Neptune Convertible Art Lens System - Nikon F Mount - Silver (Special Order Only)

Technical Specifications

• Mount type: Nikon F
• Lens Focal length: 35mm, 50mm, 80mm, front lens group convertible
• Front lens group mounting mechanism: bayonet mount
• Aperture type: multi-scaled Diaphragm + drop in aperture plate
• Multi-scaled diaphragm aperture: 35mm: extended and f/3.5 - f/22, 50mm: f/2.8 - f/22, 80mm: extended and f/4-f/22
• Field of View: 35mm: 63°, 50mm: 46°, 80mm: 30°
• Filter Thread: 52mm
• Focusing Mechanism: Helicoid
• Closest Focusing Distance: 0.25m (35mm), 0.4m (50mm), 0.8m (80mm)
• • Macro Adapter: 0.18m (35mm), 0.22m (50mm), 0.5m (80mm)
• Lens Construction: Lens base: 3 elements in 3 groups, Front lens group: 4 elements in 4 groups for each focal length
• Multi coating: Yes
• Electronic Contacts: No
• Lens body: Aluminum

Equivalent Focal Length

APS-H : 1.3x Crop Factor

• Proteus 4.0/80 Art Lens equivalent focal length = 104 mm
• Despina 2.8/50 Art Lens equivalent focal length = 65 mm
• Thalassa 3.5/35 Art Lens equivalent focal length = 45.5 mm

APS-C (Nikon, Sigma, Pentax) : 1.5x Crop Factor

• Proteus 4.0/80 Art Lens equivalent focal length = 120 mm
• Despina 2.8/50 Art Lens equivalent focal length = 75mm
• Thalassa 3.5/35 Art Lens equivalent focal length = 52mm

APS-C (Canon) : 1.6x Crop Factor

• Proteus 4.0/80 Art Lens equivalent focal length = 128 mm
• Despina 2.8/50 Art Lens equivalent focal length = 80 mm
• Thalassa 3.5/35 Art Lens equivalent focal length = 56 mm

Micro 4/3 : 2.0x Crop Factor

• Proteus 4.0/80 Art Lens equivalent focal length: 160 mm
• Despina 2.8/50 Art Lens equivalent focal length: 100 mm
• Thalassa 3.5/35 Art Lens equivalent focal length: 70 mm