December 27, 2014 at 12:08PM

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Sony A7s - Lens adaptors and Flange Focal Distance Issues?

I'm about to buy the Sony A7s to live alongside my Canon 60D, for video use. I have a bunch of Canon lenses that I'd like to continue to use on the A7s, so I'm looking into the options for that.

But at the same time, I'm considering dipping my toe in the vintage lens world, so, I'm considering doing the following:

- Buying a Holy Mantra ND - Canon EF to NEX: This allows me to use my Canon lenses on the Sony, and sorting the ND issues for SLOG2.

But I wonder, can I buy a bunch of M42 lenses, with Fotodiox lens mounts for Canon, and load it onto the Holy Mantra? Then, I have the option to use the M42 lenses on my Canon as well as the A7s.

BUT this means the following chain!
A7s -->Holy Mantra-->Fotodiox Adapter-->M42 lenses

I've not entirely got my head around FFD (Flange Focal Distance), and whether having both the Holymantra and Fotodiox lens mounts would render the M42 lenses unusable. If anyone has any knowledge in this area, I'd love to hear your thoughts.

I've not ever used M42 lenses before so would be open to hear discussion about whether going for Contax or Nikkor lenses would be wiser in the long term, but I like the idea of being able to experiment with the cheaper M42 lenses, having just spent around £2000 on other gear!

Thanks!

4 Comments

There are adapters available to connect almost lenses in existence to e-mount. I use Canon EF & FD, Pentax, Minolta, M42, T2, Tamron, Sigma & Nikon lenses w/ both the A7R and A7S. Most of the electronic lens also have automatic adapters.

You don't have to get the very expensive Metabones adapter. King, Commlite, Viltrox and several other manufacturers make equivalent or better adapters for considerably less $$$'s. I prefer the King adapter; nice fit and automatic. The Commlite allows me to use filters between the adapter and an EF lens.

December 27, 2014 at 9:15PM

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bwana
74

There are adapters available to connect almost lenses in existence to e-mount. I use Canon EF & FD, Pentax, Minolta, M42, T2, Tamron, Sigma & Nikon lenses w/ both the A7R and A7S. Most of the electronic lens also have automatic adapters.

You don't have to get the very expensive Metabones adapter. King, Commlite, Viltrox and several other manufacturers make equivalent or better adapters for considerably less $$$'s. I prefer the King adapter; nice fit and automatic. The Commlite allows me to use filters between the adapter and an EF lens.

December 27, 2014 at 9:15PM

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bwana
74

> "A7s -->Holy Manta-->Fotodiox Adapter-->M42 lenses"

Yup, that would work. Personally though I prefer getting Nikon F mount lenses, as many many many have been made, and the mount has been around for decades. So many bargains to be found there!

Be warned though that the Holymanta VND EF | NEX adapter is a dumb adapter, so you've got no control over the electronics in a lens. (such as changing the aperture, you can't do that with a Canon lens. Is one of the reasons why I prefer Nikon over Canon)

December 28, 2014 at 9:34PM

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David Peterson
Wedding Cinematographer
2582

"I've not entirely got my head around FFD (Flange Focal Distance), and whether having both the Holymantra and Fotodiox lens mounts would render the M42 lenses unusable. "

Adding two items between the lens and the body would compound any error in the manufacturing, and that your focus marks on the lens barrel would be likely be out.

I used this table to figure out how far out my Fotga K to M4/3 adapter was out, so I could get it shimmed to work properly (Infinity focus and barrel marks correct) in front of a BMPCC.
http://camera-wiki.org/wiki/Lens_mounts

Find the Lens FFD, subtract the shorter camera FFD, gives you the measurement of the adapter, between it's front and rear flanges.
So for me, it was K-mount 45.5mm, minus M4/3 systems 19.2mm, giving 26.3mm -> my Fotga unit was 0.9mm too thin, so I removed the lens flange and fitted some shims to get the required 26.3mm's

You'd have to measure from the camera side flange, to the mounting flange on the M42 adapter, when on the HolyManta unit.

You'd also want to be making sure there's no light leaks between the two adapters.

June 7, 2015 at 9:47AM

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Stewart Fairweather
Cinematographer
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