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Non-Destructive-SIGMA-Retro-adapter

Guest .

Banned
Hi All,

the idea iteslf is not mine ... again it was Uwe (NETZUSER), who did the first thinking and who was first successful with a SIGMA RETRO-Lens. :z02_respekt::z02_respekt::z02_respekt:

Remember....

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So .... waht is new then??!!

Well, first I simply tried to copy Uwe's brilliant idea on the issue ... then I came to an improvement (maybe just an alternative) to have a lens finally and irreversably turned into a RETRO lens ... that then is a NON-DESTRUCTIVE retro adapter for having a SIGMA-lens working the otrher way round ... for macro purposes. :D

To tell it beforehand ... it works!

And so it looks ... the SIGMA RETRO ADAPTER ....

sample 20.jpg

And thus, it looks when mounted ....

sample 18.jpg

What you see here ... is a SIGMA 18-200mm DC lens (the old one still without optical stabilizing) but mounted the other way round .... turning the lens into a macro-lens.

The problem however is fewer, to turn the lens,... but to connect the lens electrically to the SD-cam.

And how does it work?!

sample 5.jpg

sample 6.jpg

In order to mount your retro lens to the camera's bajonett, you need a lens bajonett (in my case, I took the bajonett from a defective 18-50mm DC lens)
Then I combined it with a 62mm SNAP-ON lens cap ... simply using micro screws. Then I took a seven-core cable (as slim as I could get one) and soldered it to the bajonett .... as shown above.
Here, you can connect the wires as jou like it .... later, when you connect wires to the other bajonett, you have to sort them precisely.

Well ....,

on the front-side of the lens (the original back-side) things are a b it more difficult. Here you need an old SIAGMA cam for exploitation (I got myself an SA 300 N which was cheapest to get on the internet).

Well, ... how to isolate the camera's bajonett is shown here.....!

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Just do it the same way, to have the other bajonett (now at the lenses front-side ....originally its backside...)

Again ... the SIGMA 18-200mm DC in RETRO arrangement.

Image quality:

Well,

since the 18-200mm DC did such a good job on the automatic bellows ... I showed some pictures ... I first tried this lens to the retro adapter.

The image results were all right ... not really perfect, as I would have expected them.

sample 21.JPG

The basic sharpness seems o.k. but a closer look into the picture's corners shows chromatic aberrations (CAs) ... watch the blue stripes!

Further testing proved, that the 24-70mm HF lens performs perfectly on retro arrangement.

sample 23.JPG

Well, those who would like to have their own SIGMA-AUTOMATIC-RETRO-ADAPTR ... just feel free to post here and put your questions ... Uwe and me will try to help!

See you with nice pictures

Klaus
 

Guest .

Banned
Hi all,

after some "difficulties" I manged to find myself a 55mm to 62mm filter-adapter.

So I now can fit the SIGMA 28-80mm HF (the other way round ... i.e. RETRO-like) to my SD9.

To sum it up ... it is a fine lens for that purpose ... have a look!

-Regentropfen-.JPG

See you with nice pictures

Klaus
 
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