Everyone with a DSLR should buy a fast 50mm prime lens. You might ask, “why do I need a 50mm prime with only one focal length when my kit zoom lens goes from 18-55mm?” There are several reasons why one should buy prime lenses. Prime lenses tend to be faster(have a wider aperture and are able to capture more light) than zoom lenses. For example, the 18-55mm Nikon kit lens is a variable aperture going from f/3.5 to f/5.6 through the zoom range, you lose 2 stops of light at f/3.5 and as you zoom in you lose another 2 at f/5.6.
Putting that in terms that most people can understand you would have to take a photograph with a much slower shutter speed with a lens at f/5.6 than you would at f/1.8. A second reason you should have a fast prime lens is that it allows you more control of the image than a variable f-stop kit zoom lens. So say you want to take a picture of your romantic partner and you want to isolate them, with an f/1.8 lens you can easily blur the background by opening the aperture all the way to f/1.8, at f/5.6 more of the background will be in focus. A third reason to buy a prime is that they have less glass, this has a few benefits. The first is sharper images since the light won’t have to go through fewer layers of glass there is less of a chance to get a weird bit of distortion. A second benefit of having less glass is that it takes less time to focus since the camera or the lens is moving fewer pieces of glass the focus can snap to where you want it right away. A final benefit of less glass in the lens is the lens weighs less, carrying a heavy lens on a neck strap for extended periods of time can be a literal pain in the neck, and make you not want to bring your camera with you. A final reason to get a 50mm lens is that it’s sort of a Goldilocks or Swiss army knife of a lens. They can take very nice portraits and they can take a nice landscape or street photography photographs. The disadvantage is that you might have too long or too short of a focal length for some photographs. If your subject is far away a 50mm wouldn’t be the best lens for it since the subject will only be a small portion of the image, but it’s unlikely that you’ll be doing long-distance wildlife photography with anything other than a long telephoto lens.
The question comes back to the Yongnuo YN50mm f/1.8. The answer is yes with some caveats. If you’re considering the Nikon 50mm 1.8 G, the Yongnuo is almost an exact clone of that lens so I would recommend buying the Yongnuo and using the savings to buy an additional lens or another camera accessory. Since this is a clone of the Nikon 50mm f/1.8 G you can’t change the aperture by hand. Some cameras don’t have the computer so it would make using this lens on them difficult. If you want the cheapest 50mm f/1.8 for Nikon and don’t mind going super old school, manual focus, and manual aperture adjustment you can get a Nikkor 50mm f/1.8 E (Nikkor Pancake) on eBay for less but the lens might be in a little rough condition. This Yongnuo 50mm is a perfect lens to start your photographic journey, even after having shot thousands of photographs with other lenses this lens is fun to shoot with. The focusing can be snappy and sharp. There are a couple of minor things I don’t love about the Yongnuo. The first is the lens cap isn’t the most secure, but I’m generally walking around with the cap off, it only matters on rainy days when you want to keep the glass free of water while you’re looking for things to photograph. The second issue is that it doesn’t come with a lens hood unlike the Nikon G, but that could be purchased for around $10.