Kodak DCS Pro 14n Digital SLRKodak's latest digital SLR brings full-frame, 13.7 megapixel resolution to market for under 5,000.<<Exposure & Flash :(Previous) | (Next): Operation & User Interface>> Page 7:Shutter Lag & Cycle Time TestsReview First Posted: 03/23/2003 |
Shutter Lag / Cycle Times
When you press the shutter release on a camera, there's usually a lag time before the shutter actually fires. This time allows the autofocus and autoexposure mechanisms time to do their work and can amount to a fairly long delay in some situations. Since this number is almost never reported on, and can significantly affect the picture taking experience, we now routinely measure it.
NOTE: My qualitative characterizations of camera performance below (that is, "reasonably fast," "about average," etc.) are meant to be relative to other cameras of similar price and general capabilities. Thus, the same shutter lag that's "very fast" for a low-end consumer camera might be characterized as "quite slow" if I encountered it on a professional model. The comments are also intended as only a quick reference: If performance specs are critical for you, rely on the absolute numbers to compare cameras, rather than my purely qualitative comments.
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Normal Card |
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Power On -> First shot | 12.4 | Camera takes a very long time to start up, due to internal dark-frame noise calibration. Production units may start up faster. |
Shutdown |
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No lens to retract, times shown are for buffer clearing. (Max clearing time with a fast memory card is ~29 seconds, but slow cards can result in very long buffer clearing times. |
Play to Record, first shot | 0.2-0.3 | Camera obeys shutter priority, it can always shoot, even when in playback mode. Times shown are approximate shutter lag times, will vary with lens being used. |
Record to play (max/min res) | 1.6 | Time for most recently shot image to appear on-screen after hitting "OK" button. Fairly typical. |
Shutter lag, full autofocus | 0.234 | Time will vary greatly with lens in use and how far lens mechanism must traverse to acquire focus. Time shown is for 104mm f/2.8 macro lens with lens already focused on subject from prior exposure. (Eg, best-case.) There was some variation, with most shots showing a shutter lag of ~0.195 secs, but as many as 30% coming in at higher values, up to 0.347 secs. (Most but not all of these occurred after the camera had been resting for 10-30 seconds between shots.) 0.234 was the average across 20 or so shots, but best performance averaged 0.195 seconds. |
Shutter lag, manual focus | 0.128 | This time should be independent of the lens in use, since AF speed isn't an issue. |
Shutter lag, prefocus | 0.119 | This is the lag time when the shutter is half-pressed and held prior to the shot. Very slightly faster than the manual focus time. |
Cycle time, JPEG large/fine
files (CF card) |
0.61 | Four-shot buffer for large/fine JPEGS. After this is full, there's an 11-30 second delay, depending on card speed, then subsequent shots occur at intervals of 6-14 seconds, again depending on card speed. (You definitely want to use fast cards with the 14n.) (Time is for saving to CF card slot - Prototype firmware didn't support SD/MMC card slot.) |
Cycle time, JPEG small/basic
files (CF card) |
0.60 | Seven-shot buffer for small/basic JPEGS. After this is full, there's an 8-20 second delay, depending on card speed, then subsequent shots occur at intervals of 4-12 seconds, again depending on card speed. |
Cycle time,
Large RAW files (CF card) |
0.58 | Seven-shot buffer for large RAW files. After this is full, there's an 10-30 second delay, depending on card speed, then subsequent shots occur at intervals of 4-25 seconds, again depending on card speed. |
Cycle Time,
Large RAW+JPEG files (CF card) |
0.61 | Shooting in combined RAW + JPEG mode drops buffer capacity back to four frames, and results in very long buffer-empty times. (30 seconds with the fastest cards I tested, up to 162 seconds with the slowest.) |
Continuous Mode,
JPEG Large/Fine (CF card) |
0.58 | Four-shot buffer, then wait 30 seconds (with a fast card) for buffer to clear, can then shoot another four shots rapidly. |
Continuous Mode, RAW Files (CF card) |
0.58 | Six- to seven-shot buffer, then wait 30 seconds (with a fast card) for buffer to clear, can then shoot another 6-7 shots rapidly. (Only impact I saw from write-accelerated cards was here, where WA cards gave 7 shots before buffer fill, normal cards gave 6.) |
Overall, the Pro 14n was a mix of great speed and noticeable sluggishness. Shooting in either JPEG or RAW mode (but not both simultaneously), it is pretty fast (~1.7 frames/second in either single-shot or continuous mode) while writing to its buffer, but you then need to wait quite a while for the buffer to empty. The buffer capacity is on the small side for a professional camera, only ~four large/fine JPEGs, or 7 RAW images. There's no question that very fast memory cards are a solid investment with the Pro 14n: Buffer-clear times with even the fastest Lexar cards I tested were on the order of 30 seconds, but stretched to as long as 162 seconds(!) when working with my "standard slow card," a 256 MB Mr. Flash unit.
I had on hand a pair of Lexar 24x memory cards, identical except that one of them was one of the new "Write Accelerated" (WA) cards. While the 14n is supposed to be able to take advantage of WA technology, that function must not have been enabled in the version firmware that my prototype unit was using, because I saw virtually no difference between the two cards. The relatively fast 24x card themselves did produce markedly better buffer clearing times than did lesser cards though.
A really neat feature of the 14n was also the source of some of my greatest frustration with it: It has the ability to write both RAW and JPEG files to its memory cards simultaneously. - That is, it can save both RAW and JPEG copies of each image shot. I could see this having a lot of advantages, with the RAW files serving as "digital negatives" in the event post-exposure manipulation was required, while preserving the speed and ease of use of a JPEG-based workflow. The problem with this is that shooting slowed to a crawl on my prototype unit when operating in this mode. The original prototype was particularly bad in this regard, with buffer capacity being reduced to only 2 shots when I was saving both RAW and JPEG files simultaneously. A subsequent firmware upgrade raised this limit to 4 shots, but the camera still required a great deal of time for its buffer to clear when operating in this mode, and a four-shot buffer can be pretty limiting if you're shooting a quickly changing subject and bracketing exposure as well.
While the 14n will support simultaneous use of both CF and SD/MMC memory cards, the firmware on my prototype unit did not have the SD/MMC slot enabled.
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