molybdenum disulfide:
products.liqui...
or on Amazon:
www.amazon.co....
Contact glue:
www.loctitepro...
Japan Hobby Tool rubber cone:
www.amazon.com...
18 different size rubber repair tool's:
www.amazon.com...
You can also buy this set.
Lens Repair Set with pointed, flat, half flat tips:
www.amazon.com...
JIS cross head screw driver's:
www.amazon.com...
Or this set, that is the set I use:
eustore.ifixit...
Lens cleaning wipes (PEC-PAD):
www.amazon.com...
Thin Cotton Buds x 200 you can buy them here:
www.muji.eu/pa...
DSLRKIT Pro Lens Vise Tool Repair Filter Ring Ajustment Steel 27mm to 130mm:
www.amazon.com...
Japan Hobby Tool Helical Grease Made in Japan:
www.amazon.com...
Loctite 222 50ml Threadlocker
www.amazon.com...
the problem is focus position sensor is dirty, its transparent plastic optic inside the focusing mechanism. there are 2 of them one is below and long, one is above and short. thoroughly cleaning both of them with lens cleaning liquid and rub dry with lint free tissue will restore correct functionality of autofocus at long (in fact at any) focal length. this is not hearsay, i did this on my own 17-85 as many people shared and recommended this method in the net... i let the problem stayed for years as i usually have no problem using it in manual focus mode. once i did the fix, my lens is like new again. if someone charged you for USM motor replacement, you have been conned, the fact that usm motor is hunting right and left, meaning the motor is doing fine, its just positioning it in the correct position is the problem. you need to replace usm motor only when the autofocus is not moving at all or moving very slowly (low powered)
Thank's for this useful information, I will take a closer look sooner :-)
Can you link to a picture or a diagram of where these position sensors are? Or if they are visible on mikeno62's video a timestamp? Thanks for the information though! mikeno62, epic teardown video, thank you as well!
Thank's James, if you look at 40:39 where I take out the little brass with a small plastic window / lens, you see the black optocoupler where there is a sender infrared led and a reciver diode, on each side, it's part of the counter circuit. So when the USM motor move the focus system, the optocoupler and the electronic circuit will count how many lines on the long curved plastic has moved and in that way figure out how much has the focus moved, of course together with the focus circuit in the camera. (I hope the explenation is correct, because I have NO service manual for this lens))
As I understand it, the optocoupler will get dirty during the years of use, so the 2 very small lenses in the optocoupler need to be cleaned with a small cotton bud and Isopropylalcohol 99%.
Thanks, yes that all sounds correct. I have built cameras/printers and many position detector setups work that way. I also just found this guy www.flickr.com/photos/nivek_woods/7506211982/in/album-72157630430286912/ from his description there was a very feint scratch in the encoding strip (the clear piece with the inscribed lines on it) and this would certainly be enough to throw off the position detection. Since he couldn't actually remove the scratch he very slightly realigned it with respect to the sensor and LED and that was enough to get his lens to work again. The sensor/LED probably don't use the entire width of the encoding strip so this makes sense. With your video I feel like I have a good shot at repairing my lens, thanks again.
this is where he mentions shifting the LED/sensor with some pieces of tape as shims! www.pbase.com/barry_2718/efs1785mm
Thank-you for this video, by following it I was able to fix my Canon EF-S 17-85mm that would usually (but not always) focus in the brightest of light. In any other lighting it would hunt, typically from closest focus to infinity (so I knew the motor was good and figured dirt was preventing enough light from reaching the focus sensors). The only difference in my procedure is that I did what some others that commented here did in completely removing the large semi-circle lens and cleaning all sides of it. I used 91% isopropyl and lint-free Kimwipes. With a set of precision screwdrivers plus care and patience a do-it-yourself-er can accomplish this. It took me right at two hours from start to testing the lens.
It was really good that it was working for you :-) and really good info about the cleaning issue. I will also make one more video that I will show, what actually happen when cleaning the parts that people mention in the comment.
Cheers
Kenneth
Merci pour cette vidéo qui m'a permis de régler mon problème d'autofocus en nettoyant la règle transparente du codeur, ainsi que la tête de lecture. Vidéo très utile aussi bien au démontage qu'au remontage. 👍
Thanks lot! I've resolve finally this old trouble with this lens! thanks lot!
Hi mikenon62 thank you for sharing this video! I had exactly the same problem as you did show at the start of this video. So I did do exactly the same as you did show in this video and it worked for me, the lens is working fine again.
There was one thing I did do extra which I noticed you didn't do! you did clean the small and large transparent plastics but not the lens from the sensor which sit just above that. I did clean that one also with a optical cleaning tissue and some lens cleaning fluid. when you have some time you can also try to do that and hopefully your lens will work fine after that, good luck!
WOW, thank's a lot for the info Gerrit, I have just buy a used version that have the same issue, so I will make another film about that issue in the lens.
Cheers
Kenneth
Good work, thanks! I suscribed your canal, it's very interesting and instructive!
Thank's Ramon, there will be more film's from me sooner.
CheersKenneth
Hi Kenneth! The filter on the lens is. powered (1.1X), for close-up. Have you tried the lens without it? K.
It's not a close-up filter, it's a filter with a warmer tone than normal skylight filter.
🤘
Hi, I open and close my Canon efs 24mm 2.8 trying an anamorphic hack... now my manual focus doesn't work except when I press the AF button... Any suggestions
Yep, mine has died and it would cast £150 to repair from Canon.
Where did you get the JIS bits from ? Amazon has Moody Tools JIS screwdriver, I don't know if it's worth or not.
The flex to the IS assy is easy to tear during reassembly, because the barrels tend to rotate.
I really like the "WERA" brand, the bits is SO MUCH better than many other brand's I have try (it has been a lot's of try and errors) that's why I use the WERA crosshead screwdriver's today.
This is the bits for the JIS, CJIS screw's, you will find it here on Wera's site:
products.wera.de/en/tools_for_power_use_the_range_of_wera_bits_bits_for_phillips_screws_851_1_j.html
And here you also can buy the set, the same I use:
www.machinemart.co.uk/p/wera-kraftform-kompakt-11-piece-sb-electronics/
Yeah, that's correct about the flex cable Dorf.
CheersKenneth
Can I get a pair of new lens focus brush Sir?
so better not buy this lens...