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07-15-2013, 11:12 AM   #1
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green button UN-focusing images

Hi. I have been looking online and cannot find anything else about this. I am still very new to photography so it could just be me.

I have been collecting lenses since I got the camera and have quite a few K series and M series lenses. With all of the K series lenses they work perfectly, I focus the shot, press the green button then take the picture or adjust the ISO from what the camera chooses. With the M series this works about 50% of the time. When I press the green button the image in the viewfinder moves up, gets lighter and needs to be refocused. When I refocus and take the picture it is a complete blur, now when I look at the viewfinder that is blurred too like it was fine before I pressed the green button and I should have left it as it was. I have two of each type of lens and have had the problem a lot on M's but not once on the K series lenses. The camera is a K-r.

Any help would be much appreciated as this is starting to get frustrating.

Thanks in advance, Eddy

07-15-2013, 11:24 AM   #2
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Maybe a stupid question, but have you adjusted the viewfinder dopler? (I think that's what it's called... the little slider above the viewfinder, behind the rubber eye-cup)

When I first had my camera, I thought there was something wrong because the AF lens would focus, but what I saw in the viewfinder was blurred because of the dopler not being adjusted.
07-15-2013, 11:25 AM   #3
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The green button only sets the shutter speed, so I don't see how that could be affecting the focus setting, as it's entirely manual with m and k lenses. Are you shooting in m mode?

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07-15-2013, 11:38 AM   #4
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When you use manual lenses and are in M mode (no auto ISO) and press the green button, the camera will close the mirror, stop down the aperture to the select on aperture ring, and then meter and adjust the shutter speed.
When the aperture stops down, it changes the DoF (DoF becomes bigger) but the critical focus shouldnt change. Some lenses can have faulty aperture blades or elements that cause the focus to change when the aperture changes, but thats a fault and should be fixed.
Your camera can have a problem with the mirror moving. This can be caused by the battery, or it can be a fault that you cant fix yourself.
Also, what can make images look fuzzy is a long shutter speed (so handshake can show up). Or the SR, if the wrong number is input - make sure the number is the same as on the lens or wider.

So make sure its not any of these things. And hopefully its not a broken lens. You can also try setting the correct shutter speed without using the green button at all - you dont actually have to use the green button, its just convenient.

07-15-2013, 12:02 PM   #5
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I only use M mode on the camera. I hope it isn't a faulty lenses and don't think it is as its on two of them. I have tried it using live view and not the viewfinder and there is no issue so far, have been testing a lot and as soon as I go back to viewfinder its there again. It isnt a shake blur. Even before I take the picture but after I press the green button it unfocuses. The camera is under warranty , its less than a month old. Just really weird it only happens on the two lenses (M-100 f4 macro and M-50 f1.7 but not on the K-55 f1.8, the K-200 f4 or a Hoya zoom lens I have)

Thanks for your replies everyone
07-15-2013, 12:07 PM   #6
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If I manually set the shutter speed and take the picture it is perfect. The problem is only there when I press the green button and am using the viewfinder, no other time. By the way the image in the viewfinder moves up slightly it looks like it could be the mirror at fault, would also explain why its fine when using live view as it doesn't need to move the mirror to get to the sensor and work out the shutter speed (like I said, I'm new so if that last statement statement was nonsense please let me know)

Thanks
07-15-2013, 12:09 PM   #7
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Posting a sample of the blurry shot with EXIF data (dont process it) will let experienced folks here help you determine the cause.
07-15-2013, 12:23 PM   #8
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QuoteOriginally posted by SickEddy Quote
By the way the image in the viewfinder moves up slightly
This is the critical detail. AFAIK, the mirror is not supposed to move. All the green button does is let the lens aperture stop down so it can meter.

The focusing screen acts like a duplicate of your sensor. Light is supposed to travel the exact same distance to get to it as it does to get to the sensor. If the mirror moves slightly, that distance is no longer correct, and your focus will be off. It doesn't take much to throw your focus way off.

When I bought my K-r new in 2011, it had a faulty aperture control unit. The first symptoms were that the mirror would flip multiple times when taking a single picture, and sometimes it would fail to completely return to its rest position. Eventually, the camera would just flip the mirror over and over when I pressed any button. I sent it in for warranty repair, they replaced the aperture control unit, and it lived happily ever after.

I was one of many who had this issue, but I believe it almost always showed up very soon in the camera's life. How old is your K-r?

I believe the aperture arm, mirror, and shutter are all linked, so it might not be the mirror mechanism itself causing the problem. Something is amiss somewhere in those mechanisms.

07-15-2013, 02:14 PM   #9
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The camera is less than a month old from brand new, it was new old stock so is under warranty. When pressing the green button in manual mode and using the liveview the mirror does not move. When using the viewfinder it does, it sounds exactly the same as when taking a picture. If i posted a sample of a blurry picture it would just be a normal picture out of focus. I have tried focusing, pressing the green button (this making what i see in the viewfinder a blur) then taking a picture without adjusting focus and it comes out as it should (focused)
Is there any definite test for the mirror movement, the place the camera came from do not do repairs so it would be sent to Pentax and I would rather not be without it if its not 100% that, I'm very sure its not the lenses. I'm just hoping its a setting that's somehow different for K and M series lenses on this camera

Thanks again everyone
07-15-2013, 02:37 PM   #10
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Hmm - this almost sounds like the view finder screen is loose - is that possible, experts?
07-15-2013, 02:59 PM   #11
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QuoteOriginally posted by crewl1 Quote
Hmm - this almost sounds like the view finder screen is loose - is that possible, experts?
Unlikely, but it's simple enough to check. Use this guide, courtesy of focusingscreen.com, to check:

PENTAX K100D / K200D / K2000D / K-m / K-x / K-r Focusing Screen Installation Instruction

Just use the pictures to see how the screen and clip is configured, then check to see if it's wiggly.

I'm really puzzled by the different results form K and M lenses. They're functionally identical: a naked bayonet, with no electrical contacts communicating with the camera. In fact, if you take a picture with any lens that doesn't have contacts, the EXIF will call it a "K or M series lens." They're the same thing, really. I'm tempted to say that the difference you're experiencing is just a coincidence.
07-15-2013, 03:18 PM   #12
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That's the bit really confusing me but so far not had a single problem with a K lens and its almost 50% of the time with any of my M lenses. I am currently doing a firmware update as its on 1.0 at the moment so I will take a look at the link while that's loading. I just hope it is a camera problem as thats covered
Thanks
07-15-2013, 03:53 PM   #13
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Firmware made no difference. Tried K55, lens worked 100% over about 50 times one after another, tried both M lenses and unfocused about 20 out of 50 times I pressed the green button. So confused
07-15-2013, 03:56 PM   #14
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I suggest you also charge your battery and leave it out of the camera overnight. Maybe even try a different battery or an AA adapter (the K-r can take AA batteries with the right adapter), as that sometimes resolves mirror issues (at least according to some forum posts, my K-r didnt have any such problems)
Btw, are the K and M lens mounts different from each other? Like, do any of your lenses have insulated mount or something? Do any protrude into the camera (so that they might bump into the mirror)? Maybe any gunk on the mount? Probably irrelevant, but who knows, I cant think of why K series would work but not M. It would be great if you could try those lenses on another digital camera, to figure out if its the lens or the camera

Last edited by Na Horuk; 07-15-2013 at 04:06 PM.
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