Dallmeyer (J.H.) Pentac · 127mm f/2.9

{"overview":"The Dallmeyer 5 Inch f\/2.9 Pentac is a large-format British lens with a roughly 127mm focal length and an f\/2.9 maximum aperture. The Pentac was a fast portrait and aerial-reconnaissance type lens, and copies turn up today on view-camera and projection mounts as well as in adapted form for medium and large format use.","market_narrative":"At recent UK auction, hammer prices for the 5 Inch f\/2.9 Pentac have sat in a tight £81–£126 band, with a median around £125 based on three saleroom results between 2023 and 2026. As of 2026, that range reflects what clean working examples sell for at wholesale auction level rather than retail dealer asking prices, so a tidy copy is typically worth around the upper end while scruffier or partial examples drop toward the lower figure.","buying_guide":"Inspect the front and rear groups for fungus, internal haze and cleaning marks, as uncoated or lightly coated brass-era Pentacs are prone to bloom and wipe scratches that affect value. Check the iris for oil on the aperture blades and sluggish movement, look for separation or balsam edge-yellowing between cemented elements, and confirm the focus or barrel mount turns smoothly without grit, since many surviving copies have been removed from original shutters or projectors.","specs":"Key documented specifications are a 5 inch (approximately 127mm) focal length and a maximum aperture of f\/2.9, sold under the Dallmeyer Pentac name; further construction details are not provided in the supplied data.","faq":[{"q":"What is a Dallmeyer 5 Inch f\/2.9 Pentac worth today?","a":"Recent UK auction hammer prices have ranged from £81 to £126, so a clean working example is typically worth around £120–£125 at saleroom level, before buyer's premium."},{"q":"How much does a Dallmeyer 5 Inch f\/2.9 Pentac sell for at auction?","a":"Three UK auction results between 2023 and 2026 show the lens selling for £81, £125 and £126, putting the realistic hammer price for a usable copy at just over £100."},{"q":"Is the Dallmeyer Pentac a good value lens for large format use?","a":"At an auction price band of roughly £80–£130 it is one of the more affordable fast British large-format lenses, though the final value depends heavily on glass condition and whether it is mounted in a usable shutter or barrel."},{"q":"What should I check before buying a Pentac?","a":"Look closely for fungus, haze, cleaning scratches, oily aperture blades and any separation in the cemented groups, as these faults are the main reasons a Pentac will sell at the lower end of the price range."}],"confidence":45,"reasoning":"Only three unverified UK auction records and no SPECS or variant data were supplied, so pricing commentary is reasonably grounded but technical detail is necessarily limited."}