If you’re using the iPhone app Cine Meter, update now to version 1.6; if you’re using Cine Meter II, update now to version 1.9. iOS 9 no longer reports correct brightness metadata on some iPhones / iPads / iPod touches, and it’s that metadata that the apps normally use to compute exposure. The new versions have workarounds for iOS 9.
[Update 2015.09.26: Cine Meter II 1.9 is now available; please update to it.]
[Update 2015.09.24: Cine Meter 1.6 is now available; please update to it.]
If you’re using the iPhone apps Cine Meter or Cine Meter II, please don’t update to iOS 9 until I can get a new release out. iOS 9 no longer reports correct brightness metadata on some iPhones / iPads / iPod touches, and it’s that metadata that Cine Meter uses to compute exposure.
If you have already updated, here’s how to test for the problem:
- For Cine Meter II, make sure you’re using the front or back camera, not Luxi or Lumu.
- Press and hold the live image to display a debug data overlay.
- Cover the camera lens so that no light gets in (do this inside a dark room for best results, not outside in daylight!).
- Read the Bv value:
- A negative number, typically -5 to -8, means your iDevice is still reporting Bv properly. Exposure readings will be correct.
- A positive number, typically 1.3 to 2.9, means your iDevice is affected, and exposure readings will be wrong.
- When you’re done, press and hold the debug overlay until it disappears.
- (Please send me an email and tell me what the result was and what iDevice you’re using; that’ll help me improve the next version.)
The waveform monitor and false-color displays still work, and (with Cine Meter II) Lumu incident readings and Luxi color-temperature measurements are unaffected; it’s just exposure readings based on Bv — brightness value metadata — that are screwed up.
I have tested iPhone 5 and iPad 3, and they’re OK, while iPhone 6 Pluses and iPad Airs are no good. I’m also informed that iPhone 6 is affected. Based on this limited data sample, I’m guessing this bug likely affects 64-bit iDevices only: iPhone 5S, 6, 6 Plus, and above; iPad Air and later; iPad Mini 2 and later; iPod touch 6G.
I’m pushing new versions of Cine Meter and Cine Meter II to the App Store today with workarounds for this problem: basically, they’ll compute scene brightness from the camera’s own settings, not brightness value metadata. Until they’re available (which depends on how long Apple takes to review them), I’ve pulled the apps from the App Store.
If you haven’t updated to iOS 9 and use Cine Meter / Cine Meter II, please hold off from updating until the new versions are available. If you have already updated and your device is affected, please use another app for exposure readings while awaiting the new versions, such as Pocket Light Meter.
Disclosure: I’m the creator of Cine Meter & Cine Meter II, so you’d better believe I have a biased interest in reporting this story! I have no material relationship to NuWaste Studios, the creators of Pocket Light Meter, and NuWaste hasn’t offered me compensation for recommending their product.