Out of focus image


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Owl07

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Dec 11, 2007
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#1
Hi, I'm starting a separate thread for another image which I have question on.

http://jksim.multiply.com/photos/hi-res/10/12?xurl=/photos/photo/10/12

========================
Shooting Mode: Manual Exposure
Tv: 1/500
Av: 8.0
ISO Speed: 100
Focal Length 135mm
White Balance: Auto
========================

I'm using my one and only lense. A Canon 28 - 135mm with "IS" enabled. Not the best exposure for this shot but am pretty puzzled why did this image of the cat go out of focus (Not sharp) even when I did a Auto Focus dead centre at the nose of the cat.

QUESTIONS:
1) Does it have to do with my aperture setting of f8 @ focal length 135mm?
2) I read that all subject at maximum focal length will have shallow DoF. Is that true for this image?

I've been shooting cats around my neighbourhood but seems like most of the shots are not exactly sharp. :dunno:
 

Owl07

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Dec 11, 2007
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#3
I kind of notice. But.... the focus point shown in my camera was on the nose of the cat. That is why I'm puzzled by this image. Any ideas.....anyone? :bsmilie:
 

flipfreak

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Nov 26, 2007
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#4
Hi, I'm starting a separate thread for another image which I have question on.

http://jksim.multiply.com/photos/hi-res/10/12?xurl=/photos/photo/10/12

========================
Shooting Mode: Manual Exposure
Tv: 1/500
Av: 8.0
ISO Speed: 100
Focal Length 135mm
White Balance: Auto
========================

I'm using my one and only lense. A Canon 28 - 135mm with "IS" enabled. Not the best exposure for this shot but am pretty puzzled why did this image of the cat go out of focus (Not sharp) even when I did a Auto Focus dead centre at the nose of the cat.

QUESTIONS:
1) Does it have to do with my aperture setting of f8 @ focal length 135mm?
2) I read that all subject at maximum focal length will have shallow DoF. Is that true for this image?

I've been shooting cats around my neighbourhood but seems like most of the shots are not exactly sharp. :dunno:
theres pretty much only 2 possibilities. user error or camera error.

if we take u out of the equation, maybe your lens is backfocusing hence the focus was behind rather than on the cat.

when u use f/8 on all lens, u would not be looking at creating a shallow dof for your pic. rather u are trying to make everything in the picture sharp.
 

OCP

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Feb 23, 2002
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#5
Another possibility is you are too near the subject. Check the minimum focusing distance of your lens.
 

#6
I kind of notice. But.... the focus point shown in my camera was on the nose of the cat. That is why I'm puzzled by this image. Any ideas.....anyone? :bsmilie:

I don't think so leh heheh... if your auto AF mode is set to the center point of your viewfinder, the cat's nose is not in the center of this picture you posted.(unless you crop it lah) I downloaded it to check. heheh

If I look at the center of the photo frame, your center is at the cat's belly. The contrast around the cat's body (ginger/ orange colour light strip fur) is not high enough..I am wondering if your AF was having a hard time picking a focus. Or did you focus on the nose, lock the AF and then recompose your shot?

But I notice that the concrete ground has very contrasty line ruts just behind the cat. I am suspecting your AF picked that over the cat's body as it has better constrast for tracking. I saw that you shot this at 135mm length so were you woobly abit? hehe.. Shot at 1/500 speed slight moving abit might not register any blur. And as you click your shutter ...the AF was still focusing on the line behind as you start to center your wooble back to the cat's belly in the middle
 

zerartul

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Jun 24, 2007
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#7
Possibility is focussing inaccuracy. Is it constand among all picture? If it is its a focusing problem. Send in for calibration. Else is actually a random error due to insufficient contrast. Anyway can tell your focus is behind the cat and quite a significant amount as you are usign f8 where ur depth of field is quite large
 

Owl07

New Member
Dec 11, 2007
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#9
hi all, thanks for your time in helping me out. Based on the consolidated comments from Sam, Zera and Flip, these are the summaries and my inputs:

1) Camera backcapturing the more contrasty background thus throwing off the focus for the cat
OWL: I indeed cropped off some of the image when posting up the cat into my multiply site. I am very sure that focusing was done on the cat's nose but it turns out it seems to be backcapturing the background. BUT at a f8 setting at maximum 135mm zoom, shouldn't I have enough DoF to cover the cat and the background? (I do have another cat image at the link below. This black and white cat looks sharper....... Think its the fur of the cat that is causing the issue? :bsmilie:)

2) Max zoom at 135mm resulting in wobbly hands...blurr image
OWL: It was a pretty sunny day and I did have my Image stabiliser switched on. Will shaky hands be possible at those setting although its true I am already pushing my 28-135mm lens to its limits.

3) Camera was too close to subject
OWL: I am very sure I was at least 3 to 4 metres away from the kitty when I zoom my lens to maximum. Thus, I should say my 28 - 135mm should be focusing within its limits.

4) Lens needs recalibration
OWL: hahaha :sweatsm: hopefully this is not the case. I've tried taking photographs around my neighbourhood and it seem that some of the images are still considerably sharp enough for me. How will you guys comment on the sharpness of the 2 images below?

http://jksim.multiply.com/photos/hi-res/11/15?xurl=/photos/photo/11/15

http://jksim.multiply.com/photos/hi-res/11/3?xurl=/photos/photo/11/3

(the 2 images above are not cropped)

Keep the comments coming!! :thumbsup::thumbsup:
 

Akino

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Aug 8, 2007
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#11
It seems like a AF problem as I can see that high contrast objects are always in focus in ur pics...Have u tried manual focus and see how is it?
 

Akino

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Aug 8, 2007
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#12
It seems like a AF problem as I can see that high contrast objects are always in focus in ur pics...Have u tried manual focus and see how is it?
 

zerartul

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Jun 24, 2007
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#13
Personally felt is a random error. At times the focus can go off abit here and there. That may just be the shot that goes off lol. Anyway its not due to camera shake. 1/500 is way too fast and with IS the chance of camera shake induce blur is very low. Also your background was sharp so the only possibility is still the focusing.
 

blurry80

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Jul 23, 2007
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#14
I've some experince in shooting cats. One difficulty you may face is that the target is too furry and the camera will have problem determining the 'Correct' focus. If you aim the eye of the cat chances you wont miss. and 1/3 infront will be in focus this will mean the nose.
 

flipfreak

Senior Member
Nov 26, 2007
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#15
actually when shooting people or animals for that matter, using a pre selected af point would be more ideal than using the auto af.

i'm assuming you were using auto af selection.
 

ExplorerZ

Senior Member
Jan 9, 2006
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#16
If, it is really back focus problem of lens, i must say that is a pretty serious backfocus... looking from the image it seems to be off by probably 10" :sweat:
most backfocus problem lens only focus probably 1-2" off.

so imho, it could be either user focus problem or AF point selection problem by either user or camera, both seems more likely than backfocusing problem cause by lens
 

Owl07

New Member
Dec 11, 2007
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#17
Thanks for all the feedback. Flipfreak, when you mention using a "pre selected af point", do you mean setting only 1 of the red square in the view finder rather then letting the camera do a auto focus on multiple points?

I'm trying to do a manual focusing but is very afraid that focus cannot be achieved coz the viewfinder is only this big and I can't really seem to be very certain that it is sharp enough. :bsmilie:

Anyone shooting images using full manual focusing? maybe can share your techniques in getting the sharpest focus? :think:
 

rexlim

New Member
Nov 3, 2004
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#18
Yes, select you AF point, dun let the cam do it.
Did you use AF-S or AF-C?
 

theRBK

Senior Member
May 16, 2005
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#19
do a lens test as catchlights suggested... :)
 

Jul 15, 2008
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#20
Hi,
I am a newbie who has just bought a Nikon D40 DSLR. I went to the Expo CATS Car-Nival last Sunday to take some photos with my D40 and found that there are some pictures that are out of focus. An example is


The settings i used were:
Manual Mode
ISO: 400
Shutter Speed: 1/60 sec
Aperture: f/6.3
Flash: SB-600

What could be the reason for the out of focus? Could it be because of
1) Too close to the subject
2) Wrong AF Point (I didn't realise that there are 3 AF points in D40 and I can actually select which AF point to use until I had this problem. Therefore I let the camera decide which AF point to use when I was shooting this picture. I will never do that again)
3) My lens is backfocusing and I need to sent it to Nikon Workshop for repair.

Hope that someone can help me find the root of the problem so that I would not make the same mistake again. Thanks
 

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