[Marcus Rowland]

One of the cameras I've been playing with is an Olympus E-500 which is 4/3 format (NOT micro 4/3). It's an OK camera, I can't say I'm wildly in love with it but since I'm going to be using it mainly to test lenses before selling them on that's really not a problem. What surprised me is the physical size of the thing - it's slightly larger than my Canon 400D, which has an APS-C sensor, and the battery is huge and fairly heavy. It's slightly smaller front to back, but the difference is only about 4mm.

What baffles me is that Olympus didn't follow the example of Pentax, Canon, Nikon, etc. and go for a DSLR design that was backwards-compatible with their older manual lenses, which were generally very good. Or did they do that and abandon the idea so fast that I don't remember it?

[Kunzite]

A good subject. I'll just offer my opinion, hoping I'm not too way off the mark.

First, I believe Olympus' only option was a new mount. They couldn't transition the OM mount to autofocus (had some attempts, but AFAIK last models were manual focus) - I don't know if that was even possible or not. Anyway, with reviving a dead, manual focus system as an alternative, starting fresh was the logical option.

About the sensor, I guess they simply overestimated the sensor costs. They choose a smaller one, hoping to compensate through aggressive marketing and excellent optics (the former I loathed, the latter I envied). Maybe they also decided on the format as being more "modern".
The mistake was, they had a smaller sensor area and no access to mainstream sensors.

[MrKodak]

A good subject. I'll just offer my opinion, hoping I'm not too way off the mark.

First, I believe Olympus' only option was a new mount. They couldn't transition the OM mount to autofocus (had some attempts, but AFAIK last models were manual focus) - I don't know if that was even possible or not. Anyway, with reviving a dead, manual focus system as an alternative, starting fresh was the logical option.

About the sensor, I guess they simply overestimated the sensor costs. They choose a smaller one, hoping to compensate through aggressive marketing and excellent optics (the former I loathed, the latter I envied). Maybe they also decided on the format as being more "modern".
The mistake was, they had a smaller sensor area and no access to mainstream sensors.

I think you're bang on the money there; in the beginning, production cost was very much a factor depending on sensor size and that was almost logarithmic in relation so it made all the sense to try and keep that cost down to enable focus elsewhere.

I also wonder if Olympus didn't look at the advantages of having a more parallel light path to the sensor as they had experience with working in both macro and also had one of the longer flange focal distances in the business.

[Rondec]

I think Kunzite is right. We have to remember that at the beginning of the digital era sensors were really expensive. The *ist D I think was released for 1500-ish dollars for a 6 megapixel APS-C sensor. And that wasn't considered outlandish in 2003. Olympus decided that to keep their costs down they would go with a smaller sensor size and this eventually led to a completely new mount and smaller cameras and lenses.

The problem for Olympus now is that they don't really have much room to work and prices of larger sensors (APS-C and full frame) have come down a bunch.

[Kunzite]

I also wonder if Olympus didn't look at the advantages of having a more parallel light path to the sensor as they had experience with working in both macro and also had one of the longer flange focal distances in the business.

Sure they did, they were making quite some noise about "telecentric design" and how that's superior to everything else
Of course, they "forgot" to say nobody's preventing the others to employ this telecentric design with the existing mounts of the time. And then, m4/3 appeared, which meant small cameras and lenses, and the "telecentric design" mantra was completely forgotten.

[johnha]

Wasn't 4/3 an industry standard or consortium based mount (similar to the L mount today)? IIRC Panasonic and others also used it. It would have provided a common resource pool and user base when early digital sensors were in their infancy (and very expensive).

[Grippy]

Wasn't 4/3 an industry standard or consortium based mount (similar to the L mount today)? IIRC Panasonic and others also used it. It would have provided a common resource pool and user base when early digital sensors were in their infancy (and very expensive).

Yep, a couple of Panasonic's and. a Leica from memory, but mostly Olympus used it.
Their higher end cameras were pretty bloody good, the E3 was one of my fav cameras, I am actually spewing I sold it, still have the E1 though,can't bare to part with it.

[Kunzite]

Wasn't 4/3 an industry standard or consortium based mount (similar to the L mount today)? IIRC Panasonic and others also used it.

It was just a proprietary mount used by more than one manufacturer. Nothing special about that, calling it "standard" was just their marketing misleading people.

[Marcus Rowland]

Thanks - thinking about it, the AF lenses I've seen for the really late 35mm Olympus bodies were horrible, hugely heavy and zero backward compatibility with earlier models. And the cameras sold very poorly. If that's the best that they could do maybe it was a mercy killing. I hadn't thought about sensor costs, that's a good explanation if true. I suspect that they started developing the line fairly early and misjudged how the price of APS-C sensors would fall.

[boriscleto]

Wasn't 4/3 an industry standard or consortium based mount (similar to the L mount today)? IIRC Panasonic and others also used it. It would have provided a common resource pool and user base when early digital sensors were in their infancy (and very expensive).

Four Thirds is a photographic system, similar in concept to Olympus’ OM system for film photography. The name ‘Four-Thirds’ derives from the size and format of the image sensor used in the camera bodies. The system was developed by Olympus in partnership with Kodak and several other photographic companies have also signed up to it to produce lenses, cameras and accessories to the same standard. These companies include Panasonic, Sigma, Fujifilm and Leica.

Four Thirds is not an open standard; Olympus controls access to the design specifications and no unauthorised third-party companies are able to use the Four Thirds logo or create supported peripherals for the system.

Panasonic Lumix DMC-L1 - Camera-wiki.org - The free camera encyclopedia

[MrKodak]

Sure they did, they were making quite some noise about "telecentric design" and how that's superior to everything else
Of course, they "forgot" to say nobody's preventing the others to employ this telecentric design with the existing mounts of the time. And then, m4/3 appeared, which meant small cameras and lenses, and the "telecentric design" mantra was completely forgotten.

And don't forget it is only partly true. Light doesn't just go in a straight line from the top of the lens to the top of the sensor or bottom to bottom.
All the light that is reflected from an object and strikes anywhere on the surface of the front lens goes through the lens and hits the same spot (if it is on focus), even the light from the bottom, top, center, left, right, corner to corner, so there is always light coming in from all different angles from the rear element to the sensor cell, depending on aperture of course.

[Kunzite]

This stuff about light path might have been just some marketing "simplification" than about telecentricity.
Just like Pentax' SR and tilting sensors.

[Marcus Rowland]

I just picked up a Yashica AF body and lens which is another example of a 35mm system that didn't make the jump to AF gracefully - the lens bayonet is bigger than the Yashica FR and the lens is considerably heavier than its Pentax or Nikon equivalent, with fewer features. They never got to a DSLR because the AF system was a big flop and they dropped out of the SLR market altogether. At least Olympus did a bit better than that!

I think it's telling that all of the current big players in APS-C DSLRs got an early start on 35mm AF systems in the 80s and early 90s then maintained compatibility for a long time - you can still use 1980s-90s AF lenses on current Minolta, Pentax, Nikon, and Canon bodies, they may not have all of the bells and whistles of modern designs but they still work. Canon and Nikon even had APS film SLRs that could use the same lenses.

[boriscleto]

I think it's telling that all of the current big players in APS-C DSLRs got an early start on 35mm AF systems in the 80s and early 90s then maintained compatibility for a long time - you can still use 1980s-90s AF lenses on current Minolta, Pentax, Nikon, and Canon bodies, they may not have all of the bells and whistles of modern designs but they still work. Canon and Nikon even had APS film SLRs that could use the same lenses.

But only Pentax and Nikon maintained backward compatibility with their manual focus lenses.

Minolta merged with Konica (another company that abandoned the market rather than develop AF) before being sold to Sony, And Sony has abandoned SLRs...

[Marcus Rowland]

But only Pentax and Nikon maintained backward compatibility with their manual focus lenses.

Minolta merged with Konica (another company that abandoned the market rather than develop AF) before being sold to Sony, And Sony has abandoned SLRs...

You're right, of course. I tend to think of Sony and Minolta as more or less interchangeable, and forgot the current circumstances. But Minolta did offer a couple of DSLRs under their own name before Sony took over, so I think it's fair to say that they handled the change to DSLR without having to reinvent the wheel with their lenses.

Canon, of course, abandoned the older manual focus FD mount completely, with a lot of wailing and gnashing of teeth from many users at the time including me, in favour of EF. They did take a couple of stabs at AF on the FD mount, but the AF never worked well. But they did this early enough that by the time DSLRs came along the EF system already had a big user base which made the transition much easier, and the old lenses worked fine on digital bodies.