# focusing screen dilemma resolved



## Sebring5 (Jun 7, 2013)

I have two manual focus lens, two auto focus lens and a 6d. I could see in Photoshop focus was often soft or off on a number of photos. Tried a Ec-A (micro prism) and a Ec-B (split image) focusing screen but had two issues: 1) I could not align the small center circle with the center focusing aid and 2) The center focusing aid went dark on smaller apertures especially if it was a low light situation. Solution? I installed the Eg-S. No center focusing aid to align or go dark. I had the more precise focusing I needed without the issues. I do use auto focus in low light with a f5.6 lens. The Eg-S is also not as clear as the Eg-A standard precision screen Canon supplies. Eg-S is designed for f2.8 or larger apertures. I'm using it successfully on f1.8, f2, f4 and f5.6 lens.

The Eg-S is available from Amazon and and other Canon retailers for less than $35. Can be installed on 6D, 5D Mark II and 5D Mark III for sure. May work on other EOS cameras as well. Works for me. I can see far better what is in focus in the viewfinder.


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## neuroanatomist (Jun 7, 2013)

Sebring5 said:



> The Eg-S is available from Amazon and and other Canon retailers for less than $35. Can be installed on 6D, 5D Mark II and *5D Mark III* for sure.



Don't be too sure... Canon does not consider the focus screen on the 5DIII to be user replaceable.


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## East Wind Photography (Jun 8, 2013)

There is also no means to adjust exposure via firmware. Changing focusing screens will affect the exposure on 5d3 for sure. In other models you either have a micro exposure adjustment or a selector for available canon focus screens.

Though I guess you could just be lucky and get one that is close to the original in light transmission and hope you don't drop a screw or two into the camera.


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## Sebring5 (Jun 8, 2013)

neuroanatomist said:


> Sebring5 said:
> 
> 
> > The Eg-S is available from Amazon and and other Canon retailers for less than $35. Can be installed on 6D, 5D Mark II and *5D Mark III* for sure.
> ...


 You are correct-Canon does not consider the focus screen on the 5DIII user replaceable. Here is a link to the installation instructions and sales page : 
http://www.focusingscreen.com/work/5d3en.htm
http://www.focusingscreen.com/index.php?cPath=21_134


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## Sebring5 (Jun 8, 2013)

East Wind Photography said:


> There is also no means to adjust exposure via firmware. Changing focusing screens will affect the exposure on 5d3 for sure. In other models you either have a micro exposure adjustment or a selector for available canon focus screens.
> 
> Though I guess you could just be lucky and get one that is close to the original in light transmission and hope you don't drop a screw or two into the camera.


 This is a Canon made part. Here is a link to their focusing screen guide and the included cautions: 
http://www.learn.usa.canon.com/app/pdfs/quickguides/CDLC_FocusingScreens_QuickGuide.pdf
The 5d3 works as well although Canon will not say so or recommend it. Supposedly, no firmware adjustment is needed for the 5d3. However, you may be correct.


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## brianymarsh (Jan 11, 2014)

I was able to install the Eg-s Focusing Screen for the 5D Mark II, into the MK III without any problems or modifications to the screen  Works really well for me! The Eg-s screen is ony $35 too!

I made a video showing the installation process:

http://brianymarsh.com/blog.html

5D Mark III - Focusing Screen for Manual Lenses on Vimeo


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