Please Help - why are pics not in focus and sharp?

[Maria]

I have a 24-70mm f/2.8L lens and am finding that it is not as sharp as i'd expect.  I'm sure it's me and not the lens so hoping someone can help me understand what i'm doing or not doing correctly.

I'm attaching a picture as an example...hand held...here are the settings:

EF24-70mm f/2.8L II USM

59.0mm

1/640 sec;   f/2.8;   ISO 400

Shutter priority;   Spot metering

shot with 70D

when you zoom into the tree it is cleary not in focus/sharp ;(

I've tried at differen shutter speeds but still having the same issue... going to try different apertures next...

[Maria]

I'm using the center AF.... i tend to use it 90% of the time... the text pic i just posted looks better but still thought it should be better than it is.... i found this: Jeffrey’s Autofocus Test Chart (http://regex.info/blog/photo-tech/focus-chart) so going to try it next - but not sure i fully understand what to do...

i noticed that things were a bit off with images of my daughter (which is what i shoot 90% of the time)... when i zoom in on the image her eyes (where i focused on) are not sharp... i was going to post some of those but thought the text one may be better as a start since the tree is soo busy...

when i crop the text and insert it's too small to see ;( not sure what else to do to make it visible?

[TCampbell]

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@Maria wrote:

I'm using the center AF.... i tend to use it 90% of the time... the text pic i just posted looks better but still thought it should be better than it is.... i found this: Jeffrey’s Autofocus Test Chart (http://regex.info/blog/photo-tech/focus-chart) so going to try it next - but not sure i fully understand what to do...

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You'll download and print the chart on your printer.  You'll place the chart so that it's leaning away from the camera at approximately a 45 degree angle (it doesn't need to be perfect... just make sure it's leaning back on a slope).  

You'll put your camera on a tripod so that that there's no way it can move after focusing.

You'll select the center focus point on the camera and frame up the shot so that the center point on the camera is pointed to the middle of the focus chart ... it is crticially important that you make sure the center AF point is exactly on the bold spot in the middle of his chart and not off to a side or above or below.  The center has extra strong contrast to make it easier to find.

Now you can focus the camera and take a shot.

After you've taken the shot... inspect it.

If the lens is "front focusing" (true focus distance is actually closer then your intended focus distance) then you'll notice the text toward the bottom of the chart will appear to be focused better.  If the lens is "back focusing" then the top of the chart will have better focus.  If the lens and camera are performing correctly... then the middle of the chart (the point you actually used to focus) will have the best focus.  This is why the chart needs to lean back on an angle... so that part of the chart is closer and part of the chart is farther away.

If the lens is consistently off in the same direction, you can apply a focus adjustment for that lens in your camera.  If it's randomly off then the lens will need service (and it's even better if you send in BOTH the lens AND the camera so that Canon can calibrate the lens specifically for YOUR camera.)

[Maria]

I'm going to try the test to see what happens. Depending on what I find I'm going to take the lens to the place I purchased it (Henry's) and see if they will do anything. Going to print it now...

[TCampbell]

Hi Maria,

Whenever the focus performance of a lens is in question, you NEED to use a focus target to test the lens rather than using a real photo. There are just too many things that can go wrong with a real photo.

For example, you've used an f/2.8 f-stop... at a 10' focusing distance, the depth of field for that focal ratio is less than 1'. It would be very easy for focus to end up on the wrong object and throw the focus.

By using a focus test chart and putting the camera on a tripod, picking the middle focus point, centering that on the mid-point of the test charter, and repeatedly taking shots (I de-focus the lens after each shot to force it to re-focus and half the time I run the focus out to max distance and half the time I run the focus in to the min distance... and keep track. Sometimes a lens can have a problem focusin in one direction... but not in the other (or the margin of error will be different depending on the direction it had to turn focus.)

You can buy a commercially made test chart... but you can also download and print out your own. Just make sure you follow the directions carefully. Here's a pretty good chart you can freely download: http://regex.info/blog/photo-tech/focus-chart

Most lenses tend to provide their sharpest performance stopped down a few stops (not wide open). Typically somewhere between f/5.6 and f/8 will yeild the best performance but it varies by lens.

It is entirely possible that you have a bad copy OR that there's an issue between the focus calibration of that lens with your specific camera (in other words, a different copy of the same lens might perform differently.)

I believe the 70D also supposts auto-focus micro adjustments -- but before plunging into that, you'll want to be sure there really is an issue.

[Maria]

yes it does have micro adjustments 😉 but need to be sure of what the issue is before doing anything...

i read that test info - not sure i completely understand but will try tomorrow in good natural light...

my fear is that there is a problem with the lens - i purchased it in late September - so no way i can return or exchange now ;( with the T1i i could see that it was a little off but assumed it was me and the need for me to learn more vs the lens... but now with the 70d it is very obvious that it is way off ;( 

i'm starting to feel very sick at the thought that it is the lens... if it is i think it has a 1 yr warranty so hoping that means i can have it looked at???

[ScottyP]

Does the 70d have any focus problems with other lenses? I guess it would be too much to hope for to see if someone has accidentally thumbed a bad AFMA value into your camera, and the lens is fine?

Or perhaps a modest AFMA will set things to rights?

Good luck. Keep everyone posted on your checks.

[ebiggs1]

Maria the picture of the label is unacceptable for a 24-70mm f2.8 L lens. 

But cameras and lenses only do what you tell them to.

It is imperative that neither moved during exposure. That makes the tree useless for now.

Also the DOF at f2.8 is very thin.

It is imperative to find out which of the three variables, the lens, the body or you are at fault. Until you know which, you, and/or us are blowing in the wind.

Don't go messing with any controls or adjustments on the camera. Plus make absolutely sure the camera is set to factory defaults.

Do you have, or can you go back to the store and try another lens on this body?

Do you own a tripod?

[Maria]

 i printed out that chart and took some shoots .... part i'm not clear on is how far away from the camera is chart supposed to be?

edited: just re-read the instructions - it says 10 feet! 😉 will try again....

[Maria]

Happy New Year everyone!

Struggled to find a spot that had enough light so finally had to go outside - and it's cold out there 😉

Took 7-8 shots and all result the same thing.... nothing is really in focus ;(

Here is one example with the following settings:

EF24-70mm f/2.8L II USM 

70.0 mm

1/1250 sec;   f/2.8;   ISO 100

Manual;   Spot metering

AF point is center and although it was aimed at the center dark text it did not focus on it well ;( thus focus appears to be on overall issue??? Assuming i did everything correctly for the test???  i was 10 feet away, tried to have the camera at the same level as the chart and used the above settings (let the camera Auto select ISO).... chart was 'roughly' at a 45 degree angle.

[Maria]

this is the center texted cropped in - really NOT in focus but that is where the AF point was!