Here is what CamelCasePropertyNamesContractResolver does, direct from the unit tests: https://github.com/JamesNK/Newtonsoft.Json/blob/95665429a431364327b4bce5332c39fda7819e7b/Src/Newtonsoft.Json.Tests/Utilities/StringUtilsTests.cs#L40-L54
[Test]
public void ToCamelCaseTest()
{
Assert.AreEqual("urlValue", StringUtils.ToCamelCase("URLValue"));
Assert.AreEqual("url", StringUtils.ToCamelCase("URL"));
Assert.AreEqual("id", StringUtils.ToCamelCase("ID"));
Assert.AreEqual("i", StringUtils.ToCamelCase("I"));
Assert.AreEqual("", StringUtils.ToCamelCase(""));
Assert.AreEqual(null, StringUtils.ToCamelCase(null));
Assert.AreEqual("iPhone", StringUtils.ToCamelCase("iPhone"));
Assert.AreEqual("person", StringUtils.ToCamelCase("Person"));
Assert.AreEqual("iPhone", StringUtils.ToCamelCase("IPhone"));
Assert.AreEqual("i Phone", StringUtils.ToCamelCase("I Phone"));
Assert.AreEqual(" IPhone", StringUtils.ToCamelCase(" IPhone"));
}