If you're looking to purchase a drone for photography or surveillance purposes, there are a few key factors to consider before making your purchase. Here is a buyer's guide to help you choose the best drone for your needs:

1. Camera Quality: The quality of the camera is one of the most important factors to consider when choosing a drone for photography or surveillance. Look for a drone with a high-quality camera that can capture clear and crisp images or video. Some features to look for include high resolution, image stabilization, and the ability to shoot in RAW format.

2. Flight Time: The flight time of the drone refers to how long it can stay in the air before needing to be recharged. Look for a drone with a flight time of at least 20 minutes to ensure that you have enough time to capture the footage or images you need.

3. Range: The range of the drone refers to how far it can fly from the controller before losing signal. Consider the distance you need the drone to fly and choose one with an appropriate range. For example, if you plan on using the drone for surveillance, you may need a drone with a longer range to cover larger areas.

4. GPS and Autonomous Features: Many drones come with GPS and autonomous features such as obstacle avoidance, return-to-home, and follow me mode. These features can be particularly useful for surveillance purposes as they allow the drone to navigate obstacles and follow a subject without the need for constant manual control.

5. Size and Portability: If you plan on using the drone for photography or surveillance on the go, consider the size and portability of the drone. Look for a compact and lightweight drone that is easy to transport and store.

6. Price: Drones can range in price from a few hundred to several thousand dollars. Consider your budget and choose a drone that offers the features you need within your price range.

7. Brand and Reviews: Finally, consider the brand and reviews of the drone before making your purchase. Look for a reputable brand with positive reviews and feedback from other users.

By considering these factors, you can choose the best drone for your photography or surveillance needs. Remember to always fly your drone responsibly and follow all local laws and regulations.