January 9, 2005 by Allen George
DSLR Part I. Introduction & Handling
I’m busy today but there’s always time to write a bit.
D-SLR. Abbreviation. Digital Single Lens Reflex. Most versatile photographic tool available.
As I mentioned yesterday, pricing can go from as low as $1200 for an entry level model to as high as $10000 for a full-frame, ruggedized, high-performance model. Also, D-SLRs are different from their lower priced digital bretheren in a number of ways. These can be broadly categorized into 4 areas:
If you, like me, entered the digital photography arena via a P&S, you’ve grown comfortable with using the rear-mounted LCD to compose your pictures. If you’ve used prosumer cameras you’ll have encountered EVFs (electronic viewfinders) or rotating LCD displays.
None of these exist in D-SLRs. And unless a major company takes a risk and redesigns a D-SLR from scratch (taking into account all technological accomplishments) you won’t see any of these features for quite some time.
I know this may sound surprising. After all, these are much more expensive than a P&S and we all know one of the major selling points touted by manufacturers is “the large, bright [insert dimension here] LCD”. Then why do most D-SLRs have an LCD screen anyway? Ah. Why indeed. This screen is not used for live image preview or image composition. It’s only used after-the-fact to review the photograph you just took. To compose the photo you’ll have to get used to the optical viewfinder again.
While others can explain it much better than me, perhaps a simple overview will suffice. In a P&S or prosumer camera, light from the lens travels directly to the sensor. A scaled down version of the sensor image is displayed on the LCD and/or EVF. In a D-SLR (I think I’ll drop the hyphen), there’s a mirror in the way. This mirror projects the image upwards at a 90 degree angle through a pentamirror/pentaprism and into your eyes via the optical viewfinder. In a D-SLR, what you see is what you get. When you press the shutter release button, this mirror snaps out of the way exposing the sensor to the light entering the lens. 1/60 of a second – or whatever shutter speed you’ve selected – later, the mirror snaps down, covering the sensor.
Voila. Picture done.
So why not do away with the mirror, pentaprism et. al? I suspect a number of factors. First, even the best and largest LCDs available on digital cameras today do not approach the resolution demanded by professionals in composing a picture. Many will want to see the smallest details and the granularity of an LCD display would be a huge problem. Secondly, EVF resolution (while improving) hasn’t reached the standard demanded by the target category. I believe the highest EVF resolution I’ve heard of is K-M’s 922K unit on their A2. Finally, interia – both on the part of D-SLR users and manufacturers. It’s easier for manufacturers to simply strip out most of the guts of a film-body SLR and replace it with a sensor as opposed to redesigning a unit from scratch. Users are hesitant about being the guinea pigs for any ‘unproven’ technology.
I believe that EVFs are the future and fully expect that by early 2007 I will see a DSLR offering an EVF. It’s just a matter of time and technology.
Build quality’s the next thing you’ll notice with DSLRs. Unlike their younger bretheren, DSLRs are heavier. They’re generally more rugged. High end versions are literally bricks, often constructed fully out of metal. These are not pocketable (or even concealable) machines.
Often DSLRs have a vast range of buttons that allow you to quickly and easily make all the changes like apeture, shutter speed, ISO, white balance, exposure/flash compensation you need without going into menus. This ensures that you’re always able to react quickly to changing situations. On my SD100, changing white balance involved entering a menu, and pressing the 4-way controller repeatedly to get to the entry I need. On DSLRs that operation is much faster. That’s simply one example of the attention to ergonomics that camera makers place for their DSLR lineup.
Allister knows that the one thing I complained about on end was the short battery life on my SD100. On my road trip to San Diego I often ran out of juice to take my pictures and I had to coax my camera to take that elusive “last shot”. No such problems for DSLR users. Since the LCD screen isn’t used for previews and I don’t think the sensor is on continuously, DSLR batteries can last for hundreds – perhaps even more than a thousand – photographs. Now that’s staying power.
I can’t think of anything material to add at this time, so I’ll end it here. I hope to discuss more about DSLRs in upcoming entries…