Learn Your Camera: Manual Focus

[richy]

I have learned a lot about photography from Zach and in general by reading articles and by watching YouTube videos. One thing that I do to try to capture flaws in paint is to manually focus the lens and not let the camera do it for you. This can be done on just about any camera although you may have to read the manual to find out how.
Check out these 2 shots I did of the rear chrome trim on a CTS-V (write up to follow probably tomorrow). The first is what happens when the camera focuses by itself. It does not really show the depth of reflection the chrome attained although the "Cadillac" is clearly in focus:

http://i156.photobucket.com/albums/t12/rhowitt/Detailing%20shots/Detailing%20shots001/DSC_2688.jpg (http://s156.photobucket.com/user/rhowitt/media/Detailing%20shots/Detailing%20shots001/DSC_2688.jpg.html)



Now see what happens when I focus it to capture the reflection in the chrome:



http://i156.photobucket.com/albums/t12/rhowitt/Detailing%20shots/Detailing%20shots001/DSC_2689.jpg (http://s156.photobucket.com/user/rhowitt/media/Detailing%20shots/Detailing%20shots001/DSC_2689.jpg.html)

You can see the clarity is much better that way. Swirls and scratches are almost always focused manually. Just thought I'd throw this out there.
Cheers!
:Picture:

[StangFan25]

Manual focus does have its place, but your example is due to focus points. In the auto focus image, it focused on the lettering, thus its in focus. In your manual focus, the focus point was on the chrome, thus its in focus.

Auto would've provided the same result had you moved the focus point off the lettering. :)

[SR99]

You might also note there's a depth of field issue in the first photo. The c and a are the sharpest. The d and i are starting to fall off, and the llac are out of focus.

In the second photo the DoF seems larger so I suspect there were other differences besides just the focus point selection difference between focus modes.

Depth of field calculators like this one:
http://www.tawbaware.com/maxlyons/calc.htm
which also includes a graphical view,
can be really helpful in understanding how changes in different parameters affect the near and far limits of acceptable focus, but also to remind that (unless the lens/camera is broken) there is always something "in focus," and the photographer may just have missed the alignment relative to what they wanted in focus in the image.

[richy]

Manual focus does have its place, but your example is due to focus points. In the auto focus image, it focused on the lettering, thus its in focus. In your manual focus, the focus point was on the chrome, thus its in focus.

Auto would've provided the same result had you moved the focus point off the lettering. :)

I just used these shots as an example. My point was that the camera will not focus on swirls by itself. Manually focusing it will do that.


You might also note there's a depth of field issue in the first photo. The c and a are the sharpest. The d and i are starting to fall off, and the llac are out of focus.

In the second photo the DoF seems larger so I suspect there were other differences besides just the focus point selection difference between focus modes.

Depth of field calculators like this one:
http://www.tawbaware.com/maxlyons/calc.htm
which also includes a graphical view,
can be really helpful in understanding how changes in different parameters affect the near and far limits of acceptable focus, but also to remind that (unless the lens/camera is broken) there is always something "in focus," and the photographer may just have missed the alignment relative to what they wanted in focus in the image.
I changed nothing but the focus.