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02-23-2012, 02:20 AM   #1
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K-5 Viewfinder and manual lenses focus problem

Hi,
I have some very irritating problem.
Besides FF in tungusten light, I have very big Front focus issue when using Manual Lenses.
It look very simply. When I make Manual Focus using Live View I can make sharp photos.
But when I use viewfinder and see its in focus, then everytime get Front Focus.
Even when I use Focus assistant ( custom menu position 25.
(I've try to check what is the name of function in english but My K-5 freezed when try to change language from polish to english :/)
So Both AF system and my eye see thing in focus when its not. Its when I use my SMC M lenses.
What is very weird, when I use My AF lenses like FA31 or DA60-250 everything is OK.
Problem is crucial for my now as I bought SMC 50 f/1.2.
So I'm thinking to send back my camera to service but I don't know its bug or feature

02-23-2012, 02:33 AM   #2
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My K5 focusses very well with my Porst 55mm 1.2 using catch in focus. It's so easy.
02-23-2012, 02:35 AM   #3
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your focusing screen might be out of alignment by the sound of it. you'll need some shims to make some adjustments to it

But I will tell you this, you are going to need a focusing screen for the 50 1.2 as focusing without one will be a nightmare (unless of course you use Catch in focus as Clavius said)
02-23-2012, 02:55 AM   #4
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Yes but both my eye and my "catch in focus" function, have FF issue. But when I use FA DA Tamrom 90 its ok. Only with old SMC Lenses I Have problem

02-23-2012, 02:56 AM   #5
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Well, Custom Setting, menu item #25 on the K-5 IS Catch-in-Focus (CIF), and PiotrKrochmal has tried that. Now, as far as I know, Front Focus may be an issue with the lens rather than with the camera and there is an option for AF-adjustment (which is what one uses for CIF) so I suggest that you take a look at this tutorial before you send your camera to service. See the how-to guidelines here:

Fixing Front and Back Focus - Introduction - PentaxForums.com


And by all means, try some other MF lenses with CIF if you can.

CIF works fine on my K-5 with all my MF-lenses, and I have quite a few. But I know: That doesn't solve your problem!

Good luck
02-23-2012, 05:37 AM   #6
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Ok i see that there is some misunderstanding of my problem, so I make some test photos. What you see is pixel to pixel crops on one page
http://krochmal.smugmug.com/photos/i-DSnPCfw/0/O/i-DSnPCfw.jpg
So all photos are made from almost exacly position about 2 meters from target. So DOF is exactly thesame ( 5 cm for Tamron and 7 for Pentax

Last edited by PiotrKrochmal; 02-23-2012 at 05:41 AM. Reason: more info :)
02-23-2012, 09:35 AM   #7
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The problem with using AF fine adjustment for this problem is when you have a manual focus lens attached, the only option is Adjust All, which will apply the AF fine adjustment to every lens you mount (except those with their own fine adjustment settings).

Based on your photos, are you saying that for all manual focus lenses, what you see in focus through the viewfinder is behind the actual focal point, but when you use any autofocus lens - even with manual focus - what you see in focus through the viewfinder is actually in focus? That would be a bizarre problem.

If you go to full manual focus when using the Tamron lens (or any autofocus lens), does what you see in focus through the viewfinder match what is in focus in photos?

If using manual focus on any lens yields front focused results, then the focusing screen being out of calibration is likely the problem. However, if front focus is only a problem when using lenses that do not offer autofocus, then I have no ideas.
02-23-2012, 10:14 AM   #8
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QuoteOriginally posted by PiotrKrochmal Quote
Hi,
I have some very irritating problem.
Besides FF in tungusten light, I have very big Front focus issue when using Manual Lenses.
It look very simply. When I make Manual Focus using Live View I can make sharp photos.
But when I use viewfinder and see its in focus, then everytime get Front Focus.
Even when I use Focus assistant ( custom menu position 25.
(I've try to check what is the name of function in english but My K-5 freezed when try to change language from polish to english :/)
So Both AF system and my eye see thing in focus when its not. Its when I use my SMC M lenses.
What is very weird, when I use My AF lenses like FA31 or DA60-250 everything is OK.
Problem is crucial for my now as I bought SMC 50 f/1.2.
So I'm thinking to send back my camera to service but I don't know its bug or feature
You are focussing on the screen using manual lenses.
First of all the standard screen is not well suited for manual focus. Get a different screen.
Second, the screen may be out of alignment. This can not be compensated with the AF microadjustment, but with a shim kit that costs approx. 50 bucks.
Third, old lenses may show a varying plane of best focus based on the f-stop you use

Focus assist should guide you correctly - if you use focus assist, AF fine adjustment would help, but be aware that you need to stop focussing exactly when the light goes on. A little bbit of additional movemenet and you are off again...

Slight movements can always change the plane of focus.

02-23-2012, 11:35 AM   #9
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QuoteOriginally posted by zapp Quote
Slight movements can always change the plane of focus.
This is often overlooked: a slight bit of sway as you are standing can throw off manual focus with a fast lens.
When troubleshooting a front/back focus issue, always start by testing with the camera on a tripod to eliminate body-movement variables. It you get correct focus on tripod but problems without it, start looking more at your technique than the equipment.
03-08-2012, 03:06 PM   #10
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I did it!
Ad mentioned, I had a problem in the manualy focusing my 50 f/1.2 lens. I had front focus. Significant. I showed you that when focusing manually Tamron 90 f/2.8 everything is alright.
Under the influence of the suggestions I bought a the focusing screen K-3 with Focusing Screen. I installed it. Despite high levels of stress, everything went according to the instructions (the main part of the manufacturer, but also look: http://ricehigh.blogspot.com/2012/02/changing-focusing-screen-of-k-5-tips).
So I did it in the LV or classic AF (T90 L77) Its OK but... Manualy by viewfinder with my new K-3 still get FF.
So instruction are clear: Two ways: first K5 focusing screen mount point should be on left -checked its ok.
second way - shim - so I changed my old fashionable metal one to new shrinked plastic. That I get with my screen in the kit and:
everything has come to be wonderful
AF blades properly. No FF when focusing manualy.
So I checked all my lenses, both AF and MF using LV MF, LV AF, AF and VF MF Yes I did it. It should take me few hours but I use PK theter software. Thanks to it all checking take me 1h. I use PS with standard emboss filter to see where the focus point is. (of course using tripod )

My reflection is that the depth of field depth is not equal by numbers.
5 cm at 50 mm lens is not equal to 5 cm at 90 mm lens.
So I hope my experience help you .
Shim was the problem
03-08-2012, 03:54 PM   #11
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QuoteOriginally posted by PiotrKrochmal Quote
I did it!
Shim was the problem
Glad that you have this resolved ! I can't Imagine how annoying it would have been!
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