pentax 50mm 1.4 faulty? help needed.


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doreymi

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Jan 2, 2010
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#1
i just purchased my first dslr, pentax kx for about a month now, bought a 50mm 1.4 yesterday. took some sample pictures with it. i realised that the pictures taken weren't quite as sharp as compared to the pictures on the internet. any possibility that the lens that i purchased was faulty? or are there any tips on using the lens?
 

airconvent

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Apr 12, 2005
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#2
Inspite of the antishake, a steady hand is still good. Also, did you try to take photos lesser than its minimum focussing distance? No way the camera can focus properly under this circumstance. To test this, mount the lens on a tripod and take a picture on remote timer.
BTW, is your focal point set correctly? If you set it off centre and forget to set it back, that can cause the camera to focus on the wrong object. Generally, lenses tend to be least sharp at the wide open end. Try moving down a stop or 2.
 

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doreymi

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Jan 2, 2010
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#5
yup. I've set my focal point correctly, taken with a tripod etc. however, the"blur" effect is still there. I've realised that i can adjust the aperture via two ways, one is turning the aperture ring, another is to set the ring to automatic and adjust the aperture via the dial on the camera, will any of these affect the quality of the picture?
 

CY_OH

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Jun 24, 2004
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Ang Mo Kio
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#6
The aperture should be set using the camera body control dial, with aperture ring at "A".

If the aperture ring is used at other positions, pictures will be taken at maximum aperture if camera not in Manual mode.
 

Jan 16, 2009
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#7
You may want to check if there is a BF/FF problem with your lens. I seem to recall there was a PDF posted that allows you to test the 50mm for that, but can't seem to find it anymore.
But ya, do post a few pictures so we can see what the problem is. There are lots of different possible reasons for blur pictures.
Don't forget to get a hood for the 50mm too, it really helps.
 

doreymi

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Jan 2, 2010
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#8


this is the sample taken by the lens.
 

zoom3

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May 18, 2007
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#9
This lens is not easy to master. Pics are typically pretty soft wide open at 1.4. It is sharpest around f8. Take some pics of the same box between f5.6 and f8.0 and compare. They should be razor sharp. If not, then there is a problem....
 

hamustar

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May 23, 2007
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#11
It shouldn't be that soft. Try shooting 45degree down on a flat wordy thing like a newspaper or a wordy flyer to confirm your BF/FF suspicions.
 

istDeS

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Dec 7, 2005
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#12
user is shooting at wide open f/1.4 and close focus distance, thin DOF have caused the pics to look unsharp.
 

Gengh

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May 6, 2007
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#14
Since it was taken with a tripod, shutter speed shouldn't be an issue. Try shooting newspaper at an angle like hamustar suggested. The DOF at f1.4 and such short focusing distance is super thin, and even minor AF inconsistencies will show up.
 

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