A
lot has been said about the iPhone 4 screen’s incredible resolution.
Packing a 960×640 (o.6 MP) resolution into a screen that small means it is 326 pixels per inch. Unless you have perfect vision, reviewers have said that you’ll just not be able to make out individual pixels. This is a very high resolution for any portable LCD screen, and when shooting HD video, a high resolution monitor is critical.
How high is the resolution of the iPhone 4’s Retina display? Engadget put it like this:
The advertised pixels per inch (PPI) of the iPhone’s display is 326, but what does that really mean? Well the calculated PPI of our 1080p 60-inch Kuro: it’s a meager 36 — luckily we don’t sit 12 inches away from it. In fact a 1080p TV could only be 7-inches if it wanted to match that PPI. A 60-inch HDTV would have to have a resolution of 16815×9500 to match it — gasp — which is four times the horizontal resolution of 4k! Speaking of which, a 4K display could only be 14-inches. But the iPhone isn’t like an HDTV; its main purpose is to display text, not video. So what about a 20-inch PC display, how many pixels would it need to match the PPI of the iPhone? Try 5600×3500, which is about double the horizontal resolution of WQXGA at 2560×1600.

The problem in this comparison is that most video assist LCD monitors may start with a high number, like 800 or 960, but really crap out in the other aspect- like with only 240 pixels on this $400 monitor. If that’s the case, what’s the point? You have to spend $1500 (list) to get a 1.2 MP screen, higher resolution than Apple’s iPhone 4. So why not use the $299 iPhone your camera monitor?
It’s the video input that’s the problem. The device is designed for video output from the dock connector, not input.
Aside from the built in camera, there is no way to get video into the iPhone. While there may be some secret hack, you can be sure that any app developed to take advantage of any digital loophole to enable video input would not be approved by Apple for the app store.

So you’d be looking at a Jailbreak, and a Cydia download at the least. That dramatically limits the potential market to a developer. Smaller market means much smaller ROI. The investment would be serious because, taking any HD output from a camera (HDMI or SDI) would require serious horsepower to crunch the incoming data stream down into something the hardware could handle, in near real time, without killing the battery or overheating the CPU and killing the phone.
Yea, you can pretty much count on it never happening.
But, that doesn’t stop some enterprising developer from OEMing the screen that Apple uses and building hardware around it. Possible? Yes. For $299? Hell no. You should expect $1500+ price tag and then, I’d rather have a 7″ or larger display for that price.
So you can pretty much count on it never happening.
ProLost wrote about Apple offering the hardware API to developers so that, potentially, someone could create an HDMI to iPod converter cable to get the video in, and then software to provide scopes, aspect ratio guidelines, etc. But Prolost announcement was about iOS 3.0. We’re now using 4.0 so I think there just hasn’t been the interest… but now the screen is the highest resolution thing out there, so maybe, just maybe, there might be enough of the pieces in place to make it happen.

Fun to consider, eh? :)
Cnet reports that iSuppli says the Retina Display likely costs around $28.50. With that price, I’d LOVE to see some manufacturers start OEMing it into production monitors.
And also love for them to not THEN charge $1500 for the monitor. I can understand a reasonable price for R&D, but if Apple can do the whole phone for a couple hundred, then a simple monitor alone has GOT to cost less.
One thing you should note, is that Marshall (who you reference being 1.2 megapixels, and higher than the iphones) is very, very misleading. They count subpixels as pixels, which is falsifying facts. The iphone 4’s resolution is actually HIGHER than the 7″ marshall you reference, which is 800×480. The iphone 4’s screen is 960×640, quite a bit higher. Just wanted to set the record straight, i hate how misleading so many companies are.
What about making a decent quality wifi video input ? There are already programs out that can monitor camera’s over wifi on the iphone.
Thanks for the insightful information and thoughts. My friend and I stumbled upon this blog after he pondered “Maybe we can use my iPhone to monitor the signal from this camera.” However, your writing would be much easier to ingest if you didn’t use annoying acronyms. I guess you assumed that anyone reading this blog might already know the meaning behind your three-letter gems, however, I didn’t, and now after looking them up, I feel that I’ve wasted time, which seems antithetical to the idea of acronyms in the first place. I was in the Army for almost 9 years and I came to hate acronyms. They really just waste time. Take the time to say or write the full phrase, or simply paraphrase. Random groupings of letters are illogical. I apologize if this turned into a rant. Anyway, what are your thoughts on affordable yet high-quality high-definition monitors for digital single lens reflex cameras? (I have to admit, I was tempted to lazily type DSLR, but that would have been extremely hypocritical.) Thank you and good night.
LCDs for vDSLRs? IMHO, EVFs rock. Get as high rez as possible. Pay COD for UPS & not an IOU, ASAP. WYSIWYG. TTYL.
There is a way to do this, but it would take some coding and an adapter cable. Jonti Olds demonstrated streaming composite video between two computers by QAM encoding the video digital data at audio frequencies between 20 Hz and 20 kHz back in 2009. The mic input on an iPhone has this bandwidth. In theory you could at digitize the composite or component output from your camcorder/whatever, compress it with H.264/whatever, QAM encode that and supply that analog signal to the iPhone’s mic input, and reverse the process there. It’s not off the shelf, but until Apple opens that API further, we’re stuck sneaking in the audio back door. BTW, there are a number of projects doing this to get low bandwidth data into the iPhone. JQAM just tested the upper limit of what was possible. Since then (2009) the smartphone hardware has just gotten faster and more capable so you don’t need sound cards to do it now.
Great information.
THis coudl indeed be taken a step further with the non-lightning devices as Fostex uses a stereo line input for audio through the dock connector. Other companies use the dock connector to get data into the iPhone, although they may be using audio as well, I don’t actually know. But two line-level audio inputs in the dock would handle a lot higher quality audio than one mic-level audio input through the headphone jack.