When I first began documenting my work in photographs before the digital era, I used a Minolta SLR and tripod with a backdrop and proper photo lighting and took a ton of photos all the while adjusting the lighting, tripod and settings on my camera. I never knew how they would turn out until they were developed and at times I would have to do it all over again, or live with a slightly blurry photo if the painting had already sold.
Now, with digital media life is so much simpler. I began with an inexpensive point and shoot camera but have since moved up to a Canon EOS Rebel T3i but still use the same basic principals...lots of pictures in different settings...though I no longer use a backdrop and photo lights.
Natural lighting tends to capture the colours more faithfully than anything man-made that I could set up previously, plus it's so much simpler. At different times of the year and under different weather conditions I tend to move around. Man-made lighting tends to cast an orange or yellow or even blue hue on everything.
The top photo is in my south facing front yard by mature evergreen trees which is ideal in spring and fall. Underneath it, the photo on the far left is taken on my dining table with a west facing window and seems to work really well in winter. Beside it is my north facing back deck and I love the colours I can capture in summer, though I prefer a sunny day with me in sun and the painting in light shadow. Since our house is higher than any of our neighbors, I don't have to worry about shadows cast by any other buildings. Depending on cloud cover, rain or snow, the third photo shows my south facing living room floor. We have a large bay window and those large evergreens that filter light. And, finally, almost any time of year and under most weather conditions, my north facing kitchen tends to capture the colours best. In the room we have a west facing window that is shadowed a little by a roof and north facing French doors...the ideal light. It would be a perfect studio.
I will often move the piece around to photograph it under several different lighting conditions to see which shows the truest colour, which can sometimes be a challenge when the work measures 5 feet but it's always worth the effort. And from there I will do whatever it takes to get an accurate photo...crouch, lie down, stand on chairs or ladders...my neighbors are quite familiar with seeing me in unusual situations and chalk it up to living near an artist.
Then, I set my camera to its highest settings, center the image, and zoom in as much as possible so it won't require much cropping and will retain a high resolution (both pixels and dpi). I have taken a couple of photography courses to learn more about photography, but I tend to let the camera do most of the work and did read the manual in order to learn how to change the settings. I brace my elbows against my body, take a deep breath and hold it, then shoot the image. I often take photos both on the manual setting where I can focus the image and on automatic - I have to admit, the eyesight just isn't what it used to be and the camera's automatic settings are fantastic.
Finally, I install my camera card into my computer and open a (free) photo editing software to view and crop the images. Some of the free editing software are IrfanView, Gimp, Picasa, Picnik, and Pixlr though I haven't tried them all and there are many more. I personally don't edit anything but cropping or dpi and pixel size so I prefer to use something that isn't too challenging. Plus, I don't tend to spend too much time at my computer. Like everything, I always do suggest research.
When I'm taking other 'fun' photos for my blog, I still use natural light as much as possible and take them from many different angles and I've found that I can get some very interesting images this way. I hope this helps!