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Performance

Once you've got over your initial excitement about the E-P1's styling, the next thing you're likely to notice is the speed. Or, rather, the lack of it. Mainly as a result of the autofocus speed it's a noticeably less immediate experience than using a modern DSLR. The traditional Olympus anti-dust sequence at startup also detracts from the sense of responsiveness, slowing the startup time to two seconds. This isn't a long time to wait in general terms but is enough to stop you ripping the camera from your pocket if something unexpected happens - you know the camera won't be ready in time.

Timings & File Sizes

Timing Notes: All times calculated as an average of three operations. Unless otherwise stated all timings were made on a 4032 x 3024 JPEG SHQ (approx. 7,500 KB per image).

The media used for these tests was:

  • 8 GB SanDisk Extreme III 30MB/s SDHC card
Action
Details
Time, secs
(8 GB SanDisk)
Power Off to On *1   2.0
Power Off to Shot   2.1
Shot to shot time (JPEG) *2 Live view 0.6-1.0
Shot to shot time (RAW) *2 Live view 0.6-1.0
Power On to Off *3   1.5

*1 This is the time from turning the switch to the 'On' position to the status display appearing on the LCD monitor (as soon as you would be able to verify camera settings). You cannot turn off the sensor cleaning, which adds substantially to this startup time.
*2 Live view black out when taking multiple shots. Occasionally it will take two shots without trying to update the view on the back of the camera (taking around 0.6 seconds between shots), but more often it will go back to giving a live-preview, delaying another shot by 1 second or more.

Continuous Drive mode

To test continuous mode the camera had the following settings: Manual Focus, Manual Exposure (1/500 sec, F4), ISO 200.

The tests carried out below measured the following results for JPEG and RAW:

  • Frame rate - Initial frame rate, this was always 3.2 fps (+/- 0.05 fps)
  • Number of frames - Number of frames in a burst
  • Buffer full rate - Frame rate if shutter release held down after burst (buffer full)
  • Write complete - How long after the last shot before the card lamp goes out

Burst of JPEG Large/SHQ images

Timing
8 GB SanDisk
Frame rate 3.2 fps
Number of frames 12*
Buffer full rate ~2.0 fps
Write complete ~4.5 sec

*In our tests, the E-P1 would occasionally hold its faster frame rate for 13 shots, but 12 was more common.

Burst of RAW images

Timing
8 GB SanDisk
Frame rate 3.2 fps
Number of frames 5
Buffer full rate ~1.3 fps
Write complete ~6.5 sec

The E-P1 comfortably achieved the quoted 3.0 frames per second shooting speed that the manufacturer asserts. Below is a sound recording of the E-P1 to give an impression of the shooting rate and shutter sound. Click on the image to download.

USB transfer speed

To test the E-P1's USB speed we transferred approximately 500 MB of images (mixed RAW and JPEG) from a SanDisk Extreme III 30MB/s SDHC card (the same card used in the other tests). When you connect the E-P1 via a USB cable, you are given a series of connection options. 'Storage' mode just has the camera act as a card reader, though its transfer rate is nowhere near as good as our dedicated USB card reader. 'MTP' mode will only show you files that haven't been renamed but (on a Windows machine at least), it will also preview the ORF (RAW) files. The transfer rate is painful enough that we wouldn't bother.

Method
Transfer rate
Olympus E-P1 USB 2.0 (Storage) 8.5 MB/sec
Olympus E-P1 USB 2.0 (MTP) 3.9 MB/sec
SanDisk Extreme III in USB 2.0 reader 16.8 MB/sec

Autofocus speed / accuracy

By far the biggest problem with the E-P1 is it's contrast detect autofocus system, which is not only slower than any SLR, it's slower than many compacts too. Having spent many hours testing different lens/body combinations and different shooting conditions - and comparing it to the Panasonic GH1 - it's obvious that the speed is limited by both the lens and the body, but also by the autofocus algorithms used by the camera's processor (an area Panasonic has worked very hard on). In all the comparisons below the figures are an average of 10 measurements and are purely the time taken to focus (from half-press to focus confirmed).

E-P1 vs Panasonic GH1 kit lens AF speed test

Let's start by looking at a direct comparison between the E-P1 and the Panasonic GH1, in both cases using the supplied kit lens. This should, theoretically, put the GH1 at a disadvantage, as its kit lens covers a considerably longer range (10x as opposed to 3x). As the measurements below show however, Panasonic's sophisticated contrast detect AF system wipes the floor with the E-P1, on average taking between a quarter and a third of the time taken by the E-P1.

In this test the focus distance was approximately 6.0 meters and the light level was approximately 7.0 EV. Interestingly the E-P1 consistently focuses more slowly at the wide end of the zoom than at the long end. Note also that after extensive testing we found no significant difference between auto area AF and single area AF (manual selection), though we did find that using the auto area at the wide end of the lens tended to lock onto the wrong part of the frame, so didn't use it that much in our real world shooting.

  • Olympus E-P1 + 14-42mm M. Zuiko, Single point (center) AF
  • Panasonic DMC-GH1 + 14-140mm Lumix, Single point (center) AF

Body comparison

Switching the GH1's kit lens for the Olympus 14-42mm reduces the focus speed difference significantly, but as the graphs below show (tests using the same settings as the previous set), even with the same lens the GH1 is over 50% faster than the E-P1 at the wide end (and around a third faster at the long end).

We've also included the Olympus E-620 in both its focusing modes in this test (in both cases using the Four Thirds 14-42mm kit lens)

  • Olympus E-P1 + 14-42mm M. Zuiko, Single point (center) AF
  • Panasonic DMC-GH1 + 14-42mm M. Zuiko, Single point (center) AF
  • Olympus E-620 + 14-42mm Zuiko, Phase Detect AF
  • Olympus E-620 + 14-42mm Zuiko, Contrast Detect AF (Live view)

 

Olympus has obviously improved contrast detect AF over the live view mode in its SLRs, but even with the same lens it can't compete with the Panasonic, and is left standing by the E-620's phase detect focus (though interestingly, the GH1 gets pretty close with its own kit lens).

Micro Four Thirds Lens comparison

As mentioned above, the body is only one factor in the focus speed equation - the lens has a big part to play too. In this comparison we're looking at the E-P1 and GH1 with three different Micro Four Thirds lenses (there's no practical difference between the 14-45mm and 14-140mm Lumix zooms, speed-wise).

  • Cameras: Olympus E-P1, Panasonic GH1
  • Lenses: Olympus 14-42mm M. Zuiko, Olympus 17mm 'pancake' F2.8 M. Zuiko, Panasonic Lumix 14-140mm 'HD'

On the GH1 the difference between the Olympus and Panasonic zooms is stark; the Lumix lens is over twice as fast (the 17mm pancake sitting almost exactly in the middle). At the wide end of the zoom the Lumix zoom is also twice as fast on the E-P1 as its own kit lens (at the tele end it's only about 20% faster).

Focusing and refocusing

Having used the EP-1 since it was launched it soon became obvious that, whilst the focus speed isn't great, the biggest problem is how the processor deals with refocusing when the subject distance doesn't change between shots - or only changes by a little. To find focus the camera racks the lens all the way out to infinity then almost all the way back to the minimum focus distance before it eventually finds the right position. And it does this every time you half-press, even if the subject is at infinity (so you have to go through the refocusing rigmarole when taking two consecutive shot of a landscape).

By comparison the Panasonic system is considerably more intelligent, using a high frequency 'wobble' to pinpoint the focus distance without having to rack backwards and forwards through the entire focus range first. The graphs below clearly show how this impacts on everyday shooting. In all cases the zooms were set to their center position.

  • Cameras: Olympus E-P1, Panasonic GH1
  • Lenses: Olympus 14-42mm M. Zuiko, Olympus 17mm 'pancake' F2.8 M. Zuiko, Panasonic Lumix 14-140mm 'HD'

These graphs tell us a lot, so let's walk through the results. Firstly there's more evidence that the Panasonic zoom is considerably faster than either Olympus lens. Secondly the 17mm pancake is slightly faster than the Olympus kit zoom (particularly when refocusing). Interestingly the GH1 offers no advantage at all when using the 17mm (with both zooms it is considerably faster than the E-P1).

Forcing the lens to move all the way from infinity to it's closest focus distance (or vice versa) gives you an idea of how quickly the lens itself can move, and narrows (though doesn't eliminate) the gap between the GH1 and E-P1 when using the Olympus lenses. It also clearly shows how much faster the Lumix kit lens can move through it's entire focus range, especially when mounted on the GH1.

The figure we're more interested in, though, is the refocus time. For this test we locked the focus on a distant building, then half-pressed the shutter to refocus on the same distance (infinity). Whilst the difference with the 17mm lens was negligible, with both zooms the E-P1 took up to twice as long as the GH1. The key comparison here is between the GH1 and the E-P1 with their own kit lenses; the E-P1 takes three times (300%) longer than the GH1 to refocus on a distant scene, making it feel much, much slower in 'real world' use.

There is a way to mitigate this problem; you can reassign the AEL/AFL button to activate the focus (i.e. remove the half-press focus activation from the shutter release). Doing this allows you to focus once and shoot as many pictures as you want of the same subject without the constant waiting for the AF to settle down. If, like me, you like to shoot a lot of pictures of the same subject, learning to use the camera with a separate AF button makes it a helluva lot less frustrating to use.

Summary

There's no getting away from the fact that the E-P1 focuses slowly compared to any SLR or to the Panasonic Micro Four Thirds cameras, and that for some types of photography this could present a serious issue. That said, the likelihood of anyone buying an E-P1 for sports action seems pretty low, and for the most part the focus speed simply doesn't impact on everyday photography of fairly static subjects.

I suspect a lot of people buying this camera will be taking the kind of considered, carefully composed shots that don't rely on focus speed (and that many will move the AF to another button to avoid the half-press delay). But for the kind of subjects that require lightning responses - young kids, street photography, sports and so on - the slow focus (especially in low light) seriously limits the E-P1's usability. I was tempted to call the focus speed the E-P1's Achilles' Heel, but for some types of photography it's more like an Achilles' Leg.

Battery life

The E-P1 uses the same BLS1 battery used in the many of the smaller E-series cameras (E-4X0 series and E-620). According to the specs, the battery should be good for around 300 shots (according to the standard CIPA testing methodology which doesn't necessarily reflect real-world figures but does allow comparisons between cameras), which is pretty low when compared to DSLRs (which don't have to power their screens). No figures are given for the use of the Art Filters, which appear to really sap battery life.

Image Stabilizer

The E-P1 has a smaller, simpler IS system than the one employed in its high-end DSLRs, such as a the E-30. Olympus claims a 4-stop advantage for this IS system (though our tests have never shown an improvement on that scale).

The stabilization test

Twenty hand-held shots were taken of a static scene, half of those with stabilization, half without, the shutter speed was decreased by a stop and repeated (from 1/125 sec to 1/5 sec). The lens used was the Olympus 50 mm F2 (producing a 100 mm equiv. FOV), the test chart was 2.0 m away from the camera. to exaggerate the effect of camera shake the camera was only supported with one hand.

The resulting 120 images were then inspected and given a blur score from zero to three where zero represented a very blurred image and three a sharp image with no noticeable blur (see crop examples below). Obviously the amount of blur which is acceptable will depend on your personal taste and the final image size (for instance a '2: Soft' will still look fine as a 4x6 print or in a web gallery). Example crops from these four blur scores can be seen below.

0: Very blurred 1: Blurred
2: Soft 3: Sharp

Results (50 mm lens, 100 mm equiv.)

Turning the IS on helps provide a similar number of stable images even when you slow the shutter speed by a fraction over two stops. This isn't the most brilliant performance we've ever seen, but it will help significantly increase the number of sharp, stable images you take home with you. And, because it's built into the camera, the E-P1 can stabilize any lens, whether it be a cheap second-hand OM or a treasured Zeiss.

IS Test Results More Graphs
IS Off
IS On (Mode 1)
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