03-09-2019 12:48 AM - edited 03-09-2019 12:53 AM
A while back I was having intermittent problems just on a Canon 85mm f/1.8 USM lens. All my other lenses work fine. Sporadically I would get, "Communications between the camera and lens is faulty. Clean the contacts". It seemed humidity played a part but I could never consistently reproduce the problem. I wound up buying a second 85mm brand new. Now, as of today, this lens is having the same problem, but all the time. My F-stop is 00 so I know there's something not right. The contacts look clean. Like I said it's only on these 85mm lenses. I did try using a soft cloth to wipe the contacts, nothing abrasive, but no luck. Any thoughts are appreciated.
Solved! Go to Solution.
03-09-2019 10:23 AM
"I wound up buying a second 85mm brand new."
Call Canon 1 (800) 652-2666. If it is brand new and it is from a real Canon USA dealer, Canon will get it right. If you are buying grey .......... well you'er on your own.
BTW, it is unlikely the contacts (other lenses work OK) but if you must clean them use a q-tip and denatured alcohol. Nothing else!
03-09-2019 05:57 AM
If you are getting an aperture setting of F00, then the lens is not communicating with the camera body. Wherever you bought the lens, they seem to have a bad batch of the lenses. Get a refund, and buy the lens elsewhere.
03-09-2019 10:23 AM
"I wound up buying a second 85mm brand new."
Call Canon 1 (800) 652-2666. If it is brand new and it is from a real Canon USA dealer, Canon will get it right. If you are buying grey .......... well you'er on your own.
BTW, it is unlikely the contacts (other lenses work OK) but if you must clean them use a q-tip and denatured alcohol. Nothing else!
03-12-2019 10:44 AM
@ebiggs1 wrote:"I wound up buying a second 85mm brand new."
Call Canon 1 (800) 652-2666. If it is brand new and it is from a real Canon USA dealer, Canon will get it right. If you are buying grey .......... well you'er on your own.
BTW, it is unlikely the contacts (other lenses work OK) but if you must clean them use a q-tip and denatured alcohol. Nothing else!
Someone with more knowledge of chemistry than I have may want to weigh in on this, but I'd be inclined to prefer isopropyl alcohol over denatured alcohol, precisely because it's already poisonous and therefore doesn't need to be "denatured" (in order to prevent it from turning up in untaxed liquor). The whole point of using alcohol to clean contacts is that in its pure form it doesn't leave a residue. By definition, denatured alcohol contains an adulterant; and depending on what that adulterant is, it might conceivably leave a residue.
03-12-2019 11:17 AM
Ethyl Alcohol vs Isopropyl Alcohol.
03-12-2019 11:40 AM
@RobertTheFat wrote:
@ebiggs1 wrote:"I wound up buying a second 85mm brand new."
Call Canon 1 (800) 652-2666. If it is brand new and it is from a real Canon USA dealer, Canon will get it right. If you are buying grey .......... well you'er on your own.
BTW, it is unlikely the contacts (other lenses work OK) but if you must clean them use a q-tip and denatured alcohol. Nothing else!
Someone with more knowledge of chemistry than I have may want to weigh in on this, but I'd be inclined to prefer isopropyl alcohol over denatured alcohol, precisely because it's already poisonous and therefore doesn't need to be "denatured" (in order to prevent it from turning up in untaxed liquor). The whole point of using alcohol to clean contacts is that in its pure form it doesn't leave a residue. By definition, denatured alcohol contains an adulterant; and depending on what that adulterant is, it might conceivably leave a residue.
Denatured alcohol is "denatured" usually by adding methanol to ethyl alcohol making it poisonous but having minor alteration on its prosperities.
03-13-2019 12:27 AM
@CaliforniaDream wrote:
@RobertTheFat wrote:
@ebiggs1 wrote:"I wound up buying a second 85mm brand new."
Call Canon 1 (800) 652-2666. If it is brand new and it is from a real Canon USA dealer, Canon will get it right. If you are buying grey .......... well you'er on your own.
BTW, it is unlikely the contacts (other lenses work OK) but if you must clean them use a q-tip and denatured alcohol. Nothing else!
Someone with more knowledge of chemistry than I have may want to weigh in on this, but I'd be inclined to prefer isopropyl alcohol over denatured alcohol, precisely because it's already poisonous and therefore doesn't need to be "denatured" (in order to prevent it from turning up in untaxed liquor). The whole point of using alcohol to clean contacts is that in its pure form it doesn't leave a residue. By definition, denatured alcohol contains an adulterant; and depending on what that adulterant is, it might conceivably leave a residue.
Denatured alcohol is "denatured" usually by adding methanol to ethyl alcohol making it poisonous but having minor alteration on its prosperities.
Sounds sensible. Thanks for the clarification.
03-13-2019 02:23 AM
Denatured alcohol has always been the goto solvent for removing grime from hard surfaces, appliances, machinery, finished products and lens contacts. It is my preferred agent although I am sure others will work.
However, I still maintain cleaning the lens contacts is a rarely needed exercise. But if you must, denatured alcohol is a highly effective solvent and cleaning agent.
03-09-2019 01:27 PM
03-09-2019 10:28 PM
I'm a Canon CPS member so I e-mailed them stating that the issue has occured with two of the same lens purchased at different times. I asked if they would replace both lenses at no cost. I've had similar experiences in the computer world with defective mainboards after warranty has expired. "Defective" is defective and they should have made the lens the right way in the first place.
I compared the lense Ihad that has the issue some of the time to the lense that's having the problem full time. Nothing appears to be wrong with the contacts. One lens fires just fine and the other not at all. Yet both lenses experience the same issue.
I have four other Canon-brand lenses that don't have the problem.
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