Pixel density revisited

Started Oct 22, 2008 | Discussions thread
bobn2
bobn2 Forum Pro • Posts: 61,125
Re: Pixel density revisited

natureman wrote:

bobn2 wrote:

natureman wrote:

What's irrelevant is to expect a review site to cater to your every
whim and post image sizes that are exactly what you (or anyone else)
may arbitrarily choose to print.

Who has ever asked them to do that?

You and some others here.

Where have I done so? I don't remember ever asking that, but maybe my memory is failing.

The point being made is that if
cameras are tested at equal output sizes it is easier to extrapolate
that to your desired output size than it is to extrapolate from a
variety of different scales.

There you go again, expecting dpreview to cater to you.

As I said, it is the role of a review site to predigest information, otherwise one might as well do all the testing for yourself. It's easy not to ask the review site to cater for you when it already does. All I'm suggesting is that its not wise for a review site to cater for the misinformed, and even less wise to misinform itself.

They're shown and compared at the maximum factory designated native
output size, not at the same magnification of the subject. A camera
with more megapixels produces a larger picture. It's supposed to,
afterall.

There you go again. I asked you where I could find that, and you didn't answer. The reason is simple, there is no such thing as a 'factory designated native output size'. This is a fantasy of your imagination. If you think this is unfair to you, then please find a reference of a factory designating a native output size. If it was such an obvious or important thing, you'd find it in all the manuals and probably the ads as well.

It's not arbitrary. It's according to the pixel count of the camera.

That's any less arbitrary than relating it to the size of the sensor? It's only in your mind that the pixel count has an unbreakable and absolute link with final image size.

Maybe the guys at dpreview should come to your house and walk you
through the process of resizing images and how to figure out
percentages of magnification?

That's an interesting one. How does one work out a 'percentage of magnification' from pixels to an image size?

Huh?? 100% magnification is exactly the maximum factory designated
native output size, of any camera.

Please tell me where to find this, I have never seen it.

You're kidding, right? If not, it's specified on some camera bodies,
and is always in the manual, and in the list of specifications in a
review, and on the manufacturer's website, and a bunch of other
places. If you have a 50D, it's 15.1 mp, 4752 x 3168 pixels. A 100%
crop is any portion of a 100% magnified image.

No, I'm not kidding. I just understand numbers and dimensions better than you. A pixel count is a number. Dimensionless. It has no relation to spatial dimensions. Magnification, according to my dictionary is 'make something look or seem bigger than it really is'. If you magnify a number,you get a bigger number. If you magnify a dimension you get a bigger dimension of the same sort. You can't magnify one sort of thing and turn it into another. Thus if you magnify a pixel count, you get a bigger pixel count. If you magnify the size of the image, you get a bigger image. Nowhere have I ever seen a camera manufacturer designate a 'native output size' for their camera. That's a decision they generally leave to the user.

Apparently you haven't heard of their sample galleries?

I have heard of sample galleries, but DPR (unlike IR, for one) doesn't put their test images in their sample galleries. That makes doing your own analysis tricky.

See above.

See above.

That's funny, coming from you. You and some others keep going on and
on about how unfair the review is to the 50D, whether you use that
word or not, but you act like you don't understand why I use that
word. Hmm.

The issue is not that the review is 'unfair'. I bear no great fondness for the 50D, in fact I generally get accused of being a Nikon troll when I correct misinformation about their cameras. The issue is that the review is misinformation, and it misinforms those whom the 50D would suit well. Misinformation coming from those who hold themselves up as authorities is always something I'm going jump on.

In a comparison, things should be as fair as possible, and comparing
cameras at their maximum factory designated native output size is
fair.

No it isn't, for many reasons, a major one being that there is no such thing as 'factory designated native output size'.

The "results" are there, and they're based on the way dpreview does
its' tests. Just because they don't make the 50D look like the best
camera ever invented, well, tough luck.

...not on me, on all those for whom the 50D would be a good fit, and don't get one because of the misinformation in the DPR review. Tough luck also on all those who could be denied better technology if DPR's campaign against pixel density actually starts influencing camera design decisions.
--
Bob

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