Teleconverter vs extention tube

[hendrik_louw]

Hi all,

I am quite a keen macro photographer with a macro lens (Tamron 90mm) that works wonders. There are however occasions where I would like to go beyond 1:1.

I'm looking for the advantages/disadvantages wrt extention tubes and teleconverters. Anyone who can give me some perspective on how they weigh up against each other?

Thanks!
Hendrik

 

[jerryharwood]

> I think you will find that an extension tube is far better, although i > use an tamron 90mm with a D70 nikon- it is superb at 1:1 rgards jerry

 

[anton_beroflex]

I did several tests shooting (macro and not) at graph-paper (millimetre-squared paper), attaching as dioptric additional lenses on the front, as extention tubes on the rear of the objectiv; as well as focusing, as on infinite, as on the minimun distance.
Both ways introduce cushion-distortion (more magnification going to the corners).
It is not a big problem though, if You shoot at flowers, insects ... with such made subjects and leaving the corners as free(empty) enough; yet, it becomes more evident taking technical pics at post-st&s!
Likewise, also other aberrations increase, yet.

And common zoom-obiectives (not specific for macro ones) when turned on macro function, already introduce these aberrations by themselves, without any attachment on them and though magnifying 1:4 only.
By that, needing macro objectives.

I would say now, while extension tubes remain such ones, You might take great advantages by finding teleconverter or dioptrical lenses on purpose designed according to the optical-layout of the objectiv You are using, or looking for it among similar ones; trying other brands and models, too.

As exemple, I remember Tamron was making a special macro-teleconverter tu use it but with the old
Tamron SP 90mm f/2,5 Macro 1:2 - Manual Focus
reaching 1:1 with its Teleconverter
as well as I own any old (Manual Focus) Macro Elicar 90mm, Macro Soligor --mm which went sold together with their +10 additional Close-up Lens.

These specific accessories You are looking for, should take into their consideration what and how aberrations work out increasing Macro magnification and getting "glasses" inside them, as designed to correct those aberrations.

But a time I not-properly placed some Teleconverters randomly with objectives, I was able to get the worse shapes I never did; take care!
Mounting an extension tube as short as possible, then keeping Macro Lens fucused near 1:1 and not as mounting a longer tube to be allowed focusing back, this may often be a well accurate way.
Of course, the diagfram would be turned on its best-quality zone; the most Objectives get it between the 3th and the 5th aperture.

I'm sorry for such long answer, but I saw nobody else was writing here, however so.
Greetings ....

 

[anton_beroflex]

I did several tests shooting (macro and not) at graph-paper (millimetre-squared paper), attaching as dioptric additional lenses on the front, as extention tubes on the rear of the objectiv; as well as focusing, as on infinite, as on the minimun distance.
Both ways introduce cushion-distortion (more magnification going to the corners).
It is not a big problem though, if You shoot at flowers, insects ... with such made subjects and leaving the corners as free(empty) enough; yet, it becomes more evident taking technical pics at post-st&s!
Likewise, also other aberrations increase, yet.

And common zoom-obiectives (not specific for macro ones) when turned on macro function, already introduce these aberrations by themselves, without any attachment on them and though magnifying 1:4 only.
By that, needing macro objectives.

I would say now, while extension tubes remain such ones, You might take great advantages by finding teleconverter or dioptrical lenses on purpose designed according to the optical-layout of the objectiv You are using, or looking for it among similar ones; trying other brands and models, too.

As exemple, I remember Tamron was making a special macro-teleconverter tu use it but with the old
Tamron SP 90mm f/2,5 Macro 1:2 - Manual Focus
reaching 1:1 with its Teleconverter
as well as I own any old (Manual Focus) Macro Elicar 90mm, Macro Soligor --mm which went sold together with their +10 additional Close-up Lens.

<center><table border=1><tr><td>

Tamron Macro 1:2 90mm f/2,5 + 1:1 Teleconverter
Tamron%20SP%2090mm%20f_2 (0.4 k)</td></tr></table></center>

These specific accessories You are looking for, should take into their consideration what and how aberrations work out increasing Macro magnification and getting "glasses" inside them, as designed to correct those aberrations.

But a time I not-properly placed some Teleconverters randomly with objectives, I was able to get the worse shapes I never did; take care!
Mounting an extension tube as short as possible, then keeping Macro Lens fucused near 1:1 and not as mounting a longer tube to be allowed focusing back, this may often be a well accurate way.
Of course, the diagfram would be turned on its best-quality zone; the most Objectives get it between the 3th and the 5th aperture.

I'm sorry for such long answer, but I saw nobody else was writing here, however so.
Greetings ....