Front-focusing? - DPChallenge Forums

Canon EF 55-200mm f/4.5-5.6 II USM

05/02/2004 10:50:46 PM · #1

I have the "plastic fantastic" Canon 50/1.8 lens and I'm wondering if it has a genuine problem -- when I shoot a head-only portrait with it, the lens will focus on the bangs, and they're sharp, but the eyes and ears will be out of focus.

I actually could see this explicitly when I shot an object sitting on a textured surface: the object was sharp, the stuff behind it was out of focus, and the texture IN FRONT of the object was sharp as well. In other words, the point that I focused on was at the back of the DOF.

It only seems to happen when the camera and subject are close together, i.e. a short focus point.

Being a noob to Canon AF products, is this an actual problem, or is it some type of user error? Is this something for which I should contact Canon for technical service?

TooCool

Canon EOS-300D Rebel

Canon EF 50mm f/1.8 II

05/02/2004 10:59:41 PM · #2

Do you have an example? What mode are you shooting in? What is the aperture?

orussell

Canon EOS Rebel T6s

05/02/2004 11:05:39 PM · #3

Probably not the most ideal solution, but try moving away from the subject, to increase your area of acceptable focus. You should be able to crop without losing too much detail if you require a tighter composition.

coolhar

Canon PowerShot Pro 90 IS

05/03/2004 07:01:52 AM · #4

I have that the two thirds of the field of focus falls in front of the focal point and one third behind it.

cpanaioti

Canon EOS-40D

Canon EF 70-300mm f/4.5-5.6 DO IS USM

05/03/2004 08:36:36 AM · #5

Also, with portraits, and pictures of living creatures in general, it is best to focus on the eyes. Press the shutter halfway to lock focus on the eyes then recompose if required and press the shutter button the rest of the way.

05/03/2004 10:05:34 PM · #6

I'd include the afore-mentioned example, but it's my entry. :)

Typically, I'm seeing the problem with wide-open apetures, and I do understand that causes shallow DOF. My concern is that the camera is 'highlighting' a focus point, but the result is that it's actually at the rear of the DOF.

Another work-around is to learn how to use the "program mode" which allows manual selection of the focus points.

I'll try to shoot a series of test shots in the next couple of days to determine exactly what the trouble is -- I already discarded the portraits that display what I'm talking about.

05/05/2004 01:53:59 PM · #7

OK now that the challenge is over, here' s a link to the photo in question:

//www.dpchallenge.com/image.php?IMAGE_ID=72755

I realize that the lo-rez doesn't really do justice to the focal depth, but in the full-rez version, there is a very distinct band that is in focus in front of the front-most red rock. The focal point was chosen on the front edge of the red rock, and even the back of the rock is beginning to get soft.