EOS 7D and resolution

Oops. Sorry for the double post. Damn news client said it failed to
send, but it didn't, obviously.

Colin D.

ColinD wrote:

A chain being only as strong as the weakest link, I feel that
resolution is already being limited by most lenses outside
their best apertures at lower than the present megapixels.
(I don't think you'll get a noticeably better image from a wide
open EF 50mm f/1.4 at 18MPix than at 8MPix + sensible upscaling
(e.g. Lanczos scaling) where needed, for a drastic example.)

Even if the lens cannot equal the sensor for resolution, the image will
still be better than with fewer pixels.

Sure, if you use arbitrary wrong definitions for 'better'.

The resultant resolution is
always a function of both lens and sensor. I've pointed this out
several times in the past.

Point out as much as you want. Doesn't mean it's true or relevant.

The maximum resolution obtainable in practical photographic work is
limited both by the camera lens and by the film/sensor. The formula
often used to predict the resolution of a camera original is:

See how you went from "better image" to a "*prediction* of
resolution"?

By your logic infinitely small sensor sizes, unable to capture
even a single photon, would produce 'better' images than any
other sensor with the same lens. Even you should be able to
see several catches with that.

Your claim, *as it stands*, is obviously wrong.

And misses a very important word to be relevant to practical use,
"noticeable" or "visible".

1/Rt2 = 1/Rs2 + 1/RL2 (Higgins, G.C.Appl. Opt. 3, v.1, 9, Jan 1964)

Ah, yes, a formula from the good old days a decade before the
first digital image sensor, back when higher resolution meant
slower films with finer, less notable grain.

As you can see, system resolution is not just lens resolution alone.

I can see that you probably don't understand 'better' or
'noticeable' --- or what tinier pixels do unless you raise the
technology in between.

Maybe you should look at the independent lens test sites and
see if your formula comes up with the right answers as you test
the same lenses at the same format size against different sensor
resolutions ...

-Wolfgang

On Wed, 30 Sep 2009 13:27:15 +0200, Wolfgang Weisselberg
wrote:

ColinD wrote:

A chain being only as strong as the weakest link, I feel that
resolution is already being limited by most lenses outside
their best apertures at lower than the present megapixels.
(I don't think you'll get a noticeably better image from a wide
open EF 50mm f/1.4 at 18MPix than at 8MPix + sensible upscaling
(e.g. Lanczos scaling) where needed, for a drastic example.)

Even if the lens cannot equal the sensor for resolution, the image will
still be better than with fewer pixels.

Sure, if you use arbitrary wrong definitions for 'better'.

The resultant resolution is
always a function of both lens and sensor. I've pointed this out
several times in the past.

Point out as much as you want. Doesn't mean it's true or relevant.

The maximum resolution obtainable in practical photographic work is
limited both by the camera lens and by the film/sensor. The formula
often used to predict the resolution of a camera original is:

See how you went from "better image" to a "*prediction* of
resolution"?

By your logic infinitely small sensor sizes, unable to capture
even a single photon, would produce 'better' images than any
other sensor with the same lens. Even you should be able to
see several catches with that.

Your claim, *as it stands*, is obviously wrong.

And misses a very important word to be relevant to practical use,
"noticeable" or "visible".

1/Rt2 = 1/Rs2 + 1/RL2 (Higgins, G.C.Appl. Opt. 3, v.1, 9, Jan 1964)

Ah, yes, a formula from the good old days a decade before the
first digital image sensor, back when higher resolution meant
slower films with finer, less notable grain.

As you can see, system resolution is not just lens resolution alone.

I can see that you probably don't understand 'better' or
'noticeable' --- or what tinier pixels do unless you raise the
technology in between.

Maybe you should look at the independent lens test sites and
see if your formula comes up with the right answers as you test
the same lenses at the same format size against different sensor
resolutions ...

What would that show?

Wally

Wally

Wolfgang Weisselberg wrote:
ColinD wrote:

A chain being only as strong as the weakest link, I feel that
resolution is already being limited by most lenses outside
their best apertures at lower than the present megapixels.
(I don't think you'll get a noticeably better image from a wide
open EF 50mm f/1.4 at 18MPix than at 8MPix + sensible upscaling
(e.g. Lanczos scaling) where needed, for a drastic example.)

Even if the lens cannot equal the sensor for resolution, the image will
still be better than with fewer pixels.

Sure, if you use arbitrary wrong definitions for 'better'.

The resultant resolution is
always a function of both lens and sensor. I've pointed this out
several times in the past.

Point out as much as you want. Doesn't mean it's true or relevant.

The maximum resolution obtainable in practical photographic work is
limited both by the camera lens and by the film/sensor. The formula
often used to predict the resolution of a camera original is:

See how you went from "better image" to a "*prediction* of
resolution"?

By your logic infinitely small sensor sizes, unable to capture
even a single photon, would produce 'better' images than any
other sensor with the same lens. Even you should be able to
see several catches with that.

Your claim, *as it stands*, is obviously wrong.

And misses a very important word to be relevant to practical use,
"noticeable" or "visible".

1/Rt2 = 1/Rs2 + 1/RL2 (Higgins, G.C.Appl. Opt. 3, v.1, 9, Jan 1964)

Ah, yes, a formula from the good old days a decade before the
first digital image sensor, back when higher resolution meant
slower films with finer, less notable grain.

As you can see, system resolution is not just lens resolution alone.

I can see that you probably don't understand 'better' or
'noticeable' --- or what tinier pixels do unless you raise the
technology in between.

Maybe you should look at the independent lens test sites and
see if your formula comes up with the right answers as you test
the same lenses at the same format size against different sensor
resolutions ...

-Wolfgang

Well, if one removes the sarcasm from your reply, there's practically
nothing left of it. *Of course* resolution is a function of both
film/sensor and the lens. If it were not so, then every lens would
deliver an image dependent only on lens resolution, regardless of sensor
resolution, a conclusion that is patently incorrect. Whether you can
'notice' a 'visible' difference depends on the manner in which you view
the image, but that is irrelevant; a difference will exist whether you
can see it with naked eye or not.



And the age of the formula is totally irrelevant also - or has E=MC^2
passed it's use-by date as well?

--

Colin D.

ColinD wrote:

I see you still misuse other peoples' domains and email addresses.

Well, if one removes the sarcasm from your reply, there's practically
nothing left of it.

Sure, if you relabel valid criticism --- like pointing out your
asocial misuse of the email address you knowingly falsely claim
as yours --- as sarcasm ...

*Of course* resolution is a function of both
film/sensor and the lens.

Obviously. Even
R = min(R_S, R_L)
is a function of both sensor and lens.
Now go away with your strawmen and *prove* your 'equation'.
You can find some data at photozone.de --- you should be able
to correlate the observed resolutions for the same lens/focal
length/aperture settings at different sensor resolutions.

But of course that would be work and it would turn out that your
claim is neither as clear-cut nor as correct as you'd like it
to be.

Whether you can
'notice' a 'visible' difference depends on the manner in which you view
the image, but that is irrelevant; a difference will exist whether you
can see it with naked eye or not.

A difference that has no impact has no relevance.
Differences that cannot be seen are thus irrelevant to visual arts.

Of course, that truth will be labled 'sarcasm' by you.

And the age of the formula is totally irrelevant also - or has E=MC^2
passed it's use-by date as well?

Not yet(!). It may yet end as phlogiston did, or be outdated Newton's
laws of gravitation --- the future will tell.

-Wolfgang

Wally wrote:
On Wed, 30 Sep 2009 13:27:15 +0200, Wolfgang Weisselberg

Maybe you should look at the independent lens test sites and
see if your formula comes up with the right answers as you test
the same lenses at the same format size against different sensor
resolutions ...

What would that show?

It would show if the formula was correct. Spot checks say
it's off.

-Wolfgang

On Thu, 1 Oct 2009 15:09:46 +0200, Wolfgang Weisselberg
wrote:

Wally wrote:
On Wed, 30 Sep 2009 13:27:15 +0200, Wolfgang Weisselberg

Maybe you should look at the independent lens test sites and
see if your formula comes up with the right answers as you test
the same lenses at the same format size against different sensor
resolutions ...

What would that show?

It would show if the formula was correct. Spot checks say
it's off.

You are not very convincing!

Wally

Wally wrote:
On Thu, 1 Oct 2009 15:09:46 +0200, Wolfgang Weisselberg

What would that show?

It would show if the formula was correct. Spot checks say
it's off.

You are not very convincing!

Tell me, what would convince you?

-Wolfgang

Sorry for the late reply. My ISP discontinued their usenet server
(probably because they don't want to tarnish their image by storing
copyright infringements and under-aged models and such).

Rich wrote in
:

Was that posted online somewhere?

Someone linked to it in DPReview, from rapidshare, but I don't think it is
there anymore. There was an 8-column periodic cycle of about 18 14-bit
ADU, IIRC, in the blackframe. The same pattern repeated in other frames,
at other ISOs. It is something that could be fixed if Canon just put a
self-calibration routine in the camera, accessible by the user. Even if it
couldn't be calibrated in the electronics by the user, the RAW data could
easily be re-written to remove the pattern.

I have a 7D pre-ordered from Amazon. I feel like I am at a casino,
gambling on IQ, because of Canon's poor QC. I hate having to erode my
relationship with a vendor to keep returning things to get a good copy.
Canon should bear the brunt of all their sloppiness - then they wouldn't be
sloppy for very long.

Wolfgang Weisselberg wrote in
:

It seems a lot of people are, uhm, a bit megapixel crazy.

Other than the increased storage requirements and processing speed, what
is crazy about resolution? You really don't have enough pixels (in terms
of proper sampling) until it takes about 3 pixels exclusive to transition
a sharp black/white subject transient, with your optics. Historical
digital cameras image poorly, and if you print at any good size or crop,
the pixel structure becomes immediately apparent, and all its artifacts.

A chain being only as strong as the weakest link, I feel that
resolution is already being limited by most lenses outside
their best apertures at lower than the present megapixels.
(I don't think you'll get a noticeably better image from a wide
open EF 50mm f/1.4 at 18MPix than at 8MPix + sensible upscaling
(e.g. Lanczos scaling) where needed, for a drastic example.)

Hardly. The noise is finer, and there is less alisasing in the 18MP
version. Low-MP images are fragile things; they only capture some of the
detail at the highest image frequencies they capture, as it depends on
luck of pixel and subject alignment, and then what you do capture at
those highest frequencies are prone to loss with any king of geometric
manipulation, like rotation, perspective correction, CA correction, etc.

And that Canon may have concluded that that's where the future is, at
least in the near term. Your vigorously defensive reaction syggests
to me that you may secretly suspect that I'm right. ;^)

Canon has concluded that they need to sell cameras and to sell
cameras they need to compete in features and marketing numbers.
Megapixel record numbers belong there.

Except for some specimen-variable vertical banding patterns at low ISOs
on the 7D (invisible for so-called "proper exposures", for the most
part), the 7D has the best IQ of any APS-C to date, while having the
highest pixel density as well. In fact, I expect the 7D to be more
usable than my 5D2 in low-key images at extremely high ISOs, because the
7D is very lacking in line noise, especially horizontal banding with
nyquist component, which causes color lines (the vertical is lower-
frequency and is more of a luminance noise).

If suddenly a serious part of the camera buyers(!) would decide
cameras needed to look like puppys and smell of burned toast ---
well, Canon would be stupid to not offer them exactly that.

As for *me*, that's not where *my* future lies, yes.

Sometimes the populous is right by accident, which is the case, IMO, with
pixel resolution.