Having read this thread for a while now, I have a few random thoughts:
1. I have a 645 camera that fits fine in my hand. I never felt cheated
that my 35 mm cameras couldn't take a larger format even the advantages
of the larger format are obvious. The very definition of the 24x36
sensor as "full frame" is just because that's how big you can make a
sensor that works with the legacy 35 mm lens designs. If for some
reason a smaller film format had been dominant (APS-C, for example) this
would be a really different discussion.
2. Of course a larger sensor is better with regard to noise. The
important question is if the smaller sensor is "good enough". If the
price of FF sensors come WAY down, then of course Pentax will have to
produce a camera using them. The question for Pentax is how expensive
that high end camera could be and are they better off chasing the 645D
market. Those prices have to come way down before this becomes much
more than a professional camera issue. If there was a full frame K10D
for $2000 USD I'm not sure how much market impact it would have. So for
me, there is a big reason not to buy a FF DSLR now: COST.
BTW, I just picked that number out of the air; I have no idea what the
cheapest FF DSLR costs.
Steve
>>> "Bob Blakely" <[EMAIL PROTECTED]> 10/15/2007 2:22 PM >>>
Yes. But ultimately, eventually, it's sensor size, whether they're
chemical
or electronic photon catchers, that determines maximum obtainable image
quality. Having a camera whose physical size is pefect for the hand and
can/could accommodate a full frame but has an APS sized sensor really
feels
like a cheat to me and hat disgusts me.
Screw Nikon, Canon and the rest. There are limits to how efficient you
can
make a sensor, any sensor. There is a reason, and or me, valid, why I
will
NOT purchase a lens that will not fill a full frame - and that be
24x36mm or
there abouts.
When I get the time, I'll derive the maximum performance limits (but
never
actually achievable) for both APS and full frame sensors.
Regards,
Bob...
--------------------------------------------------------
"Art is not a reflection of reality. it is the reality of a
reflection."
-Jean Luc Godard
----- Original Message -----
From: "Adam Maas" <[EMAIL PROTECTED]>
> Bob Blakely wrote:
>>>From my point of view...
>>
>> Only so many photons are captured by a sensor element (pixel, if you
>> will)
>> of a given size and that to a certain efficiency. There is an upper
>> limit.
>> Further, everything that has a temperature generates noise in
proportion
>> to
>> that temperature. There is a lower limit.
>>
>> The upper limit can only be expanded by increasing the element size
to
>> capture more photons per element. Maintaining the effective
resolution
>> then
>> means increasing the overall sensor size (to full frame?) The lower
limit
>> can only be pushed further down by operating the sensor at a lower
>> temperature. Currently, the K10D shows noise beginning on the side
where
>> most of the hotter the electronics is located. Red pixels light up
first,
>> then green, then blue. Noise temperature can be further reduced by
>> active
>> cooling. I suspect that this is not likely to happen with digital
cameras
>> any time soon, sensors for astrophotography and other scientific
purposes
>> excepted. Everybody knows this, and ultimately the larger sensors
will
>> prevail. When this happens, lenses with APS size image circles will
>> become
>> as useless, practically speaking, as 8 tracks.
>>
>> Have you noticed that the upper ISO limits for digital sensors and
film
>> are
>> about the same, 1600 and sometimes 3200? Tere is a reason for this
and
>> ultimately it is the physics of noise that produce thes limits.
>>
>> Noise power, N = k*T*B*Nf, where:
>>
>> k = Boltzmann's constant;
>> T = Absolute temperature;
>> B = Noise Bandwidth of the sensor or film;
>> Nf = Noise figure, a measure of sensor efficiency.
>>
>> Bottom line... there are rules and nature enforces them.
>>
>> So... where's my effecient full frame sensor?
>>
>> Regards,
>> Bob...
>
> In the Nikon D3. Improvements in fill factor (reducing the wasted
space
> between sensor sites) have significantly increased sensor performance
by
> increasing the effective area of the sensor sites by a fair margin.
The
> current crop oof 10/12MP APS-C sensors are capable of ISO6400 with
> quality superior to the old ones at 1600-3200, and can match a 5D at
> 1600-3200. The D3, which is unique in being a low-density sensor
with
> the new sensor tech, is capable of natve ISO 6400 (the cropped
bodies
> achieve it in Boost) and boost up to ISO 25,600. From the posted
samples
> 6400 on the D3 looks as good as 1600 on the similar-density 5D did,
with
> similar amounts of detail.
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