Is the Nikon D7200 a major upgrade for a Canon Rebel T3?

Yes, I realize that I only have the one lens that came with my Rebel T3.

Actually, you should be very worried about it. There is no do-it-all lens. Each lens is compromised – whether image quality, maximum aperture, zoom, IS, size / weight, price etc. You need to know what these tradeoffs are to help you identify with the best lens (s) for your needs.

In low light conditions the quality is just not good and blurry. Actually, I just do travel photography, so I do not have time to get into settings, such as taking pictures of people traveling in a busy Chinese pedestrian street at night.

If the quality is blurry, your shutter speeds are too slow. Increase the ISO sensitivity and / or open the aperture. If your aperture is maximum, then a faster lens is helpful (faster than in: has a larger aperture).

To answer the question from @osullic, I usually only do with auto or image priority. As I said, I almost exclusively travel photography. Things are going fast, I usually go with a group and do not feel like I have time to mess around with the settings in the manual …

Time and place for everything. The Av and TV modes are a fantastic addition to your bag-o-tricks for recording modes. It does not mind if you learn manual learning (learning about exposure and programming) Your Camera what to do you wants it) In fact, learning picture quality will make you a better photographer overall, and you will be more successful in Av or TV mode because You will understand why the camera thinks so.

I have added a picture of an unsatisfactory recording. Again, I understand that a higher ISO value with a faster shutter speed would have resulted in a sharper image. I just did not have time for it in the 5 seconds my friend asks how much the crab is and the waiter pulls out two crabs and explains the price for each of them.

This is about readiness. You filmed outside where your ISO was ok. You are involved. You did not adjust your camera settings. This is a mistake that can not anticipate the shot. There is nothing wrong with your equipment here – you just have to monitor the available light and the monitoring Make sure you adjust the settings in advance,

The blur is just a complaint, I think, I also feel that sometimes my photos do not have the "wow" factor that you would expect from a DSLR. I can not explain that further. I wonder if the D7200 would have twice as many megapixels.

More pixels will not help you get the "wow" factor. A great photo is the product of great lighting, superb lighting and great editing. A really good picture can be taken with good lighting and good exposure. If you do not have good lighting or lighting, you need to edit the recording to "save" the recording. Being uncomfortable in a raw editor or in Photoshop (really a editing tool) is like shooting black-and-white movies and not feeling comfortable in the darkroom. The entire process involves seeing the shot, getting the shot and producing the shot. You need to learn to use the whole process if you want to get these "wow" images.

Good luck!