first real portrait session - bad lens?

I did my first real shoot of my coworker's daughter a couple days ago. During processing I noticed that the lower half of the image is slightly out of focused (see image). Trying to figure out what the problem is. D7100 with kit AFS 55-200 DX lens. 62 mm f/4.2 @ 1/10000 sec. I did another small shoot of a friend today and noticed the same problem until I switched to my 18-55 mm lens settings at 42mm f/8 @ 1/60 and everything came out fine. Any ideas would be helpful.

Thanks,
Byram

If you can imagine a straight line from the center of your lens to the focus point on the image. Then imagine a perpendicular line from that. You will notice that the Dof is not in line with her from head to toe. If you had shot her at eye level then it would have been. Because of that it makes sense to me why her feet are not in focus. Shooting with the other lens seems fine because your settings are F8 which allows for a larger DOF.

I was considering that as well. But then here's one from today 68 mm f/8 @ 1/400. similar problem...or at least I think it is... Hard for me to image that I could be that much off perpendicular from DoF with f/8.

Without pixel peeping I don't see much of an issue with sharpness. To me it would be more important to consider the overall composition more and try to shoot in less harsh light(direct bright sunlight). That is what I'm trying to focus on with my photography.

In my opinion there is too much in focus in these shots, in particular the second. By stopping down from f/8 to f/5.6 and zooming in to say 100mm, you would get a tighter portrait with less dead space at the top and you would start to blur the background more making in less distracting. Remember your friend is the subject of the photo and a cluttered background will distract from that.
I prefer the first shot as the background is nicer, by shooting this again just a bit tighter and with less harsh light I think would help.

From a technical point of view remember that focal length and the distance from your subject have an impact on depth of field, with longer focal lengths having a shallower depth of field.

There are far more experienced portrait photographers on here who could give much more help with lighting and composition. I'm still a beginner myself and so these are the things I'm working on improving myself.

The differences I read are the different DOF due to 2 seperate apertures being used. The second you say you used f/8 this means the focal plane will be much larger than using an aperture of just f/4.2.

But as others have said concentrate on composition and lighting.

Scott Murray said:

The differences I read are the different DOF due to 2 seperate apertures being used. The second you say you used f/8 this means the focal plane will be much larger than using an aperture of just f/4.2.

But as others have said concentrate on composition and lighting.

Click to expand...

I agree with you on this Scott and I'll add that the other lens shot was at 42mm. So, 62mm @f4.2 will give quite less DoF than 42mm @ f8.

One more thing, is that when you shoot a full length shot, it's not the legs people will look at, it is the face which should be sharp...

Marcel said:

I agree with you on this Scott and I'll add that the other lens shot was at 42mm. So, 62mm @f4.2 will give quite less DoF than 42mm @ f8.

One more thing, is that when you shoot a full length shot, it's not the legs people will look at, it is the face which should be sharp...

Click to expand...

Speak for yourself

Byram Lass said:

I was considering that as well. But then here's one from today 68 mm f/8 @ 1/400. similar problem...or at least I think it is... Hard for me to image that I could be that much off perpendicular from DoF with f/8.

Click to expand...

why the need to have everything in complete focus ? I work exactly the opposite and try having as little as possible in focus. its not that flattering to have everyhting in focus. sorry to be harsh. these portraits are too busy IMO. I understand this is new to you but you can do much better. im certain.

Elliot87 said:

Without pixel peeping I don't see much of an issue with sharpness. To me it would be more important to consider the overall composition more and try to shoot in less harsh light(direct bright sunlight). That is what I'm trying to focus on with my photography.

In my opinion there is too much in focus in these shots, in particular the second. By stopping down from f/8 to f/5.6 and zooming in to say 100mm, you would get a tighter portrait with less dead space at the top and you would start to blur the background more making in less distracting. Remember your friend is the subject of the photo and a cluttered background will distract from that.
I prefer the first shot as the background is nicer, by shooting this again just a bit tighter and with less harsh light I think would help.

From a technical point of view remember that focal length and the distance from your subject have an impact on depth of field, with longer focal lengths having a shallower depth of field.

There are far more experienced portrait photographers on here who could give much more help with lighting and composition. I'm still a beginner myself and so these are the things I'm working on improving myself.

Click to expand...

no, you did a good job yourself. spot on in terms of the base for a good portrait

thanks for all the feedback. FYI, the pic of my friend was a test shot as I wasn't sure if I had a lens problem or not. Rest assured I did another zoomed in. What I can't get around is the fact that in my friend's shot (posted) the background is sharper than her feet. In fact when I look at the pic at 100% the blades of grass that are about 1.5 ft behind are her are very sharp. If a slight camera tilt makes that much difference, then I definitely need to work on my mechanics