Golden Hour

Knowing when and where sunrise or sunset occurs is the single most important aspect of controlling light when you are doing landscape photography.  Being able to position yourself ahead of time allows you to create your own accidents;  control your own luck.

Personally, I think there are few landscape photographers better at doing this than George Stocking.  George has the ability to consistently put him in a situation to allow him to capture the light.  From storm lighting to traditional Golden Hour, he exercises amazing vision with nearly every photograph.

Perspective now gives you a tool to help you create your own luck.

NOTE: This feature requires the geo-location services offered by the iPhone to operate.  NoiseTECH does not collect or send this data and it is used only to calculate the suns position, heading and the next 2 times it will cross the horizon.

Using iOS’s geo-location services, Perspective calculates the time of the approaching sunrise/sunset.  By swiping with a single finger left or right (when the iPhone is held in the portrait position), it is now possible to bring up two information displays.  The first displays the time of both the next sunrise and the next sunset as well as heading information.  The second is a virtual reality display showing the location of the sunrise/sunset as well as the specific path the sun will take for the 1 hours surrounding sunrise/sunset.

Heading display

The heading displays the time of the next sunrise/sunset as well as the number of hours and minutes.  If the sunrise/sunset happens in the immediate past (1 hour), Perspectives will indicate a time as “22 mins ago”.  There is a “sun finder” that is used to help quickly locate the position of the next sunrise/sunset.  If you are pointing basically East, the Sun finder will center on the next sunrise.  When you are pointing basically West, the Sun finder will center on the next sunset.

To the right of the Sun finder are two heading values.  The first value, 291 in this case, represents Perspectives indication of the iPhone’s compass heading.  The second value, (296), represents the calculated location of the when the sun will breach the horizon.  The second value is very useful if you have an actual compass since the most camera phone’s build in magnetometer are not very precise and can suffer from sporadic accuracy.  For reference, here are the ranges for the heading values presented by Perspectives.

A Note on Heading error

The compasses provided in mobile phones are not highly accurate, precise or repeatable.  On the iPhone 4, this error is typically about ±10° or about ±3% or so.  On the above compass, this would look something like:

When you implement the CLLocationManager, you receive information on heading from an object named CLHeading.  There is a method in the received CLHeading object, headingAccuracy, that can be targeted to get the phones estimated error.  On an iPhone 4, this is typically about 10 degrees.

It is possible to minimize this by doing a quick calibration right before use.  NoiseTECH has found the best calibration is to move the phone in the following way:

It is also possible to rotate the phone 90 degrees and repeat this with the face of the phone cutting the air moving forward.  These two movements will tend to increase the short-term accuracy of the digital compass.  Likewise, because the magnetic lines of flux of the Earths magnetic field are very small, small amounts of moving current (like those found in a smart phone) will impact the results.  Because of this, the exact information being displayed on the screen could potentially change the compass heading.  For best results, a real compass is recommended.

Sun finder display

This finally leads us to the VR Sun Finder display.  This display gives the calculated position of where the sun will cross the horizon, the path of the sun for 1 hour before and after it crosses the horizon and the error being reported by the iPhone.