Description
Dulens APO Cambrian Prime 55mm T2.0: APO optics, V+ coating and medium-format coverage
The Dulens APO Cambrian Prime 55mm combines a fully spherical, apochromatically corrected optical design with Dulens’ proprietary V+ coating. This PL version has metric focus markings, T2.0 maximum aperture and 0.51m minimum focus. Cambrian’s proposition is high fine-detail contrast with controlled chromatic error and an expressive flare response, across a coverage envelope extending to medium-format cinema sensors.
55mm optical prescription and specifications
The 55mm uses 11 elements in 10 groups, with T2.0 transmission and a 0.51m minimum-focus specification. Its approximately 750g housing is the lightest listed in this six-lens set, while retaining the same front diameter, filter interface and focus travel. The optical prescription is distinct; the series-level APO, V+ and MTF descriptions should not be mistaken for a separately published 55mm field curve.
Image height, off-axis correction and recorded field
Cambrian covers ALEXA 65 and GFX 44 × 33mm formats as well as VistaVision, full frame and Super 35. For a recording area within that coverage envelope, the relevant optical question is the image height occupied by the recorded corners. A smaller recorded field excludes the most peripheral part of the lens image, where oblique ray bundles place greater demands on astigmatism, coma, field curvature and illumination.
That coverage reserve can support more uniform contrast and detail across a full-frame or suitable large-format recording area. It is not a change in the lens’s performance at the same image height. The active recording dimensions determine how much of the field is used; coverage, off-axis MTF and illumination remain separate specifications.
APO correction: longitudinal and lateral chromatic behaviour
Cambrian’s fully spherical prescription is apochromatically corrected. Longitudinal chromatic aberration separates the best-focus positions of different wavelengths along the optical axis; lateral chromatic aberration produces wavelength-dependent image magnification across the field. The distinction matters because clean edges at the focal plane and neutral defocused highlights are related, but not identical, correction targets.
Dulens describes near-zero chromatic aberration in high-contrast scenes at wide apertures. For Cambrian, that means colour-clean subject detail without requiring vintage character to come from magenta and green focus fringes. The intended character instead comes from the defocus rendering and V+ flare response, with chromatic correction maintaining separation around backlit contours and specular detail.
V+ coating: fine-detail contrast and stray-light character
Dulens’ proprietary V+ coating is designed to retain high microcontrast comparable to multicoated optics while preserving a softer, vintage-inspired flare character. The distinction is between contrast transfer in the image-forming bundle and the additional illumination introduced by stray light. A detail-rich focal plane and expressive flare are not mutually exclusive properties.
Coating interference controls reflection at the glass interfaces; the prescription and internal baffling determine the paths available to reflected and off-axis light. Discrete ghosts and veiling glare are different manifestations: the former retain a recognisable source structure, while the latter add a broader illumination pedestal that reduces local scene modulation. V+ belongs in that complete optical system, not as a generic promise of permanent low contrast.
MTF at 40 lp/mm: modulation, image height and orientation
The reported manufacturer-attributed Cambrian figure is an average MTF above 70% at 40 lp/mm. At this frequency, one period spans 25µm in the image plane. An MTF of 0.70 expresses retained modulation at that spatial frequency, not a resolution ceiling. High transfer at 40 lp/mm concerns fine structure rather than the broad tonal separation represented by a low-frequency curve.
For field performance, sagittal and tangential behaviour must be considered with image height, aperture and focus distance. Their separation can expose orientation-dependent transfer and off-axis limitations that a single averaged value conceals. The reported figure is a series-level average, not a published 55mm curve or a minimum at every field position at T2.0.
Our Cambrian optical overview retains the detailed MTF discussion and official ZEISS Planar, Milvus and Otus reference curves. Those references provide context at the same spatial frequency; they are not a matched test against Cambrian under identical aperture and field-sampling conditions.
Spherical surfaces, defocus texture and optical vignettering
Cambrian uses fully spherical optics rather than an aspherical prescription. This avoids making aspherical surface manufacture part of the design route, although spherical construction alone does not specify the complete defocus quality. The texture within a defocused highlight, its boundary and the transition through focus depend on the aberration balance and pupil geometry as a whole.
Dulens describes rounded defocus with a cat-eye character related to its Mini Prime rendering. Off-axis clipping of the effective pupil changes the highlight outline towards the field edge. That optical vignettering is distinct from chromatic fringing and from texture within the disc. Cambrian combines this pupil-dependent character with APO correction and V+ rather than relying on unresolved focal-plane detail for a vintage signature.
PL mechanics and series interfaces
The 55mm has a 270° focus rotation, metric distance markings, an eleven-blade iris and a PL mount. The 80mm front diameter and 72mm filter thread are common across the series. Listed weight is approximately 750g; minimum focus is 0.51m from the image plane. Full specifications, original photography and footage remain in their dedicated tabs.
Cambrian series and technical support
Other focal lengths: 24mm · 32mm · 40mm · 77mm · 105mm. The complete six-lens set includes its protective case. Gafpa Gear provides technical support for coverage, PL integration and production requirements.
Film with Cambrian: one set at 50% off
50% off one complete Cambrian six-lens set
Our footage collaboration offers one complete set for €4,499.50 excluding VAT (regular set price €8,999). Just make and share some original footage with the lenses that we can use to showcase their look. No full review, big following or extensive campaign required.
See the six-lens set and filmmaker offer, or email us with your filming idea. Subject to selection and agreement before purchase. This offer applies to one complete set, not this individual lens.
Dulens APO Cambrian Prime 55mm specifications
| Focal length | 55 mm |
|---|---|
| Maximum aperture | T2.0 |
| Minimum aperture | T16 |
| Close focus (image plane) | 0.51 m |
| Mount | PL |
| Distance markings | Metric |
| Front diameter | 80 mm |
| Filter thread | 72 mm |
| Focus rotation | 270° |
| Iris blades | 11 |
| Weight | Approx. 750 g |
| Optical construction | 11 elements in 10 groups |
| Optical design | Apochromatic, fully spherical |
| Image circle / sensor coverage | Medium format: ARRI ALEXA 65 and GFX 44 × 33mm; also VistaVision, full frame and Super 35 |
Watch footage filmed with Dulens Cambrian lenses
SLEEP AWAKE DREAM — Gafpa Gear / Norbert Storm
Our film was shot entirely on the Kinefinity VISTA, using a Ronin S and tripod, with lenses including Dulens Cambrian primes. The grade uses Gafpa Gear’s upcoming VISTA-to-ARRI Log transform.
Watch SLEEP AWAKE DREAM on YouTube.
Gafpa Gear’s Cambrian 40mm video
A closer look at the 40mm from the Cambrian range.
Dulens APO Cambrian Prime 55mm photos
Cambrian reviews, first looks and further reading
Explore independent editorial coverage alongside Gafpa Gear’s own footage. Read Newsshooter’s reports from NAB and IBC below.
Newsshooter: NAB 2025 first look
Matthew Allard ACS introduces the Cambrian series from the NAB launch.
Read Newsshooter’s Cambrian first look — 6 April 2025.
Newsshooter: 24mm and 32mm at IBC 2025
A follow-up report covering the wider focal lengths shown in Amsterdam. For current lens specifications, use our Specifications tab and the manufacturer links.
Read Newsshooter’s IBC Cambrian report — 14 September 2025.
Manufacturer information
Visit the Dulens APO Cambrian series page for current manufacturer information.
