Abstract

A new and improved method to obtain the average spectral pixel responsivity and the quantum efficiency of Digital Single Lens Reflex (DSLR) cameras is outlined. Two semi-professional cameras, the Nikon D300 and the Canon 40D, are evaluated. The cameras red, green and blue pixel responsivities and quantum efficiency are retrieved by illuminating an integrating sphere with a wavelength tunable monochromator. 31 intensity calibrated monochromatic spectral lines from 4000 to 7000 Å, with a bandpass of ~12 Å, were used as a library to solve the main equations of observation for the cameras. Both cameras have peak sensitivity in the blue and minimum sensitivity in the red. The Canon 40D has blue and green channel sensitivity close to the Nikon D300. The Canon red channel has half the sensitivity of the Nikon camera.

© 2009 OSA

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. F. Sigernes, J. M. Holmes, M. Dyrland, D. A. Lorentzen, T. Svenøe, K. Heia, T. Aso, S. Chernouss, and C. S. Deehr, “Sensitivity calibration of digital colour cameras for auroral imaging,” Opt. Express 16(20), 15623–15632 (2008).
    [CrossRef] [PubMed]
  2. D. Baker and G. Romick, “The Rayleigh: interpretation of the unit in terms of column emission rate or apparent radiance expressed in SI units,” Appl. Opt. 15(8), 1966–1968 (1976).
    [CrossRef] [PubMed]
  3. F. Sigernes, J. M. Holmes, M. Dyrland, D. A. Lorentzen, S. Chernous, T. Svenøe, J. Moen, and C. S. Deehr, “Absolute calibration of optical devices with a small field of view,” J. Opt. Technol. 74, 669–674 (2007).
    [CrossRef]
  4. R. Berry, and J. Burnell, “Measuring CCD performance” in Handbook of Astronomical Image Processing, (Willmann-Bell, Inc., 2006), pp. 227–248.

2008

2007

1976

Aso, T.

Baker, D.

Chernous, S.

Chernouss, S.

Deehr, C. S.

Dyrland, M.

Heia, K.

Holmes, J. M.

Lorentzen, D. A.

Moen, J.

Romick, G.

Sigernes, F.

Svenøe, T.

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (7)

Fig. 1
Fig. 1

Experimental setup: (1) fiber bundle from lamp located in neighboring room, (2) mount / stand for integrating sphere, (3) order sorting filter wheel in front of entrance slit, (4) Jobin Yvon HR320 monochromator, (5) table, (6) exit slit plane, (7) Edmund Scientific integrating sphere, (8) laboratory lift table, (9) fiber bundle holder, (10) camera table, (11) fiber bundle used as input to spectrograph, (12) Oriel FICS 7743 spectrograph, (13) optical mount rail, and (14) DSLR camera with normal 50 mm f/1.4 objective.

Fig. 2
Fig. 2

Optical diagram. [A] Leica 150W fiber illuminator: (1) mirror, (2) Tungsten filament, (3) heat filter, (4) blocking wall, and (5) fiber bundle. [B] Jobin Yvon HR320 Monochromator: (6) f-matching lens, (7) order sorting filter, (8) entrance slit, (9) collimator mirror, (10) plane reflective grating, (11) focusing mirror, (12) flat surface folding mirror, and (13) exit slit. [C] Edmund Scientific General purpose 6 inch diameter integrating sphere: (14) sphere, and (15) transmitting diffuser (Teflon). [D] DSLR camera: (16) 50 mm normal f/1.4 objective, and (17) CMOS / CCD detector. [E] Oriel FICS 7743 spectrograph: (18) order sorting filter, (19) fiber bundle, (20) entrance slit, (21) folding mirror, (22) concave grating, and (23) CCD detector.

Fig. 3
Fig. 3

Sphere source functions. Ci(λ) is the set of observations that consists of 31 spectra from the monochromator (HR320) illuminating the 6 inch diameter integrating sphere from Edmund Optics.

Fig. 4
Fig. 4

Raw counts from the Nikon D300. Exposure time is 3 seconds at ISO 1600 with a 50 mm normal objective fixed at f/1.4. The shaded surface represents the green channel 12-bits raw counts per second. The source is a monochromatic illuminated sphere at center wavelength 5569 Å. The center y-axis slice of the surface is shown together with the calculated height of the plateau (solid horizontal line) and the 2σ standard deviation (dotted lines).

Fig. 5
Fig. 5

Camera raw data. Solid lines are the raw counts per second from the Nikon D300 camera for each color channel (Red, Green and Blue). The dotted lines are the corresponding data from the Canon 40D camera. Each curve is labeled with exposure time settings of the cameras. Both cameras were operated with identical settings using normal objective lenses (50mm f/1.4) at ISO 1600. The error bars represent the 2σ standard deviation of the count rates.

Fig. 6
Fig. 6

Processed camera data. Panel (A): Solid lines are the spectral responsivity of the Nikon D300 camera for each color channel (Red, Green and Blue). The dotted lines are for the Canon 40D camera. Panel (B) shows the corresponding calculated quantum efficiency. Both cameras were operated with identical settings using normal objective lenses (50mm f/1.4) at ISO 1600.

Fig. 7
Fig. 7

Normal objective spectral lens transmissions for the Nikon 50mm f/1.4 AF-D (red solid line) and the Canon EF 50mm f/1.4 USM (blue solid line). The dotted black line is the difference in transmission between the Nikon and Canon lens, respectively.

Equations (3)

Equations on this page are rendered with MathJax. Learn more.

u^(k)=CS^(k)Δλ , [CTS / s]
C=[C1C2C3C31]T. [R/Å]
QEi(k)[4πui(k)Δtg106CiΔλΔA]×100 , [%]

Metrics