Canon Patent For Star Tracking in Astrophotography


Egami (translated) spotted another patent filed by Canon.

The patent refers to a technique for the generation of sharp images without star trails when taking photos of the night sky with long exposures. The purpose is to generate an image where a landscape and a star are made bright and a track of the star is prevented from appearing when a star and landscape photograph is taken.

How does this work? A first detection process concerns the landscape in the test image, first detection data is produced. A second detection process detects the star from the test image in accordance with the first detection data and obtains second detection data. The exposure condition setting section obtains a first image by the imaging section with a first exposure condition which is set in accordance with the first detection data, controls the imaging section with a second exposure condition which is set in accordance with the second detection data, and obtains a second image. A first synthesis corrects a luminance value of the star to a prescribed luminance value in the second image data, and sets it to be a first synthesized image. A second synthesis synthesizes the first synthesized image and the first image, and generates a second synthesized image.

Canon patent

  • Low sensitivity, I will test taken at the proper exposure
  • Place the time, to test shooting with the same settings
  • From the difference of the two test images to detect a movement of the star, and also to calculate the proper exposure time from the mobile width
  • The production shot with appropriate exposure to the subject of non-star
  • The production shot with appropriate exposure to star
  • To obtain the final output image by synthesizing two images production
[via Egami]

Deal Alert: Canon PowerShot SX520 HS ($199), PowerShot SX400 IS ($149)

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Adorama has two good deals on Powershot cameras, both with huge instant discounts.

  • Canon PowerShot SX520 HS IS, 16MP, 42x Optical Zoom, 3″ LCD Display, AV Output/HDMI/USB 2.0, 1080pHD Video, Optical Image Stabilization, Black – on sale for $199 after $200 instant rebate
  • Canon PowerShot SX400 IS, 16MP, 30x Optical Zoom, 3″ LCD Display, AV Output/USB 2.0, Optical Image Stabilization, HD 1280x720p Video, Black – on sale for $149 after $100 instant rebate


End of Year Clearance Sale at Canon Direct Store (up to 66% off)


You are still in time to get the perfect gift for X-Mas.

The Canon Direct Store has 66% off on select products (click here). You get a $9 flat rate on overnight shipping and handling when entering code RUDOLPH at checkout.

Be sure to check also the Canon Direct Store‘s refurbished DSLRsPowershot cameras, and lenses.

More links to holiday deals. Note: most retailers offer free overnight or expedited shipping.

Adorama offers free overnight shipping, click the banner below.


This Week Canon Watch Readers Photo Selection

Arsi Ikonen‎ – Brown bear with 7D + 70-200 mm F2.8 L. I like that lens!

How it works:

1) Submit your picture with a short description on Canon Watch’s Facebook page
2) Like and comment the pictures from other readers on the Photo Stream
3) A selection of the most liked pictures will be posted every Sunday here on Canon Watch

Show us what you can do with a Canon camera!

NOTE: if you post your photo late in the week it will be evaluated the week after. Nothing gets lost :-)

Aki Zenji‎ – Silent Night, EOS 70D+EF-S10-22mm — at Yongsan Army Base.


Dominick Chiuchiolo‎ – One of my first shots with the 7DMKII and 70-200 f2.8 IS II. Long Island, NY Swans. Tres Amigos


Matthew J. Taylor‎ – Working with Canons 85mm f/1.2 prime, this was shot in my garage, the first time i put the 85mm on my 60D. Makes me wish i could afford a full frame canon… — with Sharlem Nina.


Diego Eidelman‎ – Rose wine on a summer day, 5D Mk III + 100mm macro f/2.8L IS, f/5, 1/100″, ISO 4000


Terrell Woods‎ – The coming of the storm in SoCal


Canon EF 100-400mm f/4.5-5.6L IS II Review (Photozone)

EF 100-400mm posted their review of the brand new Canon EF 100-400mm f/4.5-5.6L IS II lens. And it is a very positive one.

From the conclusion:

The king is dead, long live the king! Seems as if Canon wanted to show the new mirrorless kids who is still the boss around. The Canon EF 100-400mm f/4.5-5.6 USM L IS was already good but the Canon EF 100-400mm f/4.5-5.6 USM L IS II is even better. Canon managed to improve the image sharpness substantially (mostly in the lower range). The image center is now dead sharp and the borders and corners are easily very good at mainstream settings. The very low amount of CAs (at and beyond 200mm) is highly impressive. The vignetting remains rather typical for a lens in this class, so you will be able to spot some light falloff at fully open aperture (300/400mm). Image distortions are well controlled. The quality of the bokeh is good although the best prime lenses continue to have an edge here. Bokeh fringing is not an issue due to the relatively small max. aperture.

Photozone’s review comes with test charts and sample pictures. The EF 100-400mm f/4.5-5.6 USML IS II is shipping since last week, and can be ordered at B&H Photo and Adorama. Price is $2,199.

  • EF Mount L-Series Lens/Full-Frame Format
  • One Fluorite and One Super UD Element
  • Air Sphere and Fluorine Lens Coatings
  • Ring-Type USM AF Motor, Internal Focus
  • Optical Image Stabilizer with 3 Modes
  • Rotating Zoom Ring & Torque Adjustment
  • Weather-Sealed Design
  • Detachable, Rotatable Tripod Collar
  • Rounded 9-Blade Diaphragm

See if the EF 100-400mm f/4.5-5.6 USML IS II is available in your country: Amazon, B&H, Adorama, Canon USA, Digitalrev, eBay

EF 100-400mm f/4.5-5.6L IS II