More manual focus

I got a response from Nikon service reasonably quickly, however the response itself was fairly useless. They couldn't give me a price for doing any work without seeing the camera and said that if the focus screen wasn't a Nikon one (as far as I know Nikon don't make split prism screens for their DSLRs) they may replace it during the service.

So, next stop was to try and find a local camera repair shop and see what they could do. I phoned RCCR as they're pretty close by and had a very helpful conversation with Ray. Whilst he couldn't actually help me he was very happy to explain in detail what might be going wrong.

Conveniently I've also currently got a trial version of Lightroom 3 installed. I'd read that this allows you to do tethered shooting, and sure enough after changing the USB setting on my camera, tethered shooting worked without a hitch. This allowed me to check the focus of my photos at 1:1 on my laptop as I took them, which is a lot more useful than looking at them on the back of the camera.

Ray was worried that the mirror adjustment might noticably mess with the autofocus (contrary to what I'd read previously). It seems that he was right, thanks to the tethered shooting I saw a noticable change in sharpness as I moved the mirror adjustment this time.

According to Ray I should have seen a difference in focus performance after taking the existing shims out. The first time I took them out and put them in a few times and didn't really notice anything changing. This time I thought that instead of using the autofocus and seeing how far misaligned the split prism was I would try focusing with the split prism and see if I could tell the difference in the pictures. This turned out to be a much better idea and showed that focusing with some thick paper shims I made was clearly worse than no shims.

Unfortunately because in both cases the focus was off in the same direction I have to conclude that either my camera just can't do accurate manual focus, or that I've got a duff focus screen - if it's thicker than the existing screen plus the shims then it's probably going to be impossible to use.

So for now I've re-installed the original screen and gone back to my mostly reliable autofocus. Drat.

Installing Drupal on a Mac

The Drupal site contains full instructions for both prerequisites and installation but somethings were not immediately clear to me and some of the documentation is fairly long so I thought I'd distill them here.

Install Apache - On a Mac you don't need to do this as it's already there, you just need to enable it in System preferences under Sharing -> Web Sharing.

Install MySql - You get the option of 32 bit or 64 bit installs. It seems that at the moment it's still safer to install the 32 bit version. I downloaded the dmg version and installed both packages (so MySql will start up automatically with the machine) and the preferences panel.

Install PHP - Again this is already installed on your Mac you just need to activate it.

Download Drupal and unzip it somewhere, (the Drupal instructions will link it to Apache later on).

Configure MySql (by default installed to /usr/local/mysql/bin). The following step by step instructions assume that MySql has only just been installed and has not been configured at all yet.

Log in as root:
mysql -u root

Then the following sets up a root user password:
SET PASSWORD FOR 'root'@'localhost' = PASSWORD('secret_password');

Create a user for use by Drupal
CREATE USER 'drupal'@'localhost' IDENTIFIED BY 'another_password';

Create a database for use by Drupal
CREATE DATABASE drupalDb;

Allow the Drupal user to manipulate the Drupal database (note the ` characters that are not ')
GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, INDEX, ALTER, LOCK TABLES, CREATE TEMPORARY TABLES ON `drupalDb`.* TO 'drupal'@'localhost';
FLUSH PRIVILEGES;

Quit MySql
\q

Follow the remaining installation instructions on the Drupal site.

The Mac specific instructions on the Drupal site are a bit mangled. This page explains how to set up virtual hosts more clearly:

http://drupal.org/node/238805

One important note here is that if you put your Drupal files somewhere non-standard then you could end up getting 403 errors. This page has some suggestions on how to fix things. Personally I just put the Drupal files in a subdirectory of /Library/WebServer/Documents.

Once that's all done you ought to be able to go to the virtual site you set up and see the drupal installation start page. From there it ought to be plain sailing.

But in my case it wasn't. A final couple of useful points:
- You'll probably get an error about the files directory. Just create the directory manually and give the _www group write access to it.
- If you're installing on Snow Leopard you'll probably get an error after entering the database details. To get around this, click on advanced options and change the host name from localhost to 127.0.0.1.

Manual Focus

I've been interested in getting a manual focus screen for my D300 for a while, but the price of the Katzeye screen has put me off. However, I recently found out that you can get focus screens from on eBay for a fraction of the price, so I thought I'd take the plunge.

I chose a 180 degree split, which just means that the split line is horizontal. That means that it's easiest and most accurate to focus on vertical lines and impossible to focus on horizontal lines. The other common types are:

• 45 degree single split. This is the same as the 180 degree but with the split line at 45 degrees. One of these screens will let you focus on both horizontal and vertical lines but with less accuracy. For maximum accuracy you'd need to find a 45 degree line.

• 45 degree double split. As the name suggests this screen has two splits. Apparently the purpose of this is to help get the sensor plane aligned with what you need to focus on and is mainly useful for photography flat objects like coins and books.

Removing the focus screen on a D300 is slightly fiddly as you really need to remove two tiny screws (it's probably just about possible to change the screen without removing the screws but I wouldn't recommend it). Once the screws, and small plate they hold, have been removed you just need to unhook the wire holding the screen in and replace the screen. If you plan to do this you should follow some proper instructions.

Unfortunately, so far things have not gone to plan. Fitting the screen is in theory fairly simple. In practice the particular screen I have was about 1mm narrower than the original screen and so the wire clip holding it in slipped off one side and so didn't hold it as securely as I'd like. To counter this I removed the clip completely, bent it in slightly with some pliers, and then put it back. Not too hard but it shouldn't have been necessary and required some confidence.

Once securely fitted I tested the screen by setting the camera to autofocus and seeing if the screen agreed. It didn't. I half expected this as there were two shims between the original focus screen and camera body and I'd read guides that said to leave them in and other guides that said to take them out. So I tried removing one, then both shims. Unfortunately that didn't really help.

At this point I had to do some more research. One thing I learned is that with a 1.5mm allen key you can adjust the mirror resting position to a small degree by turning a small screw next to the bottom right hand corner of the mirror (as you look into the camera). This helped and got the focus quite close, but I couldn't adjust it far enough. Also please do note that I later found a few warnings about how this adjustment might mess up your auto focus, however, I found just as many notes saying that people had done this without any problems. For the record I have not seen any problems with my auto focus but haven't tested it thoroughly.

Finally after more research I've found a few people saying that modern DSLRs are simply not set up for manual focus at all accurately (although mostly they're not far off). Given the general lack of complaints about these screens I think in my case I may have got unlucky and got a camera that is so far away from accurate manual focus that the small adjustments available to me aren't enough.

So, I've admitted defeat and emailed Nikon Service to see what they can do adjust the focusing and how much it will cost. More details to follow as things progress...

Notes on the iPhone on IOS4 is broken

Apple recently released IOS4 for the iPhone which updated a number of things (mostly for the better).

One of the less obvious changes was to synchronise notes from the Notes app automatically with your gmail account. The iphone will automatically create a "Notes" label in gmail and file your notes there.

Anyway this would have passed unnoticed for me except that the Notes app is now bugged and anything after the first few lines of a note will be lost when you close and re-open the app. This makes the Notes app unusable and is apparently down to a bug in the gmail synchronisation.

Fine so I just turn off this feature that I didn't want anyway and everything will be OK right? Wrong. Turn off the note syncing (in the settings app under the mail settings) and any notes written since you updated your phone will vanish from the Notes app completely. Brilliant.

Fortunately they don't get deleted from gmail so you can still get at them and paste them back into the Notes app where they ought to have stayed in the first place.

So be warned, if you use the Notes app at all then turn off the gmail synching ASAP and be prepared to retrieve your newest notes from gmail.

Customer Service

It's nice to get a good bit of customer service every now and again. A while back we bought an AeroBed, which is a nice, comfortable air bed with a built in mains powered pump. Recently it sprung a leak so I went to AeroBed site and requested a puncture repair kit which were listed as free. A couple of days later I got an email asking for proof purchase which I didn't have (having bought the bed some years ago), so I sent a reply saying that and that I would be happy to pay for a kit. They replied to say that they'd send out a kit anyway, still free.

In the end I actually received two kits so I have to wonder whether they'd sent out the first kit before even getting in touch to ask for proof of purchase.

Anyway, the fact that they are still around and providing free customer support for old customers is nice thing, and I think deserves to be reported, given how often people get on the internet just to complain.

Cycling

A while ago I looked for a site that could plot out a cycle friendly route for me for my commute to work but failed to find one. I have now found CycleStreets.net and whilst I haven't actually tried the route they suggest yet I am very impressed with the (free) route planner they have on the site. Well worth a look if you want to plan a route through unfamiliar territory.

PNG and CSS colour matching

Whilst working on my new site layout I came across a couple of issues.

Firstly, at least on a mac, if you create a PNG with a certain colour and then use that same colour in a stylesheet the likelyhood is that the colour won't look the same in a browser. If you want to see this for yourself, have a look at the various test pages at libpng.org.

One way to get around this problem is to use a single pixel image as a repeating background instead of setting a colour in the stylesheet.

This brings me to the second and far more bizarre issue. In Chrome (but not firefox) a single pixel background image displays as a different colour to a background image made up of two or more pixels of the same colour. I have tested this by creating a two pixel image viewing it, then cutting it down to one pixel and viewing it again so I'm pretty sure it's not some subtle issue to do with the image itself.

My best guess is that Chrome is optimising single pixel background images somehow. However, it's not just turning it into a CSS background colour as it displays as yet another different colour.

So for now I'll have to make do with 2 pixel background images to be able to match my  backgrounds to my other graphics.

Static Sites with Haml, Sass, and ScriptMatic

I was listening to an episode of the "Herding Code" podcast recently, and they had a guest on who was singing the praises of Haml. Haml is a language for creating HTML documents that is supposedly neater and easier to use than HTML itself. Haml is also packaged with another project called Sass (although either can be used without the other) which is a language for creating CSS documents. Again Sass is supposed to be easier and quicker to write than CSS, but it also supports variables and arithmetic which can be very useful.

Since my website is currently in need of a refresh I thought I'd try using these languages and see how it went.

Haml and Sass are often used with dynamic pages generated by Rails. My site is a simple static affair, and whilst it is possible to run both Haml and Sass from the command line it's quickly going to get tedious. So, I had a look for a tool to help. My requirements were:

• Must support Haml and Sass
• Must have a live preview - automatic regeneration of the site whilst developing
• Must support partial files - so that common sections can be split out and re-used
• Must be able to export the site to HTML and CSS when it's done

I found a few recommendations, but these two seemed to be the closest match to what I wanted:

• StaticMatic
• MiddleMan

For no particular reason I've gone for StaticMatic.

So, assuming that you have ruby and gem set up, you can get things working, by running the following commands from a terminal window:

• sudo gem install haml
• sudo gem install staticmatic
• staticmatic setup mySite
• staticmatic preview mySite

At this point you should be able to go to http://localhost:3000 and see the default staticmatic page.

Now that the site is up and running we can change it a bit. By default the main files are:

• src/layout/application.haml - The default template, page content replaces "=yield"
• src/pages/index.haml - Default index content
• src/stylesheets/application.sass - Default stylesheet

As you change the Haml and Sass files in mySite/src the site should update dynamically.
Once you've got things looking how you like run "staticmatic build mySite" to build the html and css files under mySite/site which you can then upload to your live site.

Printing pictures

So today I wrote my first plug-in for the GIMP (it's really just a script but as it's written in Python it goes in the GIMP plug-ins directory).

The reason for the script is that I've found a print lab in the UK that will accept files over the internet and just print them without messing around trying to "correct" them. They give you an icm profile for their printer so that you can convert your images. They're called ProAmImaging. There are other places on the internet that seem to do the same but the sample prints I got from ProAm look pretty good so I'll be using them for now.

Anyway, the flip side of them not touching the images is that I need to scale and crop the images to the exact number of pixels needed for the print size I want. This gets tedious very quickly so I decided to write a script to automate things. What the script does is take an image size in inches, and a desired DPI, and uses them to scale and crop the image to the correct size in one step. It's nothing you couldn't do with the existing tools, but it halves the number of actions you need to do, and does the maths to work out exactly how many pixels to crop automatically.

I'd like to improve it so that it activates the crop tool with the correct aspect ratio so that you can select the crop manually, however it's not obvious to me whether that's even possible so I'll leave that for now.

A couple of things worth noting when writing Python scripts for the GIMP:

• If python doesn't like your script for some reason the GIMP won't tell you why, your script simply won't appear in the menus. There's probably a way around this but it never got so annoying that I had to figure it out. If you start with a known good script (there are loads at registry.gimp.org) and test regularly it's OK.
• The GIMP/Python documentation seems to be rather sparse (http://www.gimp.org/docs/python/index.html) and the python object interface is quite small. However you can call all the libgimp methods from Python using pbd.methodName().
• For debugging pdb.gimp_message("Your message here") is rather helpful.

Please note that this is the first time I've written a GIMP plug-in and almost the first time I've used Python so the take the above with the appropriate dosage of salt.

And finally the script itself - ScaleAndCrop.py, I hope someone else finds it useful.

High pass filter effect

This technique has been written about a number of times, not least by Strobist, but I thought I'd see how it works on this rhino rather than a person and what happens if you mess around with it a little.

I use the GIMP for post processing my photos, and by default it doesn't have a high pass filter. So the first thing to do is to head to the GIMP plugin repository to get one.
On Windows put the .scm file in "C:\Documents and Settings\Your User Name\.gimp-2.6\scripts"
On OSX put the .scm file in "~/Library/Application Support/Gimp/scripts"

If all went well you should now have a "High Pass Filter" entry under Filters > Generic.

Now we're all set, so:
Open up the photo you're going to work on
Select Filters > Generic > High Pass Filter
I'm working on a picture that's about 800 pixels wide so in the dialogue I chose:

• Filter radius: 16
• Contrast Adjust: 0
• Mode: Greyscale
• Keep original layer: Checked

Other values will also work (see below for what happens) but a radius of about 1/50th of the image width is a good place to start.

Change the layer mode on the new grey layer to Hard Light
Tweak the opacity of the layer to taste

The image below has had a different setting applied to each quarter for comparison.

and the original again for comparison:

My favourite here is the radius 16 contrast 0 section. Adding extra contrast to the high pass layer adds contrast to the final image, bleaching out some of the colour. Increasing the radius seems to emphasise larger features turning the effect from a subtleish sharpening effect to something actually affecting the image more obviously.

Tiger's spider burning bright

I recently bought a game for my iPhone, which in itself is unusual as I don't normally buy things from the iTunes store as I don't like the idea of only being able to use them whilst Apple says I can. The game in question is Spider: The Secret of Bryce Manor (developed by Tiger Style) and in this case a combination of the free demo Spider: Hornet Smash and the fact that Randy Smith was involved was enough to get me to part with the small amount of £1.79.

If you don't want to read any more, I'll say here and now that it's a very good game and if you play games on your iPhone you should buy this one.

As I said I came to the game through the demo; Hornet Smash. The demo uses the same levels as the main game but it takes a small mechanic from the main game and expands it slightly to actually make a fairly different game. Hornet Smash is more fast paced than the main game with greater dynamism as you leap non-stop around the levels tackling as many hornets as you can before inevitably succumbing to the steadily growing number. Playing well will slow the hornets' growth but I don't know if it's possible to play well enough to reach equilibrium.

In contrast, the main game only contains a few (non-multiplying) hornets and mostly plays out at a more sedate pace. The main adventure mode game is based around building webs to catch and eat enough insects in the level to open the portal to the next level. You do this by anchoring a thread to the level and then leaping to a second point to secure the thread between those points. Completely surround an empty space with threads and a web will appear between them trapping any insect that flies over it for long enough. You can anchor threads to webs, allowing you make new webs that were previously impossible. Eating insects will replenish your silk supplies and running out of silk means imminent death (there is a grace period in which to quickly eat an insect). One nice touch is that at the end of a level you are shown the complete room including your cobwebs, giving a feeling of the house gradually becoming more disused and deserted as you travel through it.

After a little practice, if you charge through the game, then the Blitzkrieg acheivement of completing it in under 30 minutes is easily achievable. But, if you do that and then leave the game you'll have missed most of what makes it enjoyable. Rushing through the levels would mean not noticing the many details in the rooms and not finding the numerous secret areas that help to tell the story of the house you are making your way through and the family that lived there. If you find and follow all the clues there is also a secret room to find. (There is also the sealed room which is easier to find but also hidden).

There are also three other game modes, one where you try to eat as many insects as possible in 3 minutes, one where you have to eat insects regularly to avoid dieing (with the frequency increasing as you eat more), and finally a mode very similar to the main game but with your threads shortened and reduced in number which makes forward planning far more important.

According the lifetime stats the game provides I've played it for over 16 hours and have now completed the game, found the secret room, and completed all of the optional achievements which I found rather fun.

So overall an excellent way to spend £1.79, highly recommended.

New Lens

I recently bought a second hand Nikon 70-210mm f4-f5.6 AF lens from eBay for £65 as I'd read some good things about it, and it comes from the same era as my 35-70mm f2.8 which I like very much (but which was also rather more expensive).

I already have an 18-200 VR so this new 70-210 is going have to be better than that lens to avoid going straight back on eBay.

I set the camera up on a tripod pointing down the garden and took a few shots with each lens at 200mm and 210mm with varying apertures. These are 100% crops from near the centre of the frame (unsharpened). The last shots are shrunk versions of the full image to give an idea of the extra reach the 70-210 has.

These results are a bit disappointing, the 70-210 is clearly putting more pixels over the same area, but I'm not convinced it's actually capturing much more detail (especially at f5.6).

I've also just taken the 70-210 down to the park to take some photos of my daughter, and I've learned how important shutter speed is with this lens at 210mm. I guess I've been spoiled by the VR on the 18-200 but it does seem that you need a shutter speed of 1/400s or faster when hand holding which means you need quite a sunny day to also get down to f8-f11.

That said, I did get some quite nice shots in the park and noticed that it might be front focusing slightly which I should be able to correct for in the camera.

In terms of build quality the 70-210 wins, feeling much more solid. But it loses out in terms of focus speed to the 18-200's built in AFS. The AF-D version of the 70-210 is supposed to focus twice as fast which would certainly help (but they are also rarer and more expensive on eBay).

So for now I'm leaning towards the 18-200 as it's only marginally less sharp, but focuses faster, has VR and can go all the way to 18mm. However, if I didn't already have the 18-200 I'd certainly be happy with 70-210, especially at the bargain price it can be had for.

Media Hardware

Hopefully the final post in this mini series about my Media PC trials (I'd much rather just be using it!). Most of the hardware in the PC is not particularly important. It's an old Athlon XP on a micro ATX motherboard in an Antec Aria case if you must know :). The imporant parts are the Hauppage WinTV-NOVA-TD 500 with remote control and a wireless Emprex keyboard with built in trackball (you can get one from Amazon here).

The TV card contains two DVB-T tuners allowing us to record two different Freeview channels at once, plus a remote control which works with the provided software and also with at least MythTV and MediaPortal.

The keyboard includes a small trackball, which allows you to completely control a PC without needing an extra mouse. It runs on 4AA batteries and as a pleasant surprise comes with 4 Duracell batteries rather than the usual generic batteries that often come with electronics. The second pleasant surprise is that plugging in the USB dongle and fitting the batteries was all that was needed to get it working. I guess that the dongle must pretend to be a normal keyboard so the computer doesn't need any special drivers to make it work. Whilst the trackball isn't the best in the world it works fine, and given the low price this keyboard is great value for money.

Media on Windows

With the new operating system came the choice of what software to use; MythTV on Windows requires you to build it yourself and I didn't fancy going down that road. I started with the software that came with the TV card. This is version 7 of their software and I dread to think what the previous versions must have been like. If you just want to watch TV it's fine, but the UI for recording is pretty poor, and in my case didn't even work. I found a couple of possible solutions on Google, but didn't bother trying them out as I knew there was more user friendly software out there that I wanted to try first.

I tried out GBPVR briefly but the flaky website (Google's cache helps here) and some rough edges put me off. I then went on to MediaPortal. I have used MediaPortal before, but not for TV as my previous TV card wouldn't work with it. On the whole I've been reasonably impressed. The UI is nice and if you tell it you have a Hauppauge remote control it all just works together. There were a couple of things that could have been easier though:

1. Picking up the programme guide information over the air doesn't seem to work for me which meant I had to follow the instructions here to set up an included tool to get listings from a RadioTimes XML feed. (Although I had to use the XmlTv plugin to read the listing file rather than the WebEPG one).
2. My first trial recording failed because apparently the TV card takes some time to wake up and so it wasn't ready when MediaPortal looked for it. There is a setting specifically for this under:
   
   
   • TV-Server Configuration
   • General Settings
   • Delay for TV card detection
   I set this to 30 seconds and since then it's been fine.
   

The final problem I've yet to satisfactorily solve is the "Black screen of death" which can happen when you plug a computer into a TV's HDMI socket and then switch the source on the TV. As I understand it, when the source on the TV is switched the HDMI connection to the computer is broken and it gives up on the display. When you switch back to the computer source on the TV the computer doesn't know and continues to ignore the display. You can get round this by getting the computer to re-detect the display but so far the ways I've found are not ideal:

• Unplug the HDMI connection, wait a couple of seconds, then plug it back in.
• Put the computer to sleep and then wake it up again.

I've found this program which turns the monitor connection on and off again and can be bound to a particular key combination, but unfortunately doesn't yet work with XP. However, it seems likely that the author will be adding XP support shortly.

To end on a positive note one thing that has worked unexpectedly well is the scheduling plugin. Once enabled you can tell it to put the computer to sleep after a certain amount of inactivity and wake up for recordings. So far it had been hibernating and waking up perfectly which definitely beats having it on all the time. One caveat, if you want to watch a DVD using a different program you need to tell the acheduler not to go to sleep or your viewing will be rudely interrupted by a hibernation screen every few minutes.

Media on Linux

I've had a media PC sitting under the TV for quite a while now and it's been very useful for recording TV and showing photos to the family. A few months ago I replaced the TV card with one supported under Linux (a Hauppage WinTV-NOVA-TD 500) and thought it would be a good opportunity to learn a bit about how Linux works, plus I'd heard good things about MythTV and wanted to try it out. A few months later the things I have learned are:

1. With a family and a full time job I don't have the hours of free time needed to get things working, especially when I know I can do the same thing under Windows with far less trouble.
2. Mythbuntu sounds like a good idea, but when things don't work (which in my experience was all too often) it's another layer of unfamiliarity to work through. i.e. "Is this a problem in MythTV, Ubuntu, or Mythbuntu specifically?". Also walkthroughs for Ubuntu may not work as various tools have been stripped out of Mythbuntu to make it lighter-weight. So if you are familiar with Linux already then Mythbuntu may help, however, if I was doing this again I'd install the full Ubuntu first and then MythTV on top.
3. MythTV has a pretty slick frontend and when it works it is good. However, it's quite fiddly to set up. If you want to get a TV card IR remote control working at the same time as a USB keyboard and mouse (which may or may not be plugged in at boot time) then be prepared for an unnecessarily convoluted fight with various configuration files. (I believe because the IR receiver in my TV card also looks like a USB device to the operating system.)
4. For some reason DVDs are jerky under Linux using either VLC or the built in DVD decoder in MythTV. The same (rather old) hardware plays DVDs fine using a free copy of PowerDVD on Windows.

So when DVDs stopped playing altogether it was the final straw. In that particular case it turned out that the DVD drive had actually died but by then the die was cast and Windows XP was back.

iTunes!

I keep my music on a NAS device and run iTunes on Windows XP machine. If the NAS device isn't turned one when I sync my iPhone iTunes will decide that my music no longer exists and put an exclamation mark next to the songs it tried to sync. Turning the NAS device on doesn't fix it, neither does telling iTunes to add the directory the songs are in (you end up with two pointers to the same file in iTunes!), instead you need to take the incredibly intuitive action of shutting down iTunes and then restarting it whilst holding down the Ctrl key.


Now all I need is some way of stopping iTunes instantly crashing every time I access the podcasts tab of my iPhone...

With thanks to Dave Nicoll: http://blog.davenicoll.com/2009/04/05/dear-itunes-that-track-with-an-exclamation-mark-is-not-missing/

Hello World

On the off chance that someone is actually reading this, be warned that this blog is mainly going to be for things I find interesting and want some record of. If you find them interesting too then so much the better, if not then please feel free to move along, there are plenty of more interesting blogs out there. In fact this first post can contain the ones I regularly read (there, now it has a purpose).

Photography
http://strobist.blogspot.com/
http://www.joemcnally.com/blog
http://www.pixelatedimage.com/blog
http://photography-thedarkart.blogspot.com/

Computers
http://www.codinghorror.com/blog/
http://www.joelonsoftware.com/