Can I just buy a lens that has manual adjustment for my photography class?

I have a Nikon L840 which does not have manual shutter or aperture (which is a requirement for class), can I just buy a lens with manual adjustments for it? Or do I need a new camera all together?

Unfortunately, my friend, you can't buy manual lenses for your Nikon Coolpix L840 camera as it has a 'fixed' lens… As in it's fixed to the body of the camera, and is not designed to be detached.

I'm afraid that, for your course, you're going to need a different camera.

Indeed that camera can't be fitted with other lenses.

If you want to use interchangeable lenses you need a DSLR or a mirrorless.

Note that the L840 has a powerful zoom lens, which would cover almost all requirements. Use that camera for at least 6 months before thinking about getting a different camera. You will need to spend lots of money to replicate the facilities offered by the L840. Ask around ay your class, ask the teacher of that class.

You must buy a new camera such as any DSLR or any mirrorless camera with interchangeable lenses.
Your Nikon L840 is a point-and-shoot camera with a fixed lens that can't be removed.

When your teacher talks about manual, he or she is referring to the camera's feature that allows you to control the shutter speed, the aperture and the ISO. This control is only found within the camera and not in the lens, so even if your Nikon L840 could accept different lenses, it still would not be sufficient for a photo class.

The problem that a lot of beginners and knowledgeable consumers have about cameras like the Nikon L840, is that they think it's just a small DSLR because of the way it looks and because they often provide some control over the exposure. Unfortunately, these super-zoom cameras are just point-and-shoot cameras that do not have the capabilities of a proper DSLR or mirrorless camera.

Therefore you will need to buy a DSLR or a mirrorless camera. Which one does not matter! There are no such thing as a bad DSLR these days. As a beginner, you will be most concerned with learning the basic technical and artistic aspects of photography. You're not going to be producing amazing work, so don't worry that your camera is a used Canon, Nikon or Pentax your dad got off of craigslist.com. It simply doesn't matter. It's kind of like someone learning to drive who want to get a Porche. It does't matter if they learn to drive with a Porche or a 1974 AMC Gremlin.

A great place to buy used gear is keh.com. They have great staff. They alway under-rate the condition of their gear, so you always get stuff in much better condition than what you expect. And their gear comes with a 6-month warranty, too. Great site - much better and safer than eBay.

Your camera already has a lens and it can't be replaced with any kind of lens. It does not have an interchangeable lens system. Yes, you need a new camera, preferably a dSLR.