Another sleepless night ?

[GyRob]

The pixcels on the sensor are like film grain on film ,so if i shoot iso 100 on a 8mp camera then shoot on a 24mp camera set at iso 100 would this be like 33 iso compared to the 8mp if both shots were veiwed on a moniter or printed the same size
Rob.

[Woolburr]

I don't think that you can make a direct comparison of that nature. There are a number of other variables that are going to come into play, not the least of which are pixel size and density, sensor size and type. ISO 100 on an 8mp Canon is probably going to look different than ISO 100 on a 24mp Hasselblad to begin with.

[Mark_Cohran]

Film grain is based on how large the silver halide particles clump together when developed. The smaller the clumps (or grains), the less grain. Grain in film could be directly impacted by the development process, so even low ISO film could be made grainier looking if desired. The finer grain of prints made from larger format film is primarily due to the reduced enlargement from the negative. If you were to look at the same size area (say 1 cm2) of a 35mm neg and a 6x6 neg, the grain in the negative would be the same for the same film type and ISO.

Digital noise is essentially the amplification of stray (typically self-heating generated) signals in the sensor sites. Since these sites are evenly distributed across the sensor surface, digital noise looks and acts differently than film grain. Digital noise would be affected more by photosite density (how close the sites are together) which would cause more or less self-heating, rather than the total area of the sensor (format). Theoretically, a large sensor with high pixel density would have more noise that a small sensor with a smaller pixel density.

Mark

[Tdragone]

Last month's PC photo had a review of a 24 MP back for a Hasselblad and it said the pixels were physically larger than that of an APS-C camera.

[GyRob]

THanks for replys on this, i rembember in my film days RB67 the image was so smooth yet sensor's size and how many pixsel's does not seem to work the same way its a shame really when so much extra cost is put into something like a 1dsmk2 yet you dont seem to get that extra cost over say a 20d in IQ.
Rob.

[EOSAddict]

I hope you cure your insomnia soon Rob, cos my brain is now befuddled! ;)

[Kenji]

THanks for replys on this, i rembember in my film days RB67 the image was so smooth yet sensor's size and how many pixsel's does not seem to work the same way its a shame really when so much extra cost is put into something like a 1dsmk2 yet you dont seem to get that extra cost over say a 20d in IQ.
Rob.

Ha... The RB 67 was a real work horse, I sold mine and most of my other film bits, when I went Digital.
However I do still have a DeVere 504 enlarger ( BxW) looking for a good home.