Focusing Problem: Why Did This Happen?

dbruno

Hey, All -

Last night, I photographed a surprise proposal at a waterfront park in Downtown Boston (not sure why I took this on, but I did). The park has a walkway with an arch above it, with all different color string light on it. I knew it would be a nightmare, as it was taking place at around 7:30 PM EST. It was pretty damn cold out too, somewhere between 10-15 degF. I went in the night before, and figured out what I would have to do with settings, positioning, etc.

The logistics went without a hitch. I was waiting around, pretending to take pictures of the skyline. They pulled up, walked over to the arch, and I was about 50 feet away when he got down on one knee. I started shooting.

I had my Canon 6D, with a 70-200 mm F2.8 IS II. Center focus point. Stabilizer "on". I was at 1/100 sec, F2.8, 200 mm, ISO 16000 (no choice). Unfortunately he was more under the arch than we discussed, but the awful lighting I could pretty much take care of in post. After "the moment", they started walking back, now about 30 feet from me, and I took more photos as he picked her up, they kissed, etc. (She still didn't know I was there). Because it was so damn cold, the plan was for me to walk to the restaurant where they were meeting family, and I would take photos for 5-10 minutes before dinner.

When I got home and looked, Every Photo from "the moment" was out of focus. Of the 24 photos from that sequence, all except for 3 had the focus point on her face, his head, on them, etc. This was not camera shake, or it certainly didn't look like it. Everything was out of focus. From the 10 where they were 30 feet from me, every photo Was in focus. For these, the focus point was on their bodies and faces, but didn't seem to matter. These were in focus.

WHY did this happen? Why was everything out of focus, even though the focus point was right on them? Was it the cold? Was I too far away? I'm not planning to do any more of these, but I would really like to know.

I have about 25 total photos to send them, but will be offering a partial refund to the mother of the bride, who hired me.

Thanks - Dave

Neil vN

I think you were simply working in such low light and such a low contrast situation, that the Canon 6D autofocus couldn't quite latch on.  

What focusing mode do you use?  Single or Servo?

BTW, an ISO setting of 16,000 isn't too crazy for this camera. 

dbruno

Thanks, Neil. I was using single focusing mode that night. For a moment I thought about a servo, but I knew they were not going to be moving around much.

ISO 16000 was the only way I could get a proper exposure, and I was using spot mode. I don't usually go below 1/100 shutter because of subject motion.

So, in the end, I took 32 photos from start to finish of the proposal in the park. I was able to deliver 12: 2 of the guy down on one knee which I really had to "massage" in post processing, and 10 that were more than acceptably in focus as they mingled and talked after the moment.

I delivered these, and some nice shots of the couple and their family from the restaurant to the bride's mother (who hired me), along with an offer to refund half the money she paid me and an explanation as to why. She said everyone loved the photos, they were very happy, and no way she wanted any money back. As I still struggle to come up with what went wrong, or if there was something I could have done differently (to learn from it), what counts is they all were happy.

Very relieved - Dave