Pixel density revisited

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

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.

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.

That being said, Victor Engel has propose a test methodology with a
whole range of output sizes, such a thing would be ideal and is well
within the capabilities of web technologies (look for instance at
what DPR has done with its lens tests)

More catering. Can't you guys figure out how to do your own resizing?

No, they are compared at exactly the same magnification.

How so? Seems to me that you just have to look at the tests to see
that the magnification varies, unless the queen has a head that
changes size from day to day.

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.

It's very useful, and especially if you have the ability to do your
own resizing and modifications to see what you'll get with your
typical workflow and/or printing choices.

What would be useful for that is a range of files to work from such
as presented by Imaging resource. The little clips on DPR are only of
any use for a quick visual comparison, and they are rendered
virtually useless, because the magnification changes in an arbitrary
way, according to the pixel count of the camera. Not only does it
make it hard to judge between pixel counts, it makes it pretty tough
to compare between sensor sizes. Fixed output size would be much more

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

The maximum factory designated native output size of each camera.

Could you advise where I find the native output size that the maker
of my cameras (Canon) has designated. I can't find it anywhere.

The dimensions of the images are there and so is enough information
to determine the magnification.

Not making it easy for us, though

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?

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.

You're going off course.

Off your course, maybe. I think mine's better.

That doesn't make sense. The images on dpreview are easily
downloadable and just as easily modifiable to any size anyone likes.

All I've ever been able to do is download the JPEGS in the clips.
That's vastly different from the original JPEGS or RAW test images.
Maybe it's just that I don't know how to do it, if you could advise?

Apparently you haven't heard of their sample galleries?

And I can't for the life of me see what 'proper' has to do with it.

That's probably why you can't understand the equity in comparing
images at 100% (or other equal percentages of magnification of their
maximum factory designated output size), or the inequity of comparing
them at arbitrary sizes.

Same point on 'factory designated output sizes', could you please
tell me where to find this information.

See above.

What I don't understand is why you keep using morally loaded terms
like 'fair', 'proper' and 'equity'. All I want from a review site is
easy to use information to inform purchasing decisions. It's best
impartial and objective, which is my proble currently with DPR. The
morally loaded terms such as 'fair' and 'proper' only come into it if
you have a preconceived notion of what's right, independent of
results. I'll make my own decisions as to what's 'right' thank you, I
don't need test methods skewed to suit others idea of the agenda for
digital camera development.

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.

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

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.

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