Got my new k-x, seems has that blur problem, what should I do?

Started Jul 4, 2010 | Discussions
liukaitc Regular Member • Posts: 105
Got my new k-x, seems has that blur problem, what should I do?

Damn..this is my first DSLR. bought like 3 weeks ago. took some photo, feel like some not as sharp as my old compact camera. but I thought that is the way it is. after browse plenty thread here. I find there is a blur prolbem about k-x. so I tried a little test. here is my test. shoot 3 continuesly at 1/80 and shoot 3 continuesly at 1/30. both at 18mm with SR on, standing at same postion. it tunrs out 3 with 1/80 all blured a bit and instead the 3 with 1/30 all sharp.....

here is the pic. 100% crop. left is 1/80, right is 1/30....

so please verify if this is the blur problem u guys talking about. if yes what should I do...

paul_do Regular Member • Posts: 376
Re: Got my new k-x, seems has that blur problem, what should I do?

what F/stop at 1/30 and 1/80? When you shoot at 1/30s the lens is close down and at 1/80s the lens is probably wide open that's why it looks sharper at 1/30s but I could be wrong unless you provide an exif for both image.
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OP liukaitc Regular Member • Posts: 105
Re: Got my new k-x, seems has that blur problem, what should I do?

sure it will change,change from f3.5 to f4, but I do not think that is the key for that blur problem of k-x. I saw many example people provide. The photo sure show different f-stop.

paul_do wrote:

what F/stop at 1/30 and 1/80? When you shoot at 1/30s the lens is close down and at 1/80s the lens is probably wide open that's why it looks sharper at 1/30s but I could be wrong unless you provide an exif for both image.
--
http://www.modelmayhem.com/PaulDo
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OP liukaitc Regular Member • Posts: 105
Re: Got my new k-x, seems has that blur problem, what should I do?

and I can provide photo at same f-stop. same outcome. when I use slow shutter speed like 1/30, 1/20. it comes out very sharp. but when I use like 1/60, 1/80, 1/125. it comes out blur as my pic show.

Raphael Mabo Senior Member • Posts: 1,164
Re: Got my new k-x, seems has that blur problem, what should I do?

The "blur problem" identifies itself as a double-image blur. Your images is too small to see if they have this or not.

Coming from a digital compact you are used to have sharp images across the frame, this comes from the the extended depth-of-field that small sensors has compared to the larger APS-C sensor. The more you open up the aperture, the more critical is the focus. So at 1/80 you have smaller depth-of-field where focus errors shows up than at 1/30.

But it is hard to judge your images and say it is that or that because they are too small here.

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OP liukaitc Regular Member • Posts: 105
Re: Got my new k-x, seems has that blur problem, what should I do?

u are not viewing it 100%??
click orginal and u can see 100% crop

Raphael Mabo wrote:

The "blur problem" identifies itself as a double-image blur. Your images is too small to see if they have this or not.

Coming from a digital compact you are used to have sharp images across the frame, this comes from the the extended depth-of-field that small sensors has compared to the larger APS-C sensor. The more you open up the aperture, the more critical is the focus. So at 1/80 you have smaller depth-of-field where focus errors shows up than at 1/30.

But it is hard to judge your images and say it is that or that because they are too small here.

opiecat Senior Member • Posts: 2,404
Re: Got my new k-x, seems has that blur problem, what should I do?

try your shots w/ a tripod, SR off, SR on and compare
hard to tell from your samples

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roland66 Junior Member • Posts: 39
Re: Got my new k-x, seems has that blur problem, what should I do?

Generally I'd guess this really might be a problem of the cam. I've seen similar with my cam but did not do systematic tests so far. Maybe I'll find time for that or at least for supplying 'tests' I did so far. Not sure if my pictures here also suffer a bit like that: http://forums.dpreview.com/galleries/3490625903/albums/pain-of-focus-ii . And it looks like I have some major problem with focus anyway ( http://forums.dpreview.com/forums/read.asp?forum=1002&message=35663706 http://forums.dpreview.com/galleries/3490625903/albums/pain-of-focus-iii ).

OP liukaitc Regular Member • Posts: 105
Re: Got my new k-x, seems has that blur problem, what should I do?

Today I shoot plenty outdoor at 18mm. the problem is obvious. I only got sharp photo when shutter speed faster than 1/320...that is abnormal. I shoot continusly 3-4 photo for each shutter speed setting(1/30,1/80,1/160,1/320 and etc). it should not happen that all the photo got blured a bit when shutter slower than 1/320....well the blur is not that huge. but still this decrese the qualty...this should not happen..

I guess I can not do anything but just keep using it. I think repair department would not admit this problem..

opiecat wrote:

try your shots w/ a tripod, SR off, SR on and compare
hard to tell from your samples

OP liukaitc Regular Member • Posts: 105
Re: Got my new k-x, seems has that blur problem, what should I do?

these set seems fine. I saw your shutter speed is like 1/320. for my camera it is fast enough to prevent any blur. you should try shutter speed slow than 1/320. my photo all got blured once I shoot slower than 1/320 at 18mm. and shoot mutilple times for each speed, so it is not blured by chance. also u can use tripod. very obvious for my camera. the best condition to detact is to shoot the scene where there is digital or words appear at far distance. so u can see if these digital and words got blured or not.

roland66 wrote:

Generally I'd guess this really might be a problem of the cam. I've seen similar with my cam but did not do systematic tests so far. Maybe I'll find time for that or at least for supplying 'tests' I did so far. Not sure if my pictures here also suffer a bit like that: http://forums.dpreview.com/galleries/3490625903/albums/pain-of-focus-ii . And it looks like I have some major problem with focus anyway ( http://forums.dpreview.com/forums/read.asp?forum=1002&message=35663706 http://forums.dpreview.com/galleries/3490625903/albums/pain-of-focus-iii ).

roland66 Junior Member • Posts: 39
No strict test but some hint

Here four pictures of some days ago (all at FL18mm with DA18-55mm/3,5~5,6AL WR). The interessting part is the center of the pictures where I focussed to (wall of building) and the sharpness there:
IMGP0281 1/30s F11, (not too bad)
IMGP0282 1/60s F8, (worst - bad)
IMGP0283 1/125s F5.6 and (not too bad)
IMGP0284 1/250s F4 (best - ok)
http://www.dpreview.com/galleries/3490625903/albums/blured-by-sr-questionmark

It's not a strict test - I didn't take a longer series of pictures and I didn't care of equal aperture. And the scene ist not ideal for a test at all (it's not a simple brick wall ... ).

But I think at any of the four apertures 11, 8, 5.6 and 4 I could expect sharp center. At least I could see no reason why center at F8 (wich is at 1/60s) should be unsharp if not misfocused or blured by shake or something else (see IMGP0282). And if really diffraction at F11 was a problem here then why would IMGP0282 at F8 be so much worse?

Blure by shake (or shake reduction) generally will more or less affect the whole frame and be different from effect of different aperture. Even if it maybe not always easy to tell the reason for unsharp blured pictures ...

And in the end ...

I guess I'm getting sick of uploading all that ugly pictures any longer. It's no joy looking at them. Hope I'll remove them all soon and only will upload nice and good and sharp pictures in near future.

Philnw2 Veteran Member • Posts: 3,683
Re: No strict test but some hint

At the largest magnification, is that 100 percent crop, if so even your worst case looked good to me.

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roland66 Junior Member • Posts: 39
No crops. Full sized picture under "Original"

I'd say the blur is obvious under "Original (4288×2848, 5.4MB)" of IMGP0282:

http://www.dpreview.com/galleries/3490625903/photos/387790/imgp0282?inalbum=blured-by-sr-questionmark

and klick "Original" there.

OP liukaitc Regular Member • Posts: 105
Re: Got my new k-x, seems has that blur problem, what should I do?

today did test again. same thing.
I took 4-5 pic for same shutter speed, all blured. so it is not my hand shaking.

left 1/160, right 1/320. it should not got any blur at 1/160 with SR on. it is just abnormal...

click orginal to see 100% crop

ozdean
ozdean Forum Pro • Posts: 27,284
Re: Got my new k-x, seems has that blur problem, what should I do?

Yes you have the mirror slap problem, it occurs between 1/60 and 1/150 on some Kxs.
Pentax Australia were able to fix mine under warranty. Send it in for repair.
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ozdean
ozdean Forum Pro • Posts: 27,284
Re: Got my new k-x, seems has that blur problem, what should I do?

BTW you will find it worst in portrait mode, if you have just purchased I would ask for a replacement camera as not all Kx's have the problem.
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OP liukaitc Regular Member • Posts: 105
Re: Got my new k-x, seems has that blur problem, what should I do?

Thank you so much for your clarify and advice.

ozdean wrote:

Yes you have the mirror slap problem, it occurs between 1/60 and 1/150 on some Kxs.
Pentax Australia were able to fix mine under warranty. Send it in for repair.
--
Regards Dean - Capturing Creation

OP liukaitc Regular Member • Posts: 105
Re: Got my new k-x, seems has that blur problem, what should I do?

just let everyone knows. I exchanged a new one a few days ago. now I think everything is fine now. I am kind happy.

My suggestion for any new KX users is do some test as soon as possible when u get your KX. so u can exchange if it has blur. and actually store policy here in New York is very nice. u do not need any reason to exchange within 30 days.

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