camera will probably be a canon EOS-300D DSLR. The will open up a
few areas where the power-shot G2 is hopeless. The G2 however has
some tricks the 300D can't do. I think some camera manufactures
may have taken a wrong turn using SLR technology. I doubt too many
visitors need to be told what SLR is but for the one or two who
don't - read on - everyone else can skip it.
Single Lens Reflex is a system
were the photographer sees what the film will see. In “view”
mode the lens focuses the image onto a screen the same size
(almost) and optical distance from the lens as the film is. This
image path is via a mirror. Usually a penta-prism and eye-piece
are used to allow viewing. The image is right way up and right way
around. A focal plane (ie near the film) shutter is used –
sometime in conjunction with a leaf shutter up front. Metering is
done via the mirror as is auto-focus. SLR lets you see how well
the image is focused and if you stop the lens down you can preview
the depth of field too. When you shoot - the auto-focus/metering
(if used) cuts in first, then the mirror flips up, the film/sensor
is exposed and the mirror pops down again.
NON-SLR DCAMs usually show you what the
sensors sees via an LCD display. This can be external, internal
(Electronic ViewFinder or EVF) or both. In a sense they are “SLR”
like in that you see through the lens (TTL). As I discuss on my G2
page, low-end DCAMs have a number of problems.
aren't of high enough resolution to get good preview, manual focus
is almost impossible because of this and in the case of the G2
using switches to change focus in manual mode is much harder that
turning a focusing ring.
The displays are slow as well, I don't
recall seeing the refresh rate in the specs but they are slow.
Following a moving target is difficult at best.
The other big
problem is shutter lag. Push the shutter and eventually
photography happens - often after the subject has gone. This is
mainly due to slow auto-focusing. These DCAMs use the primary
sensor as the focusing sensor, SLRs usually use dedicated linear
sensor(s) in the reflected path (ie via the mirror). A slow frame
rate on the sensor will mean slow focusing but a slow mechanical
system or electronics may compound the problem. I would speculate
that high end SLR focusing systems may have multiple sensors at
different distances from the lens to tell the system which way to
move instead of just hunting for improvement. Cheap auto-focusing
systems don't do well with moving subjects.
What's wrong with SLR? The
mirror retraction takes time, creates vibration, blacks out the
viewfinder (LCDs freeze too, but are potentially faster), the
whole thing take up space and costs money. The biggest issue for
me is you need to put your eye to the viewfinder.
A dual mode
camera could be built were the mirror can be locked up and then
uses the primary sensor for everything - choose the mode to suit
The Nikon Coolpix 5700 (non slr) is quoted
as having a 70ms shutter lag time – this is quite
reasonable. It has both electronic viewfinder (EVF) and external
LCD (swiveling). The EVF is 180,000 pixels which is not going
compete with a real focusing screen. I've never seen one so I
don't know how well the EVF works. Give it a larger sensor, higher
res/fast EVF and a proper focusing ring and you have my dream
camera – even without removable lenses.
LED (OLED) or some other display technology will be better for EVF
than LCD is. I for one don't need the EVF to be color if I can
have better resolution – but I don't think this would be
popular with most people.
If the 5700 was 6MP or more I'd be
very tempted. My G2 is almost 2 years old now and I'd like the
replacement have a noticeable improvement in resolution. Even
4MP(G2) to 6.5MP (300D) is not a big step up.
Here are some
(G2) photos I could not have taken with an SLR.