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Author Topic: question about extension tubes?  (Read 1926 times)

Anthonyhnj

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question about extension tubes?
« on: March 05, 2013, 10:04:02 PM »
I was in B&H today and wanted to pick up the Canon 25 extension tube.  Gentlemen helping me said that Vello just came out with a three-piece set of AF extension tubes for only 69.00.  So I purchased them, when I got home and opened the box there was some sort of grease on the inside contacts on all three tubes.  So much so, that there was even grease on  part of the metal mount.  I did not mount them to the camera and will return them and just get the canon tubes.  My question is, is it normal for there to be any sort of grease on the contacts.  Is it safe to just wipe that grease off and mount them or would someone be taking a risk.

thanks,
anthony
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question about extension tubes?
« on: March 05, 2013, 10:04:02 PM »

Mt Spokane Photography

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Re: question about extension tubes?
« Reply #1 on: March 05, 2013, 10:20:36 PM »
Its not normal to have a excessive amount, I'd also be concerned that more might flow out of the tube in hot weather and cause you to get a cleaning bill for your camera that exceded your savings on the tube.  I'd also check to see if it has a plastic barrel, and join the three togather and flex them to see if a gap opens up.  That is very bad and will ruin a image if they do that.
If you want a third party tube, get a set of Kenko tubes, they are excellent, and you get a whole set from B&H for $190.  http://www.bhphotovideo.com/c/product/375102-REG/Kenko_AEXTUBEDGC_Auto_Extension_Tube_Set.html
 
You might find a used set on Craigslist or ebay as well.
 
I have a set of really old Rokinon Tubes that came with a old film SLR, so they were basically free.  They are plastic, and the lens mount flexes easily if you put much force on them.  This makes them worthless for all but light lenses.  They are ok with my 100L and 135L, but not with a longer or heavier lens.
Since I don't use them except once every couple of years to test something out, they work fine, but for serious photography, I wouldn't bother with them.

East Wind Photography

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Re: question about extension tubes?
« Reply #2 on: March 05, 2013, 10:50:19 PM »
No grease and nothing else should be on the contacts.  Anything on them will attract dust and dirt eventually leading to AF problems and other issues like error 80.

The only thing to use on the contacts are a high grade contact cleaner specifically formulated for gold contacts and that is plastic safe.  I use a product made by Caig.  Apply it to a q-tip and clean the lens and camera contacts about once per year. 

I would return those tubes and show them to the store manager.  They will take them back but more important is to show them why they are crap so they return them as well.  You will find the canon ones very solid, well built, and grease free.  As usual you pay more but get something that will give you years of trouble free service.

Anthonyhnj

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Re: question about extension tubes?
« Reply #3 on: March 06, 2013, 12:14:49 PM »
Thank you both for the replies, it's just what I figured. I'm going to return them and buy the Canon tube. Thanks

Mt Spokane Photography

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Re: question about extension tubes?
« Reply #4 on: March 06, 2013, 12:33:39 PM »
I'd just pass on contact cleaners.  One of my jobs before I retired was to test them along with lots of other materials hyped by tons of salesmen with wild claims.  They would typically get to a high ranking person at one of our customers, who would then ask our opinion, and we needed a technical response.  The best ones did not cause any harm, but were not really worthwhile either, so we gave the customer the test results and told him that we did not recommend their use.
 
One thing of concern is that cleaners are solvent based, they dissolve grease and oils.  Those contacts in a TC are spring loaded and have lubricant to keep them from sticking.  The lubricant is on the hidden springs and should not be visible, but using a solvent based contact cleaner can dissolve the lubricant and flow it into your lens, mirror, sensor, mirror box, places where it doesn't belong. It can spray out thru piston action when you attach to the lens or to the body and the contact is depressed.
 
I'd recommend avoiding contact cleaners.

RGF

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Re: question about extension tubes?
« Reply #5 on: March 06, 2013, 12:39:56 PM »
As the little birdie said, "cheap, cheap, cheap".

East Wind Photography

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Re: question about extension tubes?
« Reply #6 on: March 06, 2013, 01:03:04 PM »
This is what I use...but sparingly and as I mentioned I use a Q-tip and then a dry one to wipe off any excess.  You are not soaking the contact just cleaning the surface.  This is what is used in the aircraft industry for contact reliability.

http://store.caig.com/s.nl/sc.2/category.299/.f

I have purchased used lenses in the past for cheap.  Supposedly had AF problems.  The contacts were cleaned with this stuff and the AF issues went away.  I've since sold the lenses for more than I paid.  Granted the contacts were in very bad shape but this stuff cleaned them completely.  For most you are better off not touching the contacts at all but there are times when a cleaning is necessary, especially if you notice AF issues or getting strange error messages on your camera.




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Re: question about extension tubes?
« Reply #6 on: March 06, 2013, 01:03:04 PM »