Author Archives: dara

Re-reviewing the Olympus E-M5

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Sunset

Most product reviews are made shortly after the product is released.  The idea is to get the word out while the thing is still new, so people who are considering getting it have some idea of what they’re in for.  The disadvantage is of course that some things become apparent only with the passage of time 

So with the benefit of 14 month’s hindsight and more than 15,000 images since my original review, would I still choose the E-M5 as my primary camera?  Has it lived up to expectations?  My answer is below.

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The case for the (still) missing Apple xMac

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Xmac

Ever since the introduction of the first Power Mac G5 towers, a number of Mac users have been holding out hope for a mid-range machine that would offer more expansion and upgradability than an iMac, at less cost than the a Power Mac G5 (or later Mac Pro).  Ars Technica’s John Siracusa gave this elusive product a name: the xMac.

The basic premise of the xMac of course was that we needed a Mac that was both semi-affordable (not huge was nice too) and at the same time somewhat future-proofed.  The iMac for all its virtues has never been a particularly friendly machine for upgrading and has only gotten worse with time.  These days, even changing the hard drive is a pain, and of course if the display goes, you’re hosed.  The Mac Pro meanwhile has always been pretty good on the expansion front, but it’s hard to justify paying $2500+ when a much less expensive machine would work equally well for my tasks.  Plus recent rumors notwithstanding, Apple seems to have more or less abandoned the Mac Pro at this point, leaving it woefully outdated (CPUs are 2 generations out of date, machines lack Thunderbolt, etc.).

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The 2013 Apple Mac Pro wastebasket edition

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Apple Mac Pros

Clearly most striking thing about Apple’s newest Mac Pro is how little it looks like it’s predecessor.  Eschewing the large silver tower design that Apple has used more or less unchanged since releasing the original Power Mac G5 in 2001, the new Mac Pro has the appearance of a sleek dark-gray cylinder, or as some have unkindly suggested, a trashcan.

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Comparing the cousins – the BMW E30 and E34

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Cousins

Thanks to a lucky search on craigslist and some quick phone calls by my resident car-expert (thanks dad!), I am now simultaneously the proud owner of a 1990 BMW 325i (E30) and a 1994 530i (E34).  Lest I give the wrong impression, I should add that the combined purchasing cost of both these vehicles came out to slightly less than the insurance payout for my wrecked 2000 328i (E46).  The plan is to put the E34 on craigslist, once things calm down a bit.

Below are my thoughts on how the two cars stack up.

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Olympus E-M1 Impressions

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Walkway

After being on a waiting list since mid September, I finally got my hands on Olympus’s new flagship camera, the OM-D E-M1, last Friday.  This is not really a review as such, as I only used the camera for a couple of days.  Here are my impressions, particular vis a vis my current camera, the E-M5:

Size and Appearance

The E-M1 is bigger than the E-M5, on account of the grip.  On the one hand, it’s an ergonomic rubberized grip which makes the camera more comfortable with larger lenses, or for those with larger hands.  On the other, it more or less ruins the classic profile of the camera and the increased size can be a nuisance with cases and bags.  I wish they’d stuck with the size and styling of the E-M5 and made the bigger grip an optional add-on (like the E-M5).

Overall build quality seems slightly more solid.  I gather that underneath there’s a much more extensive magnesive frame than the one the E-M5 had.  In any case, it feels nicer in the hand.

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make scales with # processors

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I recently had access to an 18(!) core machine, so I naturally ran my favorite benchmark – building the clang 3.2 C/C++ compiler – using between 1 and 36 threads.  The build scaled quite well.  Going from 1 to 6 threads gave a 5.5x speedup, while going up from 1 to 12 gave a 9.3x speedup.  At 18 threads, the speedup was 11.8x.  Above 18 threads, there was no speedup.  Given that the makefiles don’t seem to have been tailored specifically to many threads, that’s overall pretty good.

Below are the charts, first of time vs. number of threads used by make, then of speedup vs. number of threads used by make.

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Another case where SSDs don’t help

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The project I’m working on involves compiling a huge number of source files which means we need a sizable amount of scratch space on which to run our experiments.  Our main compute server was running a little short on disk space, so it seemed like the appropriate time to add a new disk. We considered both solid state and traditional spinning platter drives.  The SSD seemed like the better performing options, but we eventually settling on an HDD, as the price of SSDs (due to restriced suppliers) was still prohibitive.

I was curious though how much performance improvement an SSD might have yielded, so I ran a small experiment on my desktop, which does have a (small) SSD.  I built the clang C/C++ compiler version 3.2, first off the HDD (a typical 7200RPM 750GB affair, then off my SSD (a Crucial Sandforce MLC device), and finally off of a ramdisk (Linux tmpfs).

The result?

Less than a 1% difference in compile time between the 3 options.

Similar to the case of Lightroom, it looks like compiling, at least for a mid-sized project (500MB of source) doesn’t benefit from an SSD vs. a hard disk.  Considering that ramdisk and HDD performance were virtuall identical, it seems quite likely that the whole thing never even left the memory of the operating system’s disk cache.

Better Small Cars

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For much of the 1990s and 2000s, cars in the US seemed to be suffering an obesity epidemic.  Station wagons bloated into SUVs, compacts swelled into full-sized sedans and even the handful of practically every vehicle managed to grow in size and weight from one generation to the next.

A case in point is BMW’s 3-series.  Once marketed as a compact car for driving enthusiasts, the 3-series of today is more than a foot longer and 600 pounds (25%) heavier than the 3-series of early 1991.  It’s not just a BMW problem.  The Golf may well be the least-changed car stylistically over the past thirty years, but based on the weight you could make two 1979 Golfs from a single 2005 Golf (1750 lbs vs. 3550 lbs).

Fortunately, it looks like one consequence of the largest economic crisis since the Great Depression is that bigger is no longer always better.  The combination of increasing CAFE fuel economy standards and increasing pump prices has finally gotten Detroit and its foreign competitors, not to mention the almighty US consumer, to give some thought to efficiency.

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File compression on UNIX

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I’ve been moving around a lot of data lately, particularly over the network, so it seemed like a good idea to settle on a compression regimen.  Networks are fast and all, especially at school, but moving multiple gigabytes of data still doesn’t happen instantly.  So I did a comparison of the current mainstream compression programs on Linux.  The system had a fast SSD drive, so operations were mainly CPU bound.

The contenders

  • bzip2 – a fairly popular replacement for gzip, though generally believed to be slower for archiving and unarchiving.
  • compress – interesting for historical purposes and accessing old archives, but no longer really used otherwise.
  • gzip – intended as a free compress replacement, it’s still the most commonly used UNIX compression tool.
  • lzip – an FSF-endorsed LZMA-based encoder claiming higher efficiency than more common tools.
  • lzop – uses a similar algorithm to gzip, but claims to be much faster and so particularly useful for large data files.
  • xz – an LZMA-based encoder claiming high efficiency and speed.
  • zip – still the de-facto standard on Windows, but not particularly popular on Linux.

The Test

To compare, I compressed and decompressed a 220MB tar archive, containing a distribution of the clang C/C++ compiler.  For all program other than compress which only has one setting, I tried the minimum compression setting (-1), the maximum compression setting (-9) and the default setting (no option).

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Lightroom Performance – part 3

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As part of my attempt to puzzle out why Adobe Lightroom has been (comparatively) slow with my E-M5, I’ve taken a number of timings of different attributes.  Among other things I’ve concluded that:

  1. There’s no significant difference in speed between versions 1, 2, 3 and 4.
  2. Import speed scales roughly linearly with image resolution – a file with 2x the megapixels will take approx. 2x the amount of time to import.
  3. Different RAW file formats generally don’t impact processing speed, with the exception of Fuji’s RAF, Olympus’s ORF and Samsung’s SRW.  The Fuji and Olympus files are slower to process (roughly 150% and 60% respectively), and the Samsung slightly faster.
  4. Correcting for lens flaws – particularly in the case chromatic aberration, does cause some slowdown.

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