Brief Performance Test
The following images and data are from initial performance evaluation of the Canon EOS-7D. EOS-7D imaging quality was briefly compared to that of the EOS-40D and EOS-20D. Autofocus and video function were not evaluated.
Resolution and 50% MTF Performance
Methods Used for Resolution and 50% MTF
Resolution and 50% MTF were tested using the EOS-7D (18 MP, introduced 2009), EOS-40D (10 MP, introduced 2007) and EOS-20D (8 MP, introduced 2004).
RAW images files were processed with Canon Digital Photo Professional v 188.8.131.52 (DPP). In addition RAW files from the EOS-40D and EOS-20D were also processed with Capture One Pro v.3.7.8.
Capture One Pro gave better performance with the 20D and 40D files than did Digital Photo Professional.
Resolution using QA-77 target
QA-77 Target Applied Imaging, Inc.
Vertical resolution EOS-7D
Parking Garage Target - Resolution detail
|EF 35mm f/1.4L lens @ f/8 ISO 200. All images shot from same
location on tripod.
All images processed in standard settings in Digital Photo Profesional v. 3.7.8 from RAW in 16 bit 300 dpi Tiff files. Files were enlarged to 12 x 18 inches and converted to 8 bit jpg's and cropped for web pages after processing. Slight unsharp mask was applied to all images. Cameras at default standard tone/color settings and automatic white balance.
Image Detail Comparison: EOS-7D; EOS-40D; EOS-20D
Comparison of image detail with EOS-7D using EF 35mm f/1.4L @ f/8
and EF-S 17-85mm f/4-5.6 @ 33mm f/8
Images of the garage above from the EOS-7D have slightly better visible resolution on screen than those from the EOS-40D and have noticeably better detail than those from the EOS-20D. Also, images produced with the EF 35mm f/1.4L on the 7D were compared with images produced with a EF-S 17-85. There was minimally better detail produced by the L lens.
Are any of these differences in image quality between the EOS-7D and EOS-40D visible in prints?
Images were printed at 12X18 inch print size and sections were printed at total enlargement of 20X30 inches. At 12X18 print size, print quality produced by the 7D with either lens was almost indistinguishable from that produced by the 40D. At 20x30, small improvements were noted in the prints examined by close inspection produced by the 7D over those produced by the 40D.
High ISO Performance
Only ISO 100 and 1600 were compared in this initial test. Image quality at ISO 1600 with the 7D is significantly better than that of the 40D. The EOS-20D shows its age and has notably lower performance at both ISO 100 and ISO 1600.
As expected, image quality produced by the 18 MP EOS-7D is improved over that of the 10MP EOS-40D. Major improvements of the EOS-7D over EOS-40D and EOS-50D include: 1) 100% viewfinder; 2) better weather sealing; 3) higher frame rate (8 fps); 4) higher iso performance; 5) video function; and 6) better autofocus function. All of the preceeding are notable improvements. If you use your APS-c camera to produce images for general photography in good light at ISO 800 and below, the EOS-40D offers performance that will meet most needs. If you are still shooting with an EOS-20D, acquisition of an EOS-40D (50D) or EOS-7D is a major step up in image quality for general photography.
Posted 04 October 2009; revised 11 October 2009
© 2009, William L. Castleman