Why do photos look different at midday compared with sunset?

Several things change to make photography easier and often more pleasing around sunset:

• The light is not as intense, except with the sun in the frame of course.
• There is less contrast in the scene because the sky is darker.
• Shadows are less harsh, again due to darker light.
• Shadows are longer due to the low sun.
• Color temperature is warmer before sunset and it starts cooling back after.

The lower contrast and change in color temperature give photos taken around sunset a very distinct look which is one of most used by photographers. If you look at good publications and contests, it is easy to see that a significant portion of top and winning images are taken around sunset:

• Photographers call the period before sunset the Golden Hour.
• While the period after it is called the Blue Hour.

Sunrise has very similar properties with a Golden Hour after it and a Blue Hour before it.

All cameras have a limited Dynamic Range which is basically how much contrast they can capture in a single image without any overexposure or underexposure. When the sun is close to the horizon, but outside of the frame, the dynamic range of the scene is lower, so it is more likely that a camera is able to capture details everywhere.

With the sun high in the sky, it stays out of photos more easily, but the shadows it casts are extremely dark compared to lit areas, so scenes can easily exceed the maximum dynamic-range of a camera.

The reason one takes photos in a specific type of light is because a photographer wants a certain look to the image. With harsh shadows, you have to compose more carefully and possibly use fill (flashes, reflectors, etc) to get something satisfying, making sure shadows do not cause underexposure in the parts of the scene you consider important, and that direct light does not overexpose them either. This is an art though, so it is about getting the image that you are looking for, not just taking the photo at that time simply because you are there, otherwise it is more of a snapshot than photography. Many places look amazing around sunset but there also also scenes which look better in sunshine. For example, with narrow streets and very colorful places, I personally find they have more impact when captured in bright light, while I love cityscapes much more at the blue hour when lights are turned on and add yet another element and dimension to the scene.