Canon ET-155 Lens Hood

The primary purpose is to block stray light from hitting the front lens element, which helps to prevent lens flare, ghosting, and reduced contrast in your photographs.

It is specifically designed for the Canon EF400mm f/2.8L IS USM and the Canon EF800mm f/5.6L IS USM lenses.

No, the ET-155 lens hood is engineered for a precise fit on the EF400mm f/2.8L IS USM and EF800mm f/5.6L IS USM lenses only. Using it with other lenses may not provide a secure fit or could cause optical issues like vignetting.

Yes, it provides a degree of physical protection to the front of the lens element against minor bumps, scuffs, and scratches.

Clean the hood with a soft, dry microfiber cloth. If necessary, slightly dampen the cloth with water, but avoid using any solvents or abrasive cleaners.

Flare reduction means that when you have a bright light source (like the sun or a strong artificial light) in or near your frame, the hood blocks that light from entering the lens at an angle that would create distracting colored circles (ghosting) or a washed-out appearance (flare) in your image.

While it adds some size to the lens, its weight and bulk are generally considered reasonable for the protection and optical benefits it provides, especially for professional telephoto lenses.

Ensure you are using a compatible Canon lens (EF400mm f/2.8L IS USM or EF800mm f/5.6L IS USM) and that the threads on both the lens and hood are clean and free of debris. Gently align the threads and turn clockwise.

The ET-155 is designed for specific lenses and should not cause vignetting when used correctly. If vignetting occurs, double-check that the hood is fully and correctly attached and that you are not using it with an incompatible lens. Ensure no other filters or accessories are stacked in a way that could obstruct the light path.

Gently clean the affected area with a microfiber cloth. Minor cosmetic scratches are unlikely to affect performance. For significant damage, consider replacement to ensure optimal flare reduction and lens protection.