Extension Tubes on EF-S lenses

[warrick]

Hi All,

Does any one know about these
Extension Tubes
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&category=4687&item=7520200507&rd=1
Will they be OK to use with the 17-85 EF-S and a 20D
What length of tube would be best with this lens to achieve 1:1

Warrick

[etaf]

i have used these tubes for a while now on a EOS5
TELEPLUS AUTO EXTENSION TUBE (SET OF 3) CANON EOS £79 in UK new a set of three. so you may wanrt to check that price and local availability.
Remember theres no glass in extension tubes, so you just need to make sure all the controls are passed from lens to camera, autofocus etc.
http://www.marietta.edu/~mcshaffd/macro/mags.html
http://www.northrup.org/equipment/extension.htm

[warrick]

i have used these tubes for a while now on a EOS5
TELEPLUS AUTO EXTENSION TUBE (SET OF 3) CANON EOS £79 in UK new a set of three. so you may wanrt to check that price and local availability.
Remember theres no glass in extension tubes, so you just need to make sure all the controls are passed from lens to camera, autofocus etc.
http://www.marietta.edu/~mcshaffd/macro/mags.html
http://www.northrup.org/equipment/extension.htm


Thanks for the reply but the reason why I asked about these particular tubes is they state that they are for the EF-S lenses so I'm assuming that all the necessary controls are passed through

All of the other tubes I have seen are only for the EF lenses not EF-S lenses

The other part of my question was to find out which length is the best for the 17-85 EF-S lens, there seems to be a few different sizes available and I am having trouble finding out what the differences are.
Maybe someone could post some pics done with the same lens and different tubes

Warrick

[Bodog]

Sorry can't be more specific in my answer. Hopefully someone will chime in with the math. There is no one tube length that is best for your lens. Generally the more extension you have, the closer you can come to 1:1, and again generally, the longer the focal length of you lens, the farther you can be from your subject. at 17mm, you would have to be almost be touching the subject to achieve life size. 85mm should give you more working room. Extensions are stackable BTW.

[gasrocks]

General rule: if length of extension is = to length of lens (ex: 100mm extension on a 100mm lens,) you get 1:1 life size. 45mm ext on an 85mm lens = about 1/2 life size. But....... I wouldn't be putting extensions on that lens. Have any other lenses?

[warrick]

General rule: if length of extension is = to length of lens (ex: 100mm extension on a 100mm lens,) you get 1:1 life size. 45mm ext on an 85mm lens = about 1/2 life size. But....... I wouldn't be putting extensions on that lens. Have any other lenses?

I have a 100 - 300mm USM
I am trying to find an inexpensive way to play with macro without the cost of a dedicated lens, if I find that I like taking macro shots I will get one in the future

Warrick

[Bodog]

The 100-300 does a great job with ext tubes. You'll like it. You may have to manual focus with stacked tubes. I've had good results using a 25mm extension.