Many artists you talk to, especially the "old school", will get a certain bad taste look in their mouth when you mention The Camera as a tool for painting. The often quoted remark is that paintings from photos appear lifeless and devoid of emotion. Personally I can't accept that particular arguement. A flick through any National Geographic or Time magazine will show that a skilled photographer is just as adept at creating emotion, movement or mood as any similarly skilled painter. I am unsure as to why people will put limitations on their creativity. Used correctly the camera can be beneficial in many ways. Especially today with the enjoyment of the digital age and modern photo manipulation software. The digital camera can benefit traditional and modern creativity.
It is best to think of the camera as a tool in the same way we think of our palette, sketch book or oils. Many people when frowning on paintings done from photographs will imagine the artist copying the photograph exactly. This is indeed a mistake. The camera captures a fraction of a moment in time and unless you are a professional with an indepth knowlwdge of apatures, shutter speeds, lenses and so on you are going to fail to produce an image worthy to copy exactly. Even a professional will tell you that only about 1 in 10 photos is a good success rate.
Those artists that do copy from photos exactly often give themselves away. Photos have a standard format that fits on standard size photographic paper and you can see this in the artists choice of canvas size. Photos have a tendency to crop the world we see and you can see this odd cropping in the artist's canvas by the way that tree or bush neither wants to be fully in or out of the painting, or by the way the man getting on the bus appears awkward. Were we to sketch this scene we would likely portray the man more fully, or wait till the bus had departed altogether. Lenses also change our view and perspective of the world, apateurs change the light and depth of field, shutter speeds the movement, focal lengths change perspective. All these are give aways to a copied photo.
What use then is a camera? As I've said we are not to copy a photo exactly. What we do is document the scene with multiple photos. Take wide angle photos of the whole scene and of what is even going to be outside of our painting. Take close ups of detail we wish to refer to latter. With a digital camera you can take as many references as you want, there is no extra cost in down loading them to your laptop. The more references the better. In your sketch book jot down the colours you are going to use for a wall, bush etc. Colour is notoriously fickle when viewing digital images and will change vastly from one piece of hardware or software to the next dependling on your settings. As an ex-graphic designer I am somewhat able to change my colour settings to suit, but not everyone will be able to do this. You may even want to bracket some of your photos so that you retain detail in all shadow areas. Try to use more medium to high resolution images if possible. I would suggest nothing below 3mb.
So sketch out your scene in your sketch book and compose the drawing exactly how you are going to compose your painting, include details of light and shade, jot notes of colours and what pigments will be needed to reproduce these. Even better if you have the time to make a colour sketch or to begin your painting on location. Look at your composition and see what are the important elements, make detailed notes of these and document them with your camera.
At home you can finish your compostion, use the photographic images viewed on your laptop as guides to shape, relationships of space and light, complex details of form and texture. Do not use them to change the composition you sketched out as this was how you understood the scene in that moment. Instead use the camera images to fill in the detail of your sketch but not to direct it..
Like any tool you must get to know how to use it properly, don't just relying on pointing and clicking, and on automatic settings. Understanding how a camera works will give you a greater ability to avoid it's traps and enjoy it's benefits.