I take most of my pictures outdoors (bud on plant pics) so I thot I would give you some of my ideas about light.
I like the evening best for taking pictures. When the sun is in a more sideways location to the plants. Say an hour before sunset. You get a more vivid closeup of a bud. If you have trees around your grow area, getting a part shade/part sun pic makes for an interesting pic. Example below pic #4.
I also like to take pictures with a flash outside just after the sun has gone down. It is not totally dark but the flash gives a good contrast, lighting the plant nicely.
Another opportunity to take a pic that is well lit, but the sun is not shinning directly on it, is to go out into the garden as soon as clouds cover your grow area. I like this especially. Shadows are muted and the washed out directly shinning sun is much more subdued, shadows are less too. Examples are pic #2 (sun behind cloud) and #3 (being in full sun).
Pic #1 I took during mid winter (January), clouded day. The sun in winter gives a glow it seems that can not be found (by me) any other time of year. The sideways light and the clouds gave this fish a almost sureal feel. This is one of my all time fave pics. Silly but true. My first fish of the year, caught January 06, is a memorable pic only because of the light shining naturally on it. Try a mid winter pic outside with the sun shinning in late afternoon, an hour or so before sundown. You will see what I mean if you can capture it.
My husband likes to take a flashlight and train it on a plant too, when the clouds cover the sky, making for just a bit more light on the bud. I took over a thousand pics of just the Flower stage last summer/fall.....I just spent ten minutes looking for an example of his Afgoo with flashlight...cant find it at all. He was real proud of his afgoo, that plant had the biggest tops in the garden!
One more thing.....
not about natural light, but about flash that I have found to work real well. Take your pic from five feet away from the plant, use the flash, but zoom in on the pic you want. That way the flash will not wash out the pic. When harvesting, I hold a bud at arms length, zoom in, and use the flash, I get a black background that way (but I am holding that bud somewhere there is nothing directly behind it).
Take huge amounts of pics.....that way you will get some that are excellent. Most pics are ordinary, some can be as I say "picture Postcard perfect"............those can come years apart.
Be aware of your lighting/shade outdoors when taking pictures, use it to your advantage.