Use the transition that best matches both your scene and your field of view.

In general:

• hard grad: best for scenes with a clean, straight horizon, like seascapes or some architecture
• medium/softer grad: better for uneven horizons and “fuzzy” subjects like trees, mountains, and forests

At wider focal lengths, the transition appears softer in the frame, so softer or medium grads are usually more forgiving. On full frame around 24–32mm, a medium grad is often a good fit, especially for mountains and forests. A hard grad becomes more useful as focal length gets longer or when the horizon is clearly defined.

Sensor size matters too: on APS-C or smaller, a hard grad may be more appropriate because the transition covers a larger portion of the image; a medium grad can become too soft.

Practical rule: if you’re unsure, lean toward the softer option. It tends to look less obvious and works better when the horizon is broken by trees, peaks, or irregular edges. For your stated use—mostly forests and mountains at 24–32mm—a medium grad sounds like the safer, more versatile choice, with hard grads being more useful mainly for seascapes and very clean horizons.