When will electonic viewfinders improve?

Archived from groups: rec.photo.digital.slr-systems (More info?)

RichA wrote:

> Right now, in some instances using non-autofocusing long lenses,
> they are very poor for trying to focus. What is needed are
> finer pixels in these things. I'm wondering if they've reached
> a wall since I've seen no improvement in viewscreens in five years.
> -Rich

Monitors are poor ways to focus a shot, and on most (all?) SLR's you can't
anyway as the scene is directed up to the optical viewfinder. This has always
been the great advantage with SLR: the viewfinder shows you the scene as it will
be recorded including focus and DOF (if DOF preview equipped).

Optical viewfinders since AF came along have become a little bit less accurate
than the 70's ish split prism manual focus which is very accurate.

The viewscreen on the Maxxum 7D is 207,000 pixels, but also larger. IAC, there
is no way to image the scene with the shutter closed and mirror down.

The EVF on the Dimage A2 is about 922,000 pixels, so perhaps focus is possible
there to greater accuracy.

http://www.dpreview.com/news/0402/ [...] magea2.asp

Cheers,
Alan

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Archived from groups: rec.photo.digital.slr-systems (More info?)

Alan Browne wrote:
[]
> The EVF on the Dimage A2 is about 922,000 pixels, so perhaps focus is
> possible there to greater accuracy.

Be aware that these are Sigma-Pixels (TM)! Each RGB is counted
separately. It's actually a 640 x 480 VGA display - just 307200 RGB
pixels.

David

Archived from groups: rec.photo.digital.slr-systems (More info?)

David J Taylor posted:
> Alan Browne wrote:
> []
> > The EVF on the Dimage A2 is about 922,000 pixels, so perhaps focus is
> > possible there to greater accuracy.
>
> Be aware that these are Sigma-Pixels (TM)! Each RGB is counted
> separately. It's actually a 640 x 480 VGA display - just 307200 RGB
> pixels.
>
> David

Sorry for the previous post, my bad.

--
Petros
Ap' ola prin ipirche o Logos

Archived from groups: rec.photo.digital.slr-systems (More info?)

David J Taylor wrote:

> Alan Browne wrote:
> []
>
>>The EVF on the Dimage A2 is about 922,000 pixels, so perhaps focus is
>>possible there to greater accuracy.
>
>
> Be aware that these are Sigma-Pixels (TM)! Each RGB is counted
> separately. It's actually a 640 x 480 VGA display - just 307200 RGB
> pixels.


Good point. I've go to read the fine print!

I wonder why the claim 922K pixels then? The Minolta site says:

"The A2’s 922,000-pixel TFT LCD delivers clear images and sharp, contoured
information."

Are the R,G,B's spatially separated? If so, then it is little different than
calling an 8MPix R,G,B sensor 8 Mpix.

Cheers,
Alan


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Archived from groups: rec.photo.digital.slr-systems (More info?)

RichA wrote:

> On Mon, 20 Dec 2004 13:51:04 -0500, Alan Browne
> <alan.browne@freelunchVideotron.ca> wrote:
>
>
>>RichA wrote:
>>
>>
>>
>>>Interesting looking new camera. The "apochromatic" lens is a
>>>question. True apochromatism means three primary colours infocus
>>>at one point = no colour error, but I'll believe it when I see it
>>>as all these prosumers have noticeable chromatic aberration.
>>
>>
>>APO does not mean eliminates chromatic aberation, but it does of course reduce
>>it significantly. There are many APO lenses out there, I have three (1 prime, 2
>>zooms).
>>
>>Cheers,
>>Alan
>
>
> This guy sells telescope optics that make Zeiss camera lenses look bad
> by comparision:

I won't challenge that statement as I'm more ignorant about telescope optics
than Zeiss optics... and I'm pretty ignorant there too...

The fellow below does say enough to show that even if his optics are fantastic
APO's, they cannot possibly correct every wavelength of light coming through the
pipe. There will be some perfect matches, and many-many very-very close, but
not perfect.

Cheers,
Alan


>
> Defining Apochromatism
> by Thomas Back
>
> Updated 6-29-03
>
> With the proliferation of apochromatic refractors that are available
> to the amateur astronomer, it is time to define the parameters of a
> true apochromatic objective lens. The modern definition of
> "apochromat" is the following: An objective in which the wave
> aberrations do not exceed 1/4 wave optical path difference (OPD) in
> the spectral range from C (6563A - red) to F (4861A - blue), while the
> g wavelength (4358A - violet) is 1/2 wave OPD or better, has three
> widely spaced zero color crossings and is corrected for coma.


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-- e-meil: there's no such thing as a FreeLunch.

Archived from groups: rec.photo.digital.slr-systems (More info?)

David J Taylor wrote:

> Alan Browne wrote:

>>"The A2’s 922,000-pixel TFT LCD delivers clear images and sharp,
>>contoured information."
>>
>>Are the R,G,B's spatially separated? If so, then it is little
>>different than calling an 8MPix R,G,B sensor 8 Mpix.
>
>
> Marketing - why else lie?
>
> Like all LCD/TFTs, there are RGB triplets. To reduce the triplet
> visibility, the alternate rows may be staggered by 1.5 pixels
> horizontally.
>
> I don't see it in the same light as calling cameras 8MP. On the camera
> 8MP of RGB are actually delivered, with an interpolation process from the
> 2M sensor quads. The viewfinders cannot be driven with 0.9M RGB triples,
> just 0.3M. Please don't suggest that we should start naming monitors the
> same way we name cameras! I have a 3072 x 768 monitor! <G>

I suspect you're right. The possibility exists that the pixel components of a
triplet are in fact spatially seperate, in which case the 0.9M is a true claim.
What is most likely is that they follow the VGA spec, so the monitor h/w is
dividing a pixel into its color components, so 0.3M is correct.

Cheers,
Alan


--
-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: there's no such thing as a FreeLunch.

Archived from groups: rec.photo.digital.slr-systems (More info?)

David J Taylor wrote:

> Alan Browne wrote:

>>I suspect you're right. The possibility exists that the pixel
>>components of a triplet are in fact spatially seperate, in which case
>> the 0.9M is a true claim. What is most likely is that they follow
>>the VGA spec, so the monitor h/w is dividing a pixel into its color
>>components, so 0.3M is correct.
>>Cheers,
>>Alan
>
>
> Alan, in both CRTs and LCDs the R, G and B elements are spatially
> separated. Take a loupe to them and check for yourself.

I realize that. What I meant was if the source pixel (with RGB info in it) is
decomposed and presented as spatially seperated R,G,B pixles, then the display
is truly .3M.

> Are you suggesting that my LCD monitor would be more correctly described
> as 3072 x 768 pixels or 1024 x 768 pixels? I would take issue if you
> were! I view it (no pun intended) as 1024 x 768 true-colour pixels, not
> as 3072 x 1024 single-colour pixels.

I'm sure that is the case, for the reason I describe above.

But if the sptially seperated R,G,B's in the display represented spatially
seperated information from the sensor, then the spatially seperated information
in the display would be 0.9M.

In the end, they are likely driving a VGA spec'd device, and so it is 0.3M.

Cheers,
Alan
--
-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: there's no such thing as a FreeLunch.

Archived from groups: rec.photo.digital.slr-systems (More info?)

David J Taylor wrote:

> Alan Browne wrote:
> []
>
>>But if the sptially seperated R,G,B's in the display represented
>>spatially seperated information from the sensor, then the spatially
>>seperated information in the display would be 0.9M.
>
>
> OK, I see what you mean. I'm sure it's not the case as you would have to
> "bend over backwards" to dematrix from the sensor quad and re-matix to the
> RGB triples!

Never question what a software weenie will do with a pile of twinkies and a
bootle of Coke at his side will do at 2 am.

(To think of the weekends I passed in the lab 'just to see if...')

Cheers,
Alan


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-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
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-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: there's no such thing as a FreeLunch.

Archived from groups: rec.photo.digital.slr-systems (More info?)

On Mon, 20 Dec 2004 23:07:30 -0500, Alan Browne
<alan.browne@freelunchVideotron.ca> wrote:

>RichA wrote:
>
>> On Mon, 20 Dec 2004 13:51:04 -0500, Alan Browne
>> <alan.browne@freelunchVideotron.ca> wrote:
>>
>>
>>>RichA wrote:
>>>
>>>
>>>
>>>>Interesting looking new camera. The "apochromatic" lens is a
>>>>question. True apochromatism means three primary colours infocus
>>>>at one point = no colour error, but I'll believe it when I see it
>>>>as all these prosumers have noticeable chromatic aberration.
>>>
>>>
>>>APO does not mean eliminates chromatic aberation, but it does of course reduce
>>>it significantly. There are many APO lenses out there, I have three (1 prime, 2
>>>zooms).
>>>
>>>Cheers,
>>>Alan
>>
>>
>> This guy sells telescope optics that make Zeiss camera lenses look bad
>> by comparision:
>
>I won't challenge that statement as I'm more ignorant about telescope optics
>than Zeiss optics... and I'm pretty ignorant there too...
>
>The fellow below does say enough to show that even if his optics are fantastic
>APO's, they cannot possibly correct every wavelength of light coming through the
>pipe. There will be some perfect matches, and many-many very-very close, but
>not perfect.
>
>Cheers,
>Alan

They do their best, but the fastest lens set I've seen that was
truly apochromatic was about f5. Faster than that and it's very
difficult or impossible with current technology.
-Rich
>
>
>>
>> Defining Apochromatism
>> by Thomas Back
>>
>> Updated 6-29-03
>>
>> With the proliferation of apochromatic refractors that are available
>> to the amateur astronomer, it is time to define the parameters of a
>> true apochromatic objective lens. The modern definition of
>> "apochromat" is the following: An objective in which the wave
>> aberrations do not exceed 1/4 wave optical path difference (OPD) in
>> the spectral range from C (6563A - red) to F (4861A - blue), while the
>> g wavelength (4358A - violet) is 1/2 wave OPD or better, has three
>> widely spaced zero color crossings and is corrected for coma.

Archived from groups: rec.photo.digital.slr-systems (More info?)

nospam wrote:

>
> twinkies are the sponge cake with cream filling, not the chocolate
> cakes (which are ding dongs i think).

Thanks for confirming my inexpertise in the matter.



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-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: there's no such thing as a FreeLunch.

Archived from groups: rec.photo.digital.slr-systems (More info?)

Alan Browne wrote:
> nospam wrote:
>
>>
>> twinkies are the sponge cake with cream filling, not the chocolate
>> cakes (which are ding dongs i think).
>
> Thanks for confirming my inexpertise in the matter.

I can see we all have a lot to learn! BTW: my first job was in an
electronics factory making laser equipment - it was originally the McVitie
and Price factory where Jaffa Cakes were invented! BTW: Jaffa Cakes
created a problem for the tax man. Are they taxed as biscuits or as
cakes? Different tax rates!

http://www.bbc.co.uk/dna/h2g2/alabaster/A185104

has some (possibly incorrect) information.

I can recommend Jaffa Cakes while you are waiting for your pictures to
print!

David

Archived from groups: rec.photo.digital.slr-systems (More info?)

In message <cq9ra0$q55$1@inews.gazeta.pl>,
Alan Browne <alan.browne@freelunchVideotron.ca> wrote:

>But if the sptially seperated R,G,B's in the display represented spatially
>seperated information from the sensor, then the spatially seperated information
>in the display would be 0.9M.

... and how then, do you represent full luminance in a blue cell?
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS@no.komm>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><