Okay, so the gear I use personally isn't the newest, nor the most expensive. In fact, I started out on a Sony a200 entry-level camera! That being said don't be discouraged if you only have a camera phone at the moment! You can still take beautiful pictures just by using your phone! However, if you're wanting to up your game or move to the next level, I highly suggest moving up to at least a entry-level DSLR like the Canon Rebel T7 which has a crop sensor or a full-frame camera such as a Canon 6D which is what I use, although it is more expensive.
If you want to learn more about Crop sensors and full frame cameras watch this video!
Although what camera to use is important, the best thing you can do for yourself in regards to improving your horse photography is...Get a telephoto lens. Telephoto lenses start at 135 mm and due to their compression - they are the lens of choice when it comes to Horse Photography! These lenses make the horse's body look proportionate - unlike a wide-angle type lenses which distorts the horse's body making him look unbalanced.
The lens I use is the Canon 70-200mm f/2.8 It's many equine photographer's lens of choice due to the versatility and how you are able to zoom in to capture a horse's movement. The zoom capability offers a lot more flexibility than a prime lens that has no zoom feature.
The goal is to eventually upgrade your gear to professional-grade quality but you don't need to start with the best. In fact I honestly recommend buying gear within your price range at first because you are going to want to learn and practice and the best way to do that is by taking LOTS of photos. That's a lot of wear and tear on your super-expensive gear!
The next best thing you can do for yourself in regards to improving your horse photography would be to learn how to edit.
Figure out what you want to improve on or the next thing you want to learn and see if you can find some how to videos, tips and tricks, or tutorials! The amount of educational content online theses days is almost overwhelming but take advantage and use it to learn more about the technical features of taking a good photo or learning how to use Adobe Lightroom and Photoshop or even honing in on your signature editing style! The sky is truly the limit.
In order to become good at retouching you will most likely need a graphics tablet. I use a Wacom Pro Tablet.
The best angle for a horse photo is always the lowest. So don't be afraid to get down on your knees or even your stomach. (Make sure the horse can't run you over though!) Always keep those ears forward and learn how to direct the horse for portraits and action shots! The best tool for flattering shots is patience. Horses are animals and have their own emotions. Some horses are photogenic and some would much rather be grazing in their pasture. Study the horse, watch their behavior closely, and always be ready for a spontaneous shot!
To really make your subject pop from the background and to create that bokeh (soft dreamy background) your going to need a long focal length with an apeture of f2.8 / 2.0 / 1.8 etc. to get the best separation from the horse to the background. Also if you are using a low aperture such as a 2.8 be sure to have the horse a ways away from the background. The further they are from it the more blurry it will be. You cannot place them right next to the background you are shooting or it will still be in focus.
The worst time to take photos is mid day. That doesn't mean you should practice around noon it just means that you should probably try and find shade if the sun it out.
The sun creates hash shadows and our eye doesn't always pick up on them unless you train it to be aware of the differences in lighting. Soft light is ideal and why a lot of photographers shoot early morning or evening at sunrise and sunset. Overcast also eliminates shadows.
Now there are so many more things I could teach you however these are the basics to get you started improving your horse photography!
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