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Help please! Fotodiox, Sigma, A7R


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Hi, I have a job to do that requires duping 35mm transparencies. I was hoping to use a sigma 70mm macro (phenomenally sharp and goes to 1:1), but the fotodiox on the A7R is being a pain.


Every 2-3 frames it will randomly lock up the camera, and the only way to reset it is to release the lens and twist it in the mount. So the problem is electrical...


The fotodiox is the pro model, works OK with Canon lenses, though AF is really dodgy on the A7R.


Can anyone say if the problem is the camera or the adapter. I could get a Canon EF 100mm macro for less money than a Metabones...all I want is the auto aperture.


For the moment I'm trying to get by with a Tamron SP 90/2.5 - but I've only got the 2x teleconverter to get to 1:1 :(


Any suggestions welcome!


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For 1/8th of the price of the Metabones you could pick up a Pentax 50/4 Macro (M or m42 version) and a set of tubes (the lens itself goes only to 1:2). The lens is *very* sharp, and I picked up mine for less than 50€.


Alternatively, you could pick up a Contax Zeiss Makro-Planar 60mm f/2.8. It is probably the sharpest Contax ever made, short of the ApoTessar (it's a Zeiss, what did you expect?), and it comes in two versions, a "C" one that is relatively small and light and goes only to 1:2 and the older one that goes to 1:1 (mine). Optically they're the same, only the focusing helicoid and the lens barrel changed. Priced around 350€.


I don't know your preferences, but when I'm shooting macro or duping films I want full manual focus anyway.


BTW, if you need to extract more detail from the slides you can treat them like they were a panorama, shooting in sections and then stitching them together. If you're interested I described the method in detail here:


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Thanks for the suggestions. More than anything, I'd like to get the Sigma to work, but I suspect it's not realistic with the body/adapter I've got. Manual focus is what I use anyway - mostly I tend to go for Canon FD (just cos I've used them a lot in the past) but the FD 100 macro is f4, only 1:2 and the first EF 2.8 version is about the same price.


Stitching won't help with 35mm, unless I take the magnification above 1:1, but it's a great idea for the larger format copies!


Trouble is, no-one here (NZ) wants to buy the 70, so I'll end up losing money on it :(

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Sigma and Canon (or in this case Fotodiox) never worked quite well imho. There are plenty of old Sigma lenses that you cannot even use on a digital body. That's the price of having to use a reverse enginered technology, I guess.

Correct me if I'm wrong, but Canon EF mount glass should stay with the aperture closed to the last selected value. If so, why don't you try this:
- put the lens on the camera and set the desired aperture
- remove the lens from the Fotodiox and put a bit of paper or electrical tape on the contacts on the adapter or on the ones on the back of the lens to isolate them
- mount the lens again, use mf and shoot to your heart content :)

I know it's just a workaround, but it might actually save you a bit of cash and headaches.

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