Calibrating Focus on 5D Mark III?

[dorian7]

So I was shooting a newborn today with the 85mm 1.8 and I was using the point focusing and it the majority of my shots were out of focus or just not quite right. It seems to tend to front focus. Does anyone know how to correct for this? (without doing manual mode obviously)

 

[Light Guru]

Check out http://focuspyramid.com

 

[MLeeK]

Are you sure or were you shooting at f/1.8?

 

[Big Mike]

Tutorial - lens micro adjustment

 

[dorian7]

Are you sure or were you shooting at f/1.8?

I am sure that most of them were out of focus. But yes I was shooting at 1.8. The reason I say I think it is front focusing is because nothing in the image appears to be in focus, so I am assuming it doesn't focus far enough out.

 

[TCampbell]

If you're focusing on the eyes then normally a front focus will give you a sharp nose with soft eyes. It's usually not off by so much that nothing on a person's face is in focus.

When shooting a portrait, you'd normally focus specifically on the eyes. f/1.8 is provides very thin DoF. If the camera had focused on the nose and the focus was off, then at f/1.8 it's possible that nothing was in focus.

A focus target can let you test the lens. I use a Spyder Lenscal, but you can actually download and print out your own focus targets.

Test the camera/lens combination against the focus target multiple times. Each time, manually rotate the focus ring in to the minimum focus distance and test it several times to force the auto-focus to work to find focus. Then manually rotate the focus ring out the maximum focus distance and repeat several more times. The 5D III will let you program the camera to compensate for the focus error on the lens.

Unless you really want the paper-thin DoF, I'd consider increasing the f-stop slightly.

 

[Derrel]

You've seemingly been trying to find an excuse to return that camera since the day you bought it.

 

[dorian7]

Thanks for the suggestion! I will try that out. After reviewing my pictures I am wondering if I am just not using a fast enough shutter... Most were 1/80, 1/60 or some 1/100 so could that be part of the problem? I was always told 1/60 and above should be good. The other thing I am wondering is if I pressed the autofocus down and it locked then I moved a little without realizing it. Just doing some more test shots around the house makes it seem like the lens is pretty much spot on...

 

[dorian7]

Here is an example. It's not bad but it's not great.


ISO200, 1/80, f1.8

 

[Derrel]

With an 85mm lens, at that range, shot at f/1.8, you have about an inch or so of depth of field....only one plane will be in truly sharp focus, and things even slightly in front of and things located even a short distance behind that plane will be out of focus...

For example, look at the baby's eyes...they seem to be the sharpest part of the face....the nose, perhaps one inch in front of the plane of the eyes is...out of focus...this is simply...the way an 85mm lens renders its scenes when shot close, and shot wide-open...look at how totally OUT of focus the baby-blanket is, some four or so inches behind the eyes...the depth of field at this distance is very shallow...

 

[gsgary]

sound like a new driver has bought a supercar as their first car, the problem is behind the veiwfinder and not the camera at fault

 

[dorian7]

I get the DOF and how thin it is but if you look at that pic the eyes are not as sharp as a perfectly focused picture would have.

 

[gsgary]

I get the DOF and how thin it is but if you look at that pic the eyes are not as sharp as a perfectly focused picture would have.

You only have to move a bit at F1.8 for it to be out of focus

 

[Dao]

Besides the razor thin DoF, shooting at 1/80 may causing a little motion blur. Of course, it depends on how good your technique on taking photo without camera shake.

Personally, I prefer not just the eyes are in focus anyway. I believe the photo will look better with a little deeper DoF.

 

[dorian7]

Thanks for the tips here is one that I am very happy with the focus:



ISO160, 1/100, f1.8

see how much better the eye on here looks than the earlier one I posted.