Re: 610 vs 7100
Now don't take all of this too seriously. It's not worth fighting for.
I do understand your point Wayne and I know this is how it worked in analog film: A larger negative had to be enlarged less to produce the same size image. But I thought that since we are dealing with digital, the pixels are not actually enlarged (please correct me if I'm wrong), they are just given to a printer or a screen as means of interpretation. This is why I thought that a 24MP image would have the same definition whether it came from FX or DX.
I think I'm getting lost with a concept here. I wouldn't mind hearing a clearer explanation to ease my brain.
I hope you are not planning to start a fight.
I was unaware of any fight, at least on this topic.
I thought it was a discussion. And I'm not sure I can do it clearer.
Pixels are just a color definition sampled from the original source, an image of the source. They did have a size in microns on the sensor, but thereafter, in the image file, there is no size, i.e. dimensionless, just a color definition for an associated relative dimensionless area. Images can have a ride along arbitrary number (dpi, pixels per inch), just a number, which suggests an arbitrary size it might be printed on paper (and thus defines a pixel size on paper if honored, like 300 pixels per inch), but we are free to ignore it, change it for a better specific goal, or not even print it at all. But just for example, 7 microns sensor pixel to 1/300 inch printed pixel is an enlargement of known definition. Odds are someone or something will resample it first before we see it. On the video screen, we have to view it at 100% Actual size to ever see the original pixels... Yes, there are complications.
I do not disagree that 24 mp is 24 mp, but there is more to it on input.
For example, a compact camera may typically have a sensor in ballpark of perhaps about 8x6 mm size (made up numbers). It might be 16 megapixels today, but we know it does not compete with a 16 mp DX. Perhaps the pixels have similarities (ignoring size, etc), but the lenses - compressing the field of view into a tiny, or a larger area, are not the same. Saying (due to lens resolution if nothing else), there is obviously less detail in the tiny image, and obviously more detail in the larger image. And less detail, enlarged to be same size as the more detail to allow comparing, is simply not the same effect. Enlargement does not create detail. Pixels do not create detail (they hope not to hurt detail). The lens creates detail.
Because, a (same field of view) image projected onto a DX 24x16 mm sensor is larger, and can show more detail, than the image projected onto a 8x6 mm sensor, regardless if both are divided into 16 million pixels. All pixels are not equal. The DX image is larger overall (again, same field of view). An FX sensor is even larger. A smaller image requires more enlargement, which better shows shortcomings of the small image.
Make no mistake, the DX image certainly does have a size, it is about 24x16 mm (about APS film size). And FX is about 35mm film size.
No pixels in film, but this was all true of film too, 35mm, medium roll film, sheet film, etc. It is not about pixels, but I suppose film silver halide particles could roughly substitute in concept for pixels.
I think digital and film works the same way, in that enlargement is detrimental. Larger original images have a better starting point.
Depth of field guides certainly think so, and CoC (while arbitrary) is computed from media size, exactly same concept for both film and digital. Pixels are not mentioned.
