Dieter wrote:
[ Did you mean to not cc the OH list? ]
No.
1. It should support 24 bit color JPEG2000 (both lossy and
lossless) compression. JPEG is basically obsolete and I can't help
but wonder why it is still the standard format for digital
cameras since the artifacts seriously degrade images --
actually worse >>
than lower resolution would be.
Most people just take snapshots and don't care about quality.
Yes but ... there are still somewhat serious photographers. Those
that purchased cameras for > $100 in the 70s (when I was selling
them) included serious photographers. I guess that now serious
photographers would be those that use their computer to improve
their photos.
2. The so called RAW format should be Adobe DNG and/or
"OpenRAW" (which isn't actually a format). Is Adobe DNG an open
standard?
Adobe has published it, as they did with PDF.
If it is anything like PDF I want nothing to do with it. PostScript
is good, but PDF is an unending source of problems. :-(
Only the future can tell if there will be issues like with PDF.
However, PDF is a standard and there is a lot of non-Adobe software that
uses it.
For still images what about png?
Would that be better or worse than lossless JP2K? IAC, this is going to
have to be an image with a bit depth greater than 8 bits per color but
with only one color per pixel along with a block of data. Actually, the
image is monochrome and it just needs the info to show the arrangement
of the Bayer filter array.
Seems like it would be easy to give the user lots of choices of >
formats, including "write your own".
Doesn't seem like a good idea. A standard is needed.
There are plenty of standards to choose from. If someone wants to
create a new improved standard, they need an Open Camera to test it
on.
Actually, the problem is that every camera, or brand of camera, has its
own undocumented RAW format:
http://www.openraw.org/
This is the major reason that this is an open hardware issue.
4. Then there is the problem of remote control of the
camera; it appears that there are no standards here. A
computer connected by Ethernet, IEEE-1394, or USB (a camera
would probably have only one of these) should be able to
display the live preview image, obtain exposure and focus
information, and control all aspects of the >>
camera that can be controlled on the camera.
And infrared remote, which can be handy for some applications.
I presume that you mean without having to use a laptop.
A wire to a computer would be usable for studio shooting, but would
be problematic in the field. It is hard enough keeping the camera
dry.
Maybe attach a PDA (Palm pilot or whatever) to the back of the
camera?
I read a review of my camera by a photojournalist that mounted the
camera up on a wall (or something like that) at some event (press
conference?) and controlled it with the remote. The remote is like a
small TV/VCR remote. RF instead of infrared might have advantages.
Ideally you'd want a camera ID to allow controlling multiple cameras
without one camera responding to commands intended for a different
camera.
Yes, you could have a WiFi trancever for the camera with a place to set
the camera ID code.
Hmmm, manual shows a jack for a LANC cable. Local Application
Control Bus.
I thought that that was only on large format cameras.
There are three variables with a digital camera. Shutter,
Aperture, *AND* the ISO setting. So, you should be able to set any
two of them that you choose and if the third falls into the
available range, then it should work.
How do you change the sensitivity of the sensor? I'd think it was
fixed. As far as I can tell my camera doesn't allow changing the
sensitivity.
That is what happens when you set the ISO on the camera.
Does anyone make a high resolution display that is small enough
to >
use on a camera? My video/still camera only captures 720x480, even
in still mode, but even so the viewfinder resolution is a lot
lower > than that, so I can't tell how much detail I'm getting. I
suppose > with the 12 Mpixel (or whatever they're up to this week)
sensors you
can just assume you're getting a lot of detail, but I can't
assume that with only 720x480. With video, even 1920x1080 isn't
enough to assume you're getting the detail you want.
You can use the LCD for a high resolution preview.
I suppose with an OpenCamera you could program it to zoom in and then
scroll.
The LCD on the back shows the whole image.
If the camera has a focus meter, you don't need full resolution for
the EVF.
I'm not talking about focus. I don't even know what a focus meter
is.
A focus meter is what you have when you have an auto focus camera and a
manual focus lens. Like with the Nikon F3 and the auto focus finder.
Say you want a shot of small text and you want to make sure that the
text is readable. With only 720x480 or even 1920x1080 it might not
be. With 14 Mpixel that shouldn't be a problem. And I kinda doubt
that anyone makes a 14 Mpixel display.
The optical finder isn't going to do that either. You normally have a
higher resolution LCD on the back of the camera. But it probably isn't
full resolution either when showing the full frame. So, it would be a
useful feature to be able to show full resolution on the LCD (on the
rear of the camera).
Or, if the EVF is removable, then those that want a high resolution
(and large) viewfinder can purchase one. Some people use the LCD
and a hood and eyepiece. They don't need any additional
viewfinder.
I don't want a large screen in the field.
Most digital still cameras have an LCD on the back. Larger ones are
becoming a common feature. But they are not usually full resolution
either. I don't even know if 4096x3072 LCDs even exist in any size.
Actually, you only need one half that size 2048x1536 with a Bayer CFA
sensor to preview the image with no processing.
Large format backs have a Peltier cooler to cool the sensor chip to
reduce noise.
How do they prevent condensation?
That is a good question! This is limited to the moisture in the air in
the camera or between the protective glass and the sensor. After it
gets to 0 C, won't the condensation (now frozen) evaporate (actually
sublime)? IAC, if there is a protective glass over the sensor, a
desiccant will solve the problem.
I suppose with large format, lugging a giant battery around isn't a
problem since everything is big and heavy anyway.
I doubt that it takes much current to cool a chip to below 0 C. Note
that large format digital is 48x36mm. Formats larger than that are
scanner backs for studio use on still subjects.
Large format digital backs (for 120/220/70mm cameras) aren't small, but
I think that the battery is contained in them. So, it is actually a
matter of hauling extra batteries around.
If an external battery, it is probably something that could hold 6 or 8
'C' cells for a large one or something that you could attach to the
camera for a small one (like some SLRs now have). DSLRs already have a
large battery since it takes a motor to cock the conventional focal
plane shutter in a fraction of a second.
You need an external battery pack that you can put in your pocket for
cold weather. These usually use 'AA' cells so if that is what you would
be using, it is about more batteries to put in the pack.
What I'd like to see is a good interface to allow the user to
select what part of the screen they want to be in focus. And
have a button to semi-lock the focus. The auto focus would still
track the object if it moves slightly, but is prevented from
jumping to another object that is closer/farther away.
Yes, I think that serious photographers would like to be able to
use auto focus like a range finder except when shooting actions
shots. What I would like is to have a center circle and you push
the button if you have power focus and it focuses and then you
release the button and it stops unless you turn it on full time.
That sounds good. It would conserve battery life as well.
Also should have depth of field preview. (push button, lens stops
down)
Similar interface for auto exposure.
??
All the world is not 18% gray and uniformally lit. I'm not a big fan
of average or center weighted average metering. It makes sense for
the snapshot crowd, but I miss the meter my Canon FTb had. There was
a rectangle (12% of area comes to mind, but it was along time ago so
that might be wrong) that was metered, the rest of the image was
ignored. Point the rectangle at something you thought would average
out and meter it. Reframe and shoot. Some cameras had a 1-3% circle
instead.
Again, we are talking about emulating film. We need to make a shift to
using the capabilities of digital.
With an OpenCamera and electronic sensor instead of film you could
program whatever type of metering you like.
Yes, a digital camera already has the ultimate auto exposure system in
it -- the image sensor. The issue is what to do if the entire
brightness range won't fit into the RAW format. Basically, you then
need some way to determine the brightest highlight to save. You would
do it this way because with digital highlights burn out totally to white
rather than first loosing contrast like they do with film.
The issue here is that with 35mm (24x36mm) that defraction limits
resolution at f/16. Smaller sensors need a large aperture to avoid
defraction. So, you have to use a ND filter to shoot in daylight.
I just looked at the manual and it doesn't say what the minimum
aperture is. bizzare. Works fine in daylight.
If you have a video camera, it probably has a built in ND filter that
works like the built in ND filter in an auto exposure Super8 camera.
These were added to prevent the diffraction problem as well as over
exposure.
But I doubt that the lens is the limiting factor for resolution when
the sensor is only 720x480.
True, it isn't going to matter much till the Airy disk is at least as
large as half the pixel size.
There are advantages to a small sensor. Mine has 1/3" CCD.
Resolution sucks. Low light performance sucks. BUT... it has a 14x
optical zoom (35x digital zoom). I recall 35mm SLR zooms tend to
only go up to 3x.
There are larger ones. The first large one was the Nikon 50-300mm for
24x36mm format. My family had one. GOD! it was heavy. I think that my
brother has it.
14x is *really* nice. The digital zoom is nice when using the camera
as a telescope. Actually usable due to the optical stablization. I
leave the digital zoom off when recording, I can always crop the
image in the computer.
And, I didn't mention. Cameras are getting too complicated -- I
like my F3.
You could deal with complicated in studio shooting, but in the field
you need good ergonomics. The fancy features don't help if you
forget about them or can't figure out how to get into the right setup
menu or whatever. Or if you can't find the right button by feel.
The really complicated ones have too much stuff for buttons. They have
an LCD with menus.
Or if it just takes too long. The shot might disappear while you're
standing there futzing with menus.
Yes, better to capture the data and work on it in the computer when you
get home.
--
JRT
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