I have a Canon with the 'kit' lens (which I barely use) and the 50mm f1.8
I would like to have a dabble in macro photography but don't want to spend a fortune. I'm thinking about using an extension tube (no s****ing at the back). I can't manually control the aperture on either of my lenses so I know I'll need one with the connections. I've seen this one: http://www.amazon.co.uk/gp/product/B00A40EVCO
So, how 'macro' would that make my 50mm lens?
As there are no optics in any of the tubes, is there any 'quality' reason to buy anything other than the cheapest one that will work?
And if it goes well and I decide I [b]am[/b] going to spend my dotage taking pictures of the mouth parts of dead wasps... are there any particularly good value for money Canon EOS macro lenses out there?
If it helps, I've had my eye on these for a while.
http://www.amazon.co.uk/Polaroid-Focus-Extension-Digital-Cameras/dp/B004VNBAT2
There are online calculatotors that will tell you the minimum focus distance you'll get with a given tube length.
Or go for a Raynox macro conversion lens, means your lens keeps all its functions and you can use it across a number of different lenses.
Here's the DCR250 http://www.raynox.co.jp/english/dcr/dcr250/indexdcr250eg.htm which is about mid-point in their range
Put the money you would have spent on macro close up rings etc etc into a third party macro such as Sigmas 100mm f2.8. You wont look back.
I've got a set you can borrow if you want to try before you buy - drop me a line. Tubes don't have any optics in them at all, AFAIK. I also beleive - though I am perfectly willing to be corrected - that tubes offer a better image than a clip on lens.
here's a sample
[url= http://farm8.staticflickr.com/7261/7657757672_c8a542c860.jp g" target="_blank">
[url= http://www.flickr.com/photos/n_b_t/7657757672/ ]Macro work[/url] by [url= http://www.flickr.com/people/n_b_t/ ]Notoriously Bad Typist[/url], on Flickr
There's a slight difference in price between a thirty quid add-on and a four hundred and thirty quid lens, though. Sure, buy crap and buy twice, but for occasional use it's tough (for me anyway) to justify that sort of price difference.
That Raynox thing looks interesting, mind. Glowing reviews on Amazon.
^what andy said!
you drop a hell of a lot of light from a macro extension tube set so exposure times get very high which then limits to very still days or studio work and the very very close focus to get the macro magnification becomes impossible to use of anything creepy or crawly.
good macro extensions will lock out the light and be non-reflective inside also but I would put the money towards a good 100mm macro if at all possible.
http://www.flickr.com/photos/mikecdavies/sets/72157632206271518/
Some of these photos I took using extension tubes, some using a reversed 50mm lens on the end of the extension tube, and some just using a reverse 50mm on the camera body (fingerprint, £1 coin, mosquito)
See table below for possible magnifcation factors.
(The fly is at 1.88x magnifaction)
[img] 
[/img]
Less light = long exposures = tripod
cost me £40 from the bay and has connections for the lens etc.
that's the set I have
Its worth having a look at some of the instructional videos on Youtube on Focus Stacking, which can work just as well on normal photography as on Macro. This video helped me with it >>
Thanks all.
Nobody said [i]extension tubes are a gimmick and don't work[/i] and, much as I'd love one, I can't afford a shiny new macro lens so I've plumped for a set of tubes. Looking on Amazon and Ebay I reckon it's a low risk investment. I reckon I'll get back most of what I paid for them whether I abort the macro experiment or get gripped enough to buy a lens.
I got a set of cheap manual extension tubes, for playing with my 50mm. I also got a reversing ring and a raynox 250 clip on thing. All in I tihnk my macro kit cost about £40 which is IMO acceptable on a whim play money. I've aken some nice macro shots but soon got a bit bored of the speciality and was glad I didn't buy another lens.
If you just want to try it, I'd recommend manual tubes/reversing ring/raynox etc to give it a try though I'm not sure how you'd fair with no manual apperture ring on the lens for tubes? When the lens is ff does it default to wide open? If so you'll be fine!
Tubes work, but to get the best results, use a good sturdy tripod as well. A dedicated macro lens is more flexible, but it's a £££ outlay.
Don't forget, the more tubes you use, the shorter the depth of field, sometimes can be too small.
These were taken using tubes and a 'normal' lens
[url= http://farm1.staticflickr.com/105/363340127_53692acea1.jp g" target="_blank">
[url= http://www.flickr.com/photos/cheesyfeet/363340127/ ]Circuit Board 1[/url] by [url= http://www.flickr.com/people/cheesyfeet/ ]gary_foulger[/url], on Flickr
[url= http://farm1.staticflickr.com/117/363340374_c250057311.jp g" target="_blank">
[url= http://www.flickr.com/photos/cheesyfeet/363340374/ ]Soapbox Bart[/url] by [url= http://www.flickr.com/people/cheesyfeet/ ]gary_foulger[/url], on Flickr
Whereas these were with a macro lens
[url= http://farm5.staticflickr.com/4010/4467058465_c160cf20e5.jp g" target="_blank">
[url= http://www.flickr.com/photos/cheesyfeet/4467058465/ ]Ragley Grip[/url] by [url= http://www.flickr.com/people/cheesyfeet/ ]gary_foulger[/url], on Flickr
[url= http://farm5.staticflickr.com/4021/4463052604_76eff05650.jp g" target="_blank">
[url= http://www.flickr.com/photos/cheesyfeet/4463052604/ ]Philips LCD TV[/url] by [url= http://www.flickr.com/people/cheesyfeet/ ]gary_foulger[/url], on Flickr
This one is actually the pixels on my TV!
I used to use extension tubes on my 35mm when I was into insect photography. Either with a 50mm or 135mm lens. You can't easly focus the camera, just move backwards and forwards until it is clear.
I found the best solution to focus, depth of field and ease of use, was to mount two small flash guns one on either side of the lens. For any given magnification or selection of rings you used the same aperture settings, as you got closer the less light gets to the film, but the brighter the effective flash is, and it all evens out. No worries about camera shake either because it's the flash duration and not the shutter speed that controls the exosure, som you won't need a tripod.
I use this, http://photography-on-the.net/forum/showthread.php?t=190428
Blimey, some interesting reading there.
I haven't got a 35-80 lying around but see my first post - I've got the 'kit' 18-55mm sat there doing nothing. I may have a look to see:
~ if it's front focussing
~ if I can get the front elements off in a non-destructive way.
(Russ96 may want to offer an opinion on the chances of me doing [i]anything[/i] non-destructively!)
Hmmmm.... looks like I need a special tool to remove the front of an 18-55mm
Which is a shame because I could have had a play with it today.
I guess I'll wait for the tubes to arrive, see how I get on with those and keep an eye out for a cheap 35-80mm on Ebay, ideally one going v. cheap with AF problems.