DK-Optic Chiaro 3-inch(76mm) f/1.9 M645
Tribute to an Optical Legend
Veteran enthusiasts are no strangers to the "Holy Grail" of mid-20th-century portraiture and cinematography: the Super Six 3inch (76mm) f/1.9. This lens represented the absolute pinnacle of its era's quest for massive light transmission, huge image circles, and ultimate spatial separation. Its magical ability to literally "carve out" the subject from the background remains highly sought after today. Since the original 3-inch formula boasts an image circle large enough for medium format, DK-Optic has released this native M645 mount edition to fully unleash its potential. Recreated with the extreme precision of modern manufacturing, it is a tribute born of pure passion.
Pure Optical Restoration
We craft pure, native restorations—no modern additives. We have meticulously rebuilt this classic medium-telephoto "4 elements in 6 groups" oversized glass formula, taking you back to the golden age of optics where materials were spared no expense.
Signature Painterly Rendering
Rejecting the sterile, clinical look of modern lenses. As a massive 76mm ultra-fast lens, combined with the vast canvas of medium format, shooting wide open at f/1.9 pushes its dramatic "3D pop" to new heights. It delivers a signature, painterly bokeh with silky-smooth edge fall-off. Under backlit conditions, it produces rich "peacock feather" flares and layered halation. Stopped down, the image rapidly builds biting contrast, transforming into an unstoppable medium format portrait weapon.
Exclusive Customization
0.8x Speed Booster Macro Adapter: To allow modern digital medium format cameras to fully harness its massive image circle, we are introducing an optional 0.8x Speed Booster Macro Adapter. Perfectly tailored for 4433 sensors (such as Fujifilm GFX series and Hasselblad X2D). The 0.8x focal reducer losslessly "compresses" the massive 645 image circle perfectly onto the 4433 sensor. This not only increases light gathering but 100% restores the original field of view and edge-bokeh swirl as if shooting on 645 film. Furthermore, the adapter features a built-in Macro Helicoid, shattering the close-focus limitations of vintage lenses and unlocking a microscopic world of painterly light and shadow.
In-House High-Luxury Manufacturing
Leveraging our high-end cinema lens production lines, everything from the 5-axis CNC precision machining of the core brass components to the grinding of large-diameter glass elements is independently designed and hand-assembled in our advanced optical workshop. Even with the immense glass volume of the 3-inch design, our cine-grade mechanical structure ensures an extremely buttery smooth focusing feel.
Black Paint Finish
The main barrel is constructed from high-strength 7075 aerospace aluminum to reduce weight, while the core focusing helicoids and aperture control modules are machined from aerospace-grade brass, providing an unmatched, heavy-duty mechanical tactile feel.
Optical Glass: The internal large-diameter elements perfectly replicate the classic optical refractive indices and the dense, luminous transparency of the original.
Specifications & Parameters
Focal Length: 76mm (3 inch)
Format Coverage: Native 645 Medium Format
Optical Construction: 4 Groups / 6 Elements
Minimum Focus Distance: 0.7m on native mount (Closer macro focusing achievable with the Speed Booster adapter)
Aperture Setting: Manual preset (Damping feedback tuned to cine-grade standards)
Aperture Range: f/1.9 - f/11
Aperture Blades: 16 blades (Ensuring perfectly circular bokeh from wide open to stopped down)
Lens Mount: Native M645 (Mamiya 645) Mount
Optional Accessory: M645 to GFX/X2D 0.8x Speed Booster Macro Adapter
Lens Hood: Detachable threaded metal hood
Dimensions & Weight: Length 75mm / Weight 423g
Package Includes:
Chiaro 3inch f/1.9 Lens (M645 Mount)
High-precision machined all-metal front cap
Vintage-style metal lens hood
DK-Optic exclusive custom presentation box
Individual serial numbering
DK-Optic 1-Year Official Warranty
(If selected) 0.8x Speed Booster Macro Adapter
Shipping & Logistics: Global dispatch from
China (Shenzhen/Hong Kong) (Note: Because DK-Optic insists on high standards of hand-assembly and optical calibration, the initial pre-orders or special editions may require a slightly longer production cycle. Regular orders ship via DHL/UPS/FedEx with an estimated global transit time of 7-14 business days. In the event of dispatch delays due to production scheduling, our dedicated customer service will contact you in advance via email.)