Canon EOS-1DCanon leaps into the professional SLR arena, with the fastest digital SLR on the planet!<<Spec Comparison :(Previous) | (Next): Features: Image Quality>> Page 4:Features: SpeedReview First Posted: 09/24/2001 |
Features: Speed
Frame Rate
It's very clear that Canon expended great effort to make the EOS-1D as fast a camera as possible. And, they have apparently succeeded in that quest, with the eight frames-per-second speed of the 1D just a shade off the ten frames-per-second speed that the EOS-1V offers. They've also managed this feat without resorting to the "pellicle" mirror used in the earlier ultra high-speed EOS-1N RS model, where a partially-transparent mirror is used to divert light to the viewfinder. This design results in exceptional speed, since the camera doesn't have to wait for the mirror to flip up and out of the way before tripping the shutter each time. However, the downside is that almost half of the available light is lost, amounting to an effective loss of lens speed (or ISO sensitivity, depending on how you look at it) of a full f-stop. The eight frames-per-second speed can be maintained for burst lengths of as many as 21 sequential frames with the camera capturing in JPEG mode, or 16 frames in RAW mode. (In RAW mode, the camera records all the data captured by the CCD, without loss due to image compression.) Assuming you're using high enough shutter speeds (the eight frames-per-second figure requires shutter speeds of 1/500-second or faster), the only camera function that lowers this performance is the ISO bracketing option, which slows the speed to 2.7 frames-per-second.
While the EOS-1D's frame rate is by far the highest of any current (September, 2001) digital SLR, its buffer size is only average, at 21 full-resolution frames. Nikon's D1h has a buffer size of some 40+ frames, allowing it to shoot sequences nearly twice as long. It remains to be seen though, just how long a shooting sequence is really necessary. Even at eight frames-per-second, 21 frames is nearly three seconds of elapsed time. We're not familiar enough with the demands of sports, photojournalism, and fashion shooting to say whether the 40 frames of the D1h would constitute a significant advantage, but 21 frames certainly sounds like a lot to us.
Active Mirror Technology
The EOS-1D is incredibly fast, faster than many film cameras. It turns out that in the normal course of things, even the bounce of the mirror as it settles back into position after each shot would prevent frame rates this high. To overcome this, Canon developed "Active Mirror" technology for the EOS-1v model, which uses active drive electronics to damp out mirror vibrations in half the time that would be required otherwise. The sheer shot-to-shot speed of Active Mirror technology is only part of the equation though–because the mirror moves so fast, the viewfinder blackout time between exposures is reduced to only 45 milliseconds. We'll have to take Canon's word for that, but will give a subjective report of this aspect of viewfinder performance when we actually get our hands on a test sample.
Autofocus Performance
Of course, blazing frame rates are only part of the story. With rapidly moving subjects, a zillion frames per second won't do you any good if the camera can't focus on the subject. Slow autofocus speed was one of the primary complaints among pros about the EOS-D30. Its roughly three frames-per-second frame rate was slow (though manageable) for many applications, but its AF just wasn't up to the task of capturing fast-paced sports and other very active subjects. To provide a state of the art autofocus mechanism, the EOS-1D inherits the 45-zone, servo-tracking autofocus technology developed for the EOS-1v. Canon claims full AF servo tracking at the maximum eight frames-per-second shooting speed. If true, this will immediately earn the 1D a place in many sports photographers’ bags.
Shutter Lag: Faster by a whisker
In the consumer world, shutter lag (the delay between pressing the shutter button and the actual release of the shutter) is the bane of many users’ existence. In the professional world, slow shutter response simply isn't acceptable. At only 55 milliseconds (0.055 seconds), the shutter lag on the EOS-1D does appear to be the lowest on the planet for a digital SLR, at least as of this writing in late September, 2001. The original Nikon D1 had a lag of only 58 milliseconds, so Canon's edge relative to that product is fairly slim. (Oddly though, when we tested the new Nikon D1x model, we consistently measured its shutter delay at 72 milliseconds, a noticeable increase.) We're amused that a scant three milliseconds is all it takes to give Canon "top dog" bragging rights for shutter delay, but regardless of the margin, the 1D should have a very responsive shutter. (Again, stay tuned, we'll test the 1D's shutter lag in our own lab and report the real-world results.
CCD Shutter for ultra-high shutter speeds
We'll talk more about the EOS-1D's CCD technology in the next section below, but Canon chose to go with an interline-transfer CCD design. This design gives up some light-gathering area to achieve higher readout speeds and a simpler manufacturing process. As a side effect, the CCD itself can be electronically gated, to provide extremely short minimum shutter times. In the case of the EOS-1D, the minimum shutter time is only 1/16,000-second. (Flash "x" sync is also at a speedy 1/500-second.) We'll have to wait for the arrival of our test unit to know for sure, but if the CCD is indeed acting as the shutter on a full-frame basis, it will provide another subtle side benefit as well–no focal-plane distortion! Focal-plane distortion is visible in images of objects crossing the camera’s field of view very quickly. The distortion appears as a slanting of the moving subject, caused by the fact that different portions of the frame are exposed at different times, as the slit in the focal plane curtain moves across the surface of the film (or sensor.) With the "electronic shutter" offered by an interline-transfer CCD, the entire array can be gated on and off simultaneously, eliminating this distortion. Perhaps not an issue for anyone but race car photographers, but we suspect it'll be welcome there.
Reader Comments! --> Visit our discussion forum for the Canon EOS-1D!
Follow Imaging Resource: