Ahh. Someone did reply. :)
I understand what you're saying and do not doubt the truth in your words.
However, I use the ill-fated MZ-D as an example... Pentax obviously had a FF
model designed and close to production. Understandably, either the sensor
was of comparatively poor design, or the price point would have been too
high, so it was canned. The size of the lens mount does not seem to be the
factor with Pentax.
I do think camera manufacturers saw and relished the opportunity to sell new
'digital' lenses, especially in the wide-angle ranges. The APS sized sensor
enabled this market, where likely the FF sensor would not have.
Thanks for the Canon info. Weight or size is not an issue for me.
Tom C.
From: Godfrey DiGiorgi <[EMAIL PROTECTED]>
Reply-To: [email protected]
To: [email protected]
Subject: Re: 36mm x 36mm sensor?
Date: Wed, 24 Aug 2005 09:38:39 -0700
On Aug 23, 2005, at 11:35 PM, Tom C wrote:
... I have thought since day 1 of DSLR's, that the APS form factor was
largely a short term tactic to get consumers to buy new lenses to go with
those fancy new DSLR's. Sell APS DSLR's in the short term and 'digital'
glass to go with them. When FF sensors get low enough in price, get all
those new customers to upgrade to FF and sell more FF lenses. ...
That seems too closely related to a conspiracy theory. ;-)
No, the challenge to manufacturers like Nikon and Canon and Pentax, et al,
is this: they had a large range of existing good lenses designed for
film's characteristics and a 24x36mm format. Digital sensors, aside from
being very expensive as the area grows, have different characteristics.
The ideal lens mount for a digital sensor, and the ideal lens design for a
digital sensor, takes into account that the light path should be more
nearly orthogonal to the sensor even at the edges of the frame ... this
implies a lens design which "straightens" the light path, and a larger
mount.
The best compromise to allow compatibility with older lenses as well as
achieve the quality and price points required by the digital camera is to
reduce the size of the format. Moving to approximately half-frame size
allowed the vast majority of existing lenses to work well, does not
increase DoF excessively, and generally allows a photographer's kit to
remain the same with the addition of one-two additional, shorter focal
length lenses. A side benefit is that those additional lenses (and any
others designed exclusively for coverage of the half-frame format size)
can be smaller, lighter, and less expensive for their focal length and
speed.
These decisions were made up to 8-9 years ago. Sensor chip technology has
been very very fast paced in the past decade. Canon, having their own chip
design/fab system, see a market advantage in being at the cutting edge of
the technology and produce new designs faster than all the other vendors.
I don't know whether they foresaw this way back in 1985, but the EOS mount
is unarguably the most suited lens mount for 24x36 format sensors, having
the largest diameter and the shortest registration of any modern AF SLR,
as well as fully electronic coupling of all the lens controls to the body.
This serves the double purpose of fulfilling Canon's take on the backwards
compatibility game (everything in the EOS system is backwards
compatible, presuming we discount the small selection of EF-S lenses
designed specifically for the smaller format sensor cameras) and allows
them the greatest flexibility in designing larger sensors to allow
recouping the lens design/manufacturing cost investment.
That said, EOS bodies and lenses are amongst the bulkiest in the business.
The Rebel film bodies became featherweight by dint of use of very
lightweight plastic structures, pentamirrors, etc, and they've downsized
the 20D and 350D/XT bodies nicely, but that does not reduce the size of
the lenses these bodies must carry, which are designed for 24x36mm
coverage.
For me, one of my biggest priorities, once past a certain assumed level of
resolution and noise qualities, is not speed or fancy body coverings,
bazillions of features ... It's size and weight of the kit I need to
carry. My working style in the past was nearly always one body with
two/three lenses in the bag or two bodies each fitted with a single lens.
I like to walk all day with the kit and photograph the subjects I aim for
in a fluid fashion, without being too obtrusive or constrained by fatigue.
Four to six lbs is what I want the entire bag of gear to weigh, and I
don't want the bag to be overly large or obtrusive in appearance.
The Pentax DSLRs, with a half-frame format sensor, net the quality and the
noise level I need for photographic quality, and the lenses/ bodies are
compact and light. The very inexpensive yet high quality 50mm f/1.4 lens
is a perfect portrait tele, the excellent and also tiny 35/2 is a perfect
normal; the excellent 14/2.8 is a superb ultrawide at the widest FoV point
that I personally find useful and, for such a short focal length
rectilinear with that speed, it is not only small but low priced compared
to the 24x36 format coverage 14s from Nikon and Canon. I can fit two
bodies, each with a lens, or one body and three lenses into a 6lb bag.
I'm all for more resolution, lower noise, and even a larger sensor. But I
want it to fit my overall needs as the current system bits do. As I said
before, a 3:4 or 4:5 proportion format makes good sense to me for my
compositional tendencies: it uses more of the lens' image circle and
implies less wastage of pixels in cropping, and I could easily see an
8-10Mpixel sensor at 18x24 or 20x24 (for full compatibility with current
DA series lenses) being quite attractive.
Godfrey
