Focus issue, need help.

MrsLittle

TPF Noob!
Joined
Oct 22, 2011
Messages
358
Reaction score
23
Location
Incirlik Air Base, Adana Turkey (thank you Air For
Can others edit my Photos
Photos OK to edit
I was taking pictures today with my D7000 and 50mm 1.8g. I realized when I used a wide aperture, the focus was a bit off. I was focusing on the eye and the focus would be on the hair bow. I moved the focus point to the chin and then it was on the eye.
Has anyone had this problem? Is it a camera problem or lens problem?
 

Derrel

Mr. Rain Cloud
Joined
Jul 23, 2009
Messages
48,227
Reaction score
18,923
Location
USA
Website
www.pbase.com
Can others edit my Photos
Photos OK to edit
It is a "common problem". At close ranges, shooting at f/1.8 means the depth of field is VERY shallow--so shallow that missed focus is common. It can be the result of the camera, the lens, the subject, or the photographer, or a combination of those factors. I am not kidding or joking--the AF system, the photographer, the lens, and the subject can ALL contribute to slightly-off focus results whenever shooting at close ranges at f/1.4 or f/1.8...there is almost no room for error at close distances at f/1.8 with a 50mm lens...on the part of anything or any person. Seriously.

Stopping down a bit, like to say f/3.2 or f/3.5...the results are usually more "safe". At close distances, the DOF is still shallow at f/2.8 or f/3.2 or f/3.5, but there's just a little bit more leeway for errors, movement, etc,etc. The lens's performance might also get a slight bit better one full stop down from wide-open.
 
OP
MrsLittle

MrsLittle

TPF Noob!
Joined
Oct 22, 2011
Messages
358
Reaction score
23
Location
Incirlik Air Base, Adana Turkey (thank you Air For
Can others edit my Photos
Photos OK to edit
Thanks Derrel. I was at 2.8 the whole time and didn't even think to change it once. It most likely is me, since I don't have the steadiest hands. I will try a smaller aperture next time and see how it works out.
 
OP
MrsLittle

MrsLittle

TPF Noob!
Joined
Oct 22, 2011
Messages
358
Reaction score
23
Location
Incirlik Air Base, Adana Turkey (thank you Air For
Can others edit my Photos
Photos OK to edit
I have it printed out and take it with me everywhere. I haven't really memorized everything by heart quite yet. I think I might have been a little too wobbly when using that wide an aperture.
 

MTVision

Been spending a lot of time on here!
Joined
Aug 1, 2011
Messages
3,008
Reaction score
527
Location
Vermont, US
Can others edit my Photos
Photos OK to edit
MrsLittle said:
I have it printed out and take it with me everywhere. I haven't really memorized everything by heart quite yet. I think I might have been a little too wobbly when using that wide an aperture.

One thing that's helped me - even though it isn't really anything too technical - is to remember that the closer you are to your subject - the shallower the DOF. That's with pretty much any aperture. At f/11 and 4 ft. Away you are still going to have less then a foot of DOF.
 

Rephargotohp

TPF Noob!
Joined
Nov 2, 2011
Messages
680
Reaction score
148
Can others edit my Photos
Photos NOT OK to edit
Other thing to consider is when you are bent over taking a shot of a little one, we sway back and forth, you won't even realize you do it but when you do, you move the point of focus, try to take a good photographers stance, or kneel down
 

KmH

In memoriam
Supporting Member
Joined
Apr 9, 2009
Messages
41,401
Reaction score
5,705
Location
Iowa
Website
kharrodphotography.blogspot.com
Can others edit my Photos
Photos OK to edit
MrsLittle said:
I have it printed out and take it with me everywhere. I haven't really memorized everything by heart quite yet. I think I might have been a little too wobbly when using that wide an aperture.

One thing that's helped me - even though it isn't really anything too technical - is to remember that the closer you are to your subject - the shallower the DOF. That's with pretty much any aperture. At f/11 and 4 ft. Away you are still going to have less then a foot of DOF.
Yep, about 8 inches total. And don't forget 45% of that DoF will be in front of the point of focus (3.7 inches), and 55% of it will be behind the point of focus (4 inches) .

You also have to remember the plane of the DoF is always parallel to the image sensor. If the subject is at a slight angle to the image sensor, up and down or side to side, the DoF isn't.
 

Most reactions

New Topics

Top