Need help on focus issues with people

[DanelleB]

I have a Canon 7D using a 24-70mm in AV. When I take pictures of people (2 -4 in a shot), usually 2.8 to 4.5 F stop. Question is, when I take the shot, it looks great when I review it on my camera. When I go to look at in on the computer it is not crisp and in focus. I seem to take my time, go slow, yet frustrated it is not crisp. Any tips?

[cyber3d]

it would help if you posted an example with EXIF data.

[DanelleB]

Canon EOS 7D
Light source: unknown
FNumber: F/3
Exposure TIme: 1/125 sec
ISO speed: 320
Exposure Bias : 1 Step
Focal Length: 90mm
Metering Mode: Center Weighted Average


On this picture I used my 70-200mm, I thought I was far enought away to use F/3. Was it the metering mode that made the two back subject blury?

[fenris117]

I see what you're saying, but I don't think that it's the metering mode. Metering chooses how the image is exposed and doesn't really have to do with focus. Seeing the subjects are on different planes and the aperture being so wide, I don't think that it's odd that the two in the back are blurry. Also, what kind of focus mode are you using? Single point? Continuous?

[zona5101]

they have some pretty cool (and cheap) dof calculators for itouch/iphones that will pretty quickly let you know if your aperture will give you enough dof. my favoriteis this one:
myPhotoDOF
myPhotoDOF for iPhone - Free iPhone software downloads and software reviews - CNET Download.com

[RichardTaylor]

At F3 & 90mm you don't have a lot of DOF, especially if you are relatively close..

I don't know what distance (it may be in the exif data) you are shooting at however you may want to look at the DOF calculator.

Online Depth of Field Calculator

[ErikUngerPhotography]

One tip, that I need to start doing more myself, is to check your first image by zooming in to see if all the subjects are in focus or not. If not, then you know you need to use a higher aperture.

[ceremus]

Remember that you can always check your DoF by pressing the depth of field preview button, located on the front side of your camera underneath the popup flash button. By default your lens will keep its aperture wide open until the shutter is released, but that button will stop the aperture down to your selected f-stop number so you can see how far your DoF extends, either through the viewfinder or in live view mode. Quick and easy way to tell if all your subjects are sharp and within your DoF.

[DanelleB]

Originally Posted by fenris117

I see what you're saying, but I don't think that it's the metering mode. Metering chooses how the image is exposed and doesn't really have to do with focus. Seeing the subjects are on different planes and the aperture being so wide, I don't think that it's odd that the two in the back are blurry. Also, what kind of focus mode are you using? Single point? Continuous?

I usually use Al Servo focus.

Thanks so much everyone... you have given me good things to look at. I just really want to come up with those sharp crisp pictures. Another idea is to maybe shoot at F8 or F11, and try not to focus so much on the blur now?

[ErikUngerPhotography]

Getting the blur, or shallow DOF look, is something that may not work with group portraits if they are on multiple plains. You may have to shoot at 8 or 11 just in order to get everyone in the DOF. You also have to take consideration into how big the final print will be and how close/far people will be viewing it from. If you know you can get away with not everyone being in tack sharp focus, then you can try shooting a larger f stop.