Sigma 135mm f/1.8 Art DG HSM, Nikon

The estimate blends recent sales with the median asking price. Each sale counts less the older it is, and the more recent sales there are, the more they carry: with none it is the asking price, with 5 recent ones half and half. So it moves gradually, never in a jump. Figures resting on fewer than that are marked low confidence. Medians, never averages. In an asking median no shop counts for more than a third (or an equal share, with fewer shops), so one shop’s price list does not decide it. Parts-only and brand-new units are left out.

Prices quoted in CZK, EUR, PLN are converted to EUR before the median.

Time to sell counts only sales whose shop publishes its own listing date.

Shops: Cyfrowe, Kameraliike, Megapixel, Rajala Camera. 35 pages from shop archives.

Exchange rates: European Central Bank, 2026-10-09.