Archive for January, 2009

How to mount a remote AFP drive on AppleTV Take Two

Sunday, January 11th, 2009

I suppose that you have already installed NitoTV on your AppleTV as you need it to get remote drive access (note that it’s probably possible to do without it by doing everything through SSH).

The AppleTV with a native firmware above 2.0, does not have the AFP protocol in its recovery partition. So even though you upload the MacOSXUpdCombo10.4.9Intel.dmg on the AppleTV and create the recovery.dmg it will not give you access to the AFP protocol. The main reason is that the recovery.dmg image does not contain it! But if you would have an AppleTV with a 1.0 firmware it would have worked since it’s still in the recovery partition (it makes sense, doesn’t it) ?

Someone found a solution to workaround this issue, and I think it’s interesting to blog about it, since it’s in a forum post on the atvflash forums (it’s also like a note to myself, in case the post would disappear). So here is verbatim the solution:

  1. Do a factory restore of the ATV, update the firmware to the latest version and then run the patchstick again. You may be able to uninstall NitoTV but I couldn’t get this to work after a failed smart installer attempt. A freshly hacked box seems to be the most reliable method.
  2. On ATV: SSH in with terminal and enter sudo dd if=/dev/disk0s2 of=recovery2.dmg bs=1m
    This makes a recovery image of your Take 2 recovery partition.
  3. On the Mac: sFTP into the ATV, I used an app called Fugu to do this, and download recovery2.dmg to your desktop.
  4. On the Mac: Open recovery2.dmg. Once it’s mounted you’ll see a number of files in there but the one we’re interested in is called “OS.dmg”. Rename this to anything you want.
  5. On the Mac: Copy in the 1.0 recovery image you have managed to obtain. Mine was called OS-dot-DMG 1.0.dmg and the md5 = 55b909196952ff72c93aaf3553cf661e
  6.  On the Mac: Rename the image file you have just copied to “OS.dmg” and then unmount recovery2.dmg. You will now have an image of your ATV’s recovery partition called recovery2.dmg but the OS.dmg file contained within has been replaced with the 1.0 version.
  7. On the Mac: sFTP into the ATV and upload the edited recovery2.dmg to the Documents folder. Then rename this file recovery.dmg
  8. On the Mac: sFTP into the ATV and upload MacOSXUpdCombo10.4.9Intel.dmg to the Documents folder.
  9. On ATV: With the remote navigate to the DVD/NitoTV menu and select Settings > Install Software. I then ran ‘Install Perian’, ‘Install mPlayer Codecs’ and ‘Install Turbo’s kextloader’ in that order. This probably wasn’t necessary and most of it is probably already there but worth doing just to be safe.
  10. On ATV: Once all this is done you’re ready to run smart installer.
  11. 11) Unplug the ATV, plug it back in and then you should be able to mount the box on your mac and see your shares on the ATV. I’ve found that streaming video from your Mac via afp in NitoTv/DVD is a bit choppy. Streaming through the “Files” menu seems much smoother.

The only thing I need to add is that the so called “OS-dot-DMG 1.0.dmg” is the original firmware of the AppleTV that you can obtain if you own an AppleTV Take One.

The original forum post can be found here and all the credits go to Scrubadub and Magic, whoever you are.

Nikon D80 HDR bracketing tutorial

Tuesday, January 6th, 2009

Recently I dived into High Dynamic Range photography (also known as HDR) using my Nikon D80.

My interest for the HDR technology is the capability to produce images that would be almost impossible to take with a digital camera. An HDR image reveals details in the light and dark areas of your images.

HDR

HDR

For instance, on this picture we can see the details in the clouds but also on the rock and it would be very hard to achieve it without HDR.

This tutorial does not explain how to create an HDR image because there are already very good tutorials on that subject, for instance you can read Vanilla Days tutorial, it is based on the Photomatix software but it does not hurt and you could use another software.

I will rather focus on explaining how to configure a Nikon D80 to leverage a built in feature called Auto Exposure Bracketing (AEB) that makes easier the creation of HDR images. I found all the relevant informations in the user manual but they were not clear enough and I had to spend some time on it in order to get it effective.

HDR imaging works by combining the same image with different exposures into a single image using an appropriate software. No need to emphasis on the fact that the images should rigorously be the same as possible. It can be done manually by shooting several times the same pictures with different exposure time and keeping the same aperture size, but it has at least two drawbacks:

  • you need to physically touch the camera to change the exposure and it could change slightly the different images
  • it take time to reconfigure the camera and your image may change during that time (clouds may move for instance)

The Nikon D80 has a feature called bracketing that allows to shoot three times the same pictures with the same aperture but with different exposures in that order:

  1. The normal image
  2. The underexposed image
  3. The overexposed image

Here is my howto for configuring the D80 appropriately:

Configure the image quality

The first step is to set the image quality to RAW. You can change it by pressing the QUAL button and rotate the the main command until you get RAW.

Configure the ISO sensitivity

Set the ISO sensitivity to the lowest value you can afford, for instance ISO 100 works well most of the time for me.

Configure the focus mode

Focus mode should be configured to manual (perhaps it’s possible to use automatic but I never tried).

Configure the mode

Set the D80 into Aperture-priority mode (A). Exposure bracketing works with that mode.

Configure the bracketing

Press the BKT button and rotate the main dial to chose 3 shoots and the sub-command dial to choose the bracketing increment with the value 2.0EV. At this moment you configured the D80 to change the exposure of the photo each time you shoot. Therefore the first picture you take is a normal one, but the second one will be underexposed by 2EV and the third one will be overexposed by 2EV. The forth one will be exposed normally.

Configure the shooting mode

The final step is to configure the shooting mode to continuous.

Et voilà!

The next time you will take a picture keep the finder pressed and the D80 will take the three shoots for you. Now it’s up to you to make great HDR pictures!