William Optics RedCat 51 WIFD - 51 mm f/4.9 Flatfield Refractor for Astrophotography

The William travel apochromat RedCat L-RC51 RD III is perfectly suited for astrophotography and nature photography on photo tripods or travel mounts.
 

Aperture 51 mm / focal length 250 mm / focal ratio f/4.9

Petzval design with chromatic aberration free FPL53 objective

Very well corrected image field of 48 mm diameter - even suitable for full-frame cameras

Focusing via internal focusing (William Internal Focus Design - WIFD) as with telephoto lenses, compatible with EAF

360° rotation of the camera for the right display window

Camera connection via male M48 thread (suitable adapters are available) - working distance 55 mm

Flexible dovetail bar at the base, suitable for Vixen style saddle plates and Arca-Swiss style saddle plates, with female 1/4" photo thread

Soft carry case and Bahtinov mask for astrophotography are included in the scope of delivery.

The guide scope shown is not included in the scope of delivery.

Tube length only 298 mm / weight only 2.4 kg - perfect for on the way

This apochromatic refractor is intended for all astrophotographers and nature photographers who are searching for a transportable and tack-sharp telephoto lens. Due to the 4-element Petzval design, a fully corrected image field of 48 mm diameter without chromatic aberration is achieved. Thus even full-frame cameras can be used. Focusing works internally, as with many telephoto lenses, but via knobs with an additional fine focus knob (dual speed), as with telescopes. However, with 298 mm length, the apo ist not larger than a normal telephoto lens. But it can do more.
 

The application areas of the RedCat 51 apo:

Astrophotography: With 250 mm focal length and fast f/4.9, short exposure times are possible. The working distance of 55 mm allows using all popular astro cameras. mirrorless system cameras and DSLR/SLR cameras. The fine focusing allows a precise focus, the rotation the selection of the suitable image section. The supplied Bahtinov mask helps with focusing and is integrated in the objective cap.

Countryside photography and animal photography: The RedCat 51 is also perfect for, for example photographing animals. Internal focusing allows you to focus without shifting the weight, and therefore also without changing the position. The image field is thus not altered. The image quality will impress you.

Optical design:	4 elements Petzval design
ED glass:	FPL53
Focal length:	250 mm
Aperture:	51 mm
Focal ratio:	f/4.9
Image circle:	48 mm diameter
Flattener:	Flat-field objective design, no flattener required
Focuser:	WIFD (WO Internal Focus Design), compatible with EAF
Focus travel:	0-23 mm (ruler to 30 mm)
Camera connection:	M48x0.75 thread (male)
T-mounts supported:	Canon EF and RF, Nikon F and Z, Sony E, Pentax K, MFT (M4/3)
Working distance from the M48x0.75 thread:	55 mm Backfokus
360° Rotation:	yes
Base plate:	suitable for Vixen style saddle plates, Arca-Swiss style tripod heads and photo tripods
Dew shield diameter:	84 mm
Tube length:	298 mm
Extended tube length:	346 mm
Tube weight:	2.38 kg (5.25 lbs)

RedCat 51 WIFD travel apochromat

Bahtinov cap

M48 cap

Mounting ring handle bar

Dovetail Vixen / Arca Swiss style

Soft carry case

Allen key set