Believe it or not, overcast skies provide the best light for photographing leaves. With a polarizer to remove any glare from wet surfaces, damp conditions are even better! A beautiful blue sky with a couple of clouds is awesome too, but you have to deal with really stark contrasts, that might give you blown out highlights and way too dark shaded areas. I say "might" because, if positioned properly, the sun can backlight the foliage and really light it up giving the impression that the leaves are glowing themselves.
The covered bridge inside the Flume Gorge State Park, Franconia, New Hampshire. A rainy Fall 2007 day. I was hoofing it with my camera on the tripod, over my shoulder with a towel covering it. The cloud cover was dropping all afternoon and I got this shot before it got overly misty.
Mount Washington peeks out from under the clouds on this unusually warm October day. Picture taken from Bear Notch Road in New Hampshire's White Mountains, 2007.
Cathedral Ledge in North Conway, NH is a popular spot for climbers. We photographers looking for good pictures drive up on the access road. Nice view North on a sunny October afternoon in 2001.
The Quabbin Reservoir in western Massachusetts. Construction began in 1930 and by 1938, was ready for flooding. The Massachusetts towns of Dana, Enfield, Greenfield & Prescott were dissolved and flooded after residents fought all the way to the Supreme Judicial Court of Massachusetts. Connecticut also sued Massachusetts, claiming that water meant to naturally flow into the Connecticut River would be "stolen" from their state. Metropolitan Boston needed the water, so end of story. There are huge aqueducts running easterly and westerly from the reservoir. in this view, you are standing in the former town of Enfield looking North into New Hampshire. Mount Monadnock, in Jaffrey, NH is just outside the frame to the right. Notable is the visible shoreline. 2002 way a very dry year, lowering water levels.
Here is a fine example of the kind of color we get during October in exurban Massachusetts. In the fall you can just get in your car and meander through the countryside on small back roads and see this kind of beauty all around. Also, this is a great example of the kind of lighting that makes a tree glow. Although, overcast skies eliminate harsh contrasts, bright sun from the side or behind the leaves lights them up beautifully. Here, we have a late day warm sun, to the right and slightly behind the trees. Taken October 2008.
This is the Assabet River in Hudson, Massachusetts. I was standing on a bridge in Wood Park looking Northeast with the sun directly lighting the foliage. This is straight on light, so you do not get the "glow" like the behind lighting in the previous image above. Taken October 2008.
I discovered that you can find great examples of "old growth" trees in cemeteries. The trees are allowed to grow untouched by the ever present threat of development. They are usually very classic in their look, having plenty of room to grow for 100 years or more. This is a cemetery on Main Street in Hudson, Massachusetts. Taken October 2008.
A perfect "Old Growth" maple, probably a century old, all by itself in the middle of this small colonial cemetery in Marlborough, Massachusetts. Note the side/rear lighting again, making the leaves "pop" with color. Taken October 2008.
Sunsets are challenging because you are trying to take a picture of something that is extremely bright compared to your surroundings. You can approach this in different ways. You can allow the sun to be in the picture with other objects as silhouettes. You can make the sun a very small part of the composition, allowing the camera to properly expose the rest of the scene, or you can have no sun at all. Some of the best sunset images don't include the sun!
Here, the sun sets into the ocean as viewed from Harkness Memorial State Park in Waterford Connecticut. The sun is very small compared to everything else, allowing me to properly expose the sky and water the way I saw it. This picture was taken in winter, so the leafless trees look interesting.
Using at tree as a silhouette with a beautiful sky as a backdrop. The sun is in the clouds near the horizon. Taken on Prospect Hill in rural Harvard Massachusetts.
The sun is already down and just the pink light of a rapidly fading day remains in this coastal Connecticut location.
Actually a sunrise over the Sudbury River valley on the Concord/Sudbury line in Massachusetts.