Pixel density revisited

Started Oct 22, 2008 | Discussions thread
natureman Veteran Member • Posts: 3,979
Re: Pixel density revisited

bobn2 wrote:

natureman wrote:

bobn2 wrote:

Jonathan Demarais wrote:

Phil Askey wrote:

Did you read the rest of the review? The original point was that the
pixel density figure provided in the specs database should not be
used as a predictor of image quality alone.

So lets draw a line. What pixel density, given current sensor
quality, what is the highest pixel density where you can stiil get
reasonably good images?

I'm not sure that the position of this limit has been definitively
defined yet. If you look at this thread from John Sheehy:
http://forums.dpreview.com/forums/readflat.asp?forum=1018&thread=28607494&page=1

You will see a demonstration that the 1.97um pixels from a Panasonic
FZ40 outperform on an area for area basis the pixels from a Canon
40D. That's a pixel density of 26 MP/cm². If you made a FF sensor
form those pixels it would have 222MP, and you could extract a pretty
decent image from it.
--
Bob

That's FZ50, not 40. That comparison is baloney. I have an FZ50, and
while I can get a pretty decent image from it, it doesn't come close
to a larger sensor with a lower pixel density, especially at high
ISOs and/or in low-ish light.

Yes it was FZ50, my typo. No, it isn't baloney. The key thing you
said there was 'larger sensor'. John's test compares the same size
patch of a 40D sensor and a FZ50 sensor, with the same focal length
and same exposure. The image from the patch of the FZ50 is clearly
much better. Thus, if you made a sensor the same size as the 40D from
FZ50 pixels, that superiority would be passed on. What I don't
understand is why people go on about pixel density and then use
different sensor sizes to justify their argument. It is clear that
generally a larger sensor produces less noise than a small one. Pixel
density doesn't really come into it.
--
Bob

Well, I was going to add "or the same size sensor with lower pixel density", but I didn't think it was necessary to make my point.
.

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