I am often told that my candid photos of people are my strongest suit. I feel this way as well. Thus I thought that I would discuss some points that I think help me achieve good results when photographing people in a candid setting.
Select the lens
My favorite lens combination for this type of photography is my Canon 70-200mm f/2.8 with the Canon 1.4x Teleconverter. Since the overwhelming majority of my candid photography takes place with sufficient light, the resultant f/4 works very well. When the lighting is less than stellar, I kick up the ISO on my Canon 1Dx. I have had good results with an ISO of up to 25,600.
The reach of this lens combination allows me to pinpoint my subject even when they are in a crowd. I usually only have to shift my position slightly to obtain the shot I am going for.
This is what I had to shoot through in an attempt to get a photo of the smiling lady.
Picking a subject
I am a people watcher. I have always enjoyed watching interesting people. Thus the first thing I do is to scan my field of view to find the person that I am going to concentrate on for a particular photographic opportunity.
I rarely ask my subject for their permission to take their photo. If I do make eye contact with an individual and they seem like they don't want their photo taken, I will not take their photo.
Those who know me, know that my favorite subjects are pretty women and cute kids. I will occasionally take a photo of any interesting fellow but rarely.
Follow that subject with the camera to your eye
I follow that subject with my eye to the camera and my finger on the shutter waiting for "the moment" to make the capture. I shift my position as necessary to put myself in the proper position to get my shot.
I think my best candid photos are the ones where the subject's face fills most of the frame. I try to position myself close enough to the subject so that my lens can achieve this. Sometimes I am too close and my lens will not autofocus. I usually move farther away to take the shot but when that isn't possible, I will switch to manual focus to get the shot.
Capture the eyes looking at you
I find the very best shots are those where the subject is looking right at the camera. As these are candid as opposed to posed shots, I have to time my shutter press to try to capture the moment the subject is looking directly into the camera. This is where a professional camera like the Canon 1Dx shines as it will focus almost instantaneously.
As my subject is rarely motionless, I have to anticipate their movements to capture just the right moment.
When I am working my subject, I almost never have the time to review the captures I have taken of that subject. Thus I take quite a few shots at different moments in anticipation of having gotten THE shot.
My response to the often asked question "Are you getting some good pictures?" is "I won't know until I get them on my computer" is very true is this type of shooting situation.
I may find the time to pause and review the camera LCD. If I do and I find I have not gotten THE shot, I may try again if my subject is still available.
When you can't get the eyes, look for other angles that capture the mood
If I am trying to capture the mood of my subject, it is not necessary to have the subject looking into the camera. In fact, it is usually better if they are not. A shot taken from the side of the subject with part of their face shown will usually capture the emotion better than a full face shot.
Follow the subject and retake the photo until you capture what you want
If you don't get what you envision, try again if the subject is still available to you.
Like most photography, successful candid photography requires that you pick your subject and work it for the proper composition. Unlike landscapes, your candid subjects are only candid for so long!