Extension Tube Info please

[Dennis_Hammer]

I have to do a product shoot that is going to require me to shoot macro. I have ordered the canon macro 50, 100 & 180. My question is this I have been looking at the canon and the kenko extension tubes. Is there a difference? Which do you prefer? Which sizes do you use most often? I am normally the kind of guy who likes to stick with Canon accessories for Canon and try to buy the best available whenever possible. So I know there is no optics in the tubes so does the Canon ones offer anything the Kenko's don't? Thanks in advance for any info you can provide.

[Deckham]

As far as I know, these kind of extensions are all similar and make no difference. Aside from, Canon white extenders are apparently weather-proofed to the level of L lens.

[LordV]

Suspect you may have a bit of overkill on the lenses apart from the 50mm which only does 0.5:1 mag max the other two have the same max magnification of 1:1. You will obviously get differences though in background OOF areas.
I'd stick to the 100mm at first.
Going onto the tubes you need to get a set which adds upto 68mm total (eg 3 tube Kenko set). The number you use just alters the max mag you will get. As commenyed above canon tubes may be slightly better build but do not work any better than the Kenkos.
So with the 100mm macro lens you will get about 1.5:1 max with 33mm of ext tube and around 2:1 with 68mm ext tube.
Brian V.

[Glenn NK]

I read a review a year or so ago that concluded that Kenko air was as good as Canon air.

I bought my Kenko tubes about two years ago, and my 17/55 EF-S lens WILL NOT fit onto the tubes, but having an f/2.8 100 macro, there is no need to use the 17/55 with tubes.

http://www.the-digital-picture.com/Reviews/Kenko-Extension-Tube-Set-Review.aspx

[Dennis_Hammer]

Thanks for the info. I bought the lens because this is an ongoing contract that will require me to sometimes photograph installed products so I can not be sure of what focal lengths will be needed. I took into account that I would buy these in the original quote for the first four shoots, so they are basically paid for plus normal profit. Your info has been very helpful.

Thanks
Dennis