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Extension Tubes vs Teleconverters ...

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Extension Tubes vs Teleconverters ...

Postby kctsang » Fri Nov 20, 2009 11:13 pm

Hi,

I have been using both items before, however I find that teleconverters gives me greater flexibility in terms of focusing range, while X-tubes seems to give sharper pictures at the expense of focusing range. So wondering about your experiences with these items and which item you would be using most often for macro work. At the moment I am using a TC14 with my MN 105mm most often...

Cheers

:D :D :D
kctsang
 

Re: Extension Tubes vs Teleconverters ...

Postby richardlbong » Sat Nov 21, 2009 9:05 am

KC, I also have both ET and TC. I used the ET with my Canon 70-300mm lens as this lens has a minimum focusing distance of around 2 meters which is not good for macro. With the different ET, I am able to get that down to around .75 meter which is ideal for butterfly shooting. I only use the ET if I want more than 1:1 magnification from my macro lenses. With the teleconvetorh it is the other way around. I used the 1.4x TC with the Sigma 150mm most of the time as this gave me a virtual 210mm macro lens. When you use the 1.4x TC with your 105mm macro this will give you a virtual foacal length of 147mm. What this mean is yoou can now shoot from further away to get the same magnification. This is advantages when shooting butterflies, especally if you don't want to spook them. Wheter it be ET or TC, you'll still have loss of light reaching the CCD or CMOS. The amount depend on the length of the extension. With 12mm ET, loss of 1 stop aperture with 36mm, about 2.5 stop. With the 1.4x TC, also 1 stop and whith the 2x TC, 2 stop.
Hope this answer your query.
Richard
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Re: Extension Tubes vs Teleconverters ...

Postby green baron » Sat Nov 21, 2009 10:10 am

Richard,
Thanks for the clarification. I think a lot of people are unsure what is the different btw ET and TC.

So you use ET to reduce the min focusing distance of a non macro lens and TC to increasing the focusing distance or the focus lenght of the lens ?

What is the effect of using ET on a macro lens ?
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Re: Extension Tubes vs Teleconverters ...

Postby richardlbong » Sat Nov 21, 2009 11:28 am

The maco lenses normally has a minimum focus of 20cm depending on the focal length, by adding an Extension Tube, you can go in closer thus having a greater than 1:1 magnification. I've known of a number of 'spider' shooters using this technique to shoot spiders to get the better than 1:1 magnification, but than the DOF will be so shallow that they need to use the stacking techniques to get enough DOF to cover the whole spider.

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Re: Extension Tubes vs Teleconverters ...

Postby kctsang » Sun Nov 22, 2009 6:57 am

So stacking techniques sounds to me like using the bellows, however with bellows one has to
go manual for aperture and exposure... Also with bellows one can reverse the lens for even greater
magnification, and DOF almost next to nothing. Have you tried this Richard ??

However this is no good for butterflies .... I think ..

K C
:D :D :D
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Re: Extension Tubes vs Teleconverters ...

Postby richardlbong » Sun Nov 22, 2009 8:32 am

KC, bellows are rather bulky and very time consuming to work with especially with insects. Best to use it in sudio environment. Most of the insects shooters prefer either to use a close-up dioptics filter or extension tubes with the macro lenses. This way they have more portability when moving around in the 'wild'. By adding these additional to the macro lenses, the focusing can be a real pain as that precise focus point is so narrow, almost a hairline that it take quite a while to get use to. I don't use a bellow as I find that inconvenient. Stacking is out for me as I prefer the old fashion method of getting everything in with the single shot.
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