Quick fundamental question re CCDs in Panasonic cameras...

Started Jul 25, 2007 | Discussions
gfmason Regular Member • Posts: 177
Quick fundamental question re CCDs in Panasonic cameras...

With the FZ50 sensor being 1/1.8" with 10.4 million pixels, and the FZ18 being 1/2.5" with 8.3 million, should that not solve some of the questions regarding noise being discussed here re the FZ50, all else being equal (which I understand they are not)?

Dave Martin Senior Member • Posts: 2,160
Re: Quick fundamental question re CCDs in Panasonic cameras...

The FZ18 has smaller pixels than the FZ50 so one would expect the FZ18 to be noisier (other things being equal.)

If the pixels were square, the area per pixel would be:

FZ18 (1/2.5)^2/8.3 = 0.0193 sq_in/million_pixels
FZ50 (1/1.8)^2/10.4 = 0.0297 sq_in/million_pixels

The ratio of pixel areas is about 2/3. The signal to noise ratio due to shot noise would be the square root of this, about 1/2.

Dave

OP gfmason Regular Member • Posts: 177
Re: Quick fundamental question re CCDs in Panasonic cameras...

OK, let me be even dumber. The FZ18 has a larger sensor divided into fewer pixels. Why then are the FZ18 pixels smaller?

SteveBee Regular Member • Posts: 428
Re: Quick fundamental question re CCDs in Panasonic cameras...

The FZ18 sensor is smaller than the FZ50 sensor, not larger.

http://www.cambridgeincolour.com/tutorials/digital-camera-sensor-size.htm

Regards,
Steve
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Mariush Contributing Member • Posts: 645
Sensor sizes

1/2.5 is a lot SMALLER than 1/1.8 so the FZ50 sensor is larger than the one of the FZ18. So its just the other way around, noise on the FZ18 may be more (and NR may have to be increased). We will know after test, but from the pictures I have seen thus far, I was not at all impressed and noise even at 100ISO could easily be seen!!

Just to show you, a copy of part of the the table in the glossary with the sizes of sensors:

Type Aspect Ratio Dia. (mm) Diagonal Width Height
1/3.6" 4:3 7.056 5.000 4.000 3.000
1/3.2" 4:3 7.938 5.680 4.536 3.416
1/3" 4:3 8.467 6.000 4.800 3.600
1/2.7" 4:3 9.407 6.721 5.371 4.035
1/2.5" 4:3 10.160 7.182 5.760 4.290
1/2" 4:3 12.700 8.000 6.400 4.800
1/1.8" 4:3 14.111 8.933 7.176 5.319
1/1.7" 4:3 14.941 9.500 7.600 5.700
2/3" 4:3 16.933 11.000 8.800 6.600
1" 4:3 25.400 16.000 12.800 9.600
4/3" 4:3 33.867 22.500 18.000 13.500
1.8" ( ) 3:2 45.720 28.400 23.700 15.700
35 mm film 3:2 n/a 43.300 36.000 24.000

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OP gfmason Regular Member • Posts: 177
Re: Sensor sizes

Aha! So at least I can still be stupid, but for a different reason than I expected.

Thanks for the clarification(s).

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