렌즈 마운트 가이드: 머신 비전 카메라용 M12, C-마운트, CS-마운트 비교
M8, M12, C-mount, and CS-mount differ in thread, flange focal distance, and back focal length. This guide shows how to pick the right mount before you order hardware.
M12 (S-mount) uses an M12x0.5 thread with no fixed flange distance. Focus is set by threading the lens in or out and locking it. C-mount and CS-mount both use 1"-32 UN threads, but C-mount has a 17.526mm flange focal distance while CS-mount has 12.526mm. A lens can thread onto the wrong mount and still fail to focus.
The 5mm difference is the rule: a C-mount lens works on a CS camera with a 5mm spacer. The reverse usually does not work. Choose M12 for compact embedded systems, CS for compact cameras with standardized focus, and C-mount for larger sensors, adjustable iris, and maximum lens interchangeability.
M12, C-마운트, CS-마운트의 차이점은 무엇인가요?
Two parameters define a lens mount: the thread interface, which is purely mechanical, and the registration distance, which sets where the image lands relative to the sensor. C-mount and CS-mount register at the flange, so any compliant pair starts at the same nominal lens-to-sensor distance. Nominal registration is not a focus guarantee: tolerance, rear clearance, focus travel, sensor stack, image circle, and optical performance stay product-specific.
M8 and M12 register wherever the thread is locked, so the installer sets focus by hand. Commonlands manufactures lenses for all four; S-mount, board lens, and M12 name the same interface. The table compares them side by side.
| 매개변수 | M8 | M12 / S-마운트 | CS 마운트 | C-마운트 |
|---|---|---|---|---|
| 스레드 | M8x0.35 또는 M8x0.5 | M12x0.5 | 1"-32 UN | 1"-32 UN |
| 플랜지 초점 거리 | 표준화되지 않음 | 표준화되지 않음 | 12.526mm | 17.526mm |
| 초점 방법 | 나사 끼우기/빼기, 잠금 | 나사 끼우기/빼기, 잠금 | 렌즈의 초점 링; 플랜지 정렬 표준화 | 렌즈의 초점 링; 플랜지 정렬 표준화 |
| 일반적인 센서 감지 범위 | 최대 1/3" 또는 1/2.7" | 최대 1/1.8"(일부 모델의 경우 1/1.7"~1/1.6") | 컴팩트한 본체에 최대 1" | 최대 1인치 및 그 이상 |
| 일반적인 이미지 서클 | 4~7mm | 최대 9mm 및 그 이상 | 최대 16mm | 16mm 및 그 이상 |
| 아이리스 제어 | 수정됨 | 수정됨 (대부분의 모델) | 고정식 또는 수동식 | 조절 가능한 링은 흔히 볼 수 있다 |
| 시스템 크기 / 질량 | 1g 미만으로 가능한 가장 작은 크기 | 크기가 작으며, 일반적으로 2~15g 정도입니다. | 중형 | 가장 크고, 가장 무거운 |
| 일반적인 비용 | 낮음 | 각 기능별 최저 범위 | 중급 | 최고 |
| 다음에 가장 적합합니다 | 내시경, 핀홀 카메라, 초소형 무인항공기 | 임베디드 비전, 로봇공학, 드론 | 소형 산업용, ITS, 보안 | 머신 비전, 검사 |
M12(S-마운트)란 무엇인가요?
S-마운트 또는 보드 렌즈 마운트라고도 불리는 M12는 M12x0.5 미터 나사산을 사용하며, 카메라 모듈이나 PCB의 홀더에 직접 나사로 고정됩니다. M12 렌즈는 크기가 작고(일반적으로 길이 10~25mm), 무게가 가볍으며(2~15그램), 초광각 어안 렌즈부터 망원 초점 거리까지 다양한 초점 거리를 지원합니다.
M12 has no standardized flange focal distance. Each design assumes a different back focal length, so focus is set during installation by threading the lens in or out against a live image, then locking it. That makes M12 flexible for embedded systems but not interchangeable the way C-mount and CS-mount lenses are. Optically it is a rigid assembly with no internal moving groups.
Most Commonlands M12 lenses publish a focus range of roughly 50mm to infinity; the reachable near limit in your build is set by the holder, so check the MOD and holder note on each product page.
C-마운트란 무엇인가요?
C-mount uses the same 1"-32 UN thread as CS-mount but registers at a 17.526mm flange focal distance. An adjustable iris is a design choice, not a flange consequence: adjustable irises are common in this C-mount segment and rare in M12. Sensor coverage does not follow from flange distance: image circle comes from the prescription, and a longer flange pushes wide-angle designs into retrofocus layouts. C-mount lenses commonly cover 1" and beyond because they are designed to.
Unlike M12, Commonlands C-mount lenses use cam-driven focus; the focus mechanism and its near-limit behavior are product-specific, so check the product page. Other C-mount lenses move the whole cell or only the front cell, or ship fixed-focus. Working distance is typically 100mm to infinity.
On cam-focused designs the end of cam travel sets a minimum object distance (MOD), measured from the front of the lens to the object; closer than that, an extension tube is the usual fix. MOD and the focus mechanism belong to the lens, not the mount, and the softening inside MOD is not uniform across the field.
Many C-mount lenses add an adjustable iris for depth-of-field control, practical in machine vision because illumination is programmatically controlled. Use the depth of field calculator to quantify the effect. Select models are ruggedized for harsh environments, which applies to specific lenses, not the mount.
플랜지 초점 거리는 무엇인가요?
플랜지 초점 거리(FFD)는 마운트의 플랜지 기준면부터 이미지 센서 평면까지의 표준화된 거리로, 광축을 따라 측정됩니다. 이는 개별 렌즈가 아닌 마운트 시스템의 특성입니다. C-마운트의 FFD는 17.526mm이고, CS-마운트의 FFD는 12.526mm이며, M12의 경우 표준화된 FFD가 없습니다.
The standard works because both sides conform to the same number: a C-mount lens is designed so its focal plane sits 17.526mm from the flange at infinity, and a C-mount body is machined so the sensor sits at that same distance. Any compliant pair then starts in register, within the tolerance each part holds. FFD is strictly mount geometry, not focal length or working distance.
Datasheets also call it flange back distance, register distance, or flange-to-film distance. For focal-length and field-of-view math, use the EFL calculator.
머신 비전에서 ‘후초점 거리’란 무엇인가요?
Back focal length (BFL) is the distance from the rear vertex of the lens, the last glass surface, to the image plane at infinity focus. It determines whether a lens can physically reach focus on a given camera: for a given sensor, effective focal length sets field of view while BFL sets mounting clearance. The distinction from FFD is exact. FFD is fixed by the mount standard and measured from the flange. BFL is a property of one lens, measured from the last glass vertex.
For M12 lenses, datasheets specify mechanical back focal length (MBFL): the distance from the thread seating surface to the sensor at infinity focus. Because M12 has no FFD, MBFL is how compatibility is specified, and it typically ranges from 2mm on wide-angle designs to 15mm or more on telephoto designs. The holder height must match it. Two lenses of the same effective focal length can have different MBFL, so verify it per lens. For how EFL drives framing, see how to choose focal length for machine vision.
On the bench, thread the lens fully in, then back it out slowly while watching a live image. If focus never comes, the holder height is wrong for that lens. Blurry at infinity but sharp up close means the holder is too tall, and soft corners that focus cannot fix point to off-axis aberrations or a chief ray angle mismatch.
Datasheets label this dimension inconsistently (MBFL, back focal distance, or BFL) and not every maker publishes it, so check the mechanical drawing before ordering holders. See the Commonlands M12 lens holder selection guide.
렌즈 마운트 호환성 및 어댑터
Thread fit does not guarantee optical compatibility. A lens can screw onto the wrong camera and still fail to focus, because the sensor sits at the wrong distance from the lens's designed focal plane. C-mount and CS-mount share the same thread, so a single 5mm precision spacer converts one direction. The other direction has no passive fix.
CS 마운트 카메라에 장착된 C 마운트 렌즈
Yes. Add a 5mm C-to-CS adapter ring to restore the 17.526mm registration the lens was designed for. Many CS-mount cameras ship with one. The C CS mount adapter does exactly this, and no thread adapter is needed, only the spacing ring.
C-마운트 카메라에 장착된 CS-마운트 렌즈
Usually no. A CS lens expects the sensor 5mm closer than a C-mount camera provides, and the flange stops it at the correct thread engagement, so it cannot go further in. Without modifying the camera body, infinity focus is typically not achievable.
C-마운트 또는 CS-마운트 카메라에 장착된 M12 렌즈
It is possible with an adapter, and MBFL decides it first, though not alone. The Commonlands CLA127 M12-to-C/CS adapter is 3.5mm thick and does not stack onto the flange distance: it recesses the M12 thread into the 1-inch throat so the lens seat ends up close to the sensor, at an effective depth of roughly 4mm. Wide-angle M12 lenses with an MBFL below about 4mm cannot reach infinity focus through it. The image plane forms short of the sensor, and no thread position moves it back far enough.
M12 lenses with an MBFL greater than about 4mm are the practical candidates: telephoto focal lengths such as 12mm, 18mm, 25mm, and 35mm sit far enough back to reach focus. The CLA127 M12 to C-mount adapter provides the mechanical interface. Some camera bodies also carry an IR-cut filter near the sensor, so budget its thickness too, then check rear-element and barrel clearance in the throat, thread engagement, image circle, chief ray angle, your working conjugate, and which surface the drawing measures MBFL from.
M8 렌즈 vs M12 렌즈: 어떤 것을 선택해야 할까요?
M8 lenses use an 8mm thread (M8x0.35 or M8x0.5) and target extreme miniaturization. M12 lenses use a 12mm M12x0.5 thread and are the standard for embedded machine vision. The numbers are thread diameter, not focal length, and the larger M12 thread leaves more room for optical elements, which translates into image circle and correction headroom. If the system can physically accept M12, M12 is usually the safer default.
M8 lenses typically produce 4-7mm image circles and target 1/3" sensors, with 1/2.7" (about 6.7mm diagonal) as the practical upper limit. Many M12 lenses cover up to 1/1.8" (about 8.9mm diagonal), select models reach 1/1.7"-1/1.6", and the highest published M12 sensor class is 16MP (CIL340, CIL293). Neither format has a standardized flange distance, so the holder-matching rules above apply to both. For matching image circle to sensor diagonal, see sensor size and lens compatibility.
Where M8 wins is package volume: the CIL857 6mm lens weighs 0.8 grams in its M8 variant and 2 grams in M12. In endoscope housings, pinhole enclosures, wearables, and micro UAV payloads with gram-level budgets, M12 hardware does not fit. Outside those cases, M12 offers a wider focal length range (0.8mm to 100mm across the Commonlands catalog), more sub-1% distortion options, and far deeper US sourcing.
The CLA812-AL (M8x0.35 to M12x0.5) and CLA811-AL (M8x0.5 to M12x0.5) adapters mount M8 lenses securely into M12 holders. The lens still has an M8 image circle and M8 optical limits. Use adapters for evaluation on M12 development boards. For production systems where M12 fits, use an M12 lens directly.
마운트 유형별 최고의 렌즈
The table ranks one primary lens per mount with a runner-up, all stocked in San Diego and shipping same day on orders placed before 12 PM PT. M12 reach does not stop at 35mm: the catalog also lists 50mm, 75mm, and 100mm M12 telephotos.
| 마운트 | 렌즈 | EFL | F# | 센서 감지 범위 | 이 선수를 선택한 이유 |
|---|---|---|---|---|---|
| M12 / S-마운트 | CIL250 25mm 망원 렌즈 · 99달러 | 25mm | F/2.0 | 최대 8MP | Compact 20° telephoto for board cameras; IR corrected for day and night use |
| M12 / S-마운트 | CIL350 35mm 망원 렌즈 · 59달러 | 35mm | F/2.4 | 최대 2/3인치, 8~10MP | Second M12 pick; an 11mm image circle covers 2/3" sensors at a lower price |
| M8 / M12 | CIL857 6mm · 39달러 | 6mm | F/3.0 fixed | 1/2.7인치, 7.0mm 화각 | 핀홀 카메라, 내시경, USB 카메라용으로, M8 조립 시 무게가 0.8g에 불과한 가장 작고 가벼운 제품 |
| C-마운트 | CIL531 8mm · 149달러 | 8mm | F/2.8–F/16 | 최대 2/3인치, 1,200만 화소 | 조절 가능한 조리개를 갖춘 광각 렌즈; 2/3인치 센서 기준 약 58°의 수평 시야각(HFOV) |
| C-마운트 | CIL579 75mm 망원 렌즈 · 149달러 | 75mm | F/3-F/20 | 8MP | 긴 설치 간격을 위한 차선 선택 C-마운트; 넓은 조리개 범위로 실외 ITS 및 ANPR에 적합 |
| CS 마운트 | 8mm CS 마운트 · 59달러 | 8mm | F/1.8 | 최대 1/1.7인치, 1,200만 화소 | Fast normal-to-wide view, about 50° HFOV on a 1/1.7" sensor, and it saves 5mm of body depth; Raspberry Pi HQ compatible |
Every entry is a lens Commonlands stocks and characterizes in-house, picked for mount fit and application coverage, not for the longest focal length.
Weighing suppliers as well as mounts? Our guide to Edmund Optics alternatives for imaging lenses maps seven vendors to the applications where each one fits, including where board-level M12 and C-mount lenses make more sense than catalog optics.
자주 묻는 질문
M8 렌즈와 M12 렌즈의 차이점은 무엇인가요?
M8 렌즈는 8mm 나사산(M8x0.35 또는 M8x0.5)을 사용하며, M12 렌즈는 12mm M12x0.5 나사산을 사용합니다. 더 큰 M12 배럴은 더 큰 광학 요소의 탑재, 더 넓은 센서 커버리지, 그리고 더 큰 설계 자유도를 가능하게 합니다. M8은 극한의 소형화를 목표로 하며, 일반적으로 최대 1/3" 또는 1/2.7" 크기의 센서를 지원합니다.
CS 마운트 카메라에 C 마운트 렌즈를 사용할 수 있나요?
네. 렌즈와 카메라 사이에 5mm C-CS 어댑터 링을 끼우세요. 이렇게 하면 플랜지 거리 차이를 보정하여 무한원 초점이 제대로 잡히게 됩니다.
C-마운트 카메라에 CS-마운트 렌즈를 사용할 수 있나요?
일반적으로 실제 시스템에서는 그렇지 않습니다. CS 렌즈는 센서가 C-마운트 카메라가 제공하는 위치보다 5mm 더 가까이 위치할 것으로 가정합니다. 기계적인 개조를 하지 않는 한, 일반적으로 무한대 초점을 맞출 수 없습니다.
어떤 경우에 C-마운트 대신 M12를 선택해야 할까요?
크기, 무게, 보드 레벨 통합이 중요한 경우에는 M12를 선택하십시오. M12 렌즈는 더 작고 가벼우며 가격도 저렴합니다. 더 넓은 센서 커버리지, 조리개 조절 기능, 또는 표준화된 교환식 마운트 시스템이 필요한 경우에는 C-마운트를 선택하십시오.
M12 렌즈를 CS 마운트 카메라에 장착할 수 있나요?
Mechanically yes, with an adapter. Optically it depends on the lens MBFL and the adapter depth. Through the 3.5mm Commonlands CLA127 adapter the lens seat sits about 4mm from the sensor, so M12 lenses with an MBFL below about 4mm typically cannot reach focus. Telephoto focal lengths such as 12mm, 18mm, 25mm, and 35mm are the better candidates. Verify the focus range before committing.
마운트 선택에 도움이 필요하신가요?
커먼랜즈는 머신 비전 및 임베디드 비전용 M8, M12, C-마운트, CS-마운트 렌즈를 제조하며, 자사 렌즈 설계에 대한 MTF 특성 분석을 수행합니다. 샌디에이고 엔지니어링 팀은 하드웨어 주문 전에 고객과 함께 FFD, MBFL 및 어댑터 형상에 대해 상세히 논의해 드릴 수 있습니다.