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RF 300mm f/2.8 IS

Started 6 months ago | Discussions
Victor Engel Forum Pro • Posts: 20,968
RF 300mm f/2.8 IS

https://www.canonrumors.com/patent-canon-rf-300mm-f-2-8l-is-1-4x-plus-other-supertelephoto-optical-designs/

A glaring detail to me on that page is the image height. I guess this lens is for crop cameras only? With a lens that size, it seems it would make more sense to make it a full frame lens.

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Victor Engel

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Sittatunga Veteran Member • Posts: 5,413
Re: RF 300mm f/2.8 IS

Victor Engel wrote:

https://www.canonrumors.com/patent-canon-rf-300mm-f-2-8l-is-1-4x-plus-other-supertelephoto-optical-designs/

A glaring detail to me on that page is the image height. I guess this lens is for crop cameras only? With a lens that size, it seems it would make more sense to make it a full frame lens.

The image height needed to cover a 24×36mm sensor is 21.633mm (though going to the nearest micrometre is ridiculously over-precise). It's the radius of the image circle, measured from the centre of the field of view.

OP Victor Engel Forum Pro • Posts: 20,968
Re: RF 300mm f/2.8 IS

Sittatunga wrote:

Victor Engel wrote:

https://www.canonrumors.com/patent-canon-rf-300mm-f-2-8l-is-1-4x-plus-other-supertelephoto-optical-designs/

A glaring detail to me on that page is the image height. I guess this lens is for crop cameras only? With a lens that size, it seems it would make more sense to make it a full frame lens.

The image height needed to cover a 24×36mm sensor is 21.633mm (though going to the nearest micrometre is ridiculously over-precise). It's the radius of the image circle, measured from the centre of the field of view.

Oh, so it's height from center? I guess that makes sense.

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Victor Engel

 Victor Engel's gear list:Victor Engel's gear list
Canon EOS 5D Canon EOS 5D Mark II Canon EOS 600D Canon EOS 5DS Canon EF 50mm F1.8 II +13 more
Sittatunga Veteran Member • Posts: 5,413
Re: RF 300mm f/2.8 IS

Victor Engel wrote:

Sittatunga wrote:

Victor Engel wrote:

https://www.canonrumors.com/patent-canon-rf-300mm-f-2-8l-is-1-4x-plus-other-supertelephoto-optical-designs/

A glaring detail to me on that page is the image height. I guess this lens is for crop cameras only? With a lens that size, it seems it would make more sense to make it a full frame lens.

The image height needed to cover a 24×36mm sensor is 21.633mm (though going to the nearest micrometre is ridiculously over-precise). It's the radius of the image circle, measured from the centre of the field of view.

Oh, so it's height from center? I guess that makes sense.

The diagonal of a Canon APS-C sensor is just under 27mm...

John Sheehy Forum Pro • Posts: 26,698
Re: RF 300mm f/2.8 IS

Victor Engel wrote:

https://www.canonrumors.com/patent-canon-rf-300mm-f-2-8l-is-1-4x-plus-other-supertelephoto-optical-designs/

A glaring detail to me on that page is the image height. I guess this lens is for crop cameras only? With a lens that size, it seems it would make more sense to make it a full frame lens.

That link is just giving me a spinning circle, so I can't read it right now, but as far as I understand, there is little that can be done to optimize a 300mm lens for APS-C vs FF.

Maybe specs were given based on APS-C?  That "1-4x"; is that a built-in TC?  That could explain it.

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Beware of correct answers to wrong questions.
John
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