C
Chuck A
Guest
Since this is a small sensor forum I thought this might interest the readers.
I don't know if anybody has been following the newest trend over at Dpreview. They have started following and charting Pixel Density (PD) as a measure of the quality of a sensor. You can get the background here: http://www.dpreview.com/news/0807/08070301pixeldensity.asp and there are some interesting threads here: http://forums.dpreview.com/forums/readflat.asp?forum=1012&thread=28498478 & here: http://forums.dpreview.com/forums/readflat.asp?forum=1013&thread=28502048
Basically the gist is that the smaller the number the better.
Fuji F100 25MP/cm²
Fuji F40 18MP/cm²
Fuji F30/31 14MP/cm²
DSLRs seem to run between 1.4 and 3.3MP/cm².
The Ricohs are :
Ricoh GR Digital 21 MP/cm²
Ricoh GX8 21 MP/cm²
Ricoh R4 24 MP/cm²
Ricoh GR Digital II 25 MP/cm²
Ricoh GX100 25 MP/cm²
Ricoh R8 35 MP/cm²
The Canon is:
Canon PowerShot G9 28 MP/cm²
Look at some of the older smaller mp models:
The 5MP Nikon Coolpix 5000 8MP/cm²
The 3MP Nikon Coolpix 990, 995 8MP/cm²
The 2MP Olympus C-2100 UZI 6 MP/cm²
The 1.3MP Olympus E-100 RS 4 MP/cm²
It seems to me that there is much more involved here. First you have to compare models with similar mp counts to judge image quality at a particular print size. I am not sure that pixel density is the whole story. Not being an engineer I am sure that my thinking may be flawed but I thought that the size of the pixels really mattered. Just having less of them per cubic cm doesn't help if they are small and poor quality. Also, camera processing, lens sharpness and contrast and many other variables come into effect here.
For example, just looking at the test crops at Dpreview for these cameras the Nikon CP5000 has a PD of 8MP/cm² while the Fuji F31 has 14MP/cm². They have roughly the same MP and by the PD the Nikon should be a better camera. Look at the noise crops and it is clear that the F31 has much lower noise characteristics than the Nikon.
This is just one example but I think that as you went through and actually compared real life output and correlated it with PD it may not be all that cut and dried. Look at the small MP cameras and the PD numbers are 4 to 6MP/cm². But my main interest is in the quality of a certain print size. Even at 25MP/cm² the 10mp GX100 would certainly make a much better 11x14in print than the 1.3mp Olympus E-100 RS with its' 4MP/cm².
Dpreview is including pixel density numbers with all of their camera reviews. They say that it gives a clearer picture of image quality than just megapixels. While I agree with that it certainly is not the end all here. I would hate to see another flawed way of evaluating sensors by numbers to replace another flawed system.
Am I wrong here. Anybody interested in this who can maybe shed some light as to whether PD is a good number to have? Perhaps someone like Sean Reid could weigh in and help us out.
I don't know if anybody has been following the newest trend over at Dpreview. They have started following and charting Pixel Density (PD) as a measure of the quality of a sensor. You can get the background here: http://www.dpreview.com/news/0807/08070301pixeldensity.asp and there are some interesting threads here: http://forums.dpreview.com/forums/readflat.asp?forum=1012&thread=28498478 & here: http://forums.dpreview.com/forums/readflat.asp?forum=1013&thread=28502048
Basically the gist is that the smaller the number the better.
Fuji F100 25MP/cm²
Fuji F40 18MP/cm²
Fuji F30/31 14MP/cm²
DSLRs seem to run between 1.4 and 3.3MP/cm².
The Ricohs are :
Ricoh GR Digital 21 MP/cm²
Ricoh GX8 21 MP/cm²
Ricoh R4 24 MP/cm²
Ricoh GR Digital II 25 MP/cm²
Ricoh GX100 25 MP/cm²
Ricoh R8 35 MP/cm²
The Canon is:
Canon PowerShot G9 28 MP/cm²
Look at some of the older smaller mp models:
The 5MP Nikon Coolpix 5000 8MP/cm²
The 3MP Nikon Coolpix 990, 995 8MP/cm²
The 2MP Olympus C-2100 UZI 6 MP/cm²
The 1.3MP Olympus E-100 RS 4 MP/cm²
It seems to me that there is much more involved here. First you have to compare models with similar mp counts to judge image quality at a particular print size. I am not sure that pixel density is the whole story. Not being an engineer I am sure that my thinking may be flawed but I thought that the size of the pixels really mattered. Just having less of them per cubic cm doesn't help if they are small and poor quality. Also, camera processing, lens sharpness and contrast and many other variables come into effect here.
For example, just looking at the test crops at Dpreview for these cameras the Nikon CP5000 has a PD of 8MP/cm² while the Fuji F31 has 14MP/cm². They have roughly the same MP and by the PD the Nikon should be a better camera. Look at the noise crops and it is clear that the F31 has much lower noise characteristics than the Nikon.
This is just one example but I think that as you went through and actually compared real life output and correlated it with PD it may not be all that cut and dried. Look at the small MP cameras and the PD numbers are 4 to 6MP/cm². But my main interest is in the quality of a certain print size. Even at 25MP/cm² the 10mp GX100 would certainly make a much better 11x14in print than the 1.3mp Olympus E-100 RS with its' 4MP/cm².
Dpreview is including pixel density numbers with all of their camera reviews. They say that it gives a clearer picture of image quality than just megapixels. While I agree with that it certainly is not the end all here. I would hate to see another flawed way of evaluating sensors by numbers to replace another flawed system.
Am I wrong here. Anybody interested in this who can maybe shed some light as to whether PD is a good number to have? Perhaps someone like Sean Reid could weigh in and help us out.
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