focus for group portraits

[kgreen]

I took some family photo's for a friend. I shot several, & am happy with about 95% of the photo's. I think they will be very happy with the ones they get. But for my self, if I had 10 photo's I would say 8 out of the 10 were keepers. Because 2 out of the 10 photo's only one out of the group was in sharp focus with the others slightly out of focus. Would it have been better to use an auto face detection, to make sure all were in focus?? Or a smaller aperture. I had them in front of a fireplace, with lighted garland, & lighted christmas tree. So I got some with the whole photo in sharp fous, & also some shots with a larger aperture to slightly blur the background but keep the subjects in focus. I think those are the ones that I had trouble keeping all the subjects in focus. I am using a nikon d-7000 with a 35mm. Manual, no flash, tripod, & reflector.

 

[mom2maggie]

What aperture were you shooting?

 

[kgreen]

a range of 5.6 to 1.8.

 

[ukcatfan]

It definitely sounds like a DOF problem. You probably need to make the aperture smaller. What aperture did you use?

 

[photo_chick]

Also remember that there is only one plane of focus. Depth of field is the area of "acceptable shaprness" and if you pixel peep those people won't be super sharp. So even when you stop down they may not all be perfectly sharp when you view at 100%.

To know the depth of field you're working with, use a calculator.
www.dofmaster.com

 

[disneyboy2003]

Yes, as others have said, it sounds like you were using too large of an aperture, which made your depth of field very very small.

When you use a large aperture (a small f-number, such as F/1.8), your depth of field can potentially be very very small. So if all the people in your photo aren't lined up in the exact same plane of focus, some of them may appear slightly out of focus, especially if their face happens to be just a few inches behind or in front of everyone else's.

That's why with a large group photo, you should try using smaller apertures (larger f-numbers, such as F/5.6 or F/8 for example). Using smaller apertures gives you larger depths of field, so that everyone's faces can be in-focus.

I know that you wanted to use a larger aperture such as F/1.8 to blur the background. However, with larger apertures come smaller depths of field. Sometimes, the depth of field can be so razor-thin that if you focus on a person's eyes, their nose may not be in focus. So that's something to watch out for.

Go with photo_chick's recommendation to check out the online depth of field calculator. There's even an app for that for your smartphone.

 

[handicap18]

If your going to take group portrait photos, then you should use a flash. Realistically, flashes.

I did a family of 25 group shot at a wedding last year and used two slave flashes with diffusers and a flash on the camera. This way I could us a small f/stop like f/8 to make sure that everyone in the group was in focus.

When I do my portrait shoot I usually use 2 slave flashes with a soft box. This works great for 1-2 people, but when I have to do a family of 3-6 or so, I've noticed that I need to add more fill light in the front to prevent the shadows from the slaves, so I use my main speedlight on the camera at about 1/4 power.

The D7000 does have the capability of acting as a Commander flash using the popup. This means you can use a SB-600 or SB-700 (or the 800 or 900 if you have that) as slave and trigger that flash using the popup. I bought an inexpensive diffuser for the popup flash to help with the harshness of the light.

With this setup you can adjust the flash power on any flash you are using. I typically use my commander flash (either the popup or the SB-900 at its lowest power setting so the light doesn't effect the image yet will still send the signal to trigger my SB-600 slave flashes).

I'm sure the look you were going for was to have the lights from the decorations show up more, but you also have to make sure that everyone in the picture is in sharp focus. Very hard to do with apertures wider than f/5.6, thus the need for extra light.

Hope I didn't confuse you to much. I figured out what I needed with a lot of trial and error and a lot of reading.

 

[kgreen]

Thanks for all the great information! Trial, error, & lots of questions. You all are great! One more question. Which metering mode would you suggest for portraits, I used matrix, but wondering if I should have used spot. I'll have to practice some more with group shots. Thanks