# I have a Sigma 105mm 2.8.  Should I get extension tubes?



## Markw (Apr 24, 2010)

Hi all.  Ive been having a good bit of fun with my Sigma 105mm macro lately.  I am actually reallypleased with the lens.  If I were to want to get in even a little closer yet, would it be beneficial to get extension tubes or a TC? If I got a TC, I was thinking about the Kenko 1.5x.  The only problem I am having is that the DOF on my photos is ridiculously hard to get workable.  Im sure all of you know this, though.  

So, I guess the question is: which would allow me to retain a better DOF, extension tubes or a TC?  

Thanks.
Mark


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## Overread (Apr 24, 2010)

It won't matter - as you increase your magnification via any method you will lose depth of field, light and also your diffraction limit will become more of a problem.

For a 105mm lens I would say you could go either way but I would recomend the 1.5TC myself. I use a 1.4TC on my 70mm and 150mm macro lenses and its a great thing. 1.4:1 macro is not much harder than 1:1, but the little increase is very noticable and I like the setup. Image quality will remain very high and you also get to keep your workind distance and infinity focus (two things you lose with tubes). 

If you want to go even further you can condier tubes or diopters - at 105mm I would be warming more toward diopters over tubes since whilst they work the same way (reducing minimum focusing distance for magnification gain) you will get more magnfication from a longer focal length lens with diopters whilst tubes work better on shorter focal length lenses.


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