bnlearle wrote in post #12190151
The bigger the group gets, the more I scoot back, and the wider I shoot

I often shoot groups of 8 people at f/1.8 without any focus problems. And the background looks much better, imo

This thread has been really useful to me. But I had some problems trying to incorporate the information in a recent group photo (not a wedding). I posted a thread in the general section and got some great responses, but I also wanted to ask here specifically about the DOF calculator.
It was my first time using a tripod, and I assumed that (1) with the 10-second timer there would be no camera shake, so I could use a slower shutter speed, and (2) based on the DOF calculator (40D, 30 1.4, subject distance 15 ft), I could use f2.5 (which would give an ample DOF of 7.7 ft) and thus a lower ISO. There wasn't a ton of light (I also bounced a flash behind me to the upper right), which is why I didn't want to use too small an aperture if f2.5 was enough.
I thought everything would be super sharp, but instead it was noticeably blurry. Here's the photo
(EXIF 1/160, 2.5, ISO400). I originally started with 1/60 but eventually went to 1/160 because of the blurriness. I used AF to focus on the woman's blue sleeve (on the left) because (1) I'm not good at focusing and recomposing and (2) I figured that with DOF 7.7 ft, everyone would be in focus also. Not only is the sleeve not in focus, but also I can't figure out what the camera focused on (although someone pointed out possibly a plug outlet by the wall, yikes).
I may have to turn off AF next time (although I'm nervous because my eyes aren't great with MF), and I'm also wondering about the minimum focusing distance with the 30 1.4. Which brings me to the DOF calculator. I'm not exactly sure what I did wrong. I thought I had figured it out, but a few people suggested that it's not always accurate and that I really should stick to smaller apertures just to be safe.
Anyway, I apologize for the long newbie rambling, but any advice is greatly appreciated. I really want to figure this out!
Thank you!