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05-03-2011, 02:58 PM   #1
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Pentax Auto Focus issue

Hi,

I want to find out why my pics without sharp focus . ..
I used Macro mode with AF on my Kx and DA L 18-55mm. i shooted after i heard the "bit" sound of focus confirmation.

I like to use single-center focus point mode to focus the main object first, then i adjust the different angle to get the best graphic of pic. I do not step forward or backward with changing shooting distance.
Do i make my pics out focus by doing this?

Do my pics over explosure cause the focus out?

Please share your thinking/experience if you also had the same story before.

Thank You.


You may see my retouched album:
Kenneth3aracing's Album: My first Album in Pentax Forum - PentaxForums.com

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05-03-2011, 03:11 PM   #2
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Moved from "General photography".
05-03-2011, 03:21 PM   #3
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Pentax Auto Focus issue

Why my pics without sharp focus?

I took these pics with Kx - marco mode - AF on DA L 18-55mm

i like to use single-center focus point mode to focus the main object first, then move different angle to get the best graphic of pic without stepping front/back and changing shooting distance.
Do i make my pics out focus?

Do my pics over explosure which cause out focus?


Or they are in focus, but i am just so criticize?

please share your think/experience.
Thanks
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05-03-2011, 03:21 PM   #4
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Without Exif data , hard to say
Also the DaL 18-55 is not really good at macro
Your Depth of fiels is very shallow and probably you use a very large aperture

05-03-2011, 03:30 PM   #5
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QuoteOriginally posted by Kenneth3aracing Quote
i like to use single-center focus point mode to focus the main object first, then move different angle to get the best graphic of pic without stepping front/back and changing shooting distance.
Do i make my pics out focus?
Sounds like you do. The kit lens is soft, and that is about right (with the exception of the first pic, highlights are blown out) - 1 step of sharpening in PP will make the pics much better. If you use "C" or continuous focus, you may get a little better results.

Now, why are you focusing then moving around? If you are trying to offset focus from center, there are a couple ways you can do this. One is to use "Selectable Focus Points", just use your up/down/left/right pad on your camera body to select the point. The other is to go into manual focusing and do it by eye (or by what you are seeing through the viewfinder of LV). I prefer the manual way as it is more flexible, however, it does take a lot of practice and "Trail & Error"...
05-03-2011, 03:43 PM   #6
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Did you get focus confirmation before the shutter was released? Perhaps you can try that ensure that once focus is achieved/locked and not move for composition to ensure that it is not an issue with the camera.
05-03-2011, 03:47 PM   #7
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Generally speaking, yes, if you focus first then move the camera, you might get slight shift in where the focus is. Normally not noticeable, but it definitely can be in macro. DOF is very thin in macro photography, unless you stop *way* down - like f/22. So even the slightest shift matters. Also, even though you might not be *meaning* to step forward or backward, with the very small distances involved in macro photography, even the slightest change in distance will throw focus off. That can happen just from breathing.

So it's pretty common to see exactly the sort of problems you are seeing when shooting macro handheld. That's one reason why tripods are usually recommended. But if you must shoot handheld, you really have to be unbelievably careful not to move the camera after focusing. Nor can you let the wind move your subject. And unless you stop down, realize the DOF is going to be measured in millimeters and fractions thereof. No way would you get entire flowers in focus; generally, not even an entire single petal.

BTW, I merged your two threads. In the future, please don't start separate threads for the same discussion.

05-03-2011, 05:01 PM   #8
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Thanks all the quick reply and I would like to take the suggestions for my next time night shooting.
05-04-2011, 04:40 AM   #9
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QuoteOriginally posted by bobmaxja Quote
Without Exif data , hard to say
Also the DaL 18-55 is not really good at macro
Your Depth of fiels is very shallow and probably you use a very large aperture
Yes, don't use the kit lens for macros, it is rubbish


05-04-2011, 05:12 AM   #10
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you can get good "macro" shots with the kit lens

I would suggest manual focusing with the kit lens when using it in close focus mode. Like others have said, the depth of field is very thin, and it is easier to determine what you want in focus rather than letting the camera decide in AF. In addition I would suggest that you keep shutter speed to 1/100 a sec or above in the beginning. With macro and close focus situations, any camera shake can be magnified. Also as Marc S. said your subjects can't be moving about in the wind. Personally, I very rarely use AF for macros, I get much better results if I focus manually especially if I'm hand holding.

NaCl(it takes a little practice but the results are more consistant)H2O
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