Extension Tubes

grim8634

grim8634

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Graeme
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Hi All,

I have a Canon 30d with various lenses my primary being a 24 - 105 F/4 L and am interested in trying some macro stuff. I've been looking at extension tubes but haven't really got a clue what to be looking for. There are various lengths and various manufacturers. Anyone got any tips, or anything I could read up on?

Thanks a lot! :thinking:
 
Hi,

Ideally you get either a set of Kenko tubes or 2 Canon EF25's.

Here's some numbers to give you an idea what you'll be seeing afterwards with your 24-105 set at 105mm;

A 25mm tube will give you 0.6x magnification at about 23cm working distance (end of the lens to subject)
A 50mm tube will put you a fraction under 1x mag at 19cm lens to subject.
A full set of Kenko's (they're sold as a set) will give you about 1.2x at 17cm.

Hope that answers your questions.

Bob
 
Get Kenko's tubes - they retain VR (IS) and full AF + metering.
 
puddleduck said:
Get Kenko's tubes - they retain VR (IS) and full AF + metering.
Click to expand...

Both Kenko's and Canon's own retain functionality. Using AF for high magnification shots would not be a consideration though.....at these levels then almost all focussing would be manual.

Bob
 
yeah what bob said, you won't really be using auto focus. Also i found the best way to understand extension tubes is to have a play with them :)
 
Out of interest, what is the advantage in buying a Canon tube over the Kenko? Considering its just a metal tube with no optics... big price differential!
 
Sorry for the slight hijack...

Also what are the advantages of getting extension tubes over a macro lens (or more likely the other way round) I will just be dabbling in macro probably using my 50mm lens...
 
No need to apologise... I would like to know too!
 
puddleduck said:
Out of interest, what is the advantage in buying a Canon tube over the Kenko? Considering its just a metal tube with no optics... big price differential!
Click to expand...
It's simply the quality of manufacture. There have been reports of Kenko ones releasing but this may have been a tolerance issue that's long been resolved.

Craikeybaby said:
Sorry for the slight hijack...

Also what are the advantages of getting extension tubes over a macro lens (or more likely the other way round) I will just be dabbling in macro probably using my 50mm lens...
Click to expand...

Dedicated macro lenses are optimised for working at, or towards, the minimum end of their focus range whilst other lenses will be optimised for some arbitary focus distance.

Bob
 
So for dabbling in Macro occasionally would the Kenko tubes at £114 be much worse than spending more than double that for a dedicated lens?
 
Hi folks.

Kenko tubes cost 62.99 for Canon from Onestop.

I have this set for Nikon and have found them superb. Also, the fact that you get a set of three at different lengths means you can mix and match.

Hope that helps.

In answer to question above - extension tubes offer a low costs alternative to dedicated lens.

Cheers

Anth
 
stan the man said:
another thread hijack...sorry.is there any advantage to using extension tubes with a dedicated macro lens,or have i wasted my money on them :shrug:
Click to expand...

Stan,

Money's never wasted :lol:

Adding your tubes to a macro lens will further increase the native mag of the lens...the length of tube and the original focal length can be used to determine the maximum magnification that you'll achieve.

Bob
 
I've been playing with my reversed 50 today and getting some semi decent results. Just hand held, so I reckon I might give a reversing ring a go.
 
how do extension tubes differ from a teleconverter?

is the ext tubes just to create further distance from lens and sensor, while a teleconverter actually contains a lens?

if thats right, why not use a teleconvertor?:thinking:
 
urbansickness said:
how do extension tubes differ from a teleconverter?

is the ext tubes just to create further distance from lens and sensor, while a teleconverter actually contains a lens?

if thats right, why not use a teleconvertor?:thinking:
Click to expand...

Your description is spot on...tubes are empty and T/C's contain lens groups.

Putting a T/C on will increase the magnification at the expenses of image quality whereas a tube has little or no degrading effect on IQ. There is also the issue of light loss with a T/C.....doubling the magnification will cost you two aperture stops of light...not a good thing when you're already struggling a bit to keep enough for the minimal DOF. Tubes also take a little light but it's negligable in comparison.

Bob
 
I look at is as a teleconverter magnifies what your lens sees so a 100mm would be a 140 with a 1.4 or a 200 with a 2x, but extension tubes let the lens focus when its physically closer to the object so the flower or whatever you are aiming at takes up more of the view.

Edit - I need to type faster
 
I was messing about with this combo of lenses last weekend. Canon 24-105 and Kenko extention.

They come with 12, 20 & 36mm tubes so if you put them all together you get 68mm. Add that to the 24-105 at full zoom and you get things like these water droplets on a conifer hedge:
99388629.jpg



Really hard to focus, especially when the plant moves.
 
I was getting thigs like this hand holding a reversed fifty....

2617866255_24991154c3.jpg

2618566562_62bb89190f.jpg


I stepped outside to try to catch some flowers, but it was far too windy to keep in focus.
 
I use an extension tube + TC as a sort of macro at times:



2621298758_29d60e1eef_o.jpg


​

Doesn't help as much on long lenses as you tend to need a LOT of extension, the longer the lens, but you can shave off a few inches from most lenses with one. I use Kenko - cheap but they work :)
 
Blimey - what combination did you use for that? How far away was the lens and didn't you spook it?
 
I had a set of jessops ones, 3 different length tubes and can be stacked or just use 1 of them.
 
Another hijack, sorry! Do you retain the full range of a lens - i.e. Will my 100mm Macro f2.8, still go wide open (f2.8) or will it affect that value. I've just ordered myself a set of kenkos from the link above :D
 
Byker28i said:
Blimey - what combination did you use for that? How far away was the lens and didn't you spook it?
Click to expand...

Nikkor 300mm f/4 AF-S with 1.4x Kenko Pro 300 DG + a 36mm Kenko tube.

I was under 1 meter.
 
Snowball said:
Another hijack, sorry! Do you retain the full range of a lens - i.e. Will my 100mm Macro f2.8, still go wide open (f2.8) or will it affect that value. I've just ordered myself a set of kenkos from the link above :D
Click to expand...
The lens will still go wide open but the light reaching the sensor will be slightly less. Adding a tube or two implies that you'll be shooting higher magnifications and hence not want to be wide open....insufficient DOF.

Bob
 
Thanks Bob, I'll post a few up when i get them! :)
 
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