The autumn is in my opinion one of the finest season if you want to take pictures. The colors during this time is unbeatable! You can get amazing photos! I like to get the colors in the background of the horse, to create a natural framing. If you use a big aperture you will get a short depth of field and this technique can give you the leaves in the background to look like beautiful fireballs! When you use a big aperture it is important that you get your focus right, if you miss it just a little bit it can give you the result to be blurry in the wrong place !