December 2, 2015 at 12:27PM

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Using a C/Y to EOS adapter vs Mount Conversion

Hey Guys,

I'm stepping into the world of vintage glass and started with Contax Zeiss. I plan on upgrading my Contax Zeiss glass with Front Rings, Lens Gears, and a physical Leitax mount conversion. I want to do a batch conversion on all of these lenses after I've found/purchased them. In the meantime, I'd really like to start using the lenses and learn what I can from them.

I found this particular adapter on amazon: http://www.amazon.com/Fotodiox-Adapter-Contax-Yashica-Camera/dp/B001G4SH...

Is there a downside image-wise to using this kind of adapter versus a physical mount conversion like Leitax? I can't imagine there is a difference in image if the adapter has no glass and doesn't appear to affect flange distance. Just trying to see what the pros and cons are for using one over the other. Ultimately, I do plan on doing a mount conversion regardless, so it's not a matter of whether or not I'll do that. Feel free to chime in if you have any experience.

Thanks!

11 Comments

I haven't used a CY to Canon EF mount adapter, but I have used a Nikon to Canon EF mount adapter, and the results were great. Everything has to be adjusted manually ( which is a good thing for video ) but the end result is quite good.

These adapters are not so hot for photography where you're going to want to use autofocus and non-manual exposure modes, but fine for video.

December 2, 2015 at 3:04PM

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Guy McLoughlin
Video Producer
31571

I probably should've mentioned how I was using this. I'm using a GH4 (which I believe you use) with a Metabones Speedbooster EF. I guess I was trying to determine whether or not the following would be different visually:

1. GH4 -> Metabones Speedbooster -> C/Y EOS Adapter -> Contax Zeiss lens
2. GH4 -> Metabones Speedbooster -> Contax Zeiss lens with Leitax EF mount conversion.

Thanks for your reply!

RJ Ortiz

December 2, 2015 at 4:01PM

>>>1. GH4 -> Metabones Speedbooster -> C/Y EOS Adapter -> Contax Zeiss lens
>>>2. GH4 -> Metabones Speedbooster -> Contax Zeiss lens with Leitax EF mount conversion.

You're paying a $200 premium for the Metabones SpeedBooster for Canon EF lenses compared to a non-electronic SpeedBooster like the one made for Nikon lenses.

I also wonder if the SpeedBooster made for Canon EF lenses will work properly for non-electronic lenses ? ( will this effect the camera settings, or does the camera treat this adapter like a non-electronic lens ? )

Would it make more sense to buy a C/Y Metabones SpeedBooster ?
http://goo.gl/aHtPkm

December 2, 2015 at 4:33PM, Edited December 2, 4:39PM

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Guy McLoughlin
Video Producer
31571

Hey Guy,

The reason I'm trying to convert the Contax glass to EF is because I already own the Metabones EF Speedbooster and use it with other canon mount glass. Modifying the Contax glass to work with it would save me the cost of buying a second speedbooster.

RJ Ortiz

December 3, 2015 at 10:34AM

Go with the Leitax. Since it screws into the lens you won't get wiggle that is common with adapters. I used adapters until I read up on Duclos' conversions: he recommends Leitax.
At around 59 Euros, you can't really go wrong. Just make sure you get the right Leitax mount depending on the lens (the website breaks this down).

December 2, 2015 at 11:30PM

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Sathya Vijayendran
Writer/Director/Editor
214

I agree completely. From everything I've seen and read on it, the Leitax mount is the way to go. Thanks!

RJ Ortiz

December 3, 2015 at 10:33AM

Guy's suggestion to use a CY Metabones Speedbooster makes a lot of sense if you don't want to change the mount. I used to have the adapter when I was using CY lenses on M43. That's the simplest option.

December 3, 2015 at 5:57AM, Edited December 3, 5:57AM

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Sathya Vijayendran
Writer/Director/Editor
214

For future reference, it's likely neither of these work:

1. GH4 -> Metabones Speedbooster -> C/Y EOS Adapter -> Contax Zeiss lens
2. GH4 -> Metabones Speedbooster -> Contax Zeiss lens with Leitax EF mount conversion.

There is an aperture lever and a protruding metal assembly that surrounds the glass. This sticks out just far enough that it will not allow proper connection with the Metabones EF Speedbooster.

The EF Speedbooster seems to have a flat base surrounding the glass element. The Contax Speedbooster seems to have a more concave base surrounding the glass element which allows space for the aperture lever and assembly.

http://www.metabones.com/assets/p/mb_spcy-x-bm2-01s.jpg

I wish they would have just done this for all of their mounts. Maybe there is a downside to it, such as structural weakness.

So, it comes down to two options.

1. Buy a new speedbooster at a $400 premium.
2. Find a way to remove the aperture lever and assembly so that nothing sticks out farther than the mount. Something tells me that Duclos could probably do this for you when you get a Leitax mount conversion. Just be sure to ask them to try this if you plan on using an EF Speedbooster from Metabones.

December 3, 2015 at 10:00AM, Edited December 3, 10:00AM

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RJ Ortiz
Cinematographer
233

I never had a problem using any CY lenses with the Metabones CY Speedbooster. Which lens are you using?

Why use the EF Speedbooster, since the CY lens has no electronics-on a GH4?

December 3, 2015 at 10:16AM, Edited December 3, 10:29AM

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Sathya Vijayendran
Writer/Director/Editor
214

I'm considering getting a CY speedbooster now.

I was planning on using it because I already own and use it for other Canon mount glass I have.

RJ Ortiz

December 3, 2015 at 10:30AM, Edited December 3, 10:30AM

December 4, 2015 at 9:55AM

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Sathya Vijayendran
Writer/Director/Editor
214

Note the tip dated Feb 2017 on this site:
http://www.danmccomb.com/modify-contax-zeiss-lenses-metabones-speedbooster/
The aperture-indexing ring can be removed in the process of doing the Leitax mount conversion. (NO NEED to grind off the tab, as Dan had done.)

March 4, 2017 at 8:49PM

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