Blurry images...

[Life Photo-Documentaries]

<p>Thank you in advance for your inputs...<br /><br />I have been using a EOS 40D + 24-70 L 2.8 USM. I have noticed that when I focus and reframe... the image appears as back focused (blurry subject)... I am sure I set up to ONE SHOT... I used any of the 9 AF points closer to my focusing subject until "Beep-beep” audible signal... and then, reframed (not to an extreme distance).<br /><br />THEN! I got back focused images (blurry subject!) ... I feel silly asking .. but what am I missing? <br /><br />THank you again...<br /><br />Juan</p>

[mbkissel]

<p>Post an example photo showing the problem. Be sure to include the EXIF data.</p>

[philip_wilson]

Does this only occur when you reframe the shot?

[Life Photo-Documentaries]

<p>Mark... let me see If I can find one of the images... <br /><br />Philip... YES, only when I reframe the shot... <br /><br />Thank you for your responses...</p>

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[lornesunley]

<p>When you reframe the shot, you move the camera, moving the camera puts the subject out of focus ...</p>

<p>Don't do that, use manual focus if you have to, do not reframe the shot unless you are using an aperture such that you have LOTS of depth of focus to play with.</p>

<p>Also make sure the camera is not refocusing when you reframe.</p>

[douglas_vitello1]

<p>Lock and use only your central point focus cross sensor.It never hurts to use a tripod when trying to rule out bad focus issues.High ISO and IS still do not take the place of a rock solid tripod.</p>

[Life Photo-Documentaries]

<p>Lorne.. thank you for your response... In the image I posted, aperture is at 3.5... <br /><br />Mark.. as you can see... the girl on the right is soft... the boys at the “center / left" are sharper... <br /><br />I will performe some experiments using Lorne approach... </p>

[lornesunley]

<p>From the example you posted you appear to have been using a flash, if you do have a flash you are better off using something like f/8 to give yourself lots of depth of field, the flash will give you the light you need for the exposure.</p>

<p>In your example it looks like the focus point is on the center of the man's back ... are you sure you camera is not refocusing on you?</p>

[francisco_salaquanda]

<p>To me it looks like the whole image is soft. If you click on bits here and there, from the young man at the back to the back of the other guy, the face of the lady and the flowers...all are soft. Weird. Normally you would see the plane of focus, especially at f3.5.<br>

If it were me I'd be using more manual focus in these conditions or if there was a flash, shutting down the aperture more. By the look of the noise on the dark elements, maybe the 40D is struggling a bit in that light. I hope not because I'm buying one next week.<br>

The lens is a well regarded pro item, unless there is a fault in it. Is this the only image you can show us?</p>

[mbkissel]

<p>Juan,<br>

Since this only happens when you reframe, it appears to be a technique issue. I suspect (as have others), you are moving the camera slightly when you reframe or you are releasing the shutter and refocusing after reframing. Are you using a single point for focusing? Are you holding the shutter half-pressed once you have achieved focus on the subject? At wider apertures, a tiny amount of camera movement will cause the depth of field to change, and may thus lead to softer subjects in your images.</p>

[Life Photo-Documentaries]

<p>Thank you all for your responses...<br /><br />Lorne...<br /><br />I will try using a smaller aperture... <br>

ABout the camera refocusing.. this has been my point of concern... I DO KNOW where I put the focusing point... but my doubt / concern is that if for ANY reason... the camera has not been keeping the focus locked.. ! this is something “new” because I normally reframe and “never” had this issue before... I am very picky with sharpness... <br /><br />Francisco:<br /><br />THank you for commenting... I expected “the rest of the image" to be soft but definitely NOT her face... I will use more manual focusing then... <br /><br />ABout 40D.. YES... noise is exaggerated at ISO 1600... not even considerable at (H).... I think it is little better than 5D mark II in focusing in dim light (challenging ambient situations) BUT... if you intend to buy 40D for dim light events.. I strongly suggest you to CONSIDER something else... this is why I decided to buy 24-70 L.. it allows me to get more light.. BUT! as you can see may be influencing the sharpness problem of my images... <br /><br />No it is not the only image... I have more... let me put some more.. <br /><br /><br />Mark...<br /><br />Thank you for commenting... I do know is a matter of technique.. I cannot be in more agree with you... It bothers me that I cannot see WHY! I feel little bit silly-embarrased that this is happening to me... I have payed attention when reframing to DO NOT release the shutter when refocusing... I will need to experiment under controlled conditions to see if I can get to the point...<br /><br />THank you all for your comments... your inputs have provided clues to work with and see if I can fix it.. By the way.. this does not happens with the 5D mark II.. </p>

[pmind]

<p>You may want to separate focusing from your shutter release, that way you avoid accidental refocusing. I'm not sure how to do that with the 40D, or even if you can, but it really helps in tight crowds. I use only the center focus point with this technique.</p>

[philip_wilson]

<p>Lorne - I am a big user of re-focussing as I generally just use the centre AF point. This comes from many years of shooting manual focus cameras. With practice you get used to this approach and it is usually fine as the re-framing has little impact on the image. For example a 50mm lens has a horizontal angle of view of 40 degrees. With a subject at 5 meters (typical for a group of people) using F1.4 the DOF is 1.28 meters. Thus simple geometry means that if you focus on a subject at the edge of the frame using the center point then re-frame you will be have a 20 degree angle change. on a subject at 5 meters this is an error in distance of 38cm - well within the DOF on the lens In general this is rarely an issue except in very shallow DOF portraits (and even here the angle change is usually slight) I wonder if you are keeping the AF locked propery as you move the camera. I would also suggest that if you use this technique just use the venter AF point and only in One Shot mode</p>

[Marcus Ian]

<p>I'd guess that this is indeed due to refocusing, or focusing on the wrong point (then the image is reframed) - due to multiple AF points in use.</p>

<p>As philip says, if you intend to 'focus/reframe', you should be using center point AF only, with one-shot AF since a) it's the most accurate point, b) that gives you precise control of your focal point, and c) you are reframing anyway, so theres no good reason not to. <br>

Ultrashallow DOF (kind of a moot point on your 40D w/ a 24-70/2.8) <em>can</em> cause a problem when using this technique, but leads to <em>front</em> focus, <em>not</em> back focus.</p>

[Life Photo-Documentaries]

<p>Paul... thank you for your idea... There is a Custom Setting for that... <br /><br />Well after reading and doing some more home homework here and there.. I was told that 40D and even 5D MII are not good enough with accurate focusing with “side focusing points”. THis issue is NOT present when working with 1D’s series... As some of you have said... I will focus using the CENTER POINT and then, re-frame... <br /><br />ABOut the multiple points and servo settings... I am very careful when setting functions... and very careful making sure the focus is locked... <br /><br />Thank you all for your valuable assistance in my technical issue... I do appreciate your time and knowledge...<br /><br /><br /><br />What I </p>