I love this idea. A case that makes your iPhone look like an old-timey camera? That's an old gag. The Gizmon iCA (http://gizmon.com/) is an iPhone case that makes your phone work like an old-timey camera.

(Here we define "old-timey" as "back when people subcontracted all of their photography operations to a completely separate device designed specifically and solely for that purpose.")

The iCA takes most of its style from a Leica rangefinder. Its mechanical features include a big shutter button, which I assume is just a mechanical poker aligned above the iPhone's volume-up button; strap lugs, which let you wear the iPhone around your neck like a regular camera; a tripod mount; and a threaded shroud around the iPhone's lens, which would allow the case to accept screw-on accessory lenses (like fisheye, telephoto, and macro lenses).

The strap lugs are no minor feature; when you're at an event where you really should be taking lots of pictures, slinging the iPhone around your neck helps you to think of it a real camera instead of as an afterthought.

I like the iCA even if I don't think Gizmon has prosecuted the idea fully. It's cool and mostly quite functional, but it’s still clearly a novelty item. It's the sort of thing you'd bring to a party as a shrewd ploy to participate in a social event while deflecting direct attention. When pressed into an actual conversation, you can talk about your way-cool iPhone camera case instead of yourself.

Write that tip down, socially-awkward kids. This is the same reason why, when I was your age, I built a string of CPU-controlled lights to wear around my hat at a friend’s Christmas party. I got a hundred questions about the lights (“They’re actually automotive turn-signal lights, controlled by a programmable IC…”) and none about my job (“No, ‘freelance writer’ does not mean ‘technically, I’m unemployed’, dammit…”) .

But I've long been intrigued by the idea of a digital camera system that allows me to mix and match subsystems. My compact cameras are just old enough that the next time I review a new camera that I really like and which meets my needs, I'll probably buy it. None of the cameras I tried in 2011 were quite right. My perfect camera would have had the body of the Nikon P7100 (I loved its solid, mechanical control buttons and knobs), the image sensor of the Panasonic GX1 (ungodly good low-light performance), and the software of the Olympus E-P3 (its UI is clean but powerful; the code that translates sensor data into images produces fab photos that are practically perfect). And I want to use interchangeable lenses, like the Panasonic and the Olympus.

A true modular camera system could easily be produced on a planet where several competing companies were capable of working together in a way that benefits corporations and consumers at the same time. Here on Earth-1, a device like the iPhone is as close as we’re going to get. Several companies can sell cases that make the iPhone handle more like a conventional camera; at the low end, it’s a simple shell that adds a big, friendly shutter button and which makes this thin, glass object easier to handle. A high-end model would go all in, with a real strobe flash, a threaded lens mount (maybe even an integrated power zoom), and one or two mechanical function buttons, all communicating with a camera app via the iPhone’s dock connector.

There’d be open standards, so the user would be free to control all of this via the camera app of their choice. Better yet, separate apps would be fine-tuned for different shooting situations. Who better to design an app for sports photography than an actual sports photographer? What better camera to take to your daughter’s hockey game than one that’s been specifically coached on how to capture fast-moving action in dimly-lit arenas where the subject is wearing a dark uniform against a white sheet of ice?

We could completely do away with this idea that one camera can be designed to suit every user and every situation.

I know that “an iPhone dressed like a camera” is a great concept. I got a taste of it in action when I tried out Beep Industries’ POPA (http://beephq.com/) recently. It’s a dirt-simple £50 dock-enabled iPhone accessory that does two simple but cool things: it adds a comfy handgrip to the bottom edge of the phone and it puts a big red shutter button under your index finger. Unlike the mechanical poker of the iGA, the POPA’s button works electronically, just like a real pocket camera, and communicates with Beep’s free camera app.

An iPhone transforms into a Real Camera when it’s clicked into a POPA. You can hold it securely and confidently instead of like it’s a slippery $300 glass sandwich. During a dinner party, you can pick it up off the table and snap a photo spontaneously. The effect is psychological as much as it’s technological. Who cares? It’s real.

The normal role of a cameraphone is to create disposable content for your Facebook and Twitter feeds. The iPhone 4 was certainly the first mass-market phone that could take real photos. I’m talking here about the kind of shots that document your life, instead of just your lunch. The iPhone 4S upped the stakes and my praise. Where the iPhone 4 was “as good as a bad pocket camera” (yes, I meant that as a compliment) I could even go so far as to describe the iPhone 4S as “mediocre” (ditto).

These kinds of photo accessory (both real and imagined) help the iPhone reach its potential. They also nicely accommodate a trend that I used to bemoan but have now accepted: the modern public now defines “camera” as a phone feature and not a dedicated gadget, whether mobile technology is up to the challenge or not. My sister wanted me to take her family’s Christmas card photo with my iPhone. She didn’t ask for that device specifically. I was at her house for Thanksgiving and no, she said it wasn’t worth my going home for my SLR (and a tripod and an extra flash head and a radio trigger; my inner photo nerd was already scheming). A camera was a camera. I even enhanced it on my iPad right then and there, instead of Photoshopping it later that evening. She had her photo just two hours after making the request, and in the end, I felt silly for instinctively wanting to turn it into a big production.

I even shot my own Christmas card photo with the iPhone 4S. I wished that I happened to have had a decent camera with me when I was walking through Boston’s Back Bay after a meeting. I didn’t. So I snapped it with the 4S and (well, whaddya know?) it turned out that I had a decent camera with me after all.

Even as-is, the iPhone 4S has deeply upset the previously bedrock-stable balance of power in my camera bag. For years, I’ve used a big SLR for when I was in Serious Photography Mode and a decent pocket camera for casual situations. Now I’m wondering if I even need two cameras. New compact interchangeable lens cameras are enormously flexible and their large image sensors take great photos…and with my iPhone in my pocket, there are more and more situations in which I could leave my “real” camera at home entirely.

A good tech product disrupts the whole market for that kind of gadget. A revolutionary one disrupts other marketplaces as well. The iPhone 4S has clearly done both.