Patent: Canon Curved Aperture Diaphragm

[JVLphoto]

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<p>Here’s another patent filing picked up by <a href="http://egami.blog.so-net.ne.jp/2014-01-27" title="egami" target="_blank">egami</a>:</p>
<p>(translated)

<strong>Patent Publication No. 2014-13363,2014-13365</strong></p>
<li>Publication date 2014.1.23</li>
<li>Filing date 2012.6.6</li>
<p>


<strong>Canon patents</strong></p>
<li>The iris of the dome-shaped</li>
<p>
</p>
<p>If I’m reading this correctly, if the aperture follows the curvature of the glass you end up by saving some space which can lead to more compact lenses, if not for the M line, than perhaps we’ll see some smaller EF-S lenses.</p>
<p><a href="http://egami.blog.so-net.ne.jp/2014-01-27" title="egami" target="_blank">egami</a> via [<a href="http://www.canonwatch.com/canon-patent-curved-diaphragm/" title="Canon Watch" target="_blank">CW</a>]</p>
<p><strong><span style="color: #ff0000;">c</span>r</strong></p>

 

[bchernicoff]

Wouldn't that result in field curvature? Or maybe this is a way to correct that?

 

[arjay]

Wouldn't that result in field curvature? Or maybe this is a way to correct that?

It wouldn't affect curvature of field, but it sounds like a way to correct for focus shift (the 50 1.2 L has been known to have focus shift at close distances)

 

[x-vision]

If I’m reading this correctly, if the aperture follows the curvature of the glass you end up by saving some space ...

Yup. Presumably for pancake lenses.

 

[bchernicoff]

It wouldn't affect curvature of field, but it sounds like a way to correct for focus shift (the 50 1.2 L has been known to have focus shift at close distances)

You're right. I wasn't thinking it through. As the iris closes from the wide open position, the optical axis of the lens would move forwards or backwards depending on which direction the curved diaphragm was installed.

 

[mrsfotografie]

If I’m reading this correctly, if the aperture follows the curvature of the glass you end up by saving some space ...

Yup. Presumably for pancake lenses.

I agree, this is the first thing I thought when I read this item, and probably something on the mirrorless side of things.

 

[fpdv01]

I'm wondering how this would affect bokeh?
Creamier, more eye pleasing of out of focus blobs of background? Just wondering...

 

[sjprg]

Having the curved aperture closer to the lens may also have possibilities of diffraction correction???

 

[traveller]

So one of the Canon engineers was playing around with his wife's steamer basket and thought "ah ha!"...

 

[jrista]

Having the curved aperture closer to the lens may also have possibilities of diffraction correction???

Diffraction is caused by the passage of light through an aperture. Where the aperture is doesn't really have anything to do with how much diffraction occurs.

 

[jrista]

Well, here is another Canon innovation for that "Where are Canon's innovations?" thread.

 

[Mt Spokane Photography]

Its a dome shaped aperture.

Its benefit is to shorten the length of a lens. Here is the translated description of the benefit. A pancake is a good potential use.

Member x-vision is right-on!

"According to the present invention, a light volume adjustment suitable for a miniaturization is realizable. When a light volume regulation blade is especially opened to a release position in a light volume adjustment, in order that a light volume regulation blade may not take space to a radial direction, it becomes possible to miniaturize a light volume adjustment in a radial direction. And the miniaturization of the optical instrument which mounted this light volume adjustment can be attained. "

 

[StudentOfLight]

Its a dome shaped aperture.

Its benefit is to shorten the length of a lens. Here is the translated description of the benefit. A pancake is a good potential use.

Member x-vision is right-on!

"According to the present invention, a light volume adjustment suitable for a miniaturization is realizable. When a light volume regulation blade is especially opened to a release position in a light volume adjustment, in order that a light volume regulation blade may not take space to a radial direction, it becomes possible to miniaturize a light volume adjustment in a radial direction. And the miniaturization of the optical instrument which mounted this light volume adjustment can be attained. "

My dream of a 40mm f/1 cupcake is one step closer to reality!!!

 

[sjprg]

Jurist; With the aperture closer to the lens while the angle is the same, the area of the dispersal is much smaller which may allow better lens corrections in the first lens behind it. Just a thought.

 

[jrista]

Jurist; With the aperture closer to the lens while the angle is the same, the area of the dispersal is much smaller which may allow better lens corrections in the first lens behind it. Just a thought.

If this is a response to me, it is jrista - Jon Rista

As for corrections, you might be able to correct aberrations, but there is nothing you can do to correct diffraction. Diffraction is intrinsic to electromagnetic energy, it's part of the energy field itself. It doesn't matter how close the diaphragm is to the lens, diffraction is uncorrectable. (If it WAS correctable, someone would have figured out how a LONG time ago...at the very least as a solution to better subwavelength etching at lower frequencies than the EUV we use now (which is more difficult to generate.))