Sayyiduna Abdullah (may Allah be pleased with him) said that the Prophet (peace and blessings be upon him) cut off the hand for a shield whose value was five dirhams.
As for the hadith of Sayyiduna Umar (may Allah be pleased with him), we have mentioned that it is munqati' (disconnected), since only al-Qasim bin Abd al-Rahman narrated it from him, and he did not meet any of the Companions. And we have narrated earlier from Sayyiduna Abu Bakr and Sayyiduna Umar (may Allah be pleased with them both) the cutting off of the hand for five dirhams.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السرقة / 17195