Extension tubes question

Hello,

Can someone tell me the difference between an inexpensive (£7.98) eBay extension tube

http://cgi.ebay.co.uk …rs_ET&hash=item​5636b67fe3

and a more expensive (£135) Kenko extension tube?

http://www.amazon.co.u​k …ics&qid=1276385​372&sr=8-2

Thanks in advance,

Mike
____________

The main difference between the "UK Macro Extension Tube Ring 4 CANON EOS EF DSLR & SLR" and Kenko extension tubes is that the former does NOT have any electronics, while "Kenko's Auto Focus extension tubes are designed with all the circuitry and mechanical coupling to maintain auto focus and TTL auto exposure with most Canon ... lenses given there is enough light to activate the cameras AF system properly." However, manual focus may be the preferred method. There may also be better build quality with the Kenko tubes.

Not simply to 'maintain AF' and 'TTL autoexposure'!...the electrical contacts even control when the lens stops down to shooting aperture, allowing you to focus with the aperture wide open.

Im looking to get one to have macro capability on my lenses rather than buying an expensive dedicated macro lens.

Is it recommended to go with a more expensive one? Is the difference something that would really make a big difference?

What is TTL autoexposure?

How does the aperature differ from a cheap to expensive one?

Thanks,

Mike

Canon normally control the aperture from the body. Disconnect the aperture circuit and suddenly the normal EF lens is wide open no way to alter it, as Wilt has already said.

And thats exactly what you are doing with extention tubes that have no electrical contacts. Although I'm sure I've read that its possible to buy addition cables, connection rings etc. that get around the problem, that will be an expense in itself.

The other solution is to use a manual lens of course, which has manual aperture control.

"TTL autoexposure" is an abbreviation for through-the-lens auto exposure. What this means is that when when your camera is set at, for example, P(rogram) mode it will evaluate the light and set the aperture and shutter speed for proper exposure. With the inexpensive tubes, you will have to set these manually. Also with these tubes you have no control of the aperture which may translate to it being fixed at maximum setting; not good for closeups due to shallow depth of field.

Bottom line: go for the Kenko extension tubes. They cost more but it's worth it in the long run.

Trying to do macro work with a lens aperture which is not stopped down automatically at the time of exposure will only work for inanimate objects or immobile objects...it is too hard to focus when stopped down, and you have too little DOF at macro distances with a wide open lens. Foolish economizing if you purchase the cheapo extension tube without electrical signals passed between EF lens and body. It (cheapo tube) works only if you have an older manual focus lenses that have integrated aperture control ring on the lens...then you can focus wide open and then easily and immediately stop down the lens for exposure!

Thanks for the replies. Sounds like extension tubes with circuits are the way to go.

Is Kenko the best choice or is there another good choice?
Is it better to have a tube set? the Kenko one comes in a set with different 'mm' lengths. Or there are the thinner one lenght ones by Canon etc.

Cheers,

Mike

Kenko are popular and affordable. Canon offers extension tubes but cost more. Being that they are filled with air, not sure if one is better than another. Looking to get some myself soon. Read up on the subject by using the search feature for "extension tubes" in the macro sub-forum. The macro forum I am talking about is in the "Talk about Photography" forum, the other macro forum is just for posting pics. Tons of info there, including a sticky up top from Lord V (great macro photographer).

Kenko tubes are fantastic.
I wish I bought some while I could.
50mm f/1.8 + Kenko tubes = YESSSSSS!

Hi Mike,

I bought a set of 3 extension tubes made by Zeikos whilst I was in Miami earlier this year for $60.00 from a wholesaler. You can get these same ones from other suplliers - possibly here in the UK - (I have not checked this though!).
B & H Photo Video are selling these on this website:
http://www.bhphotovide​o.com …87477&Q=&is=REG​&A=details

They do work very well and yes, they do have electronic/electrical contacts too!
There are a couple of things to watch out for:
1.> you cannot attach all 3 at once
2.> you can attach any combo of 2 extension tubes
3.> if the camera fails to Turn-On. Do not Panic, simply Switch-Off, remove the Battery and all will be fine

Its worth looking into - simply because this set is so cheap and it works!

JackLiu wrote in post #10350783
The main difference between the "UK Macro Extension Tube Ring 4 CANON EOS EF DSLR & SLR" and Kenko extension tubes is that the former does NOT have any electronics, while "Kenko's Auto Focus extension tubes are designed with all the circuitry and mechanical coupling to maintain auto focus and TTL auto exposure...

No extension tubes that I have ever seen has any electronic components in them.

The significant difference between the cheapest extension tubes and Canon's or Kenko's tubes is that Canon's and Kenko's have simple wires and spring-loaded contacts that keep the lens connected to the camera electrically when the extension tube is between them.

Of course, there could also be mechanical quality differences between the cheaper units and the better ones.

I use the Kenko set with three different tube lengths.

Thanks for all the replies!
Sounds like most people prefer Kenko tubes.
DANATTHEROCK - cheers for the macro forum suggestion, it has some good reads!

Curious as I was about macro photography, I couldn't resist the cheap deal and went in for the UK Macro Extension Tube Ring 4 CANON EOS EF DSLR & SLR. I was prepared to try out the manual focus on my humble Canon 75-300mm. I can only state that I was not dissappointed! If a picture is worth a thousand words....

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