Check your camera manual first: it usually lists the recommended operating temperature range, which is the best guide for what is “too hot.” In general, excessive heat is bad for electronics, though batteries often show problems before image quality does.

Yes, sensor heat can increase noise, and this is most noticeable in long exposures, astrophotography, heavy continuous shooting, video, or at high ISO. For normal daytime photography, heat-related noise is usually not the main issue.

Low-cost ways to help:

• keep the camera in the shade
• store it in a light-colored camera bag
• avoid leaving it in hot environments
• allow breaks between long bursts or long sessions
• if you do DIY work, a small external fan can help in some setups, especially tripod/astro use

Be careful with DIY cooling: attaching a fan may block normal camera use, and ice packs or very cold objects can cause condensation, which is risky for the camera.

Specialized cooling is common in astrophotography because very long exposures benefit more from lower sensor temperatures. For most general photography, simple heat avoidance is usually the most practical budget solution.