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Author Topic: Focus mismatch between focusing screen and live view D800.  (Read 2609 times)

ACH DIGITAL

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Focus mismatch between focusing screen and live view D800.
« on: November 20, 2013, 09:43:29 AM »

Hi all.
I happened to use manual focus most of the time for my work in live view mode, so it is always tack sharp, but when shooting handheld Iím having some mismatch focus problems.
What I see in focus in my focusing screen is out of focus in the image and if I check in live view, it shows a focus mismatch.
Is this happening to someone else with the D800?
At first I thought it was my sight, but checking with the camera on a tripod I found out it actually is the camera.

ACH
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Ellis Vener

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Re: Focus mismatch between focusing screen and live view D800.
« Reply #1 on: November 20, 2013, 09:57:14 AM »

Sure it isn't a diopter setting issue?
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Ellis Vener
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ACH DIGITAL

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Re: Focus mismatch between focusing screen and live view D800.
« Reply #2 on: November 20, 2013, 10:52:35 AM »

Ellis, not it is not.
Reading a DPreview forum, I found out this:
"Above the screen sit one or more very thin brass shims like thin picture frames around the edge of the screen, between it and the electronic display screen above which itself is fixed in palce under the fixed pentaprsim."
After reading that I took the risk and opened the screen sitting and took off the one shim it brought, and now the focus concedes.
This is provably a good thing to know for anyone who might have this problem.

ACH
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AFairley

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Re: Focus mismatch between focusing screen and live view D800.
« Reply #3 on: November 20, 2013, 03:01:44 PM »

Yes, the only explanation is misalignment of the focusing screen.  Note that aligment of the focusing screen has nothing to do with the accuracy of autofocus, though.
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ACH DIGITAL

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Re: Focus mismatch between focusing screen and live view D800.
« Reply #4 on: November 20, 2013, 03:42:58 PM »

For some unknown reason Nikon placed that rectangular shim above the screen, separating it a bit from the pentaprism. I have had this camera for two years now and I was doubting my sight very badly for not being able to focus right.
Finally I woke up from that nightmare to discover it was not me, it was that thing in there.
Now my focusing con side with live view and the focusing aid light.
As I read in DpReview, some cameras even bring more than one. Not sure if it is true.
I like my D800 very much in many respects but the focusing screen housing and hinge are quite flinksy.
ACH
« Last Edit: November 20, 2013, 03:44:31 PM by ACH DIGITAL »
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pluton

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Re: Focus mismatch between focusing screen and live view D800.
« Reply #5 on: November 21, 2013, 02:19:52 AM »

Yes, the only explanation is misalignment of the focusing screen.  Note that aligment of the focusing screen has nothing to do with the accuracy of autofocus, though.

Mirror resting height also can affect apparent focus in the finder.  It's all part of what I've always called "The Shell Game Of Focusing Errors".
When you get a chance, you should have it checked at a good service facility, if you can find one.
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MarkL

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Re: Focus mismatch between focusing screen and live view D800.
« Reply #6 on: November 21, 2013, 07:50:48 AM »

My D700 had this, I never fixed it because I used af handheld and LV on a tripod. There are shims under the focusing screen and I think you can buy more.

Another irritating manufacturing tolerancing issue like af front/backfocus.
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ACH DIGITAL

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Re: Focus mismatch between focusing screen and live view D800.
« Reply #7 on: November 21, 2013, 09:54:12 AM »

Well well, when I had the Canon 5D the mirror came out. I think the tendency should then be mirrorless DSLR in the future.

ACH
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t6b9p

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Re: Focus mismatch between focusing screen and live view D800.
« Reply #8 on: November 21, 2013, 12:19:07 PM »

Many years ago I reported on a couple of forums about a similar MF focus screen issue with a Nikon D200.

I purchased a couple of the shims of different thickness (just in case) and then proceeded to take the focus screen out. The plan was to remove one shim and see which direction the focus error moved. However, when I got it apart I found there were two identical thickness shims, so I removed one and proceeded to test. MF focus was perfect first test I made.

My only guess is that, because these shims are so thin and easily "stick" to one another, the Nikon tech that assembled the focus screen didn't notice and obviously the DSLR wasn't tested by QA for MF.
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Ellis Vener

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Re: Focus mismatch between focusing screen and live view D800.
« Reply #9 on: November 21, 2013, 02:16:11 PM »

"I think the tendency should then be mirrorless DSLR in the future."

Taking the optical system out ( Mirror groundglass, pentaprism)  means it won't be an SLR camera.
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Ellis Vener
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stevesanacore

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Re: Focus mismatch between focusing screen and live view D800.
« Reply #10 on: November 21, 2013, 09:37:30 PM »

"I think the tendency should then be mirrorless DSLR in the future."

Taking the optical system out ( Mirror groundglass, pentaprism)  means it won't be an SLR camera.

Well, I think the optical focusing limitations have reached their limits with such hi resolution sensors. Personally I haven't been able to confirm focus in a viewfinder for many years. I depend on AF and always check focus on the rear or on my laptop when focus is critical (shooting wide open). I find calibrating all my lenses to each body really makes the AF accurate. I'm looking forward to trying the new Sony A7 with it's new generation digital viewfinder. It may be a game changer.
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ACH DIGITAL

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Re: Focus mismatch between focusing screen and live view D800.
« Reply #11 on: November 21, 2013, 09:52:34 PM »

Yes Steve, it is a game changer and I think it is clearly showing the way to future cameras.
ACH
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ErikKaffehr

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Re: Focus mismatch between focusing screen and live view D800.
« Reply #12 on: November 21, 2013, 11:35:49 PM »

Hi,

I agree, sort of. But DSLR may just be a term. A Hasselblad V or H is a digital SLR for instance but DSLR as a term mean the format we are used to have on Nikons and Canon. The Sony Alpha SLT 99 I have takes the same lenses as my Sony Alpha 99, has actually a mirror but it is not used for viewing.

I would not at all be surprised if Nikon and Canon offered DSLRs without mirror. I would suggest EVS-s are growing up. Many new sensors have on sensor phase detection. So the mirror is not needed. You can combine phase detection and contrast sensing AF, best of two worlds.

Sony has found that people buy cameras with a hump for the view finder. It gives the camera a professional look.

Best regards
Erik

"I think the tendency should then be mirrorless DSLR in the future."

Taking the optical system out ( Mirror groundglass, pentaprism)  means it won't be an SLR camera.

uaiomex

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Re: Focus mismatch between focusing screen and live view D800.
« Reply #13 on: November 21, 2013, 11:59:28 PM »

Amateurs buy cameras with a hump to impress and to look pro and professionals buy cameras without a hump to be inconspicuous and to look amateurish. LOL!

Eduardo




Sony has found that people buy cameras with a hump for the view finder. It gives the camera a professional look.

Best regards
Erik

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ACH DIGITAL

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Re: Focus mismatch between focusing screen and live view D800.
« Reply #14 on: November 22, 2013, 08:21:07 AM »

Even if going mirror less, I still need EVS hump on top because of many years looking through viewfinders I got used to it. I use Live view when on tripod shooting. Essentially both are needed!
But is the way to go.
I believe one has to accept this changes for better.
I remember a Calumet magazine cover from the early 90's where they illustrated the future photographer's studio. It was a Sony video camera hook to a computer with a thick cable, in front of the camera was a male model and in the computer screen was the same guy but with an armour created in software.
This image blew my mind and now is real thing.
ACH
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Rob C

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Re: Focus mismatch between focusing screen and live view D800.
« Reply #15 on: November 22, 2013, 09:38:04 AM »

Not a lot of point knocking the pentaprism viewing system per se; what should be chastised is the practice of putting in fixed screens that are totally unsuitable for the manual focussing process.

Okay I had a younger set of eyes, but I can't recall finding difficulties focussing my Nikons prior to digital.

One thing I could enjoy: a very portable viewfinder plug-in that allowed me to compose and focus on a screen without having to crouch down on my heels. I often see ground-level opportunities that I just can't approach because of not being able to work down there.

A plug-in to the socket of the cellphone would give all the screen I'd require.

Rob C

Chuck at work

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Re:
« Reply #16 on: November 22, 2013, 10:01:04 AM »

Hooking a cellphone to DSLR? Hasn't that been done already? Now hooking a certain phone to a certain camera (yours) that maybe waiting on the market for that solution.
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Rob C

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Re:
« Reply #17 on: November 22, 2013, 03:03:35 PM »

Hooking a cellphone to DSLR? Hasn't that been done already? Now hooking a certain phone to a certain camera (yours) that maybe waiting on the market for that solution.


If I knew the answer to questions like that I'd know more than I do right now.

I think that's reasonable stance on my part!

Should anyone know how/if you can do that with a D700 and a Samsung Galaxy, please let me know as well. My current project screams for it.

;-)

Rob C

ACH DIGITAL

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Re: Focus mismatch between focusing screen and live view D800.
« Reply #18 on: November 23, 2013, 06:14:16 PM »

By the way, today just arrived my Panasonic 4/3. Not a professional camera but a nice mirrorless complement for family and casual shots.
Tasting the advantages of ELV and magnification in the viewfinder with the click of a bottom.
ACH
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JohnBrew

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Re: Focus mismatch between focusing screen and live view D800.
« Reply #19 on: November 23, 2013, 06:15:37 PM »

I'm sorry you're having that problem. I do not have that problem with mine. Maybe I'm just lucky.
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