DSLR rant.

Begin rant.
August 2003.
My next 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.
The displays 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 situation.

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.
Possibly organic 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.

The camera was on the ground looking up. I could not have done this without the swivel LCD.

Given time and inclination I could have laid on the ground. However I only had about 5 seconds to take this before the crab walked off.

I was standing in 20 cm of water. I would not have gotten this angle without the LCD unless I sat down in the mud - unpleasant and the pond's owner would have throttled me for damaging his plants.

I did have a film SLR with me and didn't attempt to use it. I would have had to move sticks and grass to get in there. I doubt Hoby would have stuck around.

I held the camera up high.

Same again, the lizard was 2.5 meters up a tree.

On the other hand there have been numerous opportunities missed because of the G2s problems. The LCD is hard on my middle aged eyes and even harder in bright light.
The 300D is expected to be available in Australia in early October. Unless something more suitable is announced before then I am planning on buying one. By the time I'm ready to replace it - EVF may have matured.

End Rant,

PS, I love my 300D – see mygallery for 300D images.

March 2009 - Continued on http://nerdipedia.com/tiki-index.php?page=EVFhybrids

EKM