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-   -   HD and SD lens design by Canon (http://www.dvinfo.net/forum/general-hd-720-1080-acquisition/332375-hd-sd-lens-design-canon.html)

Steve Phillipps August 28th, 2009 11:24 AM

HD and SD lens design by Canon
 
I found a couple of links, maybe they've been posted here before.

http://www.canonusa.com/industrial_b...s_Design07.pdf

http://www.usa.canon.com/html/indust...5TVB_Canon.pdf

Interesting reading but obviously from the pov of someone wanting to sell more lenses! Don't agree at all with some of it, most notably the "fact" that SD lenses have more chromatic aberration than HD lenses, I've found the opposite.

I was looking at these because I wanted to know what lp/mm an HD lens is supposed to have as I've just had my Canon 150-600 stills lens tested and it's showing 54 lp/mm. Apparently HD is supposed to be 50, so that makes me think it should be pretty good.

Steve

Alister Chapman August 28th, 2009 03:53 PM

Hi Steve. Until lens manufacturers publish the MTF curves for lenses we are going to be in the dark about actual real world performance as opposed to "sales" speak. While resolution is very important, contrast is in many ways more important because contrast is what shows up the subtle textures and fine detail that really makes HD look good. A MTF curve will show both limiting resolution and the way the lens handles contrast.

I too have come across many SD lenses that exhibit less CA than HD equivalents.

I don't know if you've watched these:
Demystifying Digital Camera Specifications Part 1: What?s in a Pixel?

At the end of the day if when you put it on the camera it produces a good image, when taking into account factors such as focal length and aperture then that's what counts. Not whether it has an HD badge or not. I've come across a couple of so called HD lenses that I wouldn't want to use on an SD camcorder, let alone HD.


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