Back focal distance in LUCID cameras

This knowledge base article shows the various dimensions related to the optical path for LUCID cameras.

LEGEND

A: Flange to top of IR cut filter (IRCF) or window
A’: For models with no IRCF/window
B: Thickness of IRCF/window; has a refractive index (ne) of 1.525
C: IRCF/window to sensor cover glass
D: Sensor cover glass thickness
E: Bottom of sensor cover glass to image plane
F: BFD (Back focal distance)–optical and mechanical
G: Flange to retainer. See STEP files on the Downloads page to check for mechanical interference.

Optical BFD and mechanical BFD differ because the IRCF/window(B) and the sensor cover glass (D) have a refractive index that is different compared to that of air.

Phoenix cameras

Optical path dimensions for Phoenix cameras are shown below. All dimensions are in millimeters.

BFD Optical is the maximum value; all other values are typical values.

Camera Model	Sensor	Camera size	Lens mount	(A)	(A')	(B)	(C)	(D)	(E)	BFD Mechanical (F)	BFD Optical (F)
PHX004S	IMX287	24x24	C-Mount	12.7	-	1	3.22	0.7	0.4	18.02	17.526
	IMX287	24x24	NF-Mount	7.18	-	1	3.22	0.7	0.4	12.50	12
	IMX287	24x24	NM	-	-	-	-	0.7	0.4	1.10	-
	IMX287	24x24	S-Mount	-	11.87	-	-	0.7	0.4	12.97	-
PHX016S	IMX273	24x24	C-Mount	12.7	-	1	3.22	0.7	0.4	18.02	17.526
	IMX273	24x24	NF-Mount	7.18	-	1	3.22	0.7	0.4	12.50	12
	IMX273	24x24	NM	-	-	-	-	0.7	0.4	1.10	-
	IMX273	24x24	S-Mount	-	11.87	-	-	0.7	0.4	12.97	-
PHX023S	IMX392	24x24	C-Mount	12.7	-	1	3.22	0.7	0.4	18.02	17.526
	IMX392	24x24	NF-Mount	7.18	-	1	3.22	0.7	0.4	12.50	12
	IMX392	24x24	NM	-	-	-	-	0.7	0.4	1.10	-
	IMX392	24x24	S-Mount	-	11.87	-	-	0.7	0.4	12.97	-
PHX032S	IMX265	24x24	C-Mount	12.7	-	1	3.22	0.7	0.4	18.02	17.526
	IMX265	24x24	NF-Mount	7.18	-	1	3.22	0.7	0.4	12.50	12
	IMX265	24x24	NM	-	-	-	-	0.7	0.4	1.10	-
	IMX265	24x24	S-Mount	-	11.87	-	-	0.7	0.4	12.97	-
PHX050S1-P/Q	IMX264MZR/MYR	24x24	C-Mount	12.7	-	1	3.22	0.7	0.4	18.02	17.526
	IMX264MZR/MYR	24x24	NF-Mount	7.18	-	1	3.22	0.7	0.4	12.50	12
	IMX264MZR/MYR	24x24	NM	-	-	-	-	0.7	0.4	1.10	-
PHX050S	IMX264	24x24	C-Mount	12.7	-	1	3.22	0.7	0.4	18.02	17.526
	IMX264	24x24	NF-Mount	7.18	-	1	3.22	0.7	0.4	12.50	12
	IMX264	24x24	NM	-	-	-	-	0.7	0.4	1.10	-
PHX050S-P/Q	IMX250MZR/MYR	24x24	C-Mount	12.7	-	1	3.22	0.7	0.4	18.02	17.526
	IMX250MZR/MYR	24x24	NF-Mount	7.18	-	1	3.22	0.7	0.4	12.50	12
	IMX250MZR/MYR	24x24	NM	-	-	-	-	0.7	0.4	1.10	-
PHX051S	IMX568	24x24	C-Mount	12.7	-	1	3.24	0.5	0.53	17.97	17.526
	IMX568	24x24	NF-Mount	7.18	-	1	3.24	0.5	0.53	12.45	12
	IMX568	24x24	NM	-	-	-	-	0.5	0.53	1.03	-
PHX064S	IMX178	24x24	C-Mount	12.7	-	1	3.24	0.5	0.53	17.97	17.526
	IMX178	24x24	NF-Mount	7.18	-	1	3.24	0.5	0.53	12.45	12
	IMX178	24x24	NM	-	-	-	-	0.5	0.53	1.03	-
	IMX178	24x24	S-Mount	-	11.94	-	-	0.5	0.53	12.97	-
PHX081S	IMX566	28x28	C-Mount	12.87	-	1	2.39	0.5	1.2	17.96	17.526
PHX081S	IMX566	28x28	NM	-	-	-	-	0.5	1.2	1.70	-
PHX089S	IMX267	28x28	C-Mount	12.87	-	1	3.07	0.7	0.4	18.04	17.526
PHX089S	IMX267	28x28	NM	-	-	-	-	0.7	0.4	1.10	-
PHX120S	IMX304	28x28	C-Mount	12.87	-	1	3.07	0.7	0.4	18.04	17.526
PHX120S	IMX304	28x28	NM	-	-	-	-	0.7	0.4	1.10	-
PHX122S	IMX226	24x24	C-Mount	12.7	-	1	3.24	0.5	0.53	17.97	17.526
PHX122S	IMX226	24x24	NM	-	-	-	-	0.5	0.53	1.03	-
PHX124S	IMX565	28x28	C-Mount	12.87	-	1	2.39	0.5	1.2	17.96	17.526
PHX124S	IMX565	28x28	NM	-	-	-	-	0.5	1.2	1.70	-
PHX200S	IMX183	28x28	C-Mount	12.87	-	1	2.39	0.5	1.2	17.96	17.526
PHX200S	IMX183	28x28	NM	-	-	-	-	0.5	1.2	1.70	-

Triton cameras

Optical path dimensions for Triton cameras are shown below. All dimensions are in millimeters.

BFD Optical is the maximum value; all other values are typical values.

Camera Model	Sensor	Lens mount	(A)	(A')	(B)	(C)	(D)	(E)	BFD Mechanical (F)	BFD Optical (F)
TRI003S-WC	IMX991	C-Mount	12.68	-	1	2.59	0.5	1.2	17.97	17.526
TRI004S	IMX287	C-Mount	12.68	-	1	3.26	0.7	0.4	18.04	17.526
TRI005S	IMX433	C-Mount	12.68	-	1	2.59	0.5	1.2	17.97	17.526
TRI013S-WC	IMX990	C-Mount	12.68	-	1	2.59	0.5	1.2	17.97	17.526
TRI016S	IMX273	C-Mount	12.68	-	1	3.26	0.7	0.4	18.04	17.526
TRI023S	IMX392	C-Mount	12.68	-	1	3.26	0.7	0.4	18.04	17.526
TRI028S	IMX429	C-Mount	12.68	-	1	2.59	0.5	1.2	17.97	17.526
TRI02KA	AMS Dragster DR-2k-7	C-Mount	13.88	-	1	2.10	0.5	0.49	17.97	17.526
TRI032S	IMX265	C-Mount	12.68	-	1	3.26	0.7	0.4	18.04	17.526
TRI050S1-P/Q	IMX264MZR/MYR	C-Mount	12.68	-	1	3.26	0.7	0.4	18.04	17.526
TRI050S	IMX264	C-Mount	12.68	-	1	3.26	0.7	0.4	18.04	17.526
TRI050S-P/Q	IMX250MZR/MYR	C-Mount	12.68	-	1	3.26	0.7	0.4	18.04	17.526
TRI051S	IMX547	C-Mount	12.68	-	1	2.59	0.5	1.2	17.97	17.526
TRI054S	IMX490	C-Mount	12.68	-	1	3.36	0.5	0.435	17.97	17.526
TRI064S	IMX178	C-Mount	12.68	-	1	3.26	0.5	0.53	17.97	17.526
TRI071S	IMX428	C-Mount	12.68	-	1	2.59	0.5	1.2	17.97	17.526
TRI081S	IMX546	C-Mount	12.68	-	1	2.59	0.5	1.2	17.97	17.526
TRI089S	IMX267	C-Mount	12.68	-	1	3.26	0.7	0.4	18.04	17.526
TRI120S	IMX304	C-Mount	12.68	-	1	3.26	0.7	0.4	18.04	17.526
TRI122S	IMX226	C-Mount	12.68	-	1	3.26	0.5	0.53	17.97	17.526
TRI124S	IMX545	C-Mount	12.68	-	1	2.59	0.5	1.2	17.97	17.526
TRI162S	IMX542	C-Mount	12.68	-	1	2.58	0.5	1.21	17.97	17.526
TRI200S	IMX183	C-Mount	12.68	-	1	2.59	0.5	1.2	17.97	17.526
TRI204S	IMX541	C-Mount	12.68	-	1	2.58	0.5	1.21	17.97	17.526
TRI245S	IMX540	C-Mount	12.68	-	1	2.58	0.5	1.21	17.97	17.526

Triton2 cameras

Optical path dimensions for Triton2 cameras are shown below. All dimensions are in millimeters.

BFD Optical is the maximum value; all other values are typical values.

Camera Model	Sensor	Lens mount	(A)	(A')	(B)	(C)	(D)	(E)	BFD Mechanical (F)	BFD Optical (F)
TRT016S	IMX273	C-Mount	12.68	-	1	3.26	0.7	0.4	18.04	17.526
TRT023S	IMX392	C-Mount	12.68	-	1	3.26	0.7	0.4	18.04	17.526
TRT024G	GMAX4002	C-Mount	12.68	-	1	3.31	0.55	0.45	17.99	17.526
TRT028S	IMX429	C-Mount	12.68	-	1	2.59	0.5	1.2	17.97	17.526
TRT050S	IMX264	C-Mount	12.68	-	1	3.26	0.7	0.4	18.04	17.526
TRT051S	IMX547	C-Mount	12.68	-	1	2.59	0.5	1.2	17.97	17.526
TRT064S	IMX178	C-Mount	12.68	-	1	3.26	0.5	0.53	17.97	17.526
TRT071S	IMX428	C-Mount	12.68	-	1	2.59	0.5	1.2	17.97	17.526
TRT081S	IMX546	C-Mount	12.68	-	1	2.59	0.5	1.2	17.97	17.526
TRT120S	IMX304	C-Mount	12.68	-	1	3.26	0.7	0.4	18.04	17.526
TRT124S	IMX545	C-Mount	12.68	-	1	2.59	0.5	1.2	17.97	17.526
TRT162S	IMX542	C-Mount	12.68	-	1	2.58	0.5	1.21	17.97	17.526
TRT200S	IMX183	C-Mount	12.68	-	1	2.59	0.5	1.2	17.97	17.526
TRT204S	IMX541	C-Mount	12.68	-	1	2.58	0.5	1.21	17.97	17.526
TRT245S	IMX540	C-Mount	12.68	-	1	2.58	0.5	1.21	17.97	17.526

Atlas cameras

Optical path dimensions for Atlas cameras are shown below. All dimensions are in millimeters.

BFD Optical is the maximum value; all other values are typical values.

Camera Model	Sensor	Lens mount	(A)	(A')	(B)	(C)	(D)	(E)	BFD Mechanical (F)	BFD Optical (F)
ATL028S	IMX421	C-Mount	12.7	-	1	2.57	0.5	1.2	17.97	17.526
ATL050S	IMX250	C-Mount	12.7	-	1	3.24	0.7	0.4	18.04	17.526
ATL071S	IMX420	C-Mount	12.7	-	1	2.57	0.5	1.2	17.97	17.526
ATL089S	IMX255	C-Mount	12.7	-	1	3.24	0.7	0.4	18.04	17.526
ATL120S	IMX253	C-Mount	12.7	-	1	3.24	0.7	0.4	18.04	17.526
ATL168S	IMX387	TFL-Mount	9	-	1	6.34	0.7	1	18.04	17.526
ATL196S	IMX367	TFL-Mount	9	-	1	6.34	0.7	1	18.04	17.526
ATL314S	IMX342	NLM	-	2.97	-	-	0.7	1	4.67	4.500
ATL314S	IMX342	TFL-Mount	9	-	1	6.34	0.7	1	18.04	17.526

Atlas IP67 cameras

Optical path dimensions for Atlas IP67 cameras are shown below. All dimensions are in millimeters.

BFD Optical is the maximum value; all other values are typical values.

Camera Model	Sensor	Lens mount	(A)	(A')	(B)	(C)	(D)	(E)	BFD Mechanical (F)	BFD Optical (F)
ATP003S-WC	IMX991	C-Mount	10	-	1	2.24	1.1	3.83	18.17	17.526
ATP013S-WC	IMX990	C-Mount	10	-	1	2.24	1.1	3.83	18.17	17.526
ATP028S	IMX421	C-Mount	12.7	-	1	2.57	0.5	1.2	17.97	17.526
ATP050S	IMX250	C-Mount	12.7	-	1	3.24	0.7	0.4	18.04	17.526
ATP051S	IMX547	C-Mount	12.7	-	1	2.57	0.5	1.2	17.97	17.526
ATP071S	IMX420	C-Mount	12.7	-	1	2.57	0.5	1.2	17.97	17.526
ATP081S	IMX546	C-Mount	12.7	-	1	2.57	0.5	1.2	17.97	17.526
ATP089S	IMX255	C-Mount	12.7	-	1	3.24	0.7	0.4	18.04	17.526
ATP120S	IMX253	C-Mount	12.7	-	1	3.24	0.7	0.4	18.04	17.526
ATP124S	IMX545	C-Mount	12.7	-	1	2.57	0.5	1.2	17.97	17.526
ATP162S	IMX542	C-Mount	12.7	-	1	2.56	0.5	1.21	17.97	17.526
ATP200S	IMX183	C-Mount	12.7	-	1	2.57	0.5	1.2	17.97	17.526
ATP204S	IMX541	C-Mount	12.7	-	1	2.56	0.5	1.21	17.97	17.526
ATP245S	IMX540	C-Mount	12.7	-	1	2.56	0.5	1.21	17.97	17.526

Atlas10 cameras

Optical path dimensions for Atlas10 cameras are shown below. All dimensions are in millimeters.

BFD Optical is the maximum value; all other values are typical values.

Camera Model	Sensor	Lens mount	(A)	(A')	(B)	(C)	(D)	(E)	BFD Mechanical (F)	BFD Optical (F)
ATX051S	IMX537	C-Mount	12.7	-	1	2.57	0.5	1.2	17.97	17.526
ATX081S	IMX536	C-Mount	12.7	-	1	2.57	0.5	1.2	17.97	17.526
ATX081S-UC	IMX487	C-Mount	12.7	-	1	2.57	0.5	1.2	17.97	17.526
ATX124S	IMX535	C-Mount	12.7	-	1	2.57	0.5	1.2	17.97	17.526
ATX162S	IMX532	C-Mount	12.7	-	1	2.56	0.5	1.21	17.97	17.526
ATX204S	IMX531	C-Mount	12.7	-	1	2.56	0.5	1.21	17.97	17.526
ATX245S	IMX530	C-Mount	12.7	-	1	2.56	0.5	1.21	17.97	17.526
ATX245S	IMX530	TFL-Mount	9	-	1	6.26	0.5	1.21	17.97	17.526
ATX314S	IMX342	NLM	-	2.97	-	-	0.7	1	4.67	4.5
ATX314S	IMX342	TFL-Mount	9	-	1	6.34	0.7	1	18.04	17.526
ATX470S	IMX492	NLM	-	2.71	-	-	0.7	1.26	4.67	4.5
ATX470S	IMX492	TFL-Mount	9	-	1	6.08	0.7	1.26	18.04	17.526
ATX650G	GMAX3265	TFL-II	-	16.16	-	-	0.9	0.67	17.73	17.5

Properties and sizes of the IR cut filter/window

The properties and sizes of the IR cut filter (IRCF)/window for Color, Mono, SWIR, and UV cameras are shown below.

Color cameras (IRCF)

Color cameras from LUCID are equipped with an IR cut filter that is installed under the gasket of the mount.

For cameras with an IR filter, the filter has an IR coating on one side and an anti-reflective multi-coating on the other side. The transmittance of the IR filter is shown below.

The dimensions of the IRCF are as follows:

Model	Size	Thickness
24 x 24 mm Phoenix C-Mount	14 x 14 mm	1 mm
24 x 24 mm Phoenix NF-Mount	11.7 x 10 mm	1 mm
28 x 28 mm Phoenix C-Mount	18 x 14.5 mm	1 mm
29 x 29 mm Triton C-Mount	TRI204S/TRI245: 18 x 16.2 mm All others: 18 x 14.5 mm	1 mm
44 x 29 mm Triton2 C-Mount	TRT204S/TRT245: 18 x 16.2 mm All others: 18 x 14.5 mm	1 mm
55 x 55 mm Atlas TFL-Mount	27.3 x 22.3 mm	1 mm
55 x 55 mm Atlas C-Mount	18 x 14.5 mm	1 mm

Mono cameras (transparent window)

Mono cameras are equipped with a transparent glass window instead of an IR filter.

The window has an anti-reflective coating (single-layer λ/4 MgF2 @ 550 nm) on each side. The transmittance of this transparent glass window is as follows:

The dimensions of the window are the same as the IRCF above.

Model	Size	Thickness
24 x 24 mm Phoenix C-Mount	14 x 14 mm	1 mm
24 x 24 mm Phoenix NF-Mount	11.7 x 10 mm	1 mm
28 x 28 mm Phoenix C-Mount	18 x 14.5 mm	1 mm
29 x 29 mm Triton C-Mount	TRI204S/TRI245: 18 x 16.2 mm All others: 18 x 14.5 mm	1 mm
44 x 29 mm Triton2 C-Mount	TRT204S/TRT245: 18 x 16.2 mm All others: 18 x 14.5 mm	1 mm
55 x 55 mm Atlas TFL-Mount	27.3 x 22.3 mm	1 mm
55 x 55 mm Atlas C-Mount	18 x 14.5 mm	1 mm

SWIR cameras (transparent window)

SWIR cameras are equipped with the same transparent glass window as Mono cameras.

Like in Mono cameras, the window has an anti-reflective coating (single-layer λ/4 MgF2 @ 550 nm) on each side. The transmittance of the transparent glass window is as follows:

(Note: The appearance of the graph differs from the Mono because it shows a wider range of wavelengths.)

The dimensions of the window are as follows:

Model	Size	Thickness
55 x 55 mm Atlas C-Mount	22 mm (diagonal)	1 mm
44 x 29 mm Triton SWIR C-Mount	18 x 14.5 mm	1 mm
44 x 29 mm Triton2 SWIR C-Mount	18 x 14.5 mm	1 mm

UV camera

The ATX081S camera has a 18 x 14.5 mm window with a thickness of 1.0 mm. The window is made of quartz glass and has an AR coating. Its properties are shown below:

Back focal distance in LUCID cameras

Phoenix cameras

Triton cameras

Triton2 cameras

Atlas cameras

Atlas IP67 cameras

Atlas10 cameras

Properties and sizes of the IR cut filter/window

Color cameras (IRCF)

Mono cameras (transparent window)

SWIR cameras (transparent window)

UV camera

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