jaapv
RFF Sponsoring Member.
It is interesting to note that the current controversy on sensor sizes has parallels to the struggle of the film formats in the first half of last century. Then all the arguments like loss of wide-angle capacity and lower resolution were used against the new miniature format Leica had introduced.Only after WWII did 35 mm film finally get dominant versus 6x9 and sheet film. It is very funny really, to see this mini-format presented as large now. Anyway, now as then there is a great confusion between field of view, focal length and DOF. I would like to put a few things in perspective.
The focal length of a lens does not change for different sensor formats. That is a property of the lens, not of the camera. What does change is its angle and with that field of view. So if you use a wide-angle just because no other lens will take in the bulk of Aunty Mathilda, when you use a smaller format with the same lens you will simply have to step back a few metres or, if that would land you backwards into the swimming-pool, then you will have to take advantage of the friendly terms offered by your camera-manufacturer and buy a shorter lens, as is fitting for the smaller format.
The same goes for the main use of short focal lengths, i.e. perspective control. As the perspective is controlled solely by the distance of camera to subject, the choice is either to crop closer or use a lens with a larger angle of view. Fortunately lenses as short as 12 mm are being offered for rangefinders.
On the other side of the spectrum the story is essentially the same. Those of us that constantly have to crop our photographs down will welcome the smaller field of view of their longer lenses. A smaller sensor will, among other things enable one to use a smaller, fast lens for portraits. A Summilux 50, for instance, is a lot more handy than a Summilux 75. And a field of view equivalent to 180 mm on 35 mm film is something quite new for a rangefinder.
Then there is DOF. If we have to use a 35 mm lens to get the angle of view we are used to with a 50 mm on a 35 mm film camera, obviously we will not get the same DOF. The main thing will be that we will enlarge the smaller sensor more, so we will need a smaller circle of confusion. A 27 mm sensor, as a ballpark figure, will need a 0.02 mm circle of confusion as opposed to the standard 0.03.
The net result wil be that the 35 mm will, on a 1.33 sensor, behave like a 43 mm lens on a 35mm sensor. I have the impression that on a sensor, the transition between sharp and out of focus is more sharply defined than on film, maybe because of the recording medium, maybe because grain and noise behave differently, maybe because we are using the sweet spot of the lens. Anyway, this effect reduces the impression of DOF to about 40 mm equivalent. No big deal between the formats.
Better quality on a larger sensor. Clearly, that is as true for small vs large sensors as it is for 6x9 film vs 35 mm. However, as soon as the smaller format is good enough, like the small film size, this argument loses relevancy. The new book by Pölking, <Digitale Naturfotografie in der Praxis> has a full spread high resolution print comparing all the formats offered by Canon, from 6Mp APS to 16.9Mp 35 mm. The differences, albeit discernable, are extremely small, although the older 6Mp APS loses out slightly.
So the future will teach us to choose our format to our purpose and our lenses to our format. Nothing changes. In the case of the Leica M8 it will mean trading in our 135 mm lens for a 19 mm one. Or just keeping the 135 and adding to our lens stable, as most posters on this forum seem to be doing all the time. Leica is sensitive to this and will be offering "attractively priced" (though what that means with Leica is unclear) wide-angle lenses.
Where does this "full-frame" hype come from? I feel, but I know I'm fighting a losing battle here, that full-frame is a nonsensical term. Not only is 35 mm far from full-frame photographically speaking, it refers to a negative/sensor size that is printed directly without enlarging. So the "full-frame" Canon 5D is in this reference only suitable for taking passport portraits.
Canon has some difficulty competing with Leica, Nikon and Sigma in the extreme wide-angle segment. Surprising as it may seem, this is not a situation that lends itself to a quick fix. As an example, Leica needed 15 years and a lot of expertise from Minolta and Sigma to catch up (and overtake) in the field of zoom lenses.
But Canon does own their private chip factory and Cmos sensors, which are a bit less expensive to produce than CCD's anyway. So the obvious solution is to produce camera's with a larger chip, needing less short lenses.
This has, of course, to be marketed. So imagine this poor marketing executive sitting in his office on the 95th floor in Tokyo. He has to find a catch-phrase. He doesn't know the first thing about camera's but he does know about selling products. The above has been explained to him by a technical executive, but it does not add up to a positive twist to his advertising campaign. A bright young underling, who has read a Readers Digest about Ansel Adams, remembers the words: Full Frame. It sounds even better than "more megapixels"!! They cook up a 100 million dollar campaign to ram this down the collective throats of an unsuspecting public, and there you are: Full-Frame is the hallmark of a quality camera! The guy is probably a vice-president now.
The focal length of a lens does not change for different sensor formats. That is a property of the lens, not of the camera. What does change is its angle and with that field of view. So if you use a wide-angle just because no other lens will take in the bulk of Aunty Mathilda, when you use a smaller format with the same lens you will simply have to step back a few metres or, if that would land you backwards into the swimming-pool, then you will have to take advantage of the friendly terms offered by your camera-manufacturer and buy a shorter lens, as is fitting for the smaller format.
The same goes for the main use of short focal lengths, i.e. perspective control. As the perspective is controlled solely by the distance of camera to subject, the choice is either to crop closer or use a lens with a larger angle of view. Fortunately lenses as short as 12 mm are being offered for rangefinders.
On the other side of the spectrum the story is essentially the same. Those of us that constantly have to crop our photographs down will welcome the smaller field of view of their longer lenses. A smaller sensor will, among other things enable one to use a smaller, fast lens for portraits. A Summilux 50, for instance, is a lot more handy than a Summilux 75. And a field of view equivalent to 180 mm on 35 mm film is something quite new for a rangefinder.
Then there is DOF. If we have to use a 35 mm lens to get the angle of view we are used to with a 50 mm on a 35 mm film camera, obviously we will not get the same DOF. The main thing will be that we will enlarge the smaller sensor more, so we will need a smaller circle of confusion. A 27 mm sensor, as a ballpark figure, will need a 0.02 mm circle of confusion as opposed to the standard 0.03.
The net result wil be that the 35 mm will, on a 1.33 sensor, behave like a 43 mm lens on a 35mm sensor. I have the impression that on a sensor, the transition between sharp and out of focus is more sharply defined than on film, maybe because of the recording medium, maybe because grain and noise behave differently, maybe because we are using the sweet spot of the lens. Anyway, this effect reduces the impression of DOF to about 40 mm equivalent. No big deal between the formats.
Better quality on a larger sensor. Clearly, that is as true for small vs large sensors as it is for 6x9 film vs 35 mm. However, as soon as the smaller format is good enough, like the small film size, this argument loses relevancy. The new book by Pölking, <Digitale Naturfotografie in der Praxis> has a full spread high resolution print comparing all the formats offered by Canon, from 6Mp APS to 16.9Mp 35 mm. The differences, albeit discernable, are extremely small, although the older 6Mp APS loses out slightly.
So the future will teach us to choose our format to our purpose and our lenses to our format. Nothing changes. In the case of the Leica M8 it will mean trading in our 135 mm lens for a 19 mm one. Or just keeping the 135 and adding to our lens stable, as most posters on this forum seem to be doing all the time. Leica is sensitive to this and will be offering "attractively priced" (though what that means with Leica is unclear) wide-angle lenses.
Where does this "full-frame" hype come from? I feel, but I know I'm fighting a losing battle here, that full-frame is a nonsensical term. Not only is 35 mm far from full-frame photographically speaking, it refers to a negative/sensor size that is printed directly without enlarging. So the "full-frame" Canon 5D is in this reference only suitable for taking passport portraits.
Canon has some difficulty competing with Leica, Nikon and Sigma in the extreme wide-angle segment. Surprising as it may seem, this is not a situation that lends itself to a quick fix. As an example, Leica needed 15 years and a lot of expertise from Minolta and Sigma to catch up (and overtake) in the field of zoom lenses.
But Canon does own their private chip factory and Cmos sensors, which are a bit less expensive to produce than CCD's anyway. So the obvious solution is to produce camera's with a larger chip, needing less short lenses.
This has, of course, to be marketed. So imagine this poor marketing executive sitting in his office on the 95th floor in Tokyo. He has to find a catch-phrase. He doesn't know the first thing about camera's but he does know about selling products. The above has been explained to him by a technical executive, but it does not add up to a positive twist to his advertising campaign. A bright young underling, who has read a Readers Digest about Ansel Adams, remembers the words: Full Frame. It sounds even better than "more megapixels"!! They cook up a 100 million dollar campaign to ram this down the collective throats of an unsuspecting public, and there you are: Full-Frame is the hallmark of a quality camera! The guy is probably a vice-president now.
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