Viewing photographs on the iPhone 4′s 326dpi “Retina” display is absolutely incredible. It’s a 1990′s era dream come true. Text is easy for any display to render sharply but rendering fine photographic detail is quite another story. For many of us, phones and iPads have become portable portfolios that are fluid and easy to show people while on the go. Apple’s new iPhone 4 takes portable image viewing to a new level, but there are some details towards getting optimal results that are worth mentioning for demanding users.

In the past, zooming in on iPhone images led to disappointing results because it just an enlarged low resolution photograph, kinda like zooming past 100% in Photoshop or past 1:1 in Lightroom. When you sync a high pixel count image to an iPhone, iTunes “optimizes” images for the phone by lowering the pixel count and re-saving a unique JPEG for the phone. This process can lower the image quality and sharpness significantly thus many pros have been disappointed with image viewing on previous iPhones. It felt low resolution to begin with and even worse when zoomed.

With the release of iOS4 came a new iTunes image optimization routine designed to improve image viewing especially on the iPhone 4. From my tests it appears that iOS 4 now stores images at 1920×1280 pixels with a medium amount of JPEG compression. If images are even just slightly larger than this pixel count iTunes will resample images which results in a loss of image sharpness. If images are lower than this pixel count they will appear pixelated when you zoom in on them.

For photo geeks wanting to get the very best image quality on their iPhone 4, I suggest (more…)