# How accurate is the 'manual' focusing screen anyway ?



## Sporgon (Apr 16, 2015)

Dustin Abbot's posts got me interested in trying some of my old manual focus lenses from various manufacturers. I had already fitted the 's' screen to one camera body anyway, though since adopting BBF I haven't really manually focuses AF lenses for many years now. 

I think that is was Dustin who made the comment that when using manual lenses he got the occasional OOF image despite being sure that he had sharp focus in the viewfinder. I have found the same thing. I know that our eyes tend to adapt to slight OOF, a problem for people who wear glasses and a slightly inaccurate prescription can lead to headaches etc. 

However I recently tried a chipped adapter, and found, 50% of the time, much more focus accuracy with the cameras AF confirmation than I can achieve by seeing the sharpest point of focus travel thorough the viewfinder.
When you look at how microscopical the setting of the camera's AF module has to be it makes me question the accuracy of a screen that we just drop into a tray and click up into place under the cameras pentaprism. It's hardly precise in locating the screen.

So my question is; how accurate are these so called manual focus screens anyway when using fast lenses ? Anyone have any hard fact information on this ?


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## Eldar (Apr 16, 2015)

I do not have any hard facts, but I do have rather extensive experience using the Ec-S screen on my 1DX, with the Zeiss lenses I have. The majority of them being f1.4. I also have a custom made S-screen for my 5DIII. With the 1DX I have a very high hit rate, even at f1.4. With the 5DIII the situation is different. That screen is not nearly as precise as the original Canon Ec-S. The reason for buying the custom made screen was the lack of success with the focus indicators in camera.

So summing up, no hard facts, but the Ec-S screen I have for the 1DX is a lot more precise than the focus indicators. I manually focus in fairly dim light, still with a high hit rate.


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## Sporgon (Apr 16, 2015)

Eldar said:


> I do not have any hard facts, but I do have rather extensive experience using the Ec-S screen on my 1DX, with the Zeiss lenses I have. The majority of them being f1.4. I also have a custom made S-screen for my 5DIII. With the 1DX I have a very high hit rate, even at f1.4. With the 5DIII the situation is different. That screen is not nearly as precise as the original Canon Ec-S. The reason for buying the custom made screen was the lack of success with the focus indicators in camera.
> 
> So summing up, no hard facts, but the Ec-S screen I have for the 1DX is a lot more precise than the focus indicators. I manually focus in fairly dim light, still with a high hit rate.



Thanks for that Eldar. I'm not familiar with changing the screen on a 1 series. Does it still basically involve a drop down tray that the screen is sat in ? I wonder if the 1 series has a more precise fitting of the screen than the 5 and 6 series.

On the cameras that used to have interchangeable prisms the screen was a very tight, precise fit in the body, under the detachable head. Obviously the 1 series has never had this feature, but it wouldn't surprise me if it had a more precise mechanism than the cheaper bodies.


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## Eldar (Apr 16, 2015)

It might be that I have been lucky with the screen I have, but the 1DX is very accurate. The mounting procedure is as you describe.


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## NancyP (Apr 16, 2015)

The 6D super-fine focusing screen is fine. (Eg-S, I believe).


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## sanj (Apr 16, 2015)

I find it EXTREMELY difficult to get perfect focus with any of the screens that Canon makes. If only I could get a split focus screen like the old times.....


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## zlatko (Apr 16, 2015)

I have tried the S screens many times over the years, in various cameras. I always go back to the standard screens because the S screens are too dark for me.


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## drmikeinpdx (Apr 16, 2015)

After getting really frustrated with the autofocus on my 5D Classic, I tried two alternate focus screens. The Canon screen (can't remember the letter designation) did not provide enough indication of when the scene was in or out of focus. Useless. I bought an expensive screen with both a microprism and split image center area. That really snapped in and out of focus just like the film cameras of my youth. Unfortunately, the screen's point of focus did not agree with the sensor's point of focus, so I wasted money on that one.

I gave up completely on manual focus for a few years, but happened to try it with my 5D3 and the stock screen recently. It actually worked fairly well, so I have promised myself that I will start practicing manual focus again.


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## tolusina (Apr 16, 2015)

sanj said:


> I find it EXTREMELY difficult to get perfect focus with any of the screens that Canon makes. If only I could get a split focus screen like the old times.....


This^


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## RLPhoto (Apr 16, 2015)

I used an Eg-s Screen when I had my 5Dc with with a prime lens kit at the time. What it did give me was a second re-assurance when I used fast primes on that dodgy Center AF point. I was able to define the DOF slightly to significantly better depending on how bright the environment was. On a bright sunny afternoon, I could define the DOF easily on my manual OM-1 50mm prime and get consistent hits. In a dark interior, It was a wash.

But taken back with this experience, I'd still use an EG-s screen if I could in my 5D3.


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## mackguyver (Apr 16, 2015)

I found the screen in the 60D and 5DII to work quite well, but find very little difference between the stock screen and the unsupported screen in the 1D X. Also, I'm not quite sure why, but I found the screen much, much darker with f/2.8 and slower lenses than it was in the other cameras. I shoot in very low light a lot, so it was pretty much unusable and I put the stock screen back in the camera.

Another factor is the lens. The wider the lens, the harder it is to nail manual focus. With a 24 f/1.4 wide open, I had a lot of trouble, but with the 85 f/1.2 and 135 f/2, I had a 90% or better success rate.


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## chrysoberyl (Apr 16, 2015)

How hard is it to install the Eg-S screen on a 6D?


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## mackguyver (Apr 16, 2015)

chrysoberyl said:


> How hard is it to install the Eg-S screen on a 6D?


If it's like the other bodies, it's a simple, but somewhat delicate procedure. Just remember that it's VERY easy to scratch the screen. Here's more:
http://learn.usa.canon.com/app/pdfs/quickguides/CDLC_FocusingScreens_QuickGuide.pdf


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## tolusina (Apr 16, 2015)

chrysoberyl said:


> How hard is it to install the Eg-S screen on a 6D?


It was pretty nerve wracking the first time through, delving into the unfamiliar.
Once done it became like, "Is that all there is to it?".
It's rather simple. So simple that removing the screen is now a part of my sensor and mirror box dust off procedure, I also dust off the bottom of the prism and that whole area.


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## bigdaddy (Apr 16, 2015)

Hello, 

I have the Eg-S in my 6D. I think its pretty good. Putting it in was no big deal. 

I tried an Ebay import micro prism screen from china. It needs shimming to get the its focus plane to agree to my camera. I never did it though. Went back to the Eg-S. Mainly because it was to dark and there were a lot of scratches in it when I stopped the lens down to f5.6. 

bigdaddy


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## NancyP (Apr 16, 2015)

I got a small scratch near the edge when I inserted the screen, but found that it did not bother me. If I change my mind, I can buy another $37.00 screen.


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