It's because of light. You either don't have enough of it or you don't have the right kind. That's it and it doesn't just apply to pet photos, it applies to photos of your kids, that landscape you thought would be so pretty but wasn't and basically any photo that leaves you disappointed compared to the reality of the scene and what you were trying to capture.
Your camera needs light to record an image. It doesn't matter whether it's an old film camera, a top of the line DSLR or your smartphone; light is the necessary ingredient, and most of the time you will need more of it than you think. This article is for people who want to take better pet photos with the camera they've already got, so I'm going to try to keep this very simple, with just a few (hopefully) palatable bites of technical info for you to swallow.
The first complaint that many beginner photographers will have is blurry photos.
You want to catch your dog running, suspended in mid air like this:
...but your photos look more like this:
One of the ways that your camera gets light onto the sensor is by opening the shutter for different lengths of time. On a very bright day, the shutter will open for a tiny fraction of a second, maybe as short as 1/4000th or even 1/8000th of a second. That is all it needs to get enough light onto the sensor to record the scene. That's great for taking photos of moving subjects because they will be frozen in action with such a short exposure time.
The problem is that you won't always have that much light and your camera or smartphone may not have the ability to change some of the other factors that will help get more light onto the sensor. You very possibly don't even have the ability to control your shutter speed, your camera decides that for you.
So now you are taking a photo of your dog running towards you, with a shutter speed of 1/125th of a second and that sounds like it's really fast, but you'll just have to trust me that it's not. If you are photographing your pet sitting still, you MAY get away with 1/125th of a second, but even then, your pet breathing and fidgeting, your hands shaking, etc can cause blurriness in the photo. For an action shot, you really need 1/800th of a second or even faster. If you are shooting with a camera that allows you to zoom in and you are using that feature, then your shutter speed may need to be faster still.
1/1000th of a second…
This photo was taken with a shutter speed of 1/1000th of a second, and it is STILL not tack sharp on the dog's eyes because she was moving too fast for the camera's autofocus to keep up.
So what can you do? For one thing, move to an area with more light. Action shots will almost always need to be captured outdoors, at a fairly bright time of day. Get out of the shade and into the open. Place the sun at your back, so that light is falling on your pet’s face as they run towards you.
If outside is not an option (for example, an indoor cat or your pet is doing something adorable right this moment), you need to add as much light as possible. Turn on all the lights in the room and any adjacent rooms. If it’s daytime, open the curtains. The one thing I do not recommend is using the flash on your phone or point and shoot camera, unless you’re a fan of glowing, demonic eyes.
I hope you’ve found some of the tips in this article useful, let me know below if you have questions I haven’t answered, or topics you would like to see covered in the future.