Schneider APO-Tele-Xenar HM 400mm f/5.6

Schneider Apo-Tele-Xenar HM 400mm f/5.6 is the long-telephoto modern LF design — apochromatic correction + HM (high-modulation) optimization in a true-telephoto formula. The "HM" version is the studio-/architecture-grade variant, optimized for highest MTF.

Key features

• Mount: Copal 1 shutter (1s to 1/400, X-sync at all speeds)
• Focal length: 400mm (effective; physical length much shorter)
• Maximum aperture: f/5.6
• Image circle: ~200mm at f/22 — covers 4×5 with limited movements
• Optical formula: apochromatic telephoto with HM optimization
• Multi-coating standard

Use case + rendering

The 400 Apo-Tele-Xenar HM is the long-tele 4×5 for architectural detail work (compressing distant building elements) and landscape isolation. Apochromatic correction reduces fringing on high-contrast subjects; HM optimization gives sharp performance even at full aperture. The telephoto formula keeps the lens compact relative to a hypothetical 400mm symmetric design.

Compatible cameras

• Toyo 45A / Toyo 45AII / Toyo 45G — extension rails likely needed
• Cambo SC / Cambo Calumet 45NX
• Graflex Speed Graphic / Graflex Super Graphic — verify bellows clearance

Related lenses

• Schneider Apo-Tele-Xenar Compact 400mm f/5.6 — compact variant
• Schneider Tele-Xenar 360mm f/5.5 — wider tele sibling
• Schneider Apo-Tele-Xenar HM 800mm f/12 — much longer tele sibling