[Patent] Canon Files Patent For 600mm f/5.6 and 800mm f/5.6

600mm f/5.6 DO
800mm f/5.6 DO

Egami (machine translated) found a patent filed by Canon for a 600mm and a 800mm f/5.6 lens using diffractive optical elements.

  • Patent Publication No. 2012-123152
    • 2012.6.28 Release Date
    • 2010.12.8 filing date
  • Example 1
    • Focal length f = 584.99mm
    • Fno. 5.80
    • Half angle of 2.12 deg.
    • Image height 21.64mm
    • Length 360.03mm
    • BF 94.84mm
    • 17 pieces in 10 groups Lens Construction
    • 3 UD glass sheet
    • One fluorite
    • A surface diffraction plane
  • Example 3
    • Focal length f = 779.00mm
    • Fno. 5.80
    • Half angle of 1.59 deg.
    • Image height 21.64mm
    • Length 462.02mm
    • BF 120.29mm
    • 17 pieces in 10 groups Lens Construction
    • 2 UD glass sheet
    • Two fluorite
    • A surface diffraction plane
  • Low dispersion material with anomalous partial dispersion
    • To be effective in the correction of chromatic aberration
    • Specific gravity is large (heavy)
      • 3.18 fluorite
      • FK01 3.63
      • The specific gravity of small anomalous partial dispersion glass material
        • FK5 2.46
        • BK7 2.52
    • Surface may be damaged easily
    • FK01 is fragile due to temperature changes and large diameter
  • Diffractive optical element (DOE)
    • To be effective in the correction of chromatic aberration
    • Is generated by unwanted light flare and ghosting
  • Canon’s patented
    • Become positive from negative to DOE
    • DOE to place the position is hard to unwanted light incident

[Deal] Powershot G1 X Price Drops To $729

B&H has the Canon Powershot G1 X on sale for $729 (click here), that’s $70 off from the regular price. Limited quantity available. The G1 X is Canon’s first attempt in the mirrorless market. While not having interchangeable lenses, the G1 X sports a near APS-C sized sensor with 4:3 ratio. Moreover, this camera comes with a fixed yet amazingly performing lens. More specs:

  • 14.3MP 1.5″ CMOS Sensor
  • 3.0″ Vari-Angle LCD Screen
  • 28mm Wide Lens with 4x Optical Zoom
  • DIGIC 5 Image Processor
  • Hybrid Image Stabilizer
  • Optical Viewfinder
  • Up to 12,800 ISO
  • 1080p Full HD Video
  • High Dynamic Range Scene Mode
  • Manual & Numerous Other Shooting Modes

[Rumor] Canon Mirrorless System Camera Rumor – Quick Update

Canon mirrorless camera concept by D. Riesenberg

While the hints for a Canon announcement on July 23, regarding the awaited mirrorless system camera, are getting stronger by the day, there are also more and more related rumor-bits surfacing here and there. Some of the rumors I got, coming from a source I trust, are saying that Canon’s upcoming mirrorless system camera

  • has a new type of mount and that Canon will provide an adapter for EF lenses (that was already considered to be most probable, nothing really new here)
  • features an APS-C sized sensor and not the sensor of the PowerShot G1 X (most of us thought it would have this sensor) – This is a new rumoured spec of Canon’s mirrorless camera, and – I guess – a very welcome one (if true)

Any news, thoughts, speculations…?

[Review] Just Another Rebel? The T4i/650D As A Technology Sandbox

I have to say that I feel I am neglecting the Rebel T4i (EOS 650D in EU, Kiss X6i in JP). I am not part of the “just another Rebel” party, nor do I have an elitist approach to photographic gear. Nevertheless, I didn’t dedicate too much time to the latest Rebel (so far). That’s a shame, because Canon’s last iteration of the Rebel series (the xxxD series in EU) has a lot of advanced and cue-giving tech inside. So much that it should make us curios what it is about. I reported time ago that Canon may sandboxing and testing the technology (i.e. the touchscreen) that could possibly be used for its upcoming mirrorless system camera (expected for July 23). Now, there are more hints that the Rebel T4i/650D sports features and functionalities that would be more than just useful on a mirrorless camera.

Le me start saying that the T4i/650D is Canon’s first DSLR having full-time auto-focus in video mode. To accomplish this, you can use different focusing approaches, such as the contrast-detect method (used in previous Canon DSLR, slow and imprecise) or phase detection sensors in the camera (causes a blackout during live view, when the mirror flips down). But there is a third way to get auto-focus through phase detection: mixing phase detection sensors with pixels on the sensor itself. That’s what the folks at chipworks discovered when they tore down a T4i/650D. The cool thing is that such a technical solution would make up for a fast and reliable AF on a mirrorless camera. The technology is not new and was seen on Nikon’s Aptina sensor sported on the V1 and on the Fuji F300EXR. Differently from Nikon, which uses regular lines to implement the phase detection sensors, Canon uses an irregular pixel pattern. This is not totally new, as Canon two years ago published a patent for such a technology.

What are your thoughts?

Canon patent for phase detection AF

[via photographybay, chipworks]

[Rumor] Canon’s Mirrorless Camera To Be Announced July 23?

Image courtesy of canonrumors.com

Canonrumors published the above invite for a Canon event to be hold July 23th. Is this the day Canon will finally announce its eagerly awaited mirror less system camera? Looks like! CR suggests that the same day Canon could also announce the new EF 200-400 f/4L IS 1.4x lens.

Two more weeks and we will (maybe) eventually learn Canon’s mirrorless projects.

[Deal] EOS 5D Mark II Refurbished And Discounted

Concrete savings on the still excellent EOS 5D Mark II. First, the Canon Store has refurbished 5D Mark IIs for $1,759.20 (click here, to see all refurbished Canon DSLRs click here). Consider that the EOS 5D Mark II usually has a price tag of $2,199.00 and do the math. Then, B&H discounted the 5D Mark II (new, body only) to $2,079 (click here). Shipping is free if you live in the US.

The EOS 5D Mark II [click here for a comprehensive review] has a stunning 21.1-megapixel full-frame CMOS sensor with DIGIC 4 Image Processor, a vast ISO Range of 100-6400 (expandable to ISO L: 50, H1: 12800 and H2: 25600), plus EOS technologies like Auto Lighting Optimizer and Peripheral Illumination Correction. It supports Live View shooting, Live View HD videos, and more. It can shoot up to 3.9 fps, has 9 AF points plus 6 AF assist points, a new 98% coverage viewfinder, a 3.0-inch Clear View LCD (920,000 dots/VGA) and a rugged build. Full-frame shooters rejoice!