RedCat 91 WIFD
William Optics
From ~$2,748.30
2 stores
In stock
The William Optics RedCat 91 is an advanced apochromatic refractor tailored for full-frame and medium-format cameras, combining portability with superior optical performance. This 5-element Petzval design eliminates the need for backfocus adjustments, providing sharp, edge-to-edge images with pinpoint stars ideal for wide-field and detailed astrophotography. Equipped with William Optics' WIFD focuser, the RedCat 91 provides precise, stable focusing without additional adjustments. With a large 55mm image circle, the RedCat 91 is perfect for both full-frame and medium-format cameras, achieving flat-field images without requiring an additional flattener.
Specifications
| Focal ratio | f/4.9 |
| EAF Compatible | ✓ |
| Optical design | 5-Element Petzval |
| Focal length | 448 mm |
| Field Flattener Required | false |
| Focuser Type | WIFD (William Optics Internal Focus Design) |
| OTA Weight | 4.72 lb |
| Aperture | 91 mm |
| Lens Elements | 2 |
| Tube Length | 556 mm |
| Image Circle | 55 mm |
| Camera Adapter | M48 and M54 |
| Total Weight with Rings and Dovetail | 6.30 kg |