subject: Reducing Digital Camera Shutter Lag [print this page] Reducing Digital Camera Shutter Lag Reducing Digital Camera Shutter Lag
Reducing Digital Camera Shutter Lag
Do you enjoy taking candid photos, perhaps out and about in the city, at parties or even at home? If so you probably try to take your camera with you wherever you go, always ready for that picture opportunity. This means your camera might be in the glove compartment or in a backpack and using it requires taking it out, powering it up and finally shooting. Yet when you finally have the camera in your hand, you aim, you squeeze the shutter release and..... you wait. When the screen eventually clears, you have a great shot of the background, but your subject is nowhere on the scene. So what happened?
Shutter lag is what happened! So what exactly is shutter lag? It's the delay digital cameras experience between the instant when you press the shutter release button to when the photo is actually recorded. This is particularly frustrating since this problem did not seem to exist with film cameras, which utilize a mechanical shutter release.
To understand what causes shutter lag you have to understand how a digital camera captures an image. Simplifying it as much as possible, the process includes:
Focusing is set
Aperture & shutter speed are set
The CCD is reset (data from the previous picture is flushed)
Shutter opens
Image is written to CCD
Shutter closes
Interpolation / compression of image data.
Output is sent to buffer where image is finally recorded.
This all takes time. Depending on the on-board computer of a particular camera it could take from a couple of hundred milliseconds up to almost a half second. On average, the more expensive the digital camera, the shorter the shutter lag is. Professional cameras have hardly any shutter lag at all. This is simply due to the use of faster processors and more efficient electrical design.
Now for the good news (finally!). It is possible to reduce shutter lag substantially, by several magnitudes, without trading in your camera. It costs absolutely nothing and will make you a better street photographer. Here's how:
Use the pre-focus option.
What? That's it? Yes, that's it. Digital cameras generally use a two stage shutter release button, let's call them Stage 1 (S1) and Stage 2 (S2), each of which has different functions. S1 usually requires that you press the shutter release button halfway while focusing on your subject. You maintain the shutter release at S1 state, with your subject already pre-focused, while you recompose your photo, or wait for whatever you are waiting for, and then you press down fully on the button, capturing the image. It goes without saying that the subject must stay within the focus range selected during S1 when the image is eventually captured.
So what is S2? That's when you simply aim your camera and press the shutter release all the way down, bypassing S1 (and encountering long shutter lag times). To demonstrate how effective this is, I have gathered data from three different independent camera reviews, which tested models for both S1 and S2 shooting times. Some reviewers may call it pre-focusing or something similar, but the data is almost always available in a thorough review.
Lumix DMC-G1
S2 Time: 0.357 seconds
S1 Time: 0.077 seconds
Pre-focusing is 4.6 times faster than normal shooting.
Lumix DMC-FZ100
S2 Time: 0.288 seconds
S1 Time: 0.017 seconds
Pre-focusing is 16.9 times faster than normal shooting.
Lumix DMC-ZS7
S2 Time:0.45 seconds
S1 Time:0.012 seconds
Pre-focusing is 37.5 times faster than normal shooting.
If you want to improve your particular numbers even further, consider the following additional tips. These will not have the huge impact that pre-focusing has, but they will chip away some additional milliseconds:
Reduce quality settings - By selecting a smaller picture size (in megabytes) your camera might record a bit faster. The same holds true for shooting in RAW & JPG, RAW only or JPG only. The bigger the file, the longer it takes to record. This will of course affect your finished product.
Turn the flash off - Flash recycling times are inherently long, your camera is probably ready to take a picture long before the flash is. This is particularly true when taking several pictures in one shooting sequence.
Use a fully charged battery - For some reason, a fully charged battery seems to speed up several camera functions. This is anecdotal evidence since I have never seen actual scientific tests.
There are of course other types of settings that can affect shooting speeds, such as film speed, lens speed, filter types, etc. but those are outside the scope of this article.
