William Optics UltraCat 131 WIFD f/4.8 (30th Anniversary Edition)

Accepting order now! 30th Anniversary Edition

Highlights of the Ultra-CAT 131 WIFD APO

• 5 elements Petzval flat field design with FPL-53 optics
• WO Internal Focus Design (WIFD), compatible with motorised focuser
• Fast focal ratio f/4.8
• Medium format coverage (50mm)
• Anti-Shrink Lens Cell Technology
• Sensor Tilt eXterminator (STX)
• Interchangeable camera mount (Canon EF, RF / Nikon F,Z / Sony E / Pentax K / M4/3 / Fujifilm X)
• Compatible with any 48mm (2") imaging filter
• Super bright Bahtinov mask + lens cap
• Field rotator 
• x kg only including mounting base (OTA only x kg)

Exclusive features of the Ultra-CAT 131 WIFD APO:

• Sensor Tilt Corrector (STX)
• Full frame format coverage
• WO patented innovative internal focus design (WIFD)

Package Includes:

1. UltraCAT 131 APO WIFD
2. WO lens cap with bahtinov Mask 
3. Mounting rings with Saddle Handle Bar
4. Camera Angle Rotator
5. Sensor Tilt eXterminator (STX)
6. Vixen Style Dovetail Plate
7. M48, M54 and M68 adapters
8. Soft carrying case
9. Allen key set 

Optical Diagrams

Spot Diagram

William Optics Ultra-Cat 131 Specifications