SX50 Lens on Canon Rumors

Started Jul 29, 2012 | Discussions thread
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Stephen Barrett
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SX50 Lens on Canon Rumors
Jul 29, 2012

On Canon Rumors there is a Canon patent for a 24-1060mm Zoom Lens (44x) that is rumoured to be for the SX50:

http://www.canonrumors.com/tag/sx50/

Example 7 is:
• Zoom ratio 44.28
• 13.08 – - 190.43mm f = 4.30 focal length
• Fno 2.87 – 5.00 – 7.07
• 16.50 – - 1.17 deg 37.77 a half angle of view.
• 3.88 – - 3.88mm 3.33 image height
• 93.62 – - 137.94mm 94.49 lens length
• BF 1.00mm
• 13 pieces in 10 groups Lens Construction
• Two four-sided aspherical
• 3 UD glass sheet
• One fluorite
• Group 4 consists of positive and negative positive positive
• (For Focusing the fourth lens group) Rear focus

Line 2 gives the focal length as 4.3-190.43 mm.
Does anybody know what the 13.08 means?

Line 3 gives the f number as 2.78 - 5.00 (I think)
Does anybody know what the 7.07 means?

The Panasonic FZ200 has a maximum aperture of 108 mm / 2.8 = 38.6 mm.

If the patent's 5.00 is the the minimum f number at maximum focal length, then the maximum aperture for the patented lens is 190.43 / 5.00 = 38.1 mm, which is roughly the same as the FZ200. That would be great!

Comparing angular resolutions (approx 9%MTF) in my spreadsheet (assuming that the SX50 sensor is the same size and 12 MP as SX40's):

Angular Resolution at full optical zoom (in microradians)

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Lens Alone ------------- Sensor Alone ------------ Total
Panasonic FZ150-----------30.1------------------------28.6------------------41.5
Panasonic FZ200-----------16.2------------------------28.6------------------32.8

Canon SX30-----------------24.1------------------------19.0------------------30.7

Canon SX40-----------------24.1------------------------20.5------------------31.6

Canon SX50-----------------16.4------------------------16.2------------------23.1

(Smaller angle means better resolution)

You can see that, even though the FZ200 and the rumoured SX50 have about the same lens resolution, the SX50 has better sensor resolution because the image that the lens projects onto the sensor is larger. The SX50 is therefore able to retain more of the lens resolution than the FZ200 in the total camera resolution.

I was really excited about the large-aperture FZ200 but this Canon rumour has me even more excited. f/5.00 may not sound as exciting as f/2.8 but the f/5.00 is at a focal length of 1060 mm. If you zoom out to the FZ200's 600 mm you may get something close to f/2.8. So, if the rumour is true, we should get a fast lens with better low-light capability, IQ and resolution.

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