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According to Edmund Optics, the best anti-reflective coatings have R ≅ 0.4% = 0.004 over the visible spectrum (~400-700nm). R = 0.005 may be more realistic for a reasonable range of incident angles. The light reflected back to the sensor from each secondary reflection would be R2 = 0.000025 = 2.5*10-5 = -92 dB (20*log10(R2)). The number of secondary reflections Nsec increases rapidly with the number of components M (groups of elements cemented together, each of which has two air-to-glass surfaces) in a lens: 1 for one component; 6 for two components; 15 for three components; 28 for four components; 45 for five components, etc. For M components, eazy
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M = 5 components are typical for high-quality camera phones; M ≥12 components is commonplace for DSLR zoom lenses. Overall, lens flare is less severe than the number of secondary reflections suggests because stray light does not cover the whole image; it decreases with distance from bright regions. It’s easy to see why practical camera DR measurements are limited to around 70-90dB, even when sensor DR is much higher.
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Here are examples of results from high-quality cameras. Click on the thumbnails below to view full-sized images.
 |  Results for jpeg image from high-quality (Canon 90mm Tilt/Shift) lens |
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The four images are for 48-bit RAW (or TIFF derived from RAW) and 24-bit JPEG files captured on the Sony A7Rii camera with two very different lenses:
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The differences between the DR of the two lenses (medium and high quality) seems to be minor when compared to an image from a low-cost “black-box” camera we recently received.
The low-quality (SNR = 0dB, labeled Low ——— ) DR is measured as 148dB—an astonishingly high number; DR from slope is 66dB—much lower than several quality-based DR measurements (and lower than the slope-based DR for the 90-mm T/S lens). Note that the two darkest patches don’t appear on this plot because their densities (8.184 and 8.747) are beyond the 160-dB limit of the plot. (A 160dB is a range of 100 million to 1—more than expected from any sensor or camera. Put another way, if one photon were to reach the darkest patch, the lightest patch would set the chart or sensor on fire).
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