Tech Talk

Got a new Server

I finally got around to purchase a stronger server and move this website there. During the past year, traffic has more then trippled (mostly due to the free wallpapers and this stitched image (some days in excess of 5 Million hits due to the Zoomify player).

I have spent the past week setting up the server and optimizing it a bit, so it can handle the traffic being generated by this website. Today was the first day after I pointed the DNS (Domain Name Servers) to this new webserver. Amazingly the server doesn't even break a sweat, even during times of relatively high load.

This is good news, since I am working on another image that is much bigger then the Machu Picchu Picture. Finally I will also have time to write some more tutorials and most importantly work on my huge backlog of pictures and upload some new stuff.

The new server feels pretty quick, which is good news since this is the first web server I am administrating and there is so much to learn (especially in the area of performance tuning).

Hm. My database is pushing over 4 queries per second now and its almost Saturday midnight. Seems a bit excessive considering that I cache most pages (maybe 2 queries per page). Not that it would make a dent in the Server but I am getting curious how this site can push millions of database queries per day.

Computer Crash

Download Updates

Finally my big Desktop Machine gave up. What a horrible scenario. I have about 600GB of data in that machine (not all are images) and a ton of programs running on it. So far, I have always been able to save it, even when it mysteriously erased some dll files. This time the problem seems to be more severe. As soon as windows starts the monitor goes completely dark and I am unable to access the Windows boot menu.

I went in through the remote desktop and I have been trying to fix the problem without much luck. So I have started to clean up some external drives and backed up the main Hard Drive (about 300GB).

I found a pretty cool tool to build a CD containing all Windows updates, that I will be using before even connecting to the Internet (see picture, it is pulling all Windows updates).

So I spent all weekend with this instead of working on my pictures or website. I had my eye on a small IPAQ server on Ebay but I even missed to buy before the auction was over. I need to set it up to run a couple of cron scripts and automatically backup some databases across the internet (incuding the database for this website) as well as data feed creation and a bunch of other useful things.

Looks like my main machine is going to keep me busy for a while until I have everything up and running again.

iPhone vs. Smartphone

Apple's new iPhoneT-Mobile SDA
This week Apple rocked the world with the announcement of the iPhone. Despite the outrageous claims to be 5 years ahead of everyone else, the phone is a revolutionary hybrid between iPod / PDA and Phone. In this article I am going to compare some of the features to the T-Mobile SDA. Even though the MDA may be closer to what the iPhone offers, I am comparing it to the SDA since it primarily claims to be a phone. Both have very similar specifications but are completely different devices.
The iPhone was probably one of Apples closest guarded secrets. I knew my company was selling microchips to Apple, but I didn't know what products they would be in. It turns out our chips are in the iPhone and in the Apple TV. Not bad.

Bokeh - the least understood lens property

This guest article was contributed by Brian White from Background Exposure.

Warning: Reading this article may diminish your enjoyment of some photographs you view in the future because you will start to observe a flaw that would previously have gone unnoticed.

A camera lens has many different attributes. There is focal length, zoom, minimum/maximum aperture, sharpness, and chromatic abberation... and that's just off the top of my head. Lens manufacturers only tell the basics like focal lengths and apertures. Third party reviews will often get in to sharpness and "fringing". But most of these reviews are concentrate on subjects that are in focus. They usually ignore those parts of the photograph that are outside the range of "acceptable sharpness" since they're assumed to be unimportant. After, all, if they important, they would be in focus. Besides, it's all blurry anyway, right? Not always.

The Seitz 160 Megapixel Camera - a scam?

Seitz 160 Megapixel Camera

I was going through my log files the other day and I noticed a bunch of new sites referring to my 222 Megapixel Machu Picchu Image. Usually that's nothing special, the picture got linked on many sites. However I like to check most incoming links and what I found reported there was pretty amazing. My image was used as an example to demonstrate the resolution of a 160 Megapixel Digital Camera, that is expected to hit the market in 2007. While I had to manually stitch 35 images of my Canon 20D camera, this bad boy will be able to achieve a similar resolution in one shot. Looking at the picture above I do have some doubts as to if the optics can handle this kind of resolution though. Considering that for my 20D, I will not get a significant improvement beyond about f/16 (Limits of Diffraction), the image sensor must be gigantic. From the picture, it seems the lens is not nearly big enough for such a large sensor.

The sensor of my 20D is 24mmx18mm. The Machu Picchu Image did use a 7x5 matrix (7 columns, 5 rows). Lets subtract 20% for overlap, the effective sensor size was 0.8*24*7 x 0.8*18*5 = 134.4mm x 72mm. Lets assume the pixel size of the 20D and this bad boy were the same, I would need a sensor of 134x72mm for the Machu Picchu Image and a lens large enough to cover this sensor edge to edge (no vignetting). This lens doesn't seem big enough. A smaller pixel size would certainly accomplish this, but then the Limits of Diffraction dictate that you will only be able to obtain a very small depth of field.

I have seen many articles popping up about this camera and despite the size of this camera, noone has ever dared to question the limits of the optical resolution. In the heads of most people a digital camera is always limited by the sensor alone, but that is simply not true (and a reason why I believe that even most consumer point and shoot cameras above 7MP are limited by their lenses already).

From my experience with the Machu Picchu Image, there is another limitation to consider here. Lets assume that the sensor really is about 134x72mm (yes I know that would be for the 222 MP model, but who says they are not already cooking that one up). Since 134 is approximately 3.7 times larger than 36mm (standard film size), such a sensor would have a crop factor of 1/3.7. This means in order to obtain the same Field of View as a 50mm lens on a normal film camera, we need a 50mm x 3.7 = 185mm lens. Unfortunately longer lenses compress depth of field accordingly, which means a high f-stop number is required (an effect well known to the digital SLR crowd). A consumer point and shoot camera usually has a crop factor around 2.5, which means those cameras have very small sensors and are capable of achieving great depth of field. As a consequence, this giant here would need an even higher f-stop, again pushing the Limits of Diffraction.

DIY Digital Picture Frame that plays Videos too

 


Here is the DIY digital Picture Frame that I built over the weekend. This one distinguishes itself from other projects like it, that it can also play videos in an infinite loop. I have a video of a lonely Maui beach scene (1hr) that I play in the loop.
The picture frame runs Linux and is built from an old laptop.
The DIY Picture Frame was quite an interesting project. Modifying the Hardware was not so hard, but getting the Linux Software to run the way I want was a little bit more difficult, especially since the laptop did not boot everyLinux CD.
All it needs now is a nice frame around it and I am ready to hang it on my wall.
For a full description, more pictures and a video of the frame showing the Maui loop, go to the Digital Picture / Video Frame page.