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Why are DSLRs faster?
X-No-Archive: yes
One of the reasons I bought my D70 nwas because of the lack of "shutter lag" and the very rapid response after turning the beast on. I've been enjoying those features and many others. A recent comparitive review of 8 MP cameras in the New York Times Circuits page included one DSLR, and the article described it as having a faster response time than the non-interchangeable lens SLR-style cameras. Is there something intrinsic to the basic design of DSLR cameras that enable their more responsive behavior, or is just that these features were given priority by the designers? |
#2
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No: many P&S cameras have fast response now.
Yes. |
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Charlie wrote:
X-No-Archive: yes One of the reasons I bought my D70 nwas because of the lack of "shutter lag" and the very rapid response after turning the beast on. I've been enjoying those features and many others. A recent comparitive review of 8 MP cameras in the New York Times Circuits page included one DSLR, and the article described it as having a faster response time than the non-interchangeable lens SLR-style cameras. Is there something intrinsic to the basic design of DSLR cameras that enable their more responsive behavior, or is just that these features were given priority by the designers? Basically, because they cost more, the manufacturer can afford to install a faster processor, and more ram along with a larger sensor. Then there is also more room for additional specialized chips which can do some of the work done by the CPU in other, cheaper and smaller, cameras. -- Ron Hunter |
#5
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Charlie wrote:
X-No-Archive: yes One of the reasons I bought my D70 nwas because of the lack of "shutter lag" and the very rapid response after turning the beast on. I've been enjoying those features and many others. A recent comparitive review of 8 MP cameras in the New York Times Circuits page included one DSLR, and the article described it as having a faster response time than the non-interchangeable lens SLR-style cameras. Is there something intrinsic to the basic design of DSLR cameras that enable their more responsive behavior, or is just that these features were given priority by the designers? You get what you pay for. |
#6
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Even a DSLR in idiot mode will be slow because it has to take care of
everything, a nice P+S with manual controls can be fast too. Nothing electronic was as fast as my old film SLR, once I set everything to what I wanted (f stop, speed, focus) all i had to do was push the button, no lag no boot up, instant picture taking. Jean "Ron Hunter" a écrit dans le message de ... Charlie wrote: X-No-Archive: yes One of the reasons I bought my D70 nwas because of the lack of "shutter lag" and the very rapid response after turning the beast on. I've been enjoying those features and many others. A recent comparitive review of 8 MP cameras in the New York Times Circuits page included one DSLR, and the article described it as having a faster response time than the non-interchangeable lens SLR-style cameras. Is there something intrinsic to the basic design of DSLR cameras that enable their more responsive behavior, or is just that these features were given priority by the designers? Basically, because they cost more, the manufacturer can afford to install a faster processor, and more ram along with a larger sensor. Then there is also more room for additional specialized chips which can do some of the work done by the CPU in other, cheaper and smaller, cameras. -- Ron Hunter |
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Ron Hunter wrote:
Charlie wrote: X-No-Archive: yes One of the reasons I bought my D70 nwas because of the lack of "shutter lag" and the very rapid response after turning the beast on. I've been enjoying those features and many others. A recent comparitive review of 8 MP cameras in the New York Times Circuits page included one DSLR, and the article described it as having a faster response time than the non-interchangeable lens SLR-style cameras. Is there something intrinsic to the basic design of DSLR cameras that enable their more responsive behavior, or is just that these features were given priority by the designers? Basically, because they cost more, the manufacturer can afford to install a faster processor, and more ram along with a larger sensor. Then there is also more room for additional specialized chips which can do some of the work done by the CPU in other, cheaper and smaller, cameras. I suspect that's all true. But I wonder if the larger sensor also helps? Maybe with a larger sensor that gathers more light per pixel, the focusing times and exposure calculation times can be reduced. Maybe also the post processing time needed to reduce noise can be less because there's less inherent noise. Maybe sharpening can also be a bit faster because the distinctions between adjacent pixels are clearer. That's all just speculation though. I have no idea if any of it is true. Alan |
#8
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jean wrote:
Even a DSLR in idiot mode will be slow because it has to take care of everything, a nice P+S with manual controls can be fast too. Nothing electronic was as fast as my old film SLR, once I set everything to what I wanted (f stop, speed, focus) all i had to do was push the button, no lag no boot up, instant picture taking. Jean Yes, but how long did it take you to set all that stuff up. I would bet that my $400 P&S can do all that better, and faster, than you can do it manually. Once I have pushed the button half-way down (the functional equivalent of your presetting above), there is no perceptible delay on it either. This wasn't the case with my older digital, however. Much progress has been made in this respect, both with DSLR and P&S cameras sold today. -- Ron Hunter |
#9
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"Charlie" wrote in message ups.com... X-No-Archive: yes Is there something intrinsic to the basic design of DSLR cameras that enable their more responsive behavior, or is just that these features were given priority by the designers? Yes, their intrinsic design makes them go faster - conventional P&S digicams use the main sensor as their AF sensor. The circuitry analyses the image to determine if it is sharp (in focus) or blurry (out of focus). It then readjusts the lens to get focus. Because there is no way of determining if the object is blurry because it is closer than the focus point or further away, they have to try adjusting focus in both directions until they get it right. There is no way of telling if the image is perfectly clear - instead what it has to do is keep adjusting the lens until it starts becoming blurry again (overshot the focus point), then pull it back to the point where it was at it's clearest. This system is quite slow. Because this main sensor is a video sensor rather than a dedicated still image sensor, when the user presses the shutter button, the sensor needs to be cleared and charged ready to take the photo. Modern cameras can do this much faster than the cameras of only a couple of years ago. After the photo has been taken, most compact digi's only have one processor to take care of all the functions of the camera, so while it is processing the image, converting it to JPG, and saving it on the card, it can't simultaneously be analysing focus and exposure for the next image, so you can't do anything until the camera finishes processing the photo you just took. A DSLR like a film SLR has a separate AF sensor that uses phase detection techniques to determine focus. This system not only tells the camera how accurate it is focused, but tells the camera how far and in which direction it is out of focus. The camera can then start moving the focus motor, and knows exactly which direction it needs to turn. While the lens is doing this, the AF sensor continues to monitor how accurate the focus is, and can slow down the lens motor as it is nearing focus point, so that it stops right on focus. Because there is no trial-and-error involved, this system is very fast. Because the main sensor is dedicated to taking the still image (it's not also trying to do live preview and focussing), the camera can have it already pre-charged, so that as soon as the shutter button is pressed it can start recording. Once you have taken the photo, most DSLR's have multiple processing streams, that allows them to simultaneously convert to JPG, save the image to the card, and be analysing the data from the AF & exposure sensors to be ready for the next photo. If digi compacts used some of the techniques that film compacts use, then they would be faster. For example most film compacts use infrared or ultrasonic autofocus systems. While not as fast and accurate as the phase-detection system used by SLR's, these systems are faster than using the imaging sensor. Film compacts usually also use light sensors on the body to judge exposure, whereas most digi's use the imaging sensor for that as well. If a digi compact was made using an IR or ultrasonic focus system, and with a separate light sensor on the body, and if the user wasn't using live preview (or EVF), then then it would be possible for the sensor to be precharged so that the camera is ready to take the photo as soon as you press the button. Doing this would of course add to the cost, and since it is a very price sensitive market, that is usually only compared on megapixels and zoom, manufacturers would be reluctant to add a feature like this to the camera, unless it is a premium model. Actually, my 5 year old Kodak DC3400 has these very features, and when used with the viewfinder off it is much quicker than the more modern CX7430. The DC3400 is only a 2MP, 2x zoom camera, and when I bought it cost more than 5 times the price of the current 4MP, 3x Zoom CX7430. |
#10
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Justin Thyme wrote:
Thank you, at least there is one out of seven who have knowledge in addition to typing skills. -- Frode P. Bergsager |
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