Why iPhone RAW is a Big Deal

iOS 10 brought the capability to get the RAW image data from the camera and save it as a DNG file. It elevates the quality of iPhone images to a whole new level (for those who care). The following image tells it all.

Click the image for actual pixels display on non-Retina screens

Click the image for actual pixels display on non-Retina screens

On the left is how the iPhone renders the image, on the right my version converted from DNG and tweaked to taste in Capture One. Both show the actual pixels (100% magnification). Red areas are the overexposed parts. The images were captured as RAW+JPG in the upcoming Mark II Artist’s Viewfinder 5.0, so they represent the exact same moment.

With shooting RAWs you can avoid most of the pitfalls of iPhone image processing (I know them from experience):

  • Over-sharpening, which ruins images with already high contrast edges, such as tree branches against the clear sky.
  • Excessive noise reduction – usually on an unnecessary level, even at ISO 25. You know, the blotchy look at 100% which looks downright ugly.
  • Unrealistic color. Apple processes the images for punch, which is good for making your friends envious on social networking sites, but is a problem when you want to actually use them (the images, not your friends) as real photographs.
  • Sometimes overdone light falloff correction. You know, when the sky is brighter in the corners than in the center.

You also get more headroom for recovering overexposed areas (they are also better by default because of the lower contrast), but on the other hand you need to correct corner light falloff by hand.

To my eye the difference is so large that I won’t use JPGs any more when I’m photographing with the iPhone (which happens a lot, since it’s always in my pocket). No, they are not challenging DSLR (or even large sensor point and shoot) quality, but are way more usable than the JPGs.

Mark II Artist’s Viewfinder 4.7 Released

IMG_0050My Mark II Artist’s Viewfinder app is now available on the App Store.

The major new feature is the ability to create a custom wide converter, on which I posted recently.

Other than this, we have added support for a few newly released cameras:

• Canon ME20F-SH
• Fujifilm X-T2
• Hasselblad X1D-50c
• Pentax K-70
• Sony A6300, SLT-A68

This is a free update for existing Mark II Artist’s Viewfinder owners.

As you can see on the left, we offer upgrade bundles for former Viewfinder Basic/Pro/Cine edition owners, so they can upgrade for a reduced price.

Please note that if you have ALPA eFinder II, the custom wide converter feature, as well as the new cameras are only available if you also purchased the Camera Pack.

Custom Wide Converters in Viewfinder 4.7

My Mark II Artist’s Viewfinder app has a unique feature from day one. Something that no competitor managed to copy: real-time distortion correction for wide converter lenses. In the past distortion correction was available through the profiles we made for all the wide converter and device combinations the app supports. Creating these profiles involves tedious measurements, and of course a purchase of each and every converter lens and iPhone/iPad we support.

The profile approach was good a few years ago with a limited set of converters on the market, but these days you can find at least a dozen different converter lenses at online retailers. This, together with the product lineup splits Apple already implemented with the Plus phones and Pro iPads, renders the previous modus operandi financially unsustainable.

So we decided to address this situation in a way that is beneficial for both our users as well ourselves: by allowing users to create a custom wide converter. And of course we do support simple distortion correction with this! Being a simple correction, it does not always produce the almost perfect results the profile-based approach is capable of, but as you’ll se in the examples later on, very capable nevertheless.

We’ll continue to support the profile-based approach for existing combinations, but will add new profiles only if:

  • we already have the converter and the device in the lab, or
  • we receive several customer requests to support a converter – as it was the case with the Moment Wide lens, or
  • we cooperate with the converter’s manufacturer.

OK, with all that said, let’s see how it works. Once you select Custom for the wide converter, a new menu item – Custom Converter Setup – will appear on the menu.

cwc-setupTapping it will bring up the converter setup screen that you can see on the left.

You can set the converter lens’ actual conversion factor with the first slider. Since this is almost always different from what the manufacturer says, you’ll definitely need to fine tune it for your actual phone (since the conversion factor also depends on the phone’s lens as well as the distortion correction amount – be prepared for a little trial and error). We support converters with factors between 0.45 and 0.7.

The second slider is used to specify how much distortion the converter lens has. It is an arbitrary scale from 0 to 30, zero meaning that you will not want to correct the distortion (suitable for well-corrected lenses such as the Moment Wide).

The setup procedure

Here’s how I recommend to do the setup. Set distortion correction first (if needed at all). I’d recommend 15 as the starting point for 0.65x-class lenses and 20 for 0.5x-class lenses. Check how the main screen looks, and watch for overcorrection in the corners. In case you still have barrel distortion, go back to the menu, and increase correction. If the corners are overcorrected, back off a little. A tiled wall, a window or a tall building are good test targets.

Once you’re happy with the correction, mount the phone steadily, turn off Wide Mode, and set the main screen so that you have some objects or markings at the edges of frame lines. Now turn on Wide Mode and check whether the objects/markings are still at the frame lines. Go into the menu and adjust the conversion factor if not. Repeat until you are satisfied with the result.

You can create only one custom wide converter, so it is advised to take note of the parameters in case you need to restore them later.

Correction examples

Walked up to Hallgrímskirja in Reykjavík to make some examples with my iPhone 6s Plus and two olloclip converters. Here is how the 4-IN-1 Wide lens looks with no correction.

olloclip 4-IN-1 Wide on iPhone 6s Plus - No Distortion Correction

olloclip 4-IN-1 Wide on iPhone 6s Plus – No distortion correction

As you can see below, this lens has a simple spherical distortion, which can be corrected almost perfectly with the custom converter setup. My experience is that most 0.65x lenses behave the same way and would only marginally benefit from a profile. Note that I set the conversion factor ad-hoc in these examples, so you may see some discrepancy in frame line positions.

olloclip 4-IN-1 Wide on iPhone 6s Plus - Custom wide converter with distortion setting 13

olloclip 4-IN-1 Wide on iPhone 6s Plus – Custom wide converter with distortion setting 13

Now to the olloclip Ultra Wide. Distortion is huge, and without correction renders the lens pretty much unusable for viewfinder purposes.

olloclip Active Ultra Wide on iPhone 6s Plus - No distortion correction

olloclip Active Ultra Wide on iPhone 6s Plus – No distortion correction

And this is how it looks with the custom wide converter’s correction. You see some mustache-like corners as the simple correction is not able to eliminate complex distortions (which profiles can do), but the lens becomes usable.

olloclip Active Ultra Wide on iPhone 6s Plus - Custom wide converter with distortion setting 22

olloclip Active Ultra Wide on iPhone 6s Plus – Custom wide converter with distortion setting 22

Just like with profiles, the simple distortion correction works only with wide and ultra wide lenses – not with fisheyes.

When will this be available? The feature is currently in testing in version 4.7, and is planned to be released later this summer. In the meantime, comments are welcome.

The updated app is now available for download.

Artist’s Viewfinder 4.6 Available

iphone_se_wideconvThe latest update to the Mark II Artist’s Viewfinder adds complete support for the iPhone SE.

This means two things. First, we’ve measured the angle of view of the SE’s camera. Second, since the SE takes iPhone 5s cases, we’ve created a distortion correction profile for each and every wide converter that we support on the 5s. You see the complete list on the left.

As usual, we’ve added a bunch of new cameras to the app’s database. I’d encourage you to take a look on the release notes for the detailed list.

Version 4.6 is a free update for existing Mark II owners. Users of former Viewfinder Basic/Pro/Cine editions can upgrade for a reduced price.