My 5D screen is back focusing?

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Archive 2008 · My 5D screen is back focusing?

ocean7
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p.1 #1 · My 5D screen is back focusing?

Hi folks,

I am posting this issue here as I figure there are more specialists browsing the alt lenses forum

OK I have a very strange one. A few days ago I cleaned my 5D viewfinder deeply, I removed the focusing screen, the "washer" shims and the SI plate. All good so far.

Today I tried an alternative lens and I am usually good at focusing by eye but when I came home all my shots were out of focus. OK maybe I am not that good I thought so I took a few shots with an EF lens and autofocus.

Much to my surprise I realised that when the AF is acquired the object on which the AF locked is blurred in the viewfinder, but an object behind it looks sharp. It's all in the viewfinder as when I view my pictures they are tack sharp at the AF point.

What did I do wrong?

I tried adjusting the diopter, no effect. Could it be something that went wrong with the shims when I cleaned the beast? If so AF would be affected too, am I wrong?

I have no idea, please help

Thanks,

Philippe.

Nov 24, 2008 at 10:34 PM

HansenTsang
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p.1 #2 · My 5D screen is back focusing?

Try to take the focus screen off and reinstall the shims. Maybe they are not seated properly.

Nov 24, 2008 at 10:45 PM

ocean7
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p.1 #3 · My 5D screen is back focusing?

Thanks I will try this.

So if I understand correctly the focusing screen has actually no effect on AF? I can add or withdraw shims as I want and the AF will still be acurate?

Nov 24, 2008 at 10:48 PM

ocean7
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p.1 #4 · My 5D screen is back focusing?

Hansen you're a genius! One of the shims was actually not seated all right. I reinstalled it and now all is fine. Pfew! Lots of sweat for nothing!

Best,

Philippe.

Nov 25, 2008 at 12:20 AM

cogitech
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p.1 #5 · My 5D screen is back focusing?

ocean7 wrote:
Thanks I will try this.

So if I understand correctly the focusing screen has actually no effect on AF? I can add or withdraw shims as I want and the AF will still be acurate?

Yes.

Nov 25, 2008 at 02:49 AM

Cableaddict
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p.1 #6 · My 5D screen is back focusing?

Hey, I thought we were trying to call them by the official Canon name now: "Washers."

Nov 25, 2008 at 06:14 AM

Conner999
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p.1 #7 · My 5D screen is back focusing?

As you stated, the VF and FS have NO effect/impact on AF whatsoever. AF sensors are located under the mirror. However to obtain accurate manual focus, the distance from the rear element of a given lens to the sensor MUST be EXACTLY the same as the distance from element to the focus screen (FS). ANY deviation and you get front or back focus and need to re-shim and test, rinse and repeat.

The 5D is infamous for having issues (it varies by body) when you switch focus screens, even to other Canon screens (@#$%), from the original one installed (and shimmed) at the factory. 1 series bodies do not.

Glad it worked out.

Nov 25, 2008 at 12:34 PM

ocean7
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p.1 #8 · My 5D screen is back focusing?

Thanks all for your comments, much appreciated.

It's true what you said Rob. I did not notice the issue until I switched the std screen for the Ee-D (with grid). I am sure it was there before, but less noticeable with the std screen. That makes me wander at what I read in another thread: the grid screen might be more sensitive to - hence more suitable for - manual focusing.

Lesson learned about the washers then and I'll be more careful next time. I have three of these in my 5D and two are extremely thin, very hard to get them back in there!

Nov 25, 2008 at 01:44 PM

PhotoMaximum
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p.1 #9 · My 5D screen is back focusing?

THe 5D washer in my camera is very thin as well. The trick is placing the washer into the focus screen cage area and making sure the washer will clear the top tab that holds the screen. Then insert the screen and close the system. The screen should push the washer into position. Look through the camera to make sure all is well. I have done this several times and it seems easier than trying to get the washer into position perfectly...

Nov 25, 2008 at 05:31 PM

Mike Ganz
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p.1 #10 · My 5D screen is back focusing?

Cableaddict wrote:
Hey, I thought we were trying to call them by the official Canon name now: "Washers."

Correct...but the washers are used for shimming.

Nov 25, 2008 at 10:21 PM

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