Focus Mystery

[fuller1031]

Hey everyone,

Let me start off my saying that I an new to the forums, but not knew to photography. I have been an avid amateur photographer for the last five years and I am in an AP studio art class at my high school with my focus being photography. Now, I have never really had this problem yet with any of my cameras, but my newest DSLR, my Canon T2i, is having some serious problem producing focused, crisp images. I have tried a lot of things, including cleaning my lenses, getting my sensor cleaned, trying to take photos on various focus modes, etc. Everything I seem to do, my focus never seems to be sharp enough.

So, if any of you have any other suggestions for what to look into for ways to figure out what's wrong with my focus problem, please tell me. Thanks!

[ceremus]

It would be extremely helpful to us if you could upload examples of your problematic images with the EXIF data attached.

There are a lot of things that can affect sharpness, but without anything to go on we'd just be throwing random guesses.

[fuller1031]

Here's an example from just today in my class. We are doing Georgia O'keath flower abstractions. This was taken at about 6 feet away from the flower with the following settings:

Camera model: Canon Eos REBEL T2i

Fstop: f/13
exposure: 1/125 sec.
ISO: 800
Focal length: 250 mm
Metering mode: Spot

EDIT: Please notice how the whole image is soft focus. I'll post another example too in a min.

[dakwegmo]

Did you use a tripod?

[fuller1031]

Here's another example:

Camera model: Canon Eos REBEL T1i
Fstop: f/4.5
Exposure: 1/200 sec.
Focal length: 55 mm
Metering mdoe: spot

Both of these images were taken in manual settings. Again, the subject's face is not really crisp.

[fuller1031]

Originally Posted by dakwegmo

Did you use a tripod?

In the flower abstraction, I did, in the portrait example, I did not. However, given the exposure of 1/200 sec., I think it's reasonable to believe I did not shake during the exposure.

[sk66]

With the 75-300 kit lens? That lens gets pretty poor reviews and is known to be lacking in sharpness...
f/13 is probably not helping any. (try f/8)

[fuller1031]

Originally Posted by sk66

With the 75-300 kit lens? That lens gets pretty poor reviews and is known to be lacking in sharpness...
f/13 is probably not helping any. (try f/8)

Yeah... I've been reading reviews on that lens recently. It's such a bummer. I'll probably get a new one soon though. Any suggestions (especially for Canon lenses that are good for taking portraits because that's what my AP concentration is focusing on)?

And I'll try f/8 next time. Although I wanted a larger DOF, so wouldn't I want to use a higher F#?

[sk66]

Second example lens is almost wide open, not ideal, and focus is a bit short. (I can see the stitching in her jeans)

[sk66]

Originally Posted by fuller1031

Yeah... I've been reading reviews on that lens recently. It's such a bummer. I'll probably get a new one soon though. Any suggestions (especially for Canon lenses that are good for taking portraits because that's what my AP concentration is focusing on)?

And I'll try f/8 next time. Although I wanted a larger DOF, so wouldn't I want to use a higher F#?

yes/no. on your body diffraction begins to occur at ~f/11....you would be better off focus stacking images as even f/32 wouldn't give a very large dof.