Although it is generally a fairly well-made piece of equipment, its main fault is that the inner sliding sleeve is a bit too loose, thus causing lateral movement when adjusting its focal length. Although there is no facility for copying negatives, it would be fairly easy to make a suitable carrier for them, providing that it is robust enough to hold the usual 5 or 6 negatives in one strip without distorting or sagging. Had the designers given it sufficient thought, they should have made it at least 20mm longer, thus avoiding the expense of extension rings.