Unity3D Behaviours for changing LodBias and ShadowCasting for individual cameras. Add scripts to chosen cameras and modify the LodBias / ShadowCasting method as you require. Serves well to have e.g. reflection cameras draw with less quality.

CustomLodBias.cs

namespace Game.Camera
{
	using UnityEngine;

	/// <summary>
	/// Applies a custom LOD bias factor to rendering when attached to a camera
	/// </summary>
	[RequireComponent(typeof(Camera))]
	class CustomLodBias : MonoBehaviour
	{
		public float LodBiasFactor = 1F;
		float originalLodBias = 0F;

		private void OnPreCull()
		{
			originalLodBias = QualitySettings.lodBias;
			QualitySettings.lodBias = originalLodBias * LodBiasFactor;
		}

		private void OnPostRender()
		{
			QualitySettings.lodBias = originalLodBias;
		}
	}
}

CustomShadowCasting.cs

namespace Game.Camera
{
	using UnityEngine;

	/// <summary>
	/// Applies a custom shadow casting scheme to rendering when attached to a camera
	/// </summary>
	[RequireComponent(typeof(Camera))]
	class CustomShadowCasting : MonoBehaviour
	{
		public ShadowQuality OverriddenShadowQuality = ShadowQuality.All;
		ShadowQuality originalShadowQuality = ShadowQuality.All;

		private void OnPreCull()
		{
			originalShadowQuality = QualitySettings.shadows;
			QualitySettings.shadows = OverriddenShadowQuality;
		}

		private void OnPostRender()
		{
			QualitySettings.shadows = originalShadowQuality;
		}
	}
}