Why is shutter lag intrinsically low on a DSLR?

Question

It seems to me that every single DSLR on the market has low shutter lag compared to a compact camera. This is true even for the entry level models that only cost a few hundred dollars. Yet high-end compacts that cost $500 to $1000 still have long shutter lag. If you are inclined to say a superior processor, note that Canon uses their Digic III processor across the entire line and it doesn't make their expensive G9 camera fast despite making a cheaper Rebel DSLR fast.

Answer 1

The lag you are talking about is due to the camera focusing vs camera movement, charging of the CCD or CMOS and relatively slow transmission of its capture data to the circuitry of the camera for processing and storage. DSLR camera generally handle these better than point and shoot.

You can decrease lag by prefocussing  

Answer 2

DSLR's are designed based upon time honored  and successful 35 mm SLR 's.  The shutter lag has always been measured in milliseconds, so adding a sensor at the film plane has no effect on the time it takes for the shutter to open after the shutter release is depressed.

The first DSLR's cost around $2,000, so for many, it was out of range of many 35 mm SLR users ... in the past six years that has changed ... entry level DSLR's with an excellent lens costs under $500 and provide the new user with not only full adjustments, interchangeable lenses and a sensor that is over 15 times larger than most P&S cameras, it takes the owner in to a totally different realm of picture taking ... form a nearly totally automatic point and shoot, to a camera that while can be used as a P&S when using the "P" program mode, the whole advanced camera world is at their feet (selective focus, fisheye to extreme telephoto lenses, total control over the exposure and style of the photographer).

Until you can budget for a DSLR (if you still want the video feature look here;  http://www.nikonusa.com/Find-Your-Nikon/... ) here is a link to help

http://www.kenrockwell.com/tech/shutter-...

Answer 3

The primary reason for shutter lag is the processing that occurs in the interval after the release button is pressed.  In a P&S this is when all the activity takes place to focus, calculate correct exposure and Image stabilization, face detection, etc. before exposing the sensor.  Most DSLRs have a separate processor for the focus mechanism and a more sophisticated processing mechanism for faster focusing, plus they are usually doing continuous exposure calculations and "lock" the exposure when the shutter release is pressed..  Another difference is that most DSLRs have an optical viewing system which is more responsive than a processor which must write the image to the LCD viewing screen (which takes longer).  Optical systems work at the speed of light, LCD viewing screens work at the scan rate of the processor.

In addition DSLRs usually use Phase Detection type autofocus sensors which are more responsive (and expensive) than Contrast Detection sensors used in most P&S models.

In fact it is notable that most of the new crop of cameras with "Live View" exhibit some increase in shutter lag when used in Live View mode.  And several of these switch to Contrast Detection sensors for Live View processing.

HTH.

Answer 4

The primary reason for that shutter lag is the write speed of memory cards vs image size. DSLRs have a built in memory buffer so the image can be written and stored before writting to the actual memory card. This is a lot like the RAM in a computer, it writes very fast, almost instinaniously. Since DSLR cameras are flagship products, companies are more inclined to put the extra cost and technology into them. It's not just a cost thing, it's also about size. Many compact cameras simply do not have the space for this buffer chip and associated electronics. Since most people prefer the smallest ultra compacts, the companies simply don't see it as a priority.  

Answer 5

The difference comes in the way the cameras capture an image. With a point and shoot you are seeing the image in real time on the LCD screen. When you press the shutter the sensor has to stop showing you what it is seeing and record the image before it can move on to the next shot.

A DSLR works differently. Most DSLR's do not have live view LCD screens. They capture an image by a shutter opening and closing and exposing the sensor. This happens very quickly and the sensor is not working before the shutter opens. Then the image goes into a buffer for recording onto the card.