Cumulative Weekend Update

Sony Vaio Z21 News:

Some good stuff to talk about since the last weekend update. Lots of activity around Z21 support in the sony-laptop platform module, enough to publish an updated 0.8 release, which Eva has done already through the usual channel. A big update patch was posted on the linux-acpi mailing list, I took parts relevant to the sony-laptop platform module, merged them into our code, fixing some bugs in the way hotkey events were mapped to input events and pushed the fixes back to linux-acpi in order to keep upstream and our version better in sync.

A couple of new features supported now, mostly about wireless kill switch and hotkeys:
  • all hotkeys mapped to input events properly
  • better wireless kill switch support
  • compiles on 2.6.27 to 2.6.29
On special request I added a new load option to the module, if you insmod sony-laptop.ko with 'speed_stamina=3', the module will not touch the Nvidia graphics card power state any more. This is for people who need the Nvidia card so badly that booting through Windows is the lesser problem.

The Speed/Stamina switch now also reports ACPI events and I've found a way to read the switch position from the embedded controller, that means I can generate distinguishable ACPI events for either switch position.

Regarding enabling Speed mode I have been pointed to the "Nouveau" project which aims to provide a free replacement for proprietary Nvidia drivers. Maybe it's possible to reuse some code from this project to initialize the Nvidia card up to a state where a regular Xorg driver would be able to work with it. That sounds like major additional work, not sure I'll be able to do that on weekend time alone. The learning curve appears to be rather steep. However, since it's likely something that involves userspace code as well, it appears to me the correct way for now is just to report the switch position via ACPI and let userspace code handle the actual switching. Policies should not be hardcoded in kernel drivers anyway.

Digital Photography News:

After trying a Canon FD to µ4/3rds adapter from a Polish ebay seller and finding that it has got a couple of problems with infinity focusing and limits the available aperture stops to f/8, I tried to get a better version from a shop in China. It arrived on Friday a little more than a week after I ordered it and it's in a quite different arena regarding quality.

The Polish one is very simple, cut from just one block of aluminum on a CNC lathe. The adapter from China has a separate bayonet flange screwed to a CNC lathed body and also features an aperture control ring. It works correctly for all F stops and also allows infinity focusing. I'm very happy with it. I also got an almost mint 50mm f/1.4 lense for little money, including even a one year warranty against yet undiscovered defects. Both arrived in time before my easter holidays. I'll be going skiing in Italy, of course taking the camera and all lenses with me and hopefully finding enough time to enjoy both a lot.


Z21 News

Looks like there is some movement on the Z21 front again. Matthew Garret posted a patch to the linux-acpi mailing list with an rfkill based implementation of dealing with wireless devices. Interestingly, his patch also enables all the hotkey events so now I even get an ACPI event when I flip the speed/stamina switch. But still no idea about how to enable speed mode safely.

Eva made a new release with the rfkill changes integrated, which means you can now control all your wireless devices for even more power saving. Grab it from the usual place.


Vintage glass and digital backs

If you're into photography a bit, you probably know the term register distance. It's the distance between the flange of the lens and the sensory plane of the camera body. It's one important factor in lens design and every camera system has its own, a parameter carefully chosen because it has a huge impact on the overall design of all future cameras a maker is creating.

It also defines how easy it is to use lenses of a different system on your own camera. If your camera has a larger register distance than the lens you want to use, it's not doable with just a distance piece, you need some lens in between, which makes it expensive.

Now, the µ4/3rds system, by lack of the mirror box, has about the shortest register distance of any modern digital camera system, which means it's particularly easy to adapt any lens ever made. Just recently a friend, owning a large collection of Canon FD lenses, has bought an adapter to try some pieces of his collection on my camera and by that I got the chance to try some of them myself - and I found it's really a lot of fun.

I'm especially addicted to some of the fast 50mm because they easily offer apertures around f/1.8 and larger, making them very attractive for portrait photography and still motives, the shallow depth of field offering choices in composition impossible with the set of native lenses available for µ4/3rds today. Another interesting choice is long focal length lenses, the photo above was shot using a 500mm reflex lens, quite a compact design and effectively a 1000mm now due to the cameras crop factor.

This experience has considerably changed my plans for future native lenses to buy. Originally I planned to get the 14-140 as a walk-around lens, but it seems it's not going to be as good as the Pana/Leica 14-150 for 4/3rds yet almost as expensive. I'm afraid Panasonic invested too much into making a video lens and sacrificed optical quality, at least the MTF charts suggest that. So, with my newly discovered love for fast primes I'll rather have the 20mm f/1.7 which is supposed to be out late this year.

In the mean time I'll satiate my lust for experiments with vintage glass bought cheap off flea markets or ebay. Having to operate the camera manually is not really a burden and I find the results with the 50mm f/1.4 quite pleasing, and sharper than what I can achieve with the 14-45mm kit lens.

Of course the crop factor has its downsides. It's impossible to find a decent wide angle lens, I tried a Russian made 16mm fish eye and it's not coming out really wide just heavily distorted. I also tried a 24mm f/1.4 "L" for an effective 48mm, and while it works quite well the make is just not fitting the purpose: too bulky, too heavy, all in all not a good fit. I don't want to carry that pound of glass and only use a small fraction of it :-) So that limits the choice to around 50mm, or really long telephoto equipment, I think that's a good variety already.