A Hypothetical "Larger than full-frame": Lens Question

Started Jul 7, 2013 | Discussions
Mike Stratil
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A Hypothetical "Larger than full-frame": Lens Question
Jul 7, 2013

Canon Rumors has passed on rumor that Canon may be preparing a larger than full frame DSLR.

For those with appropriate technical expertise, I have a question. Is it technically possible that such a camera could use existing EOS full-frame lenses?

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Michael S

Keith Z Leonard
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Re: A Hypothetical "Larger than full-frame": Lens Question
In reply to Mike Stratil, Jul 7, 2013

I wouldn't think so, EF lenses are designed to project an image circle to cover 35mm format film.  There MIGHT be some wiggle room there, of course, but it isn't really as though those lenses are going to cover a medium format sized sensor.

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David Mosby
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Re: A Hypothetical "Larger than full-frame": Lens Question
In reply to Mike Stratil, Jul 7, 2013

Canon Rumors has passed on rumor that Canon may be preparing a larger than full frame DSLR.

For those with appropriate technical expertise, I have a question. Is it technically possible that such a camera could use existing EOS full-frame lenses?

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Michael S

Surely it would be possible to have a square sensor, larger than full frame. This would be ideal - you could still have in-camera cropping for other formats, for those who want them.

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Johanfoto
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Re: A Hypothetical "Larger than full-frame": Lens Question
In reply to David Mosby, Jul 7, 2013

David Mosby wrote:

Canon Rumors has passed on rumor that Canon may be preparing a larger than full frame DSLR.

For those with appropriate technical expertise, I have a question. Is it technically possible that such a camera could use existing EOS full-frame lenses?

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Michael S

Surely it would be possible to have a square sensor, larger than full frame. This would be ideal - you could still have in-camera cropping for other formats, for those who want them.

This is a common misconception. Many people think that full frame lenses could be used with a 36 x 36 mm sensor, because they are now also used with a 36 mm wide sensor. That is not true. A square sensor would have to be smaller than 36 x 36 mm (30 x 30 mm) in order to stay within the image circle of an full frame lens, so there's little advantage (if any) of a square sensor.

I explained that on my website some two years ago for a similar rumor about a Samsung larger-than-full-frame camera (that never materialized either):

http://www.johanfoto.com/2011/05/samsung-medium-format/

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Toccata47
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Re: A Hypothetical "Larger than full-frame": Lens Question
In reply to Mike Stratil, Jul 7, 2013

It's possible just as it's possible to use m4/3 lenses on aps-c cameras now. You won't get the benefit of the whole sensor so there's little reason to do so.

As you probably know, larger than full frame cameras came first. There are a few digital medium format cameras around today but they are typically fairly expensive relative to their 135mm counterparts.

Mike Stratil wrote:

Canon Rumors has passed on rumor that Canon may be preparing a larger than full frame DSLR.

For those with appropriate technical expertise, I have a question. Is it technically possible that such a camera could use existing EOS full-frame lenses?

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Michael S

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hotdog321
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Re: A Hypothetical "Larger than full-frame": Lens Question
In reply to Mike Stratil, Jul 7, 2013

I doubt it; I imagine they will introduce a line of specialty lenses for this hypothetical camera or the corners will be hopelessly soft. Most full-frame lenses barely cover the 35mm frame size--that's why the corners and edges are so critical.

One possible exception might be the t/s lenses. I don't know but would be glad for some input.

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Press Correspondent
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Circle Sensor
In reply to Johanfoto, Jul 7, 2013

Johanfoto wrote:

David Mosby wrote:

Canon Rumors has passed on rumor that Canon may be preparing a larger than full frame DSLR.

For those with appropriate technical expertise, I have a question. Is it technically possible that such a camera could use existing EOS full-frame lenses?

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Michael S

Surely it would be possible to have a square sensor, larger than full frame. This would be ideal - you could still have in-camera cropping for other formats, for those who want them.

This is a common misconception. Many people think that full frame lenses could be used with a 36 x 36 mm sensor, because they are now also used with a 36 mm wide sensor. That is not true. A square sensor would have to be smaller than 36 x 36 mm (30 x 30 mm) in order to stay within the image circle of an full frame lens, so there's little advantage (if any) of a square sensor.

I explained that on my website some two years ago for a similar rumor about a Samsung larger-than-full-frame camera (that never materialized either):

http://www.johanfoto.com/2011/05/samsung-medium-format/

The best invention would be a circle shaped 43-mm diameter sensor allowing a choice of 24x36 conventional (2x3) or 30.5.x30.5 square or 19x38 panorama (1x2) or 25.5x34 (3x4) or any othe proportion like 13.67x41 (1x3) at will.

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Press Correspondent
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Re: A Hypothetical "Larger than full-frame": Lens Question
In reply to hotdog321, Jul 7, 2013

hotdog321 wrote:

One possible exception might be the t/s lenses. I don't know but would be glad for some input.

Yes, you could use the shift lenses without shifting on a larger sensor. The 17mm and 24mm allow a 1.55 times larger frame, the 45mm and 90mm allow a 1.35 times larger frame in each dimention. The corner quality and vignetting of course are concerns, but this is possible. However, with manual focus and no shift, this is hardly better than using a third party medium format lenses with an adaptor.

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Muresan Bogdan
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Re: A Hypothetical "Larger than full-frame": Lens Question
In reply to Mike Stratil, Jul 7, 2013

It also depends on the distance from the lens to the sensor. The image is projected on the sensor so as you get further the image gets bigger, just like your office projector. So in theory you could use the lens. You would lose infinit focus and probably some IQ also.

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Phil
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Re: A Hypothetical "Larger than full-frame": Lens Question
In reply to Mike Stratil, Jul 7, 2013

Mike Stratil wrote:

Canon Rumors has passed on rumor that Canon may be preparing a larger than full frame DSLR.

For those with appropriate technical expertise, I have a question. Is it technically possible that such a camera could use existing EOS full-frame lenses?

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Michael S

I would expect to see Canon push the resolving power beyond current sensors for a select group of lenses then notch up the body resolution.

I'm already past the medium formats photos my customers got a few years ago so I don't think there would be enough market for them to move is that direction.

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Mike Stratil
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Thanks for the input
In reply to Mike Stratil, Jul 7, 2013

This input is very helpful. I own a lot of good Canon lenses, and the possibility of being able to use them with a new high res camera has been very appealing. Right now I am doing most of my photography with the Sigma SD1-M, whose resolution I find significantly better than that of my 5D3. Which is to say I've fallen in love with high resolution photography. But the SD1-M's deficiencies (especially slow write speeds and no live view) have been a negative. Thus, I've been very interested in the possibility of a high res Canon DSLR.

But if such a camera means getting a new suite of Canon lenses, that changes the equation a lot. It sure would be helpful if Canon would give us a clearer idea of where they plan to go.

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Michael S

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Press Correspondent
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Re: Thanks for the input
In reply to Mike Stratil, Jul 8, 2013

Mike Stratil wrote:

This input is very helpful. I own a lot of good Canon lenses, and the possibility of being able to use them with a new high res camera has been very appealing. Right now I am doing most of my photography with the Sigma SD1-M, whose resolution I find significantly better than that of my 5D3. Which is to say I've fallen in love with high resolution photography. But the SD1-M's deficiencies (especially slow write speeds and no live view) have been a negative. Thus, I've been very interested in the possibility of a high res Canon DSLR.

But if such a camera means getting a new suite of Canon lenses, that changes the equation a lot. It sure would be helpful if Canon would give us a clearer idea of where they plan to go.

Higher resolution doesn't automatically imply a bigger sensor. Nikon D800 has over 36mp with a stunning quality.

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Press Correspondent
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Re: A Hypothetical "Larger than full-frame": Lens Question
In reply to Muresan Bogdan, Jul 8, 2013

Muresan Bogdan wrote:

It also depends on the distance from the lens to the sensor. The image is projected on the sensor so as you get further the image gets bigger, just like your office projector. So in theory you could use the lens. You would lose infinit focus and probably some IQ also.

I don't think the image circle of a lens increases with the image at closer distances. The image increases in size, but does not keep the same quality at the edges. The projector lens in your example is reversed. It is a known technique to reverse the direction of a lens for extreme macro work. The same technique could be used to increase the image circle at close distances. To summarize, in your example, in addition to a closer distance, you would also need to flip the lens back forward to use it with a larger format.

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Muresan Bogdan
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Re: A Hypothetical "Larger than full-frame": Lens Question
In reply to Press Correspondent, Jul 8, 2013

Press Correspondent wrote:

Muresan Bogdan wrote:

It also depends on the distance from the lens to the sensor. The image is projected on the sensor so as you get further the image gets bigger, just like your office projector. So in theory you could use the lens. You would lose infinit focus and probably some IQ also.

I don't think the image circle of a lens increases with the image at closer distances. The image increases in size, but does not keep the same quality at the edges.

Well it increases in size as the distance from the sensor gets bigger. And I already mentioned that there might be a loss in image quality. On the old medium format some people used FF lens with the help of an extension tube.

The projector lens in your example is reversed. It is a known technique to reverse the direction of a lens for extreme macro work. The same technique could be used to increase the image circle at close distances. To summarize, in your example, in addition to a closer distance, you would also need to flip the lens back forward to use it with a larger format.

Reversing the lens gives you magnification more than increse of the image circle. But as I said this technique has been used in the past: using the lens in normal position with an extension. But in normal position not flipping it back-forward.

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tim73
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Re: A Hypothetical "Larger than full-frame": Lens Question
In reply to Johanfoto, Jul 8, 2013

Johanfoto wrote:

David Mosby wrote:

Surely it would be possible to have a square sensor, larger than full frame. This would be ideal - you could still have in-camera cropping for other formats, for those who want them.

This is a common misconception. Many people think that full frame lenses could be used with a 36 x 36 mm sensor, because they are now also used with a 36 mm wide sensor. That is not true. A square sensor would have to be smaller than 36 x 36 mm (30 x 30 mm) in order to stay within the image circle of an full frame lens, so there's little advantage (if any) of a square sensor.

There's also the question of the reflex mirror.  If the sensor is taller than 24mm then the mirror will need to be proportionally larger.  The lens mount is designed to put the lens as close as possible to the sensor whilst leaving enough clearance for the mirror, so there's little or no room for a larger mirror.

Of course with Canon's recent advances in live-view AF you could argue that reflex cameras are on the road to extinction.

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Johanfoto
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Re: Thanks for the input
In reply to Mike Stratil, Jul 9, 2013

Mike Stratil wrote:

This input is very helpful. I own a lot of good Canon lenses, and the possibility of being able to use them with a new high res camera has been very appealing. Right now I am doing most of my photography with the Sigma SD1-M, whose resolution I find significantly better than that of my 5D3. Which is to say I've fallen in love with high resolution photography. But the SD1-M's deficiencies (especially slow write speeds and no live view) have been a negative. Thus, I've been very interested in the possibility of a high res Canon DSLR.

That may come, but in the shape of a full frame DSLR, not a larger than full frame DSLR.

But if such a camera means getting a new suite of Canon lenses, that changes the equation a lot. It sure would be helpful if Canon would give us a clearer idea of where they plan to go.

Well, I think that the answer is very simple. IF Canon would introduce a camera system with a larger than full frame sensor, it must have new lenses as well. You simply cannot use your existing lenses on such a system. I think it is extremely unlikely that Canon will do so, however. There were even pictures (fake, obviously) of that Samsung camera I referred to two years ago. It never materialized nevertheless. Those Canon rumors are the same: Just rumors, probably written by people with more wishful thinking than technical knowhow.

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