Dario,
(more wordy than I wished)
I think I (we) probably understand your concern, issue, desire for an answer. It's just that there's virtually know valid way to compare images taken with different cameras, sensors, lenses, settings and come up with a meaningful result, or identify the reason for disparate results. If you consistently over and over gain like a different camera, lens, system, then go with it. Overall, I'd be highly surprised that a P&S 4 MP camera could consistently, across the board, at every focal length, aperture, and camera setting (contrast, sharpness, saturation), and post-camera manipulation, outperform a 6 MP *istD with a given lens of X quality. Maybe in some cases, it could... but even that tends to be subjective... what you see versus what I see.
If one prefers image A from a 4 MP P&S camera better than image B from an *istD with a given lens, there's no guarantee one might not prefer an *istD image compared to one from the other system, in a different set of cirumstances.
To make a valid, conclusive appraisal, one must make the playing field equal on a single test, or equal across all tests, and each must be quantified. Otherwise one is saying only that they they prefer their Volkswagen to another's Toyota. That's valid and no one needs to justify it.
Let's begin to differentiate between the camera and the RAW conversion software. Let's differentiate between the lenses, focal lengths, and apertures. Your're speaking to a large audience, many more knowledgable than myself, that just don't accept subjective blanket statements without evidence. So far you haven't provided that scientific eveidence that backs your statements. All you have is subjective assertions and opinions, which you are entitled to hold.
I haven't heard of anyone on the list exhaustively testing '3 different *istD bodies with 15 different lenses' that has compared them to an explicitly stated camera brand A/model B. If that's the case and you have, let's see the unambiguous, undisputable results to back up your statements. You, understandably, probably can't provide this. No discredit to you, we all generalize at times. Without that, let's just say it's your personal and subjective opinion, formed in probably a narrow set of circumstances that have probably not been quantified.
Regarding the pictures on the Pentax website, what is 'an offical Pentax image'? There is no such thing and they only stuck those pictures out on the website for advertising purposes.
Tom C.
From: "Dario Bonazza" <[EMAIL PROTECTED]> Reply-To: [EMAIL PROTECTED] To: <[EMAIL PROTECTED]> Subject: Re: *istD unsharpness Date: Wed, 9 Jun 2004 09:37:10 +0200
William Robb wrote:
> You don't need to be up on the technical details of digital cameras > to see the flaw in a test procedure that uses several different > lenses and conversion algorithms to compare sensor sharpness between > camera brands.
I'm not interested at all in comparing sensors. Does anybody shoot a sensor alone? Such a comparison could only make sense for a design team, prior to choose a new sensor for a new project.
First, I'm interested in understanding the reason for a poorer than expected
performance, and I'm convinced I got some explanation.
Since there are so many people here continuing denying we have a
sharpness/resolution problem, it is very difficult to go beyond this simple
starting point. I'd be tempted to ask all those negating this, to kindly
stay away for a while from this discussion, so that it can go further, but I
understand that it won't be acceptable.
Then, trying to understand which factor is responsible for a so so
performance of a given system, I'm aware there are many risks and I'm far
from considering a simple resize test (on an image obtained by a poor RAW
converter) as a final proof of the best possible results one could obtain by
the *ist D. However, it's at least a good evidence of two problems:
1 - Poor RAW conversion, making harsh unnatural edges. I'm still amazed when
people here continue writing that the Pentax approach is the most film-like.
Such a crap RAW conversion makes a mess of image rendition and makes it
impossible to add the same level of unsharp mask other cameras/camera
systems allow, because it will become too evident.
As most should know, a proper unsharp mask is related to the print size. For
getting good sharpness perception, the proper unsharp mask is the highest
one which is not visible in the print.
2 - I agree the resize down/resize up process is rough, but can be a good indication of image data loss. If you loss no image data during this resizing, your original image contained lesser information than it should. Denying this is swearing black is white.
> Nikon may take sharper pictures because of a better conversion > algorithm, or it may be a higher resolution lens, or it may be > something else altogether.
So, do you agree that Nikon (and Canon, and Olympus, and Fuji...) take sharper and better detailed pictures? If so, we can go ahead with such a discussion, as most replies to my messages negate existence of such a problem. In my experience, I still have to see a picture taken with an *ist D (I tried 3 bodies and 15 or so lenses) allowing blow ups as large as other cameras (either P&S or DSLRs) apparently allow quite easy. Is it possible that all Pentax lenses (including DA, designed to that purpose) are dogs while most lenses by other manufacturers (with the possible exception of the 18-55mm EF-S) are excellent? Very very unlikely. So I believe the conversion algorithm and/or the anti-alias filter in front of the sensor to be the suspected factors.
> If you want to find out who grows the nicest apple, don't throw a > banana into the test and say it's an awful apple.
Yes, but... has the above statement anything to do with current discussion? I'm choosing an apple (an official Pentax image) among apples (aren't we discussing image quality here?) and I'm trying to understand something useful. Nothing less, nothing more. We can use other images too, to get confirmation/denial of my conclusions.
This message is also intended as a reply to all others on the same subject, as I cannot spend so much time doing more here. My apologies to all other folks here, some of which had arguments worth considering.
I never pretend to bear the truth. I only try to understand and when I find something interesting I like to share it with other folks that could be interested too.
Now I have something else to do (sorry, I cannot spend all of my day on this
list), but I have another idea under development. Wait and tremble :-)
Dario Bonazza
