Pentax Optio RZ18 vs. Ricoh GR Digital 4
Comparison
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| Pentax Optio RZ18 | Ricoh GR Digital 4 | ||||
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Megapixels
16.00
10.40
Max. image resolution
4608 x 3456
3648 x 2736
Sensor
Sensor type
CCD
CCD
Sensor size
1/2.33" (~ 6.08 x 4.56 mm)
1/1.7" (~ 7.53 x 5.64 mm)
Sensor size comparison
Sensor size is generally a good indicator of the quality of the camera.
Sensors can vary greatly in size. As a general rule, the bigger the
sensor, the better the image quality.
Bigger sensors are more effective because they have more surface area to capture light. An important factor when comparing digital cameras is also camera generation. Generally, newer sensors will outperform the older.
Learn more about sensor sizes »
Bigger sensors are more effective because they have more surface area to capture light. An important factor when comparing digital cameras is also camera generation. Generally, newer sensors will outperform the older.
Learn more about sensor sizes »
Actual sensor size
Note: Actual size is set to screen → change »
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| 1 | : | 1.53 |
| (ratio) | ||
| Pentax Optio RZ18 | Ricoh GR Digital 4 | |
Surface area:
| 27.72 mm² | vs | 42.47 mm² |
Difference: 14.75 mm² (53%)
GR 4 sensor is approx. 1.53x bigger than RZ18 sensor.
Pixel pitch tells you the distance from the center of one pixel (photosite) to the center of the next. It tells you how close the pixels are to each other.
The bigger the pixel pitch, the further apart they are and the bigger each pixel is. Bigger pixels tend to have better signal to noise ratio and greater dynamic range.
The bigger the pixel pitch, the further apart they are and the bigger each pixel is. Bigger pixels tend to have better signal to noise ratio and greater dynamic range.
Pixel or photosite area affects how much light per pixel can be gathered.
The larger it is the more light can be collected by a single pixel.
Larger pixels have the potential to collect more photons, resulting in greater dynamic range, while smaller pixels provide higher resolutions (more detail) for a given sensor size.
Larger pixels have the potential to collect more photons, resulting in greater dynamic range, while smaller pixels provide higher resolutions (more detail) for a given sensor size.
Relative pixel sizes:
vs
Pixel area difference: 2.34 µm² (134%)
A pixel on Ricoh GR 4 sensor is approx. 134% bigger than a pixel on Pentax RZ18.
Pixel density tells you how many million pixels fit or would fit in one
square cm of the sensor.
Higher pixel density means smaller pixels and lower pixel density means larger pixels.
Higher pixel density means smaller pixels and lower pixel density means larger pixels.
To learn about the accuracy of these numbers,
click here.
Specs
Pentax RZ18
Ricoh GR 4
Total megapixels
16.60
Effective megapixels
16.00
Optical zoom
18x
1x
Digital zoom
Yes
Yes
ISO sensitivity
Auto, 80 - 6400
Auto, 80 - 3200
RAW
Manual focus
Normal focus range
45 cm
30 cm
Macro focus range
4 cm
1 cm
Focal length (35mm equiv.)
25 - 450 mm
28 mm
Aperture priority
No
Yes
Max. aperture
f3.5 - f5.9
f1.9
Metering
Centre weighted, Multi-segment, Spot
Centre weighted, Multi-segment, Spot
Exposure compensation
±2 EV (in 1/3 EV steps)
±2 EV (in 1/3 EV steps)
Shutter priority
No
Yes
Min. shutter speed
4 sec
1 sec
Max. shutter speed
1/2000 sec
1/2000 sec
Built-in flash
External flash
Viewfinder
None
Optical (optional)
White balance presets
6
6
Screen size
3"
3"
Screen resolution
460,000 dots
1,230,000 dots
Video capture
Max. video resolution
Storage types
SDHC, SDXC, Secure Digital
SDHC, Secure Digital
USB
USB 2.0 (480 Mbit/sec)
USB 2.0 (480 Mbit/sec)
HDMI
Wireless
GPS
Battery
Lithium-Ion D-LI92 rechargeable battery
Lithium-Ion DB65 rechargeable battery
Weight
190 g
190 g
Dimensions
109 x 61 x 36 mm
109 x 60 x 33 mm
Year
2011
2011
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Diagonal
Diagonal is calculated by the use of Pythagorean theorem:
where w = sensor width and h = sensor height
| Diagonal = √ | w² + h² |
Pentax RZ18 diagonal
The diagonal of RZ18 sensor is not 1/2.33 or 0.43" (10.9 mm) as you might expect, but approximately two thirds of
that value - 7.6 mm. If you want to know why, see
sensor sizes.
w = 6.08 mm
h = 4.56 mm
w = 6.08 mm
h = 4.56 mm
| Diagonal = √ | 6.08² + 4.56² | = 7.60 mm |
Ricoh GR 4 diagonal
The diagonal of GR 4 sensor is not 1/1.7 or 0.59" (14.9 mm) as you might expect, but approximately two thirds of
that value - 9.41 mm. If you want to know why, see
sensor sizes.
w = 7.53 mm
h = 5.64 mm
w = 7.53 mm
h = 5.64 mm
| Diagonal = √ | 7.53² + 5.64² | = 9.41 mm |
Surface area
Surface area is calculated by multiplying the width and the height of a sensor.
RZ18 sensor area
Width = 6.08 mm
Height = 4.56 mm
Surface area = 6.08 × 4.56 = 27.72 mm²
Height = 4.56 mm
Surface area = 6.08 × 4.56 = 27.72 mm²
GR 4 sensor area
Width = 7.53 mm
Height = 5.64 mm
Surface area = 7.53 × 5.64 = 42.47 mm²
Height = 5.64 mm
Surface area = 7.53 × 5.64 = 42.47 mm²
Pixel pitch
Pixel pitch is the distance from the center of one pixel to the center of the
next measured in micrometers (µm). It can be calculated with the following formula:
| Pixel pitch = | sensor width in mm | × 1000 |
| sensor resolution width in pixels |
RZ18 pixel pitch
Sensor width = 6.08 mm
Sensor resolution width = 4612 pixels
Sensor resolution width = 4612 pixels
| Pixel pitch = | 6.08 | × 1000 | = 1.32 µm |
| 4612 |
GR 4 pixel pitch
Sensor width = 7.53 mm
Sensor resolution width = 3733 pixels
Sensor resolution width = 3733 pixels
| Pixel pitch = | 7.53 | × 1000 | = 2.02 µm |
| 3733 |
Pixel area
The area of one pixel can be calculated by simply squaring the pixel pitch:
You could also divide sensor surface area with effective megapixels:
Pixel area = pixel pitch²
You could also divide sensor surface area with effective megapixels:
| Pixel area = | sensor surface area in mm² |
| effective megapixels |
RZ18 pixel area
Pixel pitch = 1.32 µm
Pixel area = 1.32² = 1.74 µm²
Pixel area = 1.32² = 1.74 µm²
GR 4 pixel area
Pixel pitch = 2.02 µm
Pixel area = 2.02² = 4.08 µm²
Pixel area = 2.02² = 4.08 µm²
Pixel density
Pixel density can be calculated with the following formula:
One could also use this formula:
| Pixel density = ( | sensor resolution width in pixels | )² / 1000000 |
| sensor width in cm |
One could also use this formula:
| Pixel density = | effective megapixels × 1000000 | / 10000 |
| sensor surface area in mm² |
RZ18 pixel density
Sensor resolution width = 4612 pixels
Sensor width = 0.608 cm
Pixel density = (4612 / 0.608)² / 1000000 = 57.54 MP/cm²
Sensor width = 0.608 cm
Pixel density = (4612 / 0.608)² / 1000000 = 57.54 MP/cm²
GR 4 pixel density
Sensor resolution width = 3733 pixels
Sensor width = 0.753 cm
Pixel density = (3733 / 0.753)² / 1000000 = 24.58 MP/cm²
Sensor width = 0.753 cm
Pixel density = (3733 / 0.753)² / 1000000 = 24.58 MP/cm²
Sensor resolution
Sensor resolution is calculated from sensor size and effective megapixels. It's slightly higher
than maximum (not interpolated) image resolution which is usually stated on camera specifications.
Sensor resolution is used in pixel pitch, pixel area, and pixel density formula.
For sake of simplicity, we're going to calculate it in 3 stages.
1. First we need to find the ratio between horizontal and vertical length by dividing the former with the latter (aspect ratio). It's usually 1.33 (4:3) or 1.5 (3:2), but not always.
2. With the ratio (r) known we can calculate the X from the formula below, where X is a vertical number of pixels:
3. To get sensor resolution we then multiply X with the corresponding ratio:
Resolution horizontal: X × r
Resolution vertical: X
1. First we need to find the ratio between horizontal and vertical length by dividing the former with the latter (aspect ratio). It's usually 1.33 (4:3) or 1.5 (3:2), but not always.
2. With the ratio (r) known we can calculate the X from the formula below, where X is a vertical number of pixels:
| (X × r) × X = effective megapixels × 1000000 → |
|
Resolution horizontal: X × r
Resolution vertical: X
RZ18 sensor resolution
Sensor width = 6.08 mm
Sensor height = 4.56 mm
Effective megapixels = 16.00
Resolution horizontal: X × r = 3468 × 1.33 = 4612
Resolution vertical: X = 3468
Sensor resolution = 4612 x 3468
Sensor height = 4.56 mm
Effective megapixels = 16.00
| r = 6.08/4.56 = 1.33 |
|
Resolution vertical: X = 3468
Sensor resolution = 4612 x 3468
GR 4 sensor resolution
Sensor width = 7.53 mm
Sensor height = 5.64 mm
Effective megapixels = 10.40
Resolution horizontal: X × r = 2786 × 1.34 = 3733
Resolution vertical: X = 2786
Sensor resolution = 3733 x 2786
Sensor height = 5.64 mm
Effective megapixels = 10.40
| r = 7.53/5.64 = 1.34 |
|
Resolution vertical: X = 2786
Sensor resolution = 3733 x 2786
Crop factor
Crop factor or focal length multiplier is calculated by dividing the diagonal
of 35 mm film (43.27 mm) with the diagonal of the sensor.
| Crop factor = | 43.27 mm |
| sensor diagonal in mm |
RZ18 crop factor
Sensor diagonal in mm = 7.60 mm
| Crop factor = | 43.27 | = 5.69 |
| 7.60 |
GR 4 crop factor
Sensor diagonal in mm = 9.41 mm
| Crop factor = | 43.27 | = 4.6 |
| 9.41 |
35 mm equivalent aperture
Equivalent aperture (in 135 film terms) is calculated by multiplying lens aperture
with crop factor (a.k.a. focal length multiplier).
RZ18 equivalent aperture
Crop factor = 5.69
Aperture = f3.5 - f5.9
35-mm equivalent aperture = (f3.5 - f5.9) × 5.69 = f19.9 - f33.6
Aperture = f3.5 - f5.9
35-mm equivalent aperture = (f3.5 - f5.9) × 5.69 = f19.9 - f33.6
GR 4 equivalent aperture
Crop factor = 4.6
Aperture = f1.9
35-mm equivalent aperture = (f1.9) × 4.6 = f8.7
Aperture = f1.9
35-mm equivalent aperture = (f1.9) × 4.6 = f8.7
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