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06-16-2011, 11:45 AM   #1
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SMC Pentax-M 50mm F1.7 focus problem?


I have just bought the above lense but seem to have a problem with my pics been out of focus, I'm very new to all this so it could be very simple.

I have set the camera so I can use the aperture ring, I manually focus on the subject but when I look closely at the pic it's blurred, I have use camera shake in the menu set to on.

I'm using a pentax k-r and green button for I think shutter speed

Any advice please



06-16-2011, 12:02 PM   #2
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A sample photo with Exif data would help determine the problem.

Are any other parts of the photo not blurry? If so then you just mis-focused by a tad bit.

Were you on a tripod? If so then SR should be turned off, on might have caused the blurriness.

The only advise I can give without seeing a sample would be to do a controlled focus test. Get a subject (preferably one with good contrast or with letters) and focus while only a foot or 2 away from the subject so you can be 100% sure you are in-focus. If those photos turn our blurry then you might have some internal lens problems, haze maybe. If they turn out good then it was a mis-focus.
06-16-2011, 03:45 PM   #3
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Send your hands into pentax for recalibration.

But in all seriousness, it's just really hard to manually focus on a digital viewfinder.
06-16-2011, 03:53 PM   #4
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Manual focus

Have you try Live View (LV)? I find it is way more accurate (brighter & bigger) at fine focusing than just looking through Kr viewfinder. If the problem only associate with this lens, then it is time to return the lens.

06-16-2011, 05:15 PM   #5
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I only have this manual lens, the others are auto, I will try lv screen and see if it's any better, cheers guys
06-17-2011, 07:35 AM   #6
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You cannot blame a manual focus lens for a focussing problem!

Tripod - flat subject, focus it as accurately as you can. Take shot and observe the result. Now Live view and repeat, make sure the focus is nailed. Compare the shots. If theres a difference either you can't see well enough to focus through the viewfinder or there is a back/front focus issue.

I used to have a back focus problem with my old E520 using OM lenses, annoying but consitent so I just got used to compensating for it.

Manual focus on a small plain screen is not easy. That's why SLRs had split screens in Big viewfinders.
06-17-2011, 07:52 AM   #7
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There is usually a learning curve.

First, welcome aboard.

1. Make sure your diopter is properly set. LV will help but you don't want to run around holding the camera at arms length trying to manually focus a lens.

2. That lens will only properly work in M mode. In all other modes, it will shoot wide open regardless of where you have the aperture ring set. The green button centers the meter based on that set aperture.

3. Practice on something simple, that does not move. Beware of enlarging images on the LCD as it is a poor tool for judging sharpness.

4. Try Catch in Focus. Set your camera to AF-C, set your exposure, press and hold the shutter release, and turn the focus ring slowly until the camera takes a photo. You will have to turn this feature on in your custom menu.

5. Practice on something simple (yes, I said it twice).

Using manual focus lenses is fun and quite simple once you get the hang of it.

Collection: Manual Focus

06-17-2011, 08:53 AM   #8

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If you are shooting wide-open with the 50mm 1.7, remember depth of field will often be razor-thin. Which may mean for example if you focus on a face close-up at f1.7, the tip of the nose may be in focus but not the eyes or the mouth. That is perfectly normal behaviour when shooting wide-open with fast lenses.

You may get better results for regular shooting if you stop down the aperture a notch or two.

06-17-2011, 08:57 AM   #9
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It's already been said but you may need to adjust the diopter on your viewfinder.

In your K-r manual its shown on Pg 19 as the "Diopter adjustment lever". Its the slide at the top of the viewfinder and on the K-r goes from -2.5 to +1.5. Instructions on setting it start on page 58 of your manual.

Good luck, hope that helps.
06-17-2011, 12:04 PM   #10
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Thanks to everyone who have taken the time to help, tomorrow i will put your suggestions to the test and report back, thanks again guys

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