Help with Portraits needed: My niece is graduating in May and would like me to do her senior portraits. I have been practicing with various lenses and find that my Tamron 70-300 VR has...

ifurnish Loc: Katy, TX

My niece is graduating in May and would like me to do her senior portraits. I have been practicing with various lenses and find that my Tamron 70-300 VR has been doing a good job. I have also used my 100mm 2.8. Every now and then I have trouble with the auto focus. I press the shutter 1/2 way to focus on the eyes, recompose and take the shot. Once in a while, when I try to recompose, it doesn't hold focus and the focus moves to the background making my subject blurry. What am I doing wrong?

CaptainC Loc: Colorado, south of Denver

What camera. You are a bit light on information.
If you are in Continuous AF, it will not hold focus.

ifurnish Loc: Katy, TX

CaptainC wrote:

What camera. You are a bit light on information.
If you are in Continuous AF, it will not hold focus.

I am using a Canon 6D.

Ched49 Loc: Pittsburgh, Pa.

You really don't need a zoom lens for portrait work, that's one of the reasons why your camera isn't focusing properly. You want a wide angle lens.

GoofyNewfie Loc: Kansas City

cjkorb wrote:

You really don't need a zoom lens for portrait work, that's one of the reasons why your camera isn't focusing properly. You want a wide angle lens.

Seriously?
A wide angle?
I think not!
I just checked, and it's not April 1st yet.

Ched49 Loc: Pittsburgh, Pa.

GoofyNewfie wrote:

cjkorb wrote:

You really don't need a zoom lens for portrait work, that's one of the reasons why your camera isn't focusing properly. You want a wide angle lens.

Seriously?
A wide angle?
I think not!
I just checked, and it's not April 1st yet.

If you use a 70-300 zoom lens for portrait work it must be April 1st!

Willy Loc: Alaska

katymom wrote:

My niece is graduating in May and would like me to do her senior portraits. I have been practicing with various lenses and find that my Tamron 70-300 VR has been doing a good job. I have also used my 100mm 2.8. Every now and then I have trouble with the auto focus. I press the shutter 1/2 way to focus on the eyes, recompose and take the shot. Once in a while, when I try to recompose, it doesn't hold focus and the focus moves to the background making my subject blurry. What am I doing wrong?

I believe the 6D will allow you to change button functions, if so, remove the focus function from the shutter button and put it on one of the buttons on the back of the camera body. Look in your manual under "Custom Controls"

I set mine up to focus with the * button. The only draw back to this is that you may forget to focus! I had to go through that learning curve & I still find myself forgetting once in awhile.

GoofyNewfie Loc: Kansas City

cjkorb wrote:

GoofyNewfie wrote:

cjkorb wrote:

You really don't need a zoom lens for portrait work, that's one of the reasons why your camera isn't focusing properly. You want a wide angle lens.

Seriously?
A wide angle?
I think not!
I just checked, and it's not April 1st yet.

If you use a 70-300 zoom lens for portrait work it must be April 1st!

Here on Earth that lens is a preferable choice over a wide angle.
(You must have u-verse to get the internet on your planet)

BHC Loc: Strawberry Valley, JF, USA

katymom wrote:

My niece is graduating in May and would like me to do her senior portraits. I have been practicing with various lenses and find that my Tamron 70-300 VR has been doing a good job. I have also used my 100mm 2.8. Every now and then I have trouble with the auto focus. I press the shutter 1/2 way to focus on the eyes, recompose and take the shot. Once in a while, when I try to recompose, it doesn't hold focus and the focus moves to the background making my subject blurry. What am I doing wrong?

Use the back focus button.

skidooman Loc: Minnesota

GoofyNewfie wrote:

cjkorb wrote:

You really don't need a zoom lens for portrait work, that's one of the reasons why your camera isn't focusing properly. You want a wide angle lens.

Seriously?
A wide angle?
I think not!
I just checked, and it's not April 1st yet.

:thumbup: :thumbup:

TimS Loc: GA

Lots of portraits are taken with a wide angle - gritty portraits of, say, a football player holding a ball out with the goal post behind him and a dramatic sky behind that. Aside from speciized portraits such as that, a wide angle lens is very, very unflattering to the subject. Telephoto lenses are the lenses of choice in portrait photography.

viscountdriver Loc: East Kent UK

I agree with TimS.I've alsways worked on the principle that telephoto lens should be used for portraits and that wide angle distort.

rpavich Loc: West Virginia

Mogul wrote:

quote=katymom My niece is graduating in May and w... (show quote)

As the other poster said...the reason your focus is going screwy is that it's linked to the shutter button...when you change position, and you change the focus point, it will change focus.

The solution is to change what button focus' the camera, as was suggested the * button (on a Canon at least) is the choice.

That way you can focus...and when you take your finger off of the * button...your camera won't refocus.

On the 6D the setting is found in the custom functions menu AF.

ifurnish Loc: Katy, TX

As the other poster said...the reason your focus is going screwy is that it's linked to the shutter button...when you change position, and you change the focus point, it will change focus.

The solution is to change what button focus' the camera, as was suggested the * button (on a Canon at least) is the choice.

That way you can focus...and when you take your finger off of the * button...your camera won't refocus.

On the 6D the setting is found in the custom functions menu AF.[/quote]

R Pavich, Thank you! The 6D is fairly new to me so I'm still learning the settings. Would you recommend I stick to the telephoto vs the 100mm 2.8?

TimS Loc: GA

katymom wrote:

As the other poster said...the reason your focus i... (show quote)

R Pavich, Thank you! The 6D is fairly new to me so I'm still learning the settings. Would you recommend I stick to the telephoto vs the 100mm 2.8?[/quote]

On a 6D, the 100mm might not be quite long enough for some portraits. The sweet spots for portraiture is 135mm for head and shoulder type shots and 85mm for full length shots. Although, 200mm is more flattering for head and shoulder shots and the longer the focal length, the smaller the depth of field so you get better separation between the subject and background.

Try them both out. I forget the max aperture if your telephoto zoom (note, the 100mm prime is a telephoto) but the bokeh from the prime may be more pleasing than the zoom. Also, your prime may be (probably is) much sharper than the zoom. The net effect is that I'm starting to talk myself into you using the 100mm :)

Tim