get feedback on (something)

"Feedback" is information that you get from people about something that you did. In the example above, the people who read the speaker's blog told him what they thought of his photos. Some other examples of "feedback" include:

• results from a survey of your customers
• classmates giving you advice on how to improve your writing
• the noises that an audience makes when you're performing a play

People use feedback to help them improve a product, performance, etc. which they made.

positive feedback

When feedback is "positive", it means that people are saying that they like something. "Negative" feedback is when people complain about something or say that they don't like it.

Note that you can also call feedback "good", but the meaning of "good feedback" is different from "positive feedback". "Good feedback" is anything that helps you to understand the thing that you made. "Good feedback" can be positive, negative, or a mixture of both. For example:

I showed the film to a few friends of mine who are directors, and got some good feedback from them. Most of them thought that it was too long, and one of them said that I needed to improve the audio quality.

So "good" and "bad" describe the quality of the feedback, while "positive" and "negative" describe what the feedback is.