Pentax K10D with 50mm prime lens. 1/160s at F2.5 +0.7EV
The biggest limitations to using a customer's own photos as a reference for a painting are usually quantity and quality. Here are some suggestions for taking better photos of your favorite family members.
The first priority is to try and get everyone as calm as possible with few distractions. Dogs in particular need to be kept calm so they don't overheat and pant. When taking the photo above I was at the customer's home for about 30 minutes before I started working with the camera, giving the dogs some time to settle down.
The next priority is to get good lighting in a good setting. I took this photo in the customer's sun room on a cloudy day. We moved furniture around until the sofa was right next to the window in order to maximize the available light and made sure all the room lights were turned off. Never, ever use the built-in camera flash. Good lighting does way more for a photograph than any amount of money spent on a camera and lens system.
Use the right lens. For taking photographs inside I use a fast 50mm prime lens. Outside, I use a 70-300mm variable zoom which is a fairly slow lens, but there's usually more light to work with and it lets me stand far away from my subject. My camera is an older-model 10MP digital SLR which, although dated, still takes perfectly good photographs.
Get the right exposure. To get the color of the black and tan right I had to push the exposure up so that the whites were just starting to blow out. I tried several test shots to get the right exposure setting. If I'd left exposure up to the camera the photo would be too dark to be useful.
Take shots from different angles. To get this photo I sat on the floor and had the dog sitting on a sofa. Getting the camera close to the subject's eye level makes for better portrait-type pictures. I also tried shots with the camera in different orientations.
Get help. There were three people involved in taking this photo. Me with the camera, a person sitting next to the dog to keep it in place (and whose light colored shirt accidentally worked as a light reflector) and a person standing behind and to the left of me holding hot dogs to get the dog's attention.
The last and most important rule for getting a good photograph, I think, is to take lots of shots. Some photographers who use large format film cameras don't have that option and have to have a sixth sense of when to press the shutter. With modern digital technology there is basically no limit to the number of pictures that can be taken, so you should keep at it until you know you have a great shot. Then take some more. On a photo shoot I usually take between 100 and 200 photographs in order to get a few images that will make good paintings. There's always one shot that stands out from all the others.