cheap extension tubes

[super duper]

So, I just impusle-bought some super (super super) cheap extension tubes on ebay. After I clicked "commit to buy" I read the fine print: No electrical contacts, will no meter on lenses without aperture ring......whoops!!

So, what are my options? Through them in the bin (then I'll be out a whole $6-). Or can I play with them on my lenses? Just have to guess with the exposure?? Or will that wreck my lenses?

Thanks for the help!

(if it helps I have a D300s, 18-200mm, 35/1.8, 135/2)

[ricktas]

Umm. Do you know what extension tubes are? I think you might be confusing them with tele-convertors? Extension tubes are just that, metal (usually) tubes, nothing more!

[super duper]

The write-up definatley sayes they are a set of 3 extension tubes that cannot meter......is that the norm for extension tubes?

[ricktas]

YES. I don't think you understand what extension tubes are!

[super duper]

okay Rick, no offense, but you're not helping. Yes, I know what an extension tube is, very simply. Its a tube that extends the focal length, so you can get in closer and thus increase your magnification. However, the extension tubes I've just purchased say they are incompatible with my lenses. I'm asking; how incompatible?? Will they wreck my lenses if I try to play with them?

[ricktas]

I may not be helping, but a bit of research by yourself, prior to buying would have alleviated this thread entirely. A quick google would have found that ALL extension tubes are just metal or plastic round cylinders, no electronics at all.

You have to get the right ones for your brand (cause they need to fit the lens mounting system), then you need to shoot all your photos in manual, including manually focusing. As long as you brought the ones for your camera brand, they will work.

[jim]

Extension tubes vary a bit. I wouldn't look for anything beyond a compatible mount for $6—as Rick says. But it is possible to pay a lot more and get tubes that allow full communication between camera and lens, including autofocus. Eg these:

http://cgi.ebay.com.au/ws/eBayISAPI....m=120731197559

Or at least I suppose so. I'll know for sure if my set ever show up.

[super duper]

Thanks for the help Rick. Yes, obviously research would've helped. I thought I knew enough, but I got confused when the website specifically said it wouldn't meter on lenses without an aperture ring.

Thanks for you "help", albeit without a healthy dose of condescension

Just out of curiosity, do you tell everyone who asks a question "you don't know what you're talking about" and "try google first"?

[Scotty72]

Rick is not quite right but, close.

You are getting extension tubes (for super close up) and telephoto converters mixed up.

Extension tubes are for allowing you to get your lens within centimeters of the subject.

They often do have electronics in them but they are for focusing- nothing to do with metering.

The telephoto converters make your long lens even longer (eg a 200mm lens with a 2x TC) will give you an effective 400mm reach. But yes, you do lose stops of light with the TCs.

Scotty

[super duper]

Thanks Jim, handy to know there are more technical ones.

[Scotty72]

BTW. Having forked out for expensive tubes that could focus, I think it a waste of money as by the nature of macro stuf, you tend to do much of it manually anyhow.

[ricktas]

T

Just out of curiosity, do you tell everyone who asks a question "you don't know what you're talking about" and "try google first"?

No, but if people buy products without researching them and knowing what they are getting BEFORE they buy.... condescension is appropriate at times.

[super duper]

condescension is appropriate at times

lol...but..for all your condescension, it seems...

Rick is not quite right

you don't know as much you think

[Kym]

I use these manual tubes, they work quite well.

NB: change the air as the polluted air from China reduces image quality

[KevPride]

No, but if people buy products without researching them and knowing what they are getting BEFORE they buy.... condescension is appropriate at times.

But sometimes the old adage "If you can't say something nice, don't say anything at all." applies.

[MarkChap]

Rick is not quite right but, close.

You are getting extension tubes (for super close up) and telephoto converters mixed up.

Extension tubes are for allowing you to get your lens within centimeters of the subject.

They often do have electronics in them but they are for focusing- nothing to do with metering.

The telephoto converters make your long lens even longer (eg a 200mm lens with a 2x TC) will give you an effective 400mm reach. But yes, you do lose stops of light with the TCs.

Scotty

lol...but..for all your condescension, it seems...

you don't know as much you think

well see now, a bit of research would have shown that in fact Scotty IS the one that is not quite right.
The electrical contacts in the better quality tubes DO indeed provide metering, which is more important than AF, as with macro most times you will use the good old move in and out way of manual focus, the contacts will then allow your lens (that has electronic aperture control) to close down to the correct aperture as set on the camera.
So in fact the contacts are required for metering.

[Scotty72]

Fair enough. I just wasn't going to go on to explain the loss of light and it's effects. A) I could think how to explain it simply (I know the what but - happy to admit - not the technical details) and I tend to agree with Rick: not explaining to ppl something they could easily find out..

[pixy]

AFAIK extention tubes allow you to focus closer they come in non-metering ( cheap ) and those that meter ( more expensive ).

Without an apture ring you will not be able to set apture. you will need auto tubes to work properly.

jack.

[jim]

My Kenko extension tubes referred to above arrived today, and they promise a lot of fun with my old macro lens, but also do intriguing things with the 300 f4. While they allow both AF and metering, I'd agree with Mark that metering is far more important. Metering is flawless, AF is seriously compromised (by the reduced effective aperture I presume). Not that AF matters much for macro anyway, but it's sad to see the 300 f4 hunting vainly to for focus at a couple of metres (it invariably goes the wrong way for some reason...)

But if you're into macro, I'd say they're well worth the $130 odd.

[Scotty72]

Ok, I've read up some more. Now I understand it a bit more.