Contents 1. What change when you use the different imager size camera?

1. What happens? 2. Focal Length 2. Iris (F Stop) 3. Flange Back Adjustment

2. Why Bokeh occurs? 1. F Stop 2. Circle of confusion diameter limit 3. Airy Disc

4. Bokeh by Diffraction 5. 1/3” lens Response (Example)

6. What does In/Out of Focus mean? 7. Depth of Field

8. How to use Bokeh to shoot impressive pictures.

9. Note for AF100 shooting

3. Crop Factor 1. How to use Crop Factor

2. Foal Length and Depth of Field by Imager Size

3. What is the benefit of large sensor?

4. Appendix 1. Size of Imagers 2. Color Separation Filter 3. Sensitivity Comparison

4. ASA Sensitivity

5. Depth of Field Comparison by Imager Size

6. F Stop to get the same Depth of Field

7. Back Focus and Flange Back (Flange Focal Distance)

8. Distance Error by Flange Back Error

9. View Angle Formula

10. Conceptual Schema – Relationship between Iris and Resolution

11. What’s the difference between Video Camera Lens and Still Camera Lens

12. Depth of Field Formula

1.What changes when you use the different

imager size camera?

Return

+ + 35mm Full Frame (CANON, NIKON, LEICA etc.) 28mm Wide Lens

AG-AF100

58mm

It becomes

Standard Lens

2m

X

<35mm Still Camera>

<4/3 inch>

0m

*distance to object：2m

*Iris：F4

X 0.4m

0.9m

Depth of Field

0.26m 0.2m

0.6m 0.4m

F4

F2 X

0.26m 0.2m X

0.26m 0.2m

2. Iris (F Stop) changes

Depth of Field changes

3. Flange Back Adjustment Tolerance Changes 35mm Full Size: Tolerance <0.8mm f = 50mm @F22

-- > 4/3” : Tolerance <0.21mm f = 25mm @F11

Adjustment becomes more precise.

1. Focal Length changes

F4 F2

1-1.What happens? • If you have 50mm lens of 35mm full size lens

(Canon, Nikon and so on.), what happens when you use it with 4/3 .

View of Field

Iris F5.6 fl. 50mm lens

with 35mm Full Frame

Iris F5.6 fl. 25mm lens

with 4/3” camera

Depth of Field

50mm with 35mm Full Frame (Canon, Nikon and so on)

50mm lens

with 4/3” camera

The view of field becomes

2 times telephoto size.

25mm lens

with 4/3” camera

Iris F2.8

with 4/3” camera

The depth of field becomes deeper.

Return

1-2. Focal length

• Focal length changes if the imager size changes.

• To get the same view angle (Horizontal angel).

• If you compare 35mm Full Frame with another lens, – Standard View Angle: 39.6degree (Horizontal)

• Wide Standard Tele

• View Angle 65.5 ° 39.6° 10.3 °

• 35mm Full Frame: 28mm 50mm 200mm

• ANSI Super 35mm: 19mm 35mm 138mm

• Normal 35mm: 17mm 31mm 122mm

• 4/3” : 14mm 25mm 99mm

• 2/3” : 7.5mm 13.3mm 53mm

• 1/3” : 4mm 7.2mm 29mm

Return Focal Length

25mm

35mm

35mm Full Size

4/3”

Super 35mm

50mm

1-3. Iris (F Stop)

• If an imager size change, depth of field will change. – If F stop is the same, depth of field will change by a imager size

– If you want to keep the same depth of field, you have to change F stop.

Return

2m

X

X

X

<35mm Still Camera>

<Super 35mm Film>

<4/3 inch>

<2/3 inch>

<1/2 inch>

<1/3 inch>

0m

*distance to object：2m

*Iris：F4

＜Focus area＞

X

X

X

7.5m

0.4m

0.7m

0.9m

2.0m

3.5m

Depth of Field 9.2m 0.9m

0.6m 1.6m

3.2m 0.8m

0.4m 0.3m

0.26m 0.2m

0.6m 0.4m

F3

F22

F14

F11

F5.6

F4

3.2m 0.8m

0.8m 3.2m

3.2m 0.8m

3.2m 0.8m

3.2m 0.8m

3.2m 0.8m

1-3-1.Flange Back Adjustment

13.2mm

25mm

50mm

Image Plain

Flange focal

Length

Lens Mount

Focal Length

Return

Distance 5m

Flange Back 0.1mm error

50mm : 0.8m error (16%)

25mm : 3.2m error (64%)

5m

4.2m

0.1mm

2.8m

1.3m

5m

5m

5m

1-3-2.What happens if Flange Back is not correct?

• If an object is 5m far from a camera and an error is as follows,

– error 0.1mm 0.05mm 0.01mm 0.005mm

– Focal length = 100mm : 4.78m 4.9m 5.0m 5.0m

– Focal length = 50mm : 4.2m 4.6m 4.9m 4.9m

– Focal length = 25mm : 2.8m 3.6m 4.6m 4.8m

– Focal length = 13.2mm : 1.3m 2.1m 3.9m 4.4m

– Focal length = 7.2mm : 0.48m 0.87m 2.6m 3.4m

Return

f L

Image Plane

(CCD or Film) Flange Focal

Distance

m

d

Lens Mount

Δm

M’ = m + Δm

Distance scale becomes incorrect.

Even if you set lens scale to 5m,

the actual focus is not 5m.

5m

1-3-3.Flange Focal Distance Tolerance

Return

f L

Image Plane

(CCD or Film) Flange Focal

Distance

m

d

Lens Mount

Δm

M’ = m + Δm

Iris F5.6 F4 F2.8 F2 F1.6

7.2mm Flange Back Error 0.03mm 0.022mm 0.015mm 0.011mm 0.009mm

Iris F11 F8 F5.6 F4 F3.2

13.2mm Flange Back Error 0.11mm 0.08mm 0.056mm 0.04mm 0.032mm

1/3” Distance = 5m

2/3” Distance = 5m

Iris F22 F16 F11 F8 F5.6

25mm Flange Back Error 0.41mm 0.30mm 0.21mm 0.15mm 0.11mm

4/3” Distance = 5m

Iris F44 F31 F22 F16 F11 F5.6

50mm Flange Back Error 1.7mm 1.2mm 0.86mm 0.62mm 0.42mm 0.21mm

35mmm Full Frame Distance = 5m

Size 1/2, then accuracy: 1/4

The wider the lens becomes, the more precise the flange back adjustment requires.

2. Why bokeh (Diffraction) occurs?

• Fraunhofer Diffraction

• d=1.22 λF (Airy Disk Radius) λ : wavelength of light,

– F: F Stop (= f/N: N = Effective Diameter)

– If the wavelength is the same, bokeh is determined by F Stop only.

Return

Airy Disc

F Stop • F = f/N (f: Focal Length, N: Effective Diameter of Iris)

– The bigger F number becomes, the shorter the diameter of iris becomes.

– The shorter focal length becomes, the shorter the diameter of iris becomes under the condition of the same F stop

Return

Focal Point IRIS

F4

IRIS

F2.8

F Stop: F2

N

f=50mm

N: Effective

Diameter f =50mm

Close

(Deep)

OPEN

(Shallow)

N=25mm

N=17.9mm

N=12.5mm

F Stop F4

F Stop F2.8

F Stop: F2

N

f=25mm

f =25mm

N=12.5mm

N=6.25mm

N=8.9mm

Focal Point

2-2. the circle of confusion diameter limit

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• CoC (Circle of Confusion) is d/(1000~1500) where d is the diagonal measure of the original image.

• For examples, if CoC = d/1101, the resolution of imager becomes 1080 TV Line (2 x 1101/2.04).

16:9 Imager

1101 lines

If aspect ratio is 6:9, the height becomes

d/2.04. So the vertical resolution

becomes 1080TV Line.

If F Stop becomes bigger, Airy Disc

becomes bigger. Finally 2d=2.44λF)

becomes the same as CoC, you

cannot distinguish 2 lines。

CoC

Airy Disc

CoC > Airy Disc Diameter

You can distinguish

2 lines.

CoC < Airy Disc Diameter

You cannot distinguish 2

lines.

CoC

Airy Disc Diameter

F2 F4

Airy Disc Diameter

2 x 1.22 Ｆ d =6mm

CoC=0.00545mm

0.00537mm

0.0107mm

F2

0.00268mm

F8 F4.1

2-2-2. Comparison by Imager Size

Return

• d=2.44 λＦ(Airy Disk Diameter)

F2 F4

0.00537mm F8

0.0107mm F2.8

F16

0.0215mm

F5.6 0.00752mm

F11

0.0148mm 0.00268mm 0.00376mm

1/3”

CoC=0.00545mm 2/3”

CoC=0.00999mm

4/3” CoC=0.0185mm

F4 F4

F8 F8

F16 F16

F5.6 F5.6

F11 F11 F22 F22

2-2-3. Comparison by Imager Size

Return

• d=2.44 λＦ(Airy Disk Diameter)

F5.6 F11

0.0148mm F22

0.0295mm F8

F44

0.0590mm

F16 0.0215mm

F32

0.0429mm 0.00349mm 0.0107mm

APS-C CoC=0.0244mm

ANSI

Super35 CoC=0.0260mm 35mm Full Frame

CoC=0.0375mm

F22 F22

F44 F44 F32 F32

F32 F32

F22 F22

F32 F32

Comparison by TV Format (PAL) • d=2.44 λＦ(Airy Disk Diameter)

F2 F4

5.4μ

F8 10.7μ

F2.8 F16

21.5μ F5.6 7.5μ

F11 14.8μ

2.7μ 3.8μ

2/3” CoC=19μ at PAL

F2 F2 F2.8 F2.8 F4

5.4μ

F4 5.4μ

F5.6 7.5μ

F5.6 7.5μ

F8 10.7μ

F8 10.7μ

F11 14.8μ

F11 14.8μ

F16 F16 F22 F22

Return

Comparison by TV Format (720p) • d=2.44 λＦ(Airy Disk Diameter)

F2 F4

5.4μ

F8 10.7μ

F2.8 F16

21.5μ F5.6 7.5μ

F11 14.8μ

2.7μ 3.8μ

2/3” CoC=15μ at 720p

F2 F2 F2.8 F2.8 F4

5.4μ

F4 5.4μ

F5.6 7.5μ

F5.6 7.5μ

F8 10.7μ

F8 10.7μ

F11 F11 F16 F16

Return

Comparison by TV Format (1080i) • d=2.44 λＦ(Airy Disk Diameter)

F2 F4

5.4μ

F8 10.7μ

F2.8 F16

21.5μ F5.6 7.5μ

F11 14.8μ

2.7μ 3.8μ

2/3” CoC=10 at 1080i

F2 F2 F2.8 F2.8 F4

5.4μ

F4 5.4μ

F5.6 7.5μ

F5.6 7.5μ

F8 10.7μ

F8 10.7μ

F11 F11

2/3”

Return

Comparison by TV Format (1080i) • d=2.44 λＦ(Airy Disk Diameter)

F2 F4

5.4μ

F8 10.7μ

F2.8 F16

21.5μ F5.6 7.5μ

F11 14.8μ

2.7μ 3.8μ

1/3” CoC=5.5 at 1080i

F2 F2 F2.8 F2.8 F4

5.4μ

F4 5.4μ

F5.6 7.5μ

F5.6 7.5μ

F8 10.7μ

F8 10.7μ

1/3”

Return

Comparison by TV Format (1080i) • d=2.44 λＦ(Airy Disk Diameter)

F2 F4

5.4μ

F8 10.7μ

F2.8 F16

21.5μ F5.6 7.5μ

F11 14.8μ

2.7μ 3.8μ

1/4” CoC=4.1 at 1080i

F2 F2 F2.8 F2.8 F4

5.4μ

F4 5.4μ

F5.6 7.5μ

F5.6 7.5μ

1/4”

Comparison by TV Format (1080i) 4/3”

• d=2.44 λＦ(Airy Disk Diameter)

F5.6 F11

14.8μ

F22 29.5μ

F8 F44

59.0μ F16 21.5μ

F32 42.9μ

7.5μ 10.7μ

4/3” CoC=42μ at 1080i

F8 F8 F11

14.8μ

F11 14.8μ

F16 21.5μ

F16 21.5μ

F22 29.5μ

F22 29.5μ

F32 42.9μ

F32 42.9μ

F44 F44

Return

2-3.Airy Disc Calculation In case of F11:

– Purple 380–450 nm d=0.005~0.006mm Diameter =0.01~0.012mm

– Blue 450–495 nm d=0.006~0.0066mm Diameter =0.012~0.013mm

– Green 495–570 nm d=0.0066~0.0076mm Diameter =0.013~0.015mm

– Yellow 570–590 nm d=0.0076~0.0079mm Diameter =0.015~0.016mm

– Orange 590–620 nm d=0.0079~0.0083mm Diameter =0.016~0.017mm

– Red 620–750 nm d=0.0083~0.010mm Diameter =0.017~0.020mm

• Use 550nm in the middle of wavelength as the value varies by wavelength.

– F8： 550nmで0.0053(Diameter 0.0105）

– F5.6： 550nmで0.0038(Diameter 0.0075)

– F4： 550nmで0.0027(Diameter 0.0054)

• CoC 1300 (Film Equivalent） 1102 (HD 1080TV Line)

– 35mm film (20.3mm) : 0.03328 mm 0.038

– ANSI Super 35 (28.6mm): 0.022mm 0.026

– ASP-C (12.4mm) : 0.02080mm) 0.025

– 4/3” (9.73mm) : 0.01665mm 0.019

– 2/3” (5.39mm) : 0.0085mm 0.0096

– 1/2” (3.92mm) : 0.0062mm 0.0070

– 1/3” (2.94mm) : 0.0046mm 0.0052 Return

2-4.Bokeh (The Blur) by Diffraction

• The limit of Bokeh is CoC = Diameter of Airy Disc (2.44 F)

– Assumption: Bokeh starts around -3dB.

– 1080TV L 765TV L 541TV L Recommend to use the same as or

– 0dB (-3dB) （-6dB) less than the following values.

– 35mm Full Frame: F27.9 F39.4 F55.8 F32

– ANSI Super 35: F19.3 F27.3 F38.6 F22

– APS C (E Mount): F18.2 F25.6 F36.2 F22

– 4/3 inch: F13.8 F20 F27.6 F16

– 2/3 inch: F7.4 F10.5 F14.9 F11

– 1/2 inch: F5.4 F7.6 F10.8 F8

– 1/3 inch: F4.1 F5.7 F8.1 F5.6

– 1/4 inch: F3.1 F4.3 F6.1 F4

Bokeh (The Blur) starts. Good Area

The limit of CoC Return

１）F=1.6 ND=２ １/232.5 2)F=2.8 ND=2 1/81.5 3)F=4 ND=1 1/203.5

4)F=5.6 ND=1 1/94.3 5)F=8 ND=1 WFM GAIN 6)F=11 ND=1 WFM GAIN

2-5. 1/3” Lens Response (Example)

Return

2-6. What does In/Out of Focus mean?

Return

16:9 Imager

1101 lines

CoC

d =6mm (1/3”)

CoC=0.00545mm

1101 lines

= 0.00545mm

Assumption:

1/3” imager and 1101 line resolution. You cannot resolve the more line than 1101.

Even if you draw 2202 lines, it becomes 1101.

Even if you draw 4404 lines, it becomes 1101.

Out of focus means you can distinguish 2 points.

In focus means you cannot distinguish 2 points.

Even if you shoot more than 1101 lines, it becomes 1101 lines.

2202 lines

4404 lines

In Focus

Out of Focus

Out of Focus

you can distinguish

the difference.

You cannot distinguish

the difference.

2-7.Depth of Field

Return

F Stop becomes bigger (more closed), depth of field

becomes deeper.

Image Plain (IN Focus)

CoC

CoC

CoC

IRIS

F4

IRIS

F2.8

IRIS

F2

Depth of Field = In Focus

Depth of Field = In Focus

Depth of Field=

In Focus

ε= F x CoC CoC/2: ε = N/2 : f+l If l << f then ε= f/N x CoC = F x CoC

ε

ε

ε

ε

ε

ε

Focal

Length: f

N

S T=f + l

1/f = 1/S + 1/T f = ST/(S+T)

f l

N: Effective

Diameter

CoC

F=f/N

f l

1101 lines

= 0.00545mm (1/3”)

Actual In- Focus

Close

(Deep)

OPEN

(Shallow)

Ideal IN-Focus

Resolution is 1101. Every point’s size becomes CoC.

If you can see this size, it means that resolution is 2202. It contradicts the assumption.

2-8. How to use Bokeh to shoot impressive pictures. -- Utilize ND Filter or -3/-6dB gain--

• Daylight shooting:

– F Stop becomes F11 or more at 2/3” camera.

• If depth of field becomes deep, a picture becomes flat.

– Use ND filter, Shutter Speed or -3, -6dB gain to make F Stop open.

• Adjust F stop as follows to get the same depth of field.

– Sensitivity is the same even if the imager size is different.

• 4/3” camera without ND filter: 2/3” camera : 1/4 ND filter , 1/3” camera: 1/16

ND filter

– Sensitivity has 1 stop difference.

• 4/3” camera : F22, 2/3” camera becomes F16. So add 1/2 ND filter,

• 3/2” camera: F11, 1/3” camera becomes F8. So add 1/2 ND filter and becomes

F5.6

– Sensitivity has 2 stop difference

• 4/3” camera: F22, 2/3” camera becomes F11. So you don’t need ND filter.

• 3/2” camera: F11, 1/3” camera becomes F5.6. So you don’t need ND filter.

Return

2-9.Note for AF100 shooting

• Still picture’s lens characteristics – zoom lens is not true zoom lens.

• It use Vari-focal lens: If you change zoom ratio, focusing will change.

– Iris change in incremental steps.

Movie shooting method is required for AG-AF100.

manual setting

no zooming shooting

Shooting with parallel moving is better than PAN for 24p

mode. Return

3. Crop Factor

Crop

Factor

50mm (@35mm Full) Crop

Factor

50mm (@ANSI Super35)

Attach 35mm

Lens

The same View

angle

Attach Super

35mm Lens

The same View

angle

35mm Full 1 50mm (Standard) 0.7 - -

APS C 1.5 75mm 33mm 1.1 37mm 32mm

ANSI Super 35 1.4 70mm 36mm 1 34mm (Standard)

DIN Super 35 1.5 75mm 33mm 1.0 34mm 33mm

Normal 35 1.6 82mm 31mm 1.1 37mm 31mm

4/3” 2.0 100mm 25mm 1.4 48mm 25mm

2/3” 3.8 190mm 13.2mm 2.6 88mm 13.2mm

1/2” 5.2 260mm 9.6mm 3.6 122mm 9.6mm

1/3” 6.9 345mm 7.2mm 4.8 163mm 7.2mm

Return

3.1 How to use Crop Factor

• Focal Length conversion – Divide focal length by Crop Factor to get the same

view angle

– 39.6°50mm/2.0 = 25mm @4/3” (35mmFull to 4/3”)

– 39.6°35mm/1.4 = 25mm @4/3” (Super35 to 4/3”)

• Iris Conversion – Divide Iris by Crop Factor to get the same depth of

field • F11 @35mm full -- > F5.6 @4/3” (F11 divided by 2)

• F11 @ANSI Super 35 -- > F8 @4/3” (F11 divided by 1.4)

• F11 @2/3” -- > F5.6 @1/3” (F11 divided by 1.8)

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3-2. Focal Length and Depth of Field by Imager Size

35mm F41 F26 F22 F18 F11

APS-C F27 F17 F15 F12 F7

35mm Movie F26 F16 F14 F11 F6.8

4/3” F21 F13 F11 F9 F5.6

2/3” F11 F6.7 F5.6 F4.6 F3

1/2” F8 F4.9 F4 F3.2 F2.1

1/3” F5.6 F3.6 F3 F2.4 F1.6

35mm 24mm 50mm 100mm 200mm 300mm

APS-C 16mm 33.2mm 66mm 133mm 199mm

35mm Movie 15mm 31mm 63mm 126mm 189mm

4/3” 12mm 25mm 50mm 100m 150mm

2/3” 6.1mm 13mm 25mm 51mm 76mm

1/2” 4.4mm 9.2mm 18mm 37mm 55mm

1/3” 3.3mm 6.9mm 14mm 28mm 42mm

F Number Conversion Table for the same Depth of Field

Focal Length Conversion Table for the same angle of view

Note:1/2”: 1 F-stop, 1/3”: 2 F-stop compared with 2/3” Return

3-3. What’s the benefit of large sensor?

Imager Size Iris Iris Iris Iris iris Focal Length

35mm Full Size 11 8 5.6 4 2.8 50mm

ANSI Super 35 7.6 5.5 3.9 2.8 1.9 34.6mm

DIN Super 35 7.3 5.3 3.7 2.7 1.9 33.3mm

APS-C 7.2 5.2 3.6 2.6 1.8 32.5mm

Normal 35mm

Movie

6.7 4.9 3.4 2.4 1.7 30.6mm

4/3” 5.4 4 2.8 2 1.4 24.7mm

2/3” 2.9 2.1 1.5 1.1 0.7 13.3mm

1/2” 2.1 1.5 1.1 0.8 0.5 9.7mm

1/3” 1.6 1.2 0.8 0.6 0.4 7.3mm

1/4” 1.2 0.9 0.6 0.4 0.3 5.4mm

You can understand it is very difficult to get shallow depth of field in case of video camera.

Return

4. Appendix

Return

4-1.Size of Imagers

Return

35mm Full Frame

Super35

APS C

4/3”

•35mm Full Frame: 2 Stop brighter than 4/3”.

The area is 4 times bigger than 4/3”

•Super 35 and APS C are almost the same.

•Super 35 and APS C: 1 Stop brighter than 4/3”

The area is 2 times bigger than 4/3”.

F8(F9)

F11(F12)

F16(F18))

If each sensor’s performance is the same, sensitivity is

proportional to the imager area.

CANON 5D

Panasonic AF100

Sony F3/Canon 7D

16:9 4:3

Vertical Horizontal Diagonal Vertical Horizontal Diagonal

35mm Full Frame 20.3 36.0 41.3 24.0 36.0 43.3

ANSI Super　35 14.0 24.9 28.6 18.7 24.9 31.1

DIN Super 35 13.5 24.0 27.5 18.0 24.0 30.0

Sony F3 13.3 23.6 27.1

APS-C 13.2 23.4 26.9 16.7 23.4 28.7

35mm Movie 12.4 22.0 25.3 16.0 22.0 27.2

4/3" (AF100) 10.0 17.8 20.4 13.0 17.8 22.0

2/3" 5.4 9.6 11.0

1/2" 3.9 7.0 8.0

1/3" 2.9 5.2 6.0

Note: Sony F3 is APS C. It is not Super35mm.

RED ONE Imager size: 15x30 (Physical Size) 13.7 x 24.4 mm Effective Size

4.2 Color Separation Filter -- Bayer Pattern --

• Single sensor requires color separation filter to get R,G,B signal. – 3CCD/3MOS doesn’t require it. But it requires prism to separate light to

R,G,B. So 3CCD/3MOS is more expensive than single sensor camera.

– 3CCD/3MOS camera’s color reproduction is better than single sensor camera’s.

• Green component is 2 times more than R,B one because of increasing resolution. – Human eyes are the most sensitive to green color. So if green color

resolution is increased, total resolution will increase.

– Total pixel count is 12 million. So G is 6million, R and B are 3 million. That means Luminance resolution is close to 6 million.

– 4/3” imager’s resolution is better than RED ONE. • RED One claims 4K camera. But it is not true. Because it is single CMOS

camera. So it is 2K camera. But it has 4k signal processing.

R

B G

G R

B G

G R

B G

G

R

B G

G R

B G

G R

B G

G

Color Separation Filter

RED ONE: approx. 2304x4096

4/3”: approx. 2800x4976

Return

4.3 Sensitivity Comparison • AF100 has single MOS. 2/3” camcorder has 3 CCD.

• Is AF100 more sensitive than 2/3”? – No, it isn’t. 4/3” is 4 times bigger than 2/3”.

– But 2/3” has 3 CCD. So 4/3” sensor’s area is 1.14 times bigger than 2/3” CCD. 178mm2 / (51.84mm2 x 3) = 1.14 So total area is almost the same.

– But color separation filter reduces light density and 4/3” pixel size is around half of 2/3” because of 14 mil. So actually AF100’s sensitivity is less than HPX3000.

2.2 M 2/3” x3 CCD

Panasonic HPX3000

AF100 12M 4/3” x1 MOS

AJ-HPX3000: F10 (F11) AG-AF100: F8 (F9)

Area = 178mm2

Area = 51.84mm2

2.2 M 2/3” x3 CCD

Panasonic HPX3000

Area = 51.84mm2

2.2 M 2/3” x3 CCD

Panasonic HPX3000

Area = 51.84mm2

2.2 M 2/3” x3 CCD

Panasonic HPX3000

Area = 51.84mm2

2/3” x3 = 155 mm2

Pixel size:

4/3”:0.00001278

2/3”: 0.00002356

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4.4 ASA Sensitivity

• ASA＝200 x (1+M)2 x F2 / (E x T)

– ASA：Film Sensitivity. =ISO

– M ： size of Imager / size of subject

• M is negligible (M=0)

– F ：F Stop

– E ：illumination Intensity (Lux.)

– T ：Exposure Time (sec.)

2/3”

Panasonic

HPX3000

• AG-AF100 (60Hz and 50Hz are the same ASA)

– ASA200 (-6dB), ASA300 (-3dB),

– ASA400 (0dB), ASA600 (+3dB)

– ASA800 (+6dB), ASA1600(+12dB), ASA3200(+18dB)

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4/3 inch 2/3 inch

5.2x2.9mm

1/3 inch

9.6x5.4mm

35mm

movie film

17.3x13.0mm 22x16mm

*simulation

2m

X

X

X

<35mm Still Camera>

<35mm movie film>

<4/3 inch>

<2/3 inch>

<1/2 inch>

<1/3 inch>

shallow

deep

Dep

th o

f fi

eld

0m

*distance to object：2m

*Iris：F4

*Bust shot

＜Focus area＞

X

4-5.Depth of Field Comparison by Different Imager Size

35mm

Still Camera

36x24mm

1/2 inch

7.0x3.9mm

4:3 16:9

X

X

7.5m

0.4m

0.7m

0.9m

2.0m

3.5m

Depth of Field 6.6m 0.9m

0.6m 1.4m

2.7m 0.7m

0.4m 0.3m

0.2m 0.2m

0.5m 0.4m

Return

2m

The same Depth

of Fields 0m

＜Focus area＞

4-6.To get the same Depth of Field

F3

F22

F14

F11

F5.6

F4

F Number

2.8m 0.7m

0.7m 2.8m

2.8m 0.7m

2.8m 0.7m

2.8m 0.7m

2.8m 0.7m

<35mm Still Camera>

<35mm movie film>

<4/3 inch>

<2/3 inch>

<1/2 inch>

<1/3 inch>

The same Depth

of Fields

F1.6

F11

F7

F5.6

F2.9

F2.1

0.9m 0.5m

0.5m 0.9m

0.9m 0.5m

0.9m 0.5m

0.9m 0.5m

0.9m 0.5m

<35mm Still Camera>

<35mm movie film>

<4/3 inch>

<2/3 inch>

<1/2 inch>

<1/3 inch>

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4-7.Back Focus and Flange Back

• Back Focus: the distance

between the rear element of a lens

and the camera focal plane

• Flange Back (flange focal length):

Distance between the lens mount

and the camera focal plane.

Flange Back

Back Focus

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4-8.Distance Error by Flange Back Error

• Distance between subject and kens:L Focal length: ｆ, Distance between focal point and focal plane:ｌ ｌ=f2 / （L - ｆ)

– L=f + f2 /l

• Get L from d (distance between subject

and focal plane) – L =( d+√(d2-4df) ) /2

• Get d from L (distance between lens and focal plane) ,

l (distance between focal point and focal plane) – d= L + f + l

• Distance 1m – Flange Back 0.1mm error

• 25mm lens:169mm(17%)、50mm lens:33mm(3%) error,

• 100mm lens 6mm error

– Flange Back 0.01mm error • 25mm lens:14mm(1%)、50mm lens: 3mm(0.3%) error,

• 100mm lens: 0.6mm error

• Distance 10m – Flange Back 0.1mm error

• 50mm lens: 6.5m error (65%), 100mm lens: 1m(11%) error

– Flange Back 0.01mm error • 25mm lenns: 1.9m(19%), 50mm lens: 3mm error,

• 100mm lens: 96mm(1%) error

• Distance 100m – Flange Back 0.01mm error

• 100mm lens: 11m(11%) error

• The shorter the focal length become, the more accuracy is required. – 35mm Full Frame: 0.01mm accuracy, 4/3” (2.5µ), 2/3”: 0.6µ,1/3” 0.15µ

f L

Focal Plane

Flange Back

l

d

100m 10m 1m 50cm4.5mm 0.00020 0.00203 0.02043 0.04127.2mm 0.00052 0.00519 0.05260 0.106813.2mm 0.00174 0.01747 0.17900 0.368225mm 0.00625 0.06281 0.65835 1.393250mm 0.02503 0.25253 2.78640 6.3508100mm 0.10020 1.02051 12.7017 38.1966

The value of l

Return

4-9.View Angle Formula

f x θ

d

w

h

Return

To get focal length to make field of view and distance same.

Focal length = f1,f2 (f1: focal length of h1, f2: focal length of h2)

h1 Θ

d1 d2

h0

h2

d4

D

D’

Θ’

d3

h0

Focal length = f1

Focal length = f2

1

𝑑1 +

1

𝑑2=

1

𝑓1,

ℎ0

ℎ1=

𝑑1

𝑑2

Therefor D is expressed as follows.

D= d1 + d2 = 𝑑12

𝑑1−𝑓1

d1 = 𝐷+ 𝐷2−4𝐷∗𝑓1

2, d2 =

𝐷− 𝐷2−4𝐷∗𝑓1

2

d3,d4 is a well as d1,d2. The

condition is that distance is same.

D=D’ h0

ℎ2=

𝑑3

𝑑4 =

𝐷+ 𝐷2−4𝐷∗𝑓2

𝐷− 𝐷2−4𝐷∗𝑓2

f2= 𝐷2− (

ℎ0−ℎ2 ∗𝐷

ℎ2+ℎ0)2

4𝐷

To get distance to make field of view same in case that each

lens has different focal length.

h1 Θ

d1 d2

h0

h2

d4

D

D’

Θ’

d3

h0

Focal length = f1

Focal length = f2

1

𝑑1 +

1

𝑑2=

1

𝑓1,

ℎ0

ℎ1=

𝑑1

𝑑2

Therefor D is expressed as follows.

d1 = 𝑓1∗(ℎ1+ℎ0)

ℎ1, d2 =

𝑓1∗(ℎ1+ℎ0)

ℎ0

D = d3+d4 = 𝑓1∗(ℎ1+ℎ0)2

ℎ0∗ℎ1

1

𝑑3 +

1

𝑑4=

1

𝑓2 ,

ℎ0

ℎ2=

𝑑3

𝑑4

Therefor d3,d4 I expressed as follows.

d3 = 𝑓2∗(ℎ2+ℎ0)

ℎ2, d4 =

𝑓2∗(ℎ2+ℎ0)

ℎ0

D’ = d3+d4 = 𝑓2∗(ℎ2+ℎ0)2

ℎ0∗ℎ2

Focal length = f1,f2 (f1: focal length of h1, f2: focal length of h2)

4-10. Conceptual Schema Relationship between Iris and Resolution

Resolution

F Stop

Diffraction

1/3”

2/3”

35mm Full

4/3”

Open Close

Aberration

Return

Note: It is not real characteristics.

Actually flat portion’s resolution is the

same as the other size.

4-11. What’s the difference between

Video Camera Lens and Still Camera Lens

• Video Zoom Lens (True Zoom) – Zoom lenses (sometimes referred to as "true" zoom) are ideally

parfocal in that focus is maintained as the lens is zoomed (focal length and magnification changed. Many so-called "zoom" lenses, particularly in the case of fixed lens cameras, are actually

• Still Camera Zoom Lens (Not True Zoom) – varifocal lenses, which gives lens designers more flexibility in optical

design trade-offs (focal length range, maximum aperture, size, weight, cost) than parfocal zoom, and which is practical because of auto-focus, and because the camera processor can automatically adjust the lens to keep it in focus while changing focal length ("zooming") making operation essentially the same as a parfocal zoom.

• Iris of Video Lens – Iris change smoothly.

• Iris of Still Camera Lens – Iris change in incremental steps.

• Refer to – http://en.wikipedia.org/wiki/Parfocal_lens

– http://en.wikipedia.org/wiki/Varifocal_lens Return

4-12. Depth of Field Formula

Circle of confusion diameter limit (CoC) based on d/1300 d/1300 d: Diagonal of Imager

– d/1300

– 35mm film : 0.03328 mm

– ASP-C (NEX5) : 0.02080mm

– 4/3”(Four Thirds): 0.01665mm

• Relationship of Diameter of CoC and Depth of Field as Figure 1.

= F x =d/1000~1500)

• Co-efficient depends on film, digital still camera or HD video camera. D= 1300 as for still picture. In case of HD video, it becomes 1102（1080TV Line) .

• Depth of Field

– Forward DoF = cF(s-f)2/(f2+cF(s-f))

– Backward DoF = cF(s-f)2/(f2-cF(s-f))

– Where F is F Stop, c is the diameter of CoC, s is distance from a camera to a subject, f is focal length.

Fig.１

Return

When Sensor size is changed, how dose Depth of Field change?

F Stop: F2

f=50mm

N=25mm

F Stop: F1

f=25mm

N=25mm

35mm Standard

View Angle 4/3” Standard

View Angle

ε ε ε/4 ε/4

CoC’

=CoC/2 CoC

35mm 4/3”

CoC=c 0.033 0.017

f 50mm 25mm

F 2 1

Assumption S>>f,

35mm cFs2/(f2+cFs)

4/3” c’F’s2/(f’2+c’F’s)

Condition: c’ = 4/3’s CoC = c/2, F’ = 4/3’s F’ = F/2, f’= 4/3’s f =f/2

c’F’s2/(f’2+c’F’s) = cFs2/4/((f2/4)+(cFs/4)) = cFs2 /(f2+cFs)

Assumption : focal length and CoC become half.

If F stop change to half, 4/3’s DoF becomes the same as the

35mm’s. At that time, 4/3’ ε becomes ε/4.