Highest resolution Viewfinder.

In article ,
says...
I don't think that anyone would really need the full resolution of a
6-8 meg image in an eyepiece. Indeed, I don't think many people's eyes
could resolve that. The question is what resolution would be needed in
a satisfactory viewfinder. I don't think any ZLR has attained that but
I wonder if about twice that provided by Minolta would suffice. I
don't own one but examining one in store persuades me they have not
far to go.


--
James V. Silverton
Potomac, Maryland, USA


I think they need to go to twice what is currently available, but I dont
think its going to be achieved soon, because of the size problem.

I have Several EVF cameras, and NONE of them are easily usable for focusing,
even the ones that "magnify" the view when manually focusing are not easy to
use with a "busy" image. There is simply not enough resolution in the EVF.


--
Larry Lynch
Mystic, Ct.

The magnifying bit probably compounds
the problem. I have one of those hood
things that snap over the LCD and it has
a 3x magnifying lens, it just makes the
pixels look larger.

Larry wrote:
[]
I think you may have missed the point I was making (because I was
making it badly).

The point is this:

At this time its NOT POSSIBLE to cram as many pixels into the space
it takes for an EVF as we would like to have.

I really picked up more on the point of manufacturers deliberately
misleading customers about the number of pixels in the EVF or LCD. I
suspect that it would be possible to make a good enough LCD - but probably
not cost effectively just yet.

I used a 640 x 480 EVF (VGA resolution) for a while and it was quite good,
whether I would need twice the number of pixels or even twice the
resolution for my purposes I don't know. I have the feeling that VGA
resolution might actually be good enough.

Certainly, the Panasonic FZ20 has fewer pixels in the display but manual
focussing with the LCD is no problem because of the central area
enlargment as soon as the manual focus ring is moved. I'd be interested
to know how that compares with the "magnifying EVF" cameras you have, as
far as ease of focussing is concerned.

Cheers,
David

irwell wrote:
The magnifying bit probably compounds
the problem. I have one of those hood
things that snap over the LCD and it has
a 3x magnifying lens, it just makes the
pixels look larger.

This is different - they use a smaller area of the sensor and present that
magnified up on the LCD or EVF. It's more like zooming in to 1:1
magnification with your image processing software, and presenting a small,
central selection of that on the viewfinder.

Cheers,
David

David J Taylor wrote:
On the Minolta A2 they have a viewfinder which is VGA resolution -
640 x
480 pixels. This is (in my opinion) highly misleadingly described as

"900,000 pixels" on the camera box and elsewhere - it is just over
300,000
pixels. The is the same resolution as a standard TV.

Standard TV is around 320 x 240 (QVGA; e.g., Quarter VGA).
http://www.micron.com/products/imagi...y/formats.html

--
National Television Standards Committee (NTSC). 4:3
horizontal-to-vertical picture aspect ratio. Most television is
interlaced, not progressive-scan. There are two fields per frame. This
format specifies 525 lines total (242 active lines per field) but not
how many pixels across. Horizontal resolution is typically 330 pixels
across. TV-type pixels are usually not square.
--

wrote:
David J Taylor wrote:
On the Minolta A2 they have a viewfinder which is VGA resolution -
640 x 480 pixels. This is (in my opinion) highly misleadingly
described as

"900,000 pixels" on the camera box and elsewhere - it is just over
300,000 pixels. The is the same resolution as a standard TV.

Standard TV is around 320 x 240 (QVGA; e.g., Quarter VGA).
http://www.micron.com/products/imagi...y/formats.html

--
National Television Standards Committee (NTSC). 4:3
horizontal-to-vertical picture aspect ratio. Most television is
interlaced, not progressive-scan. There are two fields per frame. This
format specifies 525 lines total (242 active lines per field) but not
how many pixels across. Horizontal resolution is typically 330 pixels
across. TV-type pixels are usually not square.

Yes, Kell factor and all that. With today's TVs, though, there can be a
framestore in the receiver which means that the resolution can be nearer
to VGA. The horizontal resolution is much greater than 330 pixels. (For
example, British TV is 6MHz bandwidth and 52us scan time, so that's about
312 cycles per picture width, or 624 pixels. You need a little more than
that to avoid aliasing, and typically 720 and 768 are the number of pixels
across a digital TV picture).

Cheers,
David

wrote:
David J Taylor wrote:
On the Minolta A2 they have a viewfinder which is VGA resolution - 640 x
480 pixels. This is (in my opinion) highly misleadingly described as
"900,000 pixels" on the camera box and elsewhere - it is just over 300,000
pixels. The is the same resolution as a standard TV.

Standard TV is around 320 x 240 (QVGA; e.g., Quarter VGA).

Nope. VGA.

http://www.micron.com/products/imagi...y/formats.html

Claims for NTSC:
"525 lines total (242 active lines per field)"
= vertical 2*242=484 active lines (2 fields = 1 frame)
"typically 330 pixels across"
= 330x484
Claims for PAL (and SECAM):
"625 lines, 290 active lines per field"
= vertical 2*290=580 activel lines (2 fields = 1 frame)
"Typically, it is 425 pixels across"
= 425x580

Both sound very much off base in the horizontal resolution. Yes,
TV pixels are not square, but they are not that much deformed!
Perhaps he means line pairs 'across' (or the much less relevant
chrominance resolution??), so we get 660x484 and 850x580? This ---
though a bit off base --- matches with
http://www.cs.sfu.ca/CC/365/li/mater...4/Chap3.4.html
which says:
NTSC: 720 x 480 luminance resolution
360 x 480 chrominance resolution
1/59.94s per field (1/29.97s per frame) (see other sources)

PAL: 720 x 576 luminance resolution
360 x 576 chrominance resolution
1/25s per field (1/50s per frame)

Note that the eye is much more luminance than chrominance
sensitive (compare JPEG!)

DVDs also use 720 pixel horizontzally. Your TV set may not be
able to display the full resolution, though.

see also:
http://www.labdv.com/leon-lab/video/interlace_en.htm
http://tangentsoft.net/video/glossary.html

Thus we get close to 640x480, i.e. VGA, much closer than QVGA.
VHS, however, only records half the lines and is much closer to
QVGA quality.

-Wolfgang

Wolfgang Weisselberg wrote:
[]
VHS, however, only records half the lines and is much closer to
QVGA quality.

-Wolfgang

I was wondering if the QVGA claim related to a VHS-processed TV picture!

VHS records all the lines by the way (or so I believe, at least in the PAL
system) but does so at reduced horizontal luminance resolution. The
colour resolution is also reduced.

Cheers,
David

http://www.cs.sfu.ca/CC/365/li/mater...4/Chap3.4.html

which says:
NTSC: 720 x 480 luminance resolution

It says, "Ordinary TV -- ~320 lines".


see also:
http://www.labdv.com/leon-lab/video/interlace_en.htm

It says, "CIF resolution [NTSC] 320x240."


"...one needs to know Common Intermediate Format (CIF). CIF refers to
the number of squares of color (pixels) in columns and rows."
http://www.buildings.com/Articles/de...ArticleID=2209

wrote:
http://www.cs.sfu.ca/CC/365/li/mater...4/Chap3.4.html

which says:
NTSC: 720 x 480 luminance resolution

It says, "Ordinary TV -- ~320 lines".

I see no justification for that statement in that document. You can (on
UK TV) quite often see interlace flicker (unless you view with dimmed
lighting to reduce the eye's response speed), which says that information
at close to the limiting resolution is present. That would be 480 lines
(or so) vertically on NTSC or 575 lines on the European PAL standard.

see also:
http://www.labdv.com/leon-lab/video/interlace_en.htm

It says, "CIF resolution [NTSC] 320x240."

It says:

"Note: vertical resolution is less than 525 or 625 lines per image because
some are used for blanking (synchronization). CIF is Common Intermediate
Format, noninterlaced, every pixel carries Luma and Chroma, this format is
less demanding because 1/4 of full size but it carries very accurate data.
Yes, NTSC isn't 30fps but 29.97 !
So we have Luma coded with 720x576 pixels (NTSC 720x485) and Chroma with
360x576 (NTSC 360x485) therefore every line carries meaningful information
and dealing with interlaced video makes sense (versus CIF). "



"...one needs to know Common Intermediate Format (CIF). CIF refers to
the number of squares of color (pixels) in columns and rows."
http://www.buildings.com/Articles/de...ArticleID=2209

This reference to CIF is not relevant here - it is a video-conferencing
format, not an analogue TV format:

http://www.graphics.cornell.edu/DISCOVER/CIF.html

Even analog TV is better than CIF video conferencing!

Cheers,
David