Saturday, November 20, 2010

Considering Buying an iMac for Photography?

The new Apple iMacs look incredible. You can even get a quad core 27" one now. That beautiful screen and fast CPU with multiple cores is perfect for photography... right? Well, yes, but at some point, you'll probably wish you had sunk a little extra investment in a Mac Pro.

The Problem
I bought a 24" 3.06GHz dual core iMac in late 2008 when I was shooting with a Canon 40D in full 10MPx RAW mode. The iMac handled it perfectly - it was awesome. Aperture 2 had no problem with those RAWs, and my nearly empty hard drive zipped along. I figured that two cores running at 3.06GHz should be enough for years ago come... But things started slowing down quickly, and there was little I could do about it.

In late 2009, I upgraded my camera to a Canon 5D Mark II. I now had 21MPx of RAW goodness, but of course that came with a price - slower processing and twice as much hard drive usage. I quickly filled up my iMac's "measly" 500GB drive, and since you can't upgrade the hard drive in an iMac, I had to go external. I bought a Drobo RAID enclosure and a couple of drives to start me out. The Drobo's great and offers data protection, but the housing alone is $300, and the file transfer speed went from 100MB/sec internal to 25MB/sec external. Believe me, you notice that your RAW files are coming across Firewire or USB, and it hurts.

In early 2009, Aperture 3 came out with brushes and other new features that I had been waiting for, but they too, came with a price - performance. I started waiting for brush strokes to catch up with my mouse, and got used to seeing the "Apple beachball". More RAM probably would have helped, but I was already maxed out at 4GB. By now, my Drobo had three drives instead of two. Needless to say, I was quickly outgrowing my iMac.

What made matters worse, because of my RAM situation, I had to close every app when running Aperture to eek out any little bit of performance I could. I would have had *no* problem shelling out $500 for 8GB of RAM at that point, but it wasn't an option - the box would have said "sorry buddy, I'm full".

The Solution.
When the 2010 Mac Pros came out, I went for it and got a 6-core 3.33GHz Mac Pro with 12GB of RAM and an extra slot for 16GB if I need it. If I wanna sell my car, I could go up to 32GB (it's too expensive now, but will come down by the time I "need" it). It's amazing. Since Aperture doesn't use all of the cores, it's not *that* much faster than the best performance I ever saw on the iMac, it's just that it *never* slows down and I can do anything else on the computer at the same time without ever seeing the spinning beachball. I've run two VMs along-side Aperture with no problem. I think you get the point. I'm now a little more future proof than before. There's plenty of hardware to spare, so by the time Aperture 4 or the 5D Mark II comes out, it shouldn't phase this machine a bit.

Also, with 5 available hard drive bays, I was able to turn off my Drobo and get back to 100MB/sec drive access. I even now have the option getting 2X, 3X, 4X, or 5X that performance by RAIDing the drives internally. Or, I could go nuts and get solid state drives which run up to 285MB/sec (as compared to a really fast spinning hard drive at 100MB/sec). All of these options come with different price tags, but they're only getting cheaper, and they're always available. I currently have 2TB of internal storage with plenty of room to grow. I can also upgrade my graphics card, monitor/display, and even add on components someday like Intel Light Peak and USB3 PCI cards. I can add on things that I don't even know about yet.

I also have the choice of displays with a Mac Pro. Many photographers are frustrated that Apple chose glossy for their displays instead of matte. Glossy screens basically become a mirror when you're viewing a dark scene or if your computer room is brightly lit. I just bought my Dell 27" U2711 and love it.

Don't Worry If You're Not A Nut
All of this craziness is because I refused to shoot JPG mode. If I had, the 2008 iMac would still be great. Someone out there is loving their new 24" iMac they just bought on eBay and questions why anyone would have sold it. If you're a sensible person, then just be happy with your JPGs, but if you're like me, and want the fully quality of RAW mode photography, then give some serious consideration to a Mac Pro over an iMac. I believe that I'll still be using this computer (with various upgrades) 4-5 years out, where I couldn't stand the iMac anymore after 2 years. The extra price of a Mac Pro becomes worth it when you realize how much longer you'll be using it.

If you shoot RAW mode and don't want to scream at your computer in a couple of years, then consider a Mac Pro over an iMac. You can still buy brand new 2009 model Mac Pros for cheap. Consider this one - an 8-core 2.26GHz for $2500, or this one - a 4-core 2.66GHZ for $1899.

If you're a serious photographer and you can convince yourself to go for it, I'm sure you'll be glad you bought the (more) future-proof Mac Pro over the sexy, but what-you-see-is-what-you-get iMac.

Wednesday, November 10, 2010

ETTL in the Studio

Strobist info:
* Key: 580EX II and 430EX II in a Westcott 28" Softbox above, camera right
* 430EX II in Morris 15x18" Softbox, camera left

* Savage 107" Seamless Charcoal Paper

In my past studio work, I'd use an Alien Bee B800 and several old Nikon speedlights triggered optically and by Pocket Wizards - all in full manual mode. This gives total control, but requires a lot more setup and tinkering. If the subject will stay still, you're set, but if you meter for the subject to be three feet from the key light and they move back a foot, they've just underexposed themselves a little bit. If they move closer by a foot, the difference is even more obvious, and you might clip some highlights.

This is where ETTL (Canon's fully automatic flash metering) really helps out. Here, I used a 580EX II on-camera to trigger three remote flashes - a 580EX and two 430EX II's. The remote 580ex and one of the 430ex's were in my softbox, camera right in group "A" and the other 430EX was in group B.

With ETTL, I can set the ratio of the two groups (A:B) in-camera - their power isn't determined until a split second before the shot. As I press the shutter, the on-camera 580EX quickly sends out coded pulses of light that tell each of the remote flash groups to send out a pulse of light at a known power. The camera quickly meters those pulses, then figures out how bright each flash needs to be. It then sends out another message to the flashes telling them how much power to use, and to fire at the same time. This all happens immediately before the shot - just about too fast to notice.

The drawback of ETTL is that two back-to-back shots might have slightly different exposures, but in the case of shooting children, the benefits outweigh it. If the kid moves forward, the flashes will fire with less power. If the kid moves back, the flashes fire with more. If the kid moves toward one light or the other, each light compensates accordingly.

In this shot, I used A:B mode on the flash with a ratio of 4:1 - the fill flash was 2 stops weaker (1/4 as bright) as key, just to fill in the shadows a little bit. Total flash exposure compensation was +2/3eV, which, sure enough, meant darkening it 2/3 stops in post-processing (but that's okay, because it actually reduces ISO noise to darken a photo). I was impressed at how well ETTL did. The on-camera flash was told not to contribute to the shot - just to master the remote slave flashes.

You may be wondering why I used two flashes in the key softbox - I've never done that before, and I didn't plan on it this time. It was a quick hack at the last second, because the 580EX II key light wasn't recharging as fast as I wanted, so I ball-bungeed a 430EX II next to it. With two flashes, each didn't have to work as hard, so recharging was faster.