Taiwanese lens manufacturer William Optics is proposing to make a flatfield Petzval lens aimed at star gazers and photographers that it claims is the world’s sharpest 250mm.

Originally conceived as a compact and lightweight telescope for astrophotographers, the Redcat 250mm F4.9 uses a pair of synthetic fluorite elements to correct the usual field curvature of the Pretzval design to produce a sharp image right across the frame, according to the company. It is also claimed the lens is corrected to apochromatic standards.

A manual focus lens with a single aperture setting, the Redcat 250mm F4.9 is being promoted for normal subjects as well as for astrophotography on its Kickstarter campaign page. Those using it at night might not get to appreciate its startling red finish, but daylight photographers shooting wildlife could feel a little conspicuous.

Designed with a 44mm covering circle the lens is good for full frame cameras, and comes with an interchangeable T-mount system that allows options for Canon EF, Nikon F and Sony E cameras, with Micro Four Thirds and Pentax K to follow shortly. The lens weighs 1.47kg / 3.24lbs, measures 225mm x 80mm, and features a field rotation function for turning the camera on the mount, with markings for every degree. A reversible mount on the tripod foot has fittings for Arca-Swiss and Vixen style heads, and the lens comes with what is described as a ‘patented’ Bahtinov Mask for astro-focusing.

Sample shot with the Redcat 250mm f/4.9

At the time of writing the funding campaign had raised over $47,000 – well beyond the goal of $30,000. With most of the discounted deals gone, the lens can be had for $648, which the company says represents 93% of the full retail price. Visit the Redcat 250mm f/4.9 campaign page for more information, or the William Optics website.

Disclaimer: Remember to do your research with any crowdfunding project. DPReview does its best to share only the projects that look legitimate and come from reliable creators, but as with any crowdfunded campaign, there's always the risk of the product or service never coming to fruition.