full frame cameras mean big lenses?

Started Nov 18, 2011 | Discussions
nemist
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full frame cameras mean big lenses?
Nov 18, 2011

I was reading something recently regarding CCD sensor and CMOS sensor differing with how they gather light when the sensor is hit by photons at a perpendicular angle. As I understand it (very foggy), CMOS sensors can't render the light well if not hit at a certain angle, but CCD can? I read this under the context of large lenses don't necessarily mean large bodies; i.e. Leica M9 has small lenses (relatively), but also sports a CCD. The reason I ask is because I would very much like to see an affordable full frame mirror less camera with relatively compact lenses, and Canon hasn't thrown a punch in the mirror less ring yet. I doubt it will happen, but would making a relatively compact mirror less option require a different kind of sensor? Or, why is their the association, or myth, that larger cameras require larger lenses? Thanks.

Gearóid Ó Laoi, Garry Lee
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Re: full frame cameras mean big lenses?
In reply to nemist, Nov 18, 2011

I think that lenses can be made smaller if the sensor is closer to the back of the lens. When there is a mirror, optical trickery is required to overcome this wider gap and this entails bigger lenses. That's why mirrorless cameras, all other things being equal, have smaller lenses.

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pekelnik
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Re: full frame cameras mean big lenses?
In reply to nemist, Nov 18, 2011

There is a rumor about full frame exchangable lens fuji X100 replacement next year.

As for lens size, the resolution limit of a lens is tied not only to glass quality but also to the width of the aperture (actual width, not the ratio between aperture and focal length). I'm not sure how close we are to this limit now but if the tolerances decrease a lot you will find the small glass hitting the limit sooner than the large one.

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Tinu_ch
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Re: full frame cameras mean big lenses?
In reply to nemist, Nov 18, 2011

nemist wrote:

I was reading something recently regarding CCD sensor and CMOS sensor differing with how they gather light when the sensor is hit by photons at a perpendicular angle. As I understand it (very foggy), CMOS sensors can't render the light well if not hit at a certain angle, but CCD can?

I can't really comment on this, but I would be suprised if CCD vs CMOS would perform different with regard to the angle the light is coming in. The narrower the angle the less light will hit the sensitive area of the sensor (just plain geometry, but maybe reflection comes into it too).

I read this under the context of large lenses don't necessarily mean large bodies; i.e. Leica M9 has small lenses (relatively), but also sports a CCD.

The Leica M9 is a mirrorless camera. The rear of the lens can reach into the camera and some of the M lenses get really close to the sensor. This makes it easier to design small but sharp wideangle lenses (one strenght of the Leica M system). The bad news: towards the corners of the sensor the light does come in in a very narrow angle causing additional vignetting (not so much of a problem with film emulsions, more so with image sensors). The good news: with modern digital cameras the light is not going straight from the lens to the sensor but is caught and guided by microlenses in front of the sensor. To deal with this specific problem the M8 and M9 have a special microlens layout: http://www.dpreview.com/reviews/leicam8/

The reason I ask is because I would very much like to see an affordable full frame mirror less camera with relatively compact lenses, and Canon hasn't thrown a punch in the mirror less ring yet.

Leica has an established lens line-up on the market since decades and has a following that accepts mind-numbing prices. Canon would have to develop and produce all the lenses. A big investment with a high risk. To widen the market they had to sell camera and lenses at fraction of the Leica prices while being instantly compared to them ...

I doubt it will happen, but would making a relatively compact mirror less option require a different kind of sensor?

I do not think a different kind of sensor would solve the major issues.

Or, why is their the association, or myth, that larger cameras require larger lenses?

Larger sensors require larger lenses to offer similar characteristics. With a mirror box all wideangle lenses have to be retrofocus designs, adding quite a bit to the bulk. As Olympus has shown well back in OM times it is possible to build quite small wideangle lenses for FF SLRs (google for ZUIKO lenses). A similar system with FF sensor would meet with quite some interest I guess ...

Tinu

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GoldenSpark
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Re: full frame cameras mean big lenses?
In reply to nemist, Nov 18, 2011

The size of a lens is decided fundamentally by the focal length, the image circle presented to the sensor and the aperture.
As these three parameters get larger the lens must also get larger.

Since large sensors will always give you better performance than small ones, large lenses for full frame sensors are inevitable.

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JackM
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EF lenses were designed for film, so I'm not sure
In reply to nemist, Nov 18, 2011

I'm not sure CCD/CMOS/film has anything to do with it, otherwise Canon would have had to scrap its entire EF lens lineup.

Remember that Leica lenses are primes and have no AF motors. Zoom and AF mechanisms both make a lens larger.

I agree though, I think Canon could do something really special with a FF compact. We already know Leica is developing a new camera to sit somewhere between m4/3 and the M9, and it will not be a re-badged Panasonic. Canon could compete in this space.

This is a full frame camera:

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JackM
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Re: full frame cameras mean big lenses?
In reply to GoldenSpark, Nov 18, 2011

GoldenSpark wrote:

The size of a lens is decided fundamentally by the focal length, the image circle presented to the sensor and the aperture.
As these three parameters get larger the lens must also get larger.

Since large sensors will always give you better performance than small ones, large lenses for full frame sensors are inevitable.

This is a Full Frame camera:

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SteveHorn
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Canon hint
In reply to nemist, Nov 18, 2011

I recall a report of an interview with a Canon executive who was asked if Canon would produce a mirrorless camera. The reply was for that market it doesn't matter if the camera has a mirror, what mattered is that the camera is small.

When I look at my Olympus OM1 I keep wishing that a modern digital full frame reflex camera could be as neat and beautiful as my Olympus. The camera is small, the viewfinder is huge, it has a mirror and the lenses are small.

I would be very happy if Canon could produce a line of EOS cameras and EF lenses as small as possible, while retaining the quality of full frame. The 5Dmk3 perhaps and some new small primes that are sharp at full aperture?

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Peter Galbavy
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Re: full frame cameras mean big lenses?
In reply to nemist, Nov 18, 2011

Lookup "microlenses" WRT camera sensors. All should become clear. Pun intended.

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