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Old Apr 20, 2005, 5:19 PM   #1
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I must be stupid or something but 1/1.8" means nothing to me.

1/1 would be a whole so a 1/1.8" CCD is nearly 2". (I know that can't be true)

How do I work 1/1.8" into mm?
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Old Apr 20, 2005, 5:29 PM   #2
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here are some figures I know of:
4/3" CCD = 18x13.5mm
1" CCD = 12.8x9.6mm
2/3" CCD = 8.8x6.6mm
1/1.7" CCD - anyone know?
1/1.76" CCD - anyone know?
1/1.8" CCD = 7.176x5.319mm
1/2" CCD = 6.4x4.8mm
1/2.4" CCD - anyone know?
1/2.5" CCD = 5.76x4.29mm
1/2.7" CCD = 5.371x4.035mm (or is it 5.27x3.96mm?)
1/3" CCD = 4.8x3.6mm
1/3.2" CCD = 4.536x3.416mm
1/3.6" CCD = 4x3mm
1/4" CCD = 3.2x2.4mm
1/5" CCD = 2.55x1.91mm
1/6" CCD = 2.15x1.61mm
1/7" CCD = 1.85x1.39mm

What other ones did I miss? I didn't include the 3:2 ratio dSLR sensors.
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Old Apr 20, 2005, 5:44 PM   #3
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I guess it's nearly 1/2" and not 2" like I said in my original post. I can't see how they work that out, but thanks for giving me the mm size
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Old Apr 20, 2005, 5:53 PM   #4
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The 1/1.8" designation is based on an old spec that looked at the outside video tube diameters. For whatever reason, these type designations have continued.

You may also see it referenced as being .556" (simply do the division, since 1 divided by 1.8 = .556). Hence, a 1/1.8" (.556") CCD is larger than a 1/2.5" (.40") CCD.

But, the actual sensor sizesare smaller than their type designations(as you can see from the previous reply).




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Old Apr 20, 2005, 8:29 PM   #5
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JimC is right.

For example, just using the 1/1.8" size I said the dimensions of the sensor are 7.176 by 5.319 mm. Diagonally, that sensor is about 8.932mm. Translated to inches that is 0.35 inches approximately, which is much smaller than 0.556 inches.

I'd like camera manufacturers to start mentioning the "inch" sizes of sensors in terms of its smallest side being 1/1.8". For a 4:3 aspect ratio sensor, that would mean approximately an 18.8 by 14.1mm sensor. If the next 7-megapixel Canon digital Elph had a sensor that size, I would think its ISO 800 and 1600 performance would be quite good.
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Old Apr 20, 2005, 10:02 PM   #6
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Go here for an article about sensor sizes and their derivation:

http://www.dpreview.com/learn/?/key=Sensor_Sizes
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Old Apr 22, 2005, 6:02 PM   #7
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It is a matter of fractions and math.

1/4 is smaller than 1/2 so
1/1.8 is smaller than 1/1.

When the denominator(the bottom number) is bigger, it makes a smaller number overall.

Jason
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Old Apr 23, 2005, 1:26 PM   #8
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jwebbtrumpet wrote:
Quote:
It is a matter of fractions and math.

1/4 is smaller than 1/2 so
1/1.8 is smaller than 1/1.

When the denominator(the bottom number) is bigger, it makes a smaller number overall.

Jason
I can see that now. Thanks. It's just that having a decimal point in a fraction threw me
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Old Apr 23, 2005, 9:13 PM   #9
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pianoplayer88key wrote:
Quote:
here are some figures I know of:
4/3" CCD = 18x13.5mm
1" CCD = 12.8x9.6mm
2/3" CCD = 8.8x6.6mm
1/1.7" CCD - anyone know?
1/1.76" CCD - anyone know?
1/1.8" CCD = 7.176x5.319mm
1/2" CCD = 6.4x4.8mm
1/2.4" CCD - anyone know?
1/2.5" CCD = 5.76x4.29mm
1/2.7" CCD = 5.371x4.035mm (or is it 5.27x3.96mm?)
1/3" CCD = 4.8x3.6mm
1/3.2" CCD = 4.536x3.416mm
1/3.6" CCD = 4x3mm
1/4" CCD = 3.2x2.4mm
1/5" CCD = 2.55x1.91mm
1/6" CCD = 2.15x1.61mm
1/7" CCD = 1.85x1.39mm

What other ones did I miss? I didn't include the 3:2 ratio dSLR sensors.

Which camera would use a 1/7" CCD (Except cameraphones)? 1/7" is like an ant in a camera:-)
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Old Apr 24, 2005, 7:36 AM   #10
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Ixus 700 wrote:
Quote:
pianoplayer88key wrote:
Quote:
here are some figures I know of:
4/3" CCD = 18x13.5mm
1" CCD = 12.8x9.6mm
2/3" CCD = 8.8x6.6mm
1/1.7" CCD - anyone know?
1/1.76" CCD - anyone know?
1/1.8" CCD = 7.176x5.319mm
1/2" CCD = 6.4x4.8mm
1/2.4" CCD - anyone know?
1/2.5" CCD = 5.76x4.29mm
1/2.7" CCD = 5.371x4.035mm (or is it 5.27x3.96mm?)
1/3" CCD = 4.8x3.6mm
1/3.2" CCD = 4.536x3.416mm
1/3.6" CCD = 4x3mm
1/4" CCD = 3.2x2.4mm
1/5" CCD = 2.55x1.91mm
1/6" CCD = 2.15x1.61mm
1/7" CCD = 1.85x1.39mm

What other ones did I miss? I didn't include the 3:2 ratio dSLR sensors.

Which camera would use a 1/7" CCD (Except cameraphones)? 1/7" is like an ant in a camera:-)
Some of the early cameras actually did use ants as the imager. Something to do with chemicals in their blood being sensitive to light or something.
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