Turtleback SLR Mount links SLR lens and iPhone

The iPhone SLR Mount from Turtleback is the latest product in a trend that blurs the lines between your iPhone and your everyday camera. Featured this month on Photojojo, this accessory is basically a fake sensor floating in-between an attachment to your iPhone and an attachment to your lens.

After I finished laughing at how awkward my Nikkor lenses looked jutting out from the comparatively dainty iPhone 4, I took the iPhone SLR Mount out to the garden with my 28mm f/2.8. (Click on the photos to enlarge them.)

The “sensor” in the lens is a cool idea. The iPhone essentially focuses on the sensor instead of the scene, leaving full control of the focus and aperture to the lens. The problem with the sensor, though, is that it gets dirty very easily and is not easy to clean. And because the iPhone is focusing directly on the sensor, all of the dirt on the sensor is crisp in the frame.

Most new DSLR cameras feature automatic sensor cleaning as you turn your camera on or off, but the sensor in the SLR mount needs to be cleaned manually. When I got the SLR lens mount, the sensor had a little bit of debris on it and even after blowing air on it, gently wiping it with a lens cloth, and shaking it, the spots would not come off. The texture of the sensor is also visible in your photos. It kind of looks cool (the canvas texturizer in Photoshop comes to mind), but it is problem if you really want a clean photo.

The iPhone SLR Mount works only with lenses that have a manually adjustable aperture. So, that kit lens that you use every day may not work in the SLR mount. The reason is that the iPhone camera needs a lot of light to take a good photo. When the aperture on your lens is small, it limits the amount of light that can get to the iPhone and your photo gets dark. Your DSLR makes up for this by raising the ISO or changing the shutter speed, but there are no controls for this in the iPhone.

Another problem with using an SLR lens is that the iPhone 4 screen is not good for focusing. Even with the screen’s 326 ppi resolution, you still can’t quite tell where your plane of focus lies. On a DSLR, you could give yourself more leeway by upping your f-stop, but in order to give the iPhone enough light, you have to use a large aperture—making a shallow depth of field.

The lens mount comes with a heavy-duty iPhone case that could easily be used as an everyday case if you don’t mind the bulge around the camera for the lens attachment. The thick, metal case gives access to all ports and buttons, holes to attach a neck strap, and two different tripod attachments—one for landscape and one for portrait mode. This is a great feature if you like using a tripod with your heavy telephoto lens so you can keep your photos clear and your arms energized.

The SLR mount is extremely hard to use in a normal camera app. Because you are using an SLR lens without a mirror system in the camera, the image appears in the iPhone screen upside-down. This was extremely frustrating. When I moved the lens up, the image would go down. It was a photographer’s nightmare. After using the attachment for just a few minutes, it felt like I was playing a FPS videogame with really poorly designed user controls.

I emailed Photojojo just to make sure that I wasn’t crazy or stupid and put the lens together wrong. It turned out that I was using it exactly how it is designed. (Even the promotional photos of the mount show the hand model taking a photo upside down!) Photojojo suggested that I download the free version of almost DSLR ($2). This app flipped the image for me as I was shooting it, but saved it upside down. So I had to open and edit the photos in another application before they were rightside-up. For $250, it would be nice if the iPhone SLR mount came with a free app that would help you take, edit, and save your photos right-side up.

It is going to be a long time before you can leave your DSLR at home and rely on your iPhone to cover an important photographic event, but the iPhone SLR Mount is an interesting step in that direction. For now, if you want to get a DSLR effect in your iPhone, it’s best to stick to the App Store.

[Lauren Crabbe is an intern for Macworld.]