Analysis of Fader ND (mark I) filter image quality

In February 2010, I purchased an 82mm Fader ND Filter (ND2 to ND400) from the official eBay store for Light Craft Workshop.  The label on the filter reads "82mm  Fader ND [W]  HL-OPTICS".

The purpose of a Neutral Density (ND) filter is to reduce the amount of light, therefore allowing for slower shutter speeds.  A variable ND filter allows you to vary the amount of light by rotating the front of the filter.

When shooting video, the shutter speed is normally fixed - it is tied to the frame rate giving the required Shutter Angle (e.g. 180 degrees) controlling motion blur.  When shooting video, the only way to prevent over exposure in bright light is to Stop Down the aperture.  This limits your ability to use the aperture to control depth of field.

A variable ND filter is particularly useful for video, since it allows you to control exposure independently of the aperture and ISO.  Specifically you set your fixed shutter speed, choose your depth of field, then set exposure using a variable ND filter or ISO gain (for bright or dim light respectively).

Variable ND filters can be constructed by stacking a Circular Polariser (CPL) filter and a Linear Polariser (LP) filter.  However I heard some people had issues with colour shifts, and I preferred to just buy a variable ND filter ready to use.

I believed that I would be able to use the variable ND filter for normal photography and not just video.  I've found though that image sharpness is severely affected, and out-of-focus (Bokeh) areas of the image have a crazing pattern.

More chickens

We've now got five chickens, having purchased another two today.

This is our family of hens.

"Beatrice" is a Silver Laced Wyandotte, purchased 13th June 2010.


"Snowball" is a White Wyandotte Bantam, purchased 13th June 2010.


"Dotty" is a Cuckoo Pekin Bantam, purchased 1st November 2009. Sadly she had to be put-down on 7th March 2011 after developing paralysis from a virus.


"Edna" is an Isa Brown, purchased 1st November 2009.


"Dora" is an Australorp, purchased 1st November 2009.


Click here to view more photos of our hens.

New chicken coop

Recently I wrote about how I had designed an automatic door opener for our chicken coop by modifying an alarm clock.  Refer to this posting for more details of the design:

http://blog.stead.id.au/2010/01/building-automatic-chicken-door-opener.html

We've now replaced the old chicken coop with a much larger one.

Note the chicken coop is a one-off, home-made design purchased off eBay, which we've then modified to suit our needs.

There's plenty of space in the nesting boxes for our hens.  In fact it's probably too big now, so we'll definitely have to get some more girls.

Plus the most important thing, I've converted my automatic door opener to suit.  Now it operates vertically, and hence why the clock is on a 90 degree angle.

The operating mechanism is much less prone to error.  Specifically there is less friction, and dirt/grit doesn't collect in the tracks.  It may also be less prone to forced entry by cunning animals (e.g. raccoons) that you have in other countries.

Here's a video of the automatic door opener in action. Our three hens come out in the order Dora first, then Dotty the bantam and then finally Edna pushes past.

Resolving FOSCAM connection dropouts

I bought a FOSCAM FI8908W wireless IP webcam off eBay recently. It has lots of features for the price.

However, I've had problems with being unable to connect to the camera after a period of time (an hour or so). Power cycling the camera would fix the problem.

I've tried upgrading to the latest firmware (version 11.14.2.17 is supposed to fix WiFi disconnection problems), but it did not fix my problem.

The problem is not related to my browser or the wireless network. I've tried disabling DHCP (router based static IP). It turns out the problem is that the webcam simply ceases to respond to ARP requests (once in this broken state).

The ARP protocol is a mechanism to translate between IP addresses and Ethernet MAC addresses. Without ARP, you cannot perform IP communications over Ethernet (since all Ethernet traffic must be destined to MAC addresses). The ARP protocol allows network devices to discover the MAC addresses of the designated IP address.

Simply adding a static ARP entry on your PC will restore communications. This show how on Windows to determine the MAC address of your webcam (e.g. IP address 192.168.1.20) and then create a static ARP entry:

c:\> ping 192.168.1.20

Pinging 192.168.1.20 with 32 bytes of data:

Reply from 192.168.1.20: bytes=32 time=7ms TTL=64
Reply from 192.168.1.20: bytes=32 time=3ms TTL=64
Reply from 192.168.1.20: bytes=32 time=3ms TTL=64
Reply from 192.168.1.20: bytes=32 time=3ms TTL=64

Ping statistics for 192.168.1.20:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 3ms, Maximum = 7ms, Average = 4ms

c:\> arp -a

Interface: 192.168.1.1 --- 0x10003
Internet Address Physical Address Type
192.168.1.20 01-12-23-34-45-56 dynamic

c:\> arp -s 192.168.1.20 01-12-23-34-45-56

c:\> arp -a
Interface: 192.168.1.1 --- 0x10003
Internet Address Physical Address Type
192.168.1.20 01-12-23-34-45-56 static

To make this change persist after rebooting, simply add the "arp -s" command to a batch file that you run from your Windows startup folder.

How to fold a photographic light tent

A photographic light tent or cube is invaluable for product photography.  It allows you to light a photographic subject with soft shadows and a non-distracting background such that a photograph will look its best.  It is ideal for product photography such as when you're selling things on eBay.  These eggs were photographed using the light tent:


The tent is sold in a folded/collapsed shape, but when you open the package it springs open.  It is very difficult to collapse back into the original shape - if you don't know the technique.

I purchased my light tent from DealExtreme here:
    http://www.dealextreme.com/details.dx/sku.5224

Many of the customer comments say that they can't figure out how to collapse the light tent for storage or transportation.  Taking note of this, I was very careful when I first opened the light tent.

Learnings (Part 3): Using Predictive Autofocus

Any modern DSLR camera supports (or should support) predictive autofocus tracking. While they might have this capability, there is an art to using it effectively, and therefore getting in-focus shots of moving subjects.

This is actually something I only learnt on the 19th of August, 2009.  Yes, I remember the date, it's an important date.  This is after having a DSLR many years, and never being able to effectively shoot moving subjects.  I would resort to doing things like:

• Stopping down, therefore increasing the depth of field, such that the moving subject might still be in focus.
• Increasing the shutter speed ('cause clearly I didn't understand the difference between motion blur and just plain out-of-focus).
• Pre-focusing in front of a moving subject.

These can give acceptable results, but why not get the camera do what it's supposed to do.

Music of Manolo Camp

I've been looking at Creative Commons licensed music for use with my videos.  There are a number of licenses, but typically they allow sharing and use in non-commercial products.

There is a lot of web sites dedicated to free music, and I've found some music by Manolo Camp that I really like.  Here's two web sites with his music for download:

• Opsound.org
• ccMixter.org

For example try Morning Coffee or Ships in the fog.  I'm already picturing some video that I can shoot for that second track.  Anyway, hope you like it.

Update 11/12/10: I've published my first video using Manolo Camp's music "Medieval". I think the music really adds polish to the video.