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Pixels and sensor size - a new angle..
I have been following the numerous topics on how many pixels we will get to
with interest but I have a question which doesn't quite fit in. It just occured to me that you could obtain the same pictures by using a slightly larger sensor and moving it further from the lens. Which in itself would allow larger sensors per pixel or more sensors of the same size (effectively giving a higher resolution image). Is my logic correct? I realise there isn't much room to move the sensor further from the lens but there is some. Thanks in advance, John |
#2
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Pixels and sensor size - a new angle..
On Mon, 4 Sep 2006 17:21:29 +0100, John Ortt wrote:
I have been following the numerous topics on how many pixels we will get to with interest but I have a question which doesn't quite fit in. It just occured to me that you could obtain the same pictures by using a slightly larger sensor and moving it further from the lens. Which in itself would allow larger sensors per pixel or more sensors of the same size (effectively giving a higher resolution image). Is my logic correct? I realise there isn't much room to move the sensor further from the lens but there is some. You wouldn't have to move the enlarged sensor even one millimeter. Just mount the lens on an extension tube. You'll probably have to redesign the lens though, as you might not care much for its new focusing ability. |
#3
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Pixels and sensor size - a new angle..
John Ortt wrote: I have been following the numerous topics on how many pixels we will get to with interest but I have a question which doesn't quite fit in. It just occured to me that you could obtain the same pictures by using a slightly larger sensor and moving it further from the lens. Which in itself would allow larger sensors per pixel or more sensors of the same size (effectively giving a higher resolution image). Is my logic correct? I realise there isn't much room to move the sensor further from the lens but there is some. Thanks in advance, John The distance from the lens to the sensor is determined by the FL of the lens and the distance to the subject. Moving the lens further away is the same as defocusing it. Scott |
#4
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Pixels and sensor size - a new angle..
"ASAAR" wrote in message ... On Mon, 4 Sep 2006 17:21:29 +0100, John Ortt wrote: I have been following the numerous topics on how many pixels we will get to with interest but I have a question which doesn't quite fit in. It just occured to me that you could obtain the same pictures by using a slightly larger sensor and moving it further from the lens. Which in itself would allow larger sensors per pixel or more sensors of the same size (effectively giving a higher resolution image). Is my logic correct? I realise there isn't much room to move the sensor further from the lens but there is some. You wouldn't have to move the enlarged sensor even one millimeter. Just mount the lens on an extension tube. You'll probably have to redesign the lens though, as you might not care much for its new focusing ability. In addition, using an extension tube results in not being able to reach infinity. Jim |
#5
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Pixels and sensor size - a new angle..
"John Ortt" schreef in bericht ... I have been following the numerous topics on how many pixels we will get to with interest but I have a question which doesn't quite fit in. It just occured to me that you could obtain the same pictures by using a slightly larger sensor and moving it further from the lens. The problem is not that a larger sensor can not be places in a camera. The problem is that a larger sensor is more expensive to produce. Sensors of different sizes are produced, the smaller ones are cheaper and make the total construction of the camera smaller. Most camera's nowadays are build around the sensor. The sensor determines what lenssystems can be used and from there the formfactor of the camera. But for rollfilm camera's the larger sensor was not a problem either. Sensors of the size of 'the standard' 35 mm format are expensive to produce. So even for DSLR's most sensors are produced smaller. For DSLR's it is even an disadvantage, because the distance to the lensflange is 'predetermined' so the camera can not become a lot smaller. (Actually DSLR's are not smal compared to some non-af slr's from 20 years ago). ben Which in itself would allow larger sensors per pixel or more sensors of the same size (effectively giving a higher resolution image). Is my logic correct? I realise there isn't much room to move the sensor further from the lens but there is some. Thanks in advance, John |
#6
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Pixels and sensor size - a new angle..
On Mon, 4 Sep 2006 17:21:29 +0100, John Ortt, wrote:
I have been following the numerous topics on how many pixels we will get to with interest but I have a question which doesn't quite fit in. It just occured to me that you could obtain the same pictures by using a slightly larger sensor and moving it further from the lens. Which in itself would allow larger sensors per pixel or more sensors of the same size (effectively giving a higher resolution image). Is my logic correct? I realise there isn't much room to move the sensor further from the lens but there is some. Yes, you can do it, *BUT*... in order to maintain focus over the same range, you end up with a bigger, bulkier camera. Think along the lines of a scale model train set, with a slightly larger scale. Let's say that you move the sensor back an extra 10%. The focal length is now 1.1 as long. The sensor area is 1.1 x 1.1 = 1.21 its original value. So a 5 megapixel sensor can go to 6 megapixels of the same size. Length, width, and height all increase by 10%. Volume increases to 1.331 the original value. The weight increases by 1/3rd to give you 1/5th more pixels (ouch)... *ASSUMING* that you don't need more re-inforcing for the body. This is the classic trivia about how an ant can hold several times its body weight, but if you magnified all the dimensions to make a 10-foot-long ant (as per various B monster movies), the ant would collapse under its own weight. In real-life, your camera will probably be 50% heavier (hand-waving number) to maintain structural integrity. And if you go to a lens menufacturer and ask for a longer, thicker, and wider lens, prices go through the roof. Now on to my rant about form versus function. 50 years ago, consumer cameras had two cylinders. Unexposed film unrolled off one cylinder to a flat area, was exposed, and then rolled onto a second spool. The lens had to go in front of the area where the film was flat. Wrap that all up in a metal or plastic body, and you have the sterotypical lens-in-front-of-a-flat-space-with-cylinders-on-both-sides shape that we all recognize as a camera. Digital cameras do *NOT* work that way, so why do we keep the old shape? The shoulder-mounted video-cam shape makes a lot more sense, at least for professional (and possibly prosumer) cameras. Start off with a big long lens. Put a big sensor at the back end. Put buttons on the top *NEAR THE MIDDLE*, with an EVF and/or LCD sticking out the side. For brownie points, make the EVF/LCD detachable, with plugs on both sides of the camera, to accomadate lefties. Add a flash on a stalk that is hinged at the front to be able to stand up, for separation from the lens (look Ma, no red-eye). Wrap that all up in a metal/plastic body. Here's a crude side view (fixed font required to view properly). I show the stalk in both the popped-up and the folded-down positions. Comments? * Built-in flash on * a stalk that is * hinged at the front. | | | | | Control |______*** buttons hinge O ^^^^^^^^^ |================================| ] [ | lens ] [ LCD/EVF | back ] [ | =================================| / \ / \ Shoulder mount -- Walter Dnes; my email address is *ALMOST* like Delete the "z" to get my real address. If that gets blocked, follow the instructions at the end of the 550 message. |
#7
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Pixels and sensor size - a new angle..
John Ortt wrote: I have been following the numerous topics on how many pixels we will get to with interest but I have a question which doesn't quite fit in. It just occured to me that you could obtain the same pictures by using a slightly larger sensor and moving it further from the lens. Which in itself would allow larger sensors per pixel or more sensors of the same size (effectively giving a higher resolution image). Is my logic correct? I realise there isn't much room to move the sensor further from the lens but there is some. Thanks in advance, John But the problem is that silicon sells by square inch or cm. Larger sensors are more expensive- that is the whole issue. Sensors are gang-fabricated. A round plate of silicon is processed with a number of individual sensors produced on each plate. There is a limit to the size of the plates available, and the processing equipment is limited to the size of the plate it will take. The total cost to fabricate N chips from one plate is nearly constant per plate, so the greater N, the cheaper each chip is. Larger chips means lower N, higher cost. |
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