対数軸目盛りでチャートを描画するには、Y軸のLogBaseプロパティに対数の底（10など）を設定します。

◎サンプルコード（VB）

Imports System.Drawing
Imports C1.Chart
Imports C1.Win.Chart

Public Class Form1
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim Series1 As C1.Win.Chart.Series = New C1.Win.Chart.Series
        Series1.BindingX = "X"
        Series1.Binding = "Y"
        Series1.ChartType = ChartType.LineSymbols
        Series1.DataSource = New System.Drawing.Point() {
            New Point(1, 1),
            New Point(2, 10),
            New Point(3, 100),
            New Point(4, 1000)
        }
        FlexChart1.Series.Clear()
        FlexChart1.Series.Add(Series1)
        FlexChart1.AxisY.LogBase = 10
    End Sub
End Class

◎サンプルコード（C#）

using System;
using System.Drawing;
using System.Windows.Forms;
using C1.Chart;
using C1.Win.Chart;

namespace FlexChart_LogBase
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            var series1 = new Series()
            {
                Binding = "Y",
                BindingX = "X",
                ChartType = ChartType.LineSymbols,
                DataSource = new PointF[] { 
                    new PointF(1, 1), 
                    new PointF(2, 10), 
                    new PointF(3, 100), 
                    new PointF(4, 1000) }
            };
            flexChart1.Series.Clear();
            flexChart1.Series.Add(series1);
            flexChart1.AxisY.LogBase = 10;
        }
    }
}