Peter W Gallagher

I guess there will be a "troubleshooting" topic in due course... But here goes.
 
I loaded up some Olympus Pen-f raw files via the SD card dongle into Photos on iOS. But when I open them from Affinity for iPad, it seems to find only the JPEGs. I know that the raws are on my iPad because LightRoom for iPad displays them as "raw" in the choose dialog. Affinity opens them in the Photo personna and not in the Develop personna. From the size and lack of any meta-data I'm pretty sure they are the embedded JPEGs. A .DNG file downloaded from Dropbox opens immediatedly in the Develop personna and displays a "RAW:" tag with image info in the top left of the Develop screen.
 
Am I holding it wrong?

OK. But Lightroom for iPad has no problem opening raw files imported into the Photos app (using my SD card reader dongle). And even Readdle Documents for iPad (a file manager of sorts), although it cannot display raw files, will pass them to Affinity Photo via the "share" extension AS RAW rather than as JPEG. If the raw passes through the share extension I'm really puzzled that it will not open directly!
 
Serif has created a wonderful product here, but not being able to import from LOCAL storage is a major deficit for me, especially on the road (the only time I need to process raws on the iPad).
 
I hope your developers will re-address this.

Thank you for sharing these notes, dmstraker. They're a great addition to the AP Manual and the videos.
 
Your notes are also a fine tribute to the James Ritson videos that, in my view, are the best set of tutorial videos for any image-processing program that I've used. For their concision, thoughtful focus, broad topic coverage and low-key tone I rate them higher than even the polished performances of Julianne Kost on Adobe's products.
 
I guess, since you've apparently watched and paid attention to all of them, you must like them too  :).
 
Peter

Hi Peter, you're correct that raw handling is important, and raw converters will handle demoisaicing differently with varying results.
 
There are several more steps involved - which are again handled differently between raw converters. Demosaiced raw data starts as "scene referred", which is a measurement of light in the scene. You will very rarely (if at all) see a raw file in its linear "scene referred" form. It then goes through gamma curve correction, gets mapped to a colour space and has a tone curve applied to produce a result more in line with the user's expectations (similar to an in-camera JPEG).
 
 
So to answer your question - yes, there's a difference between SerifLabs and Core Image RAW.
 
SerifLabs will demosaic, gamma correct and tone map, but as you've found, the additional tone curve is optional. If you turn this off, you'll only see the image with a gamma curve correction. No additional sharpening is added by default - this is left entirely up to the user. Colour noise reduction is added by default; previously it wasn't, and we faced a lot of criticism over raw development quality because users are so used to having raw processing software apply it automatically. The harsh reality is that yes, your camera really is that noisy ;). You can turn this off if you wish on the Details panel, I just wouldn't recommend it.
 
I've done some analysis, trying to make a SerifLabs-decoded image match a Core Image RAW-decoded image, and I've come to the conclusion that Core Image takes some additional steps. It adds sharpening whether you like it or not, there's no doubt about that. It certainly performs colour noise reduction, and I also believe it does some luminance denoising and then dithers slightly by adding in some fine noise to retain texture. This approach wouldn't be entirely out of step; for quite a while, Apple's H264 decoder added some fine noise to reduce blocking and banding (this is back in 2007/2008 when its hardware-based H264 support was less comprehensive). I'm unsure of Apple's modern approach to H264 but I expect it's more refined now.
 
 
At this stage of Photo's development, the raw handling could still use some improvements, and over time it will be improved: namely a better approach to demosaicing and some more effective noise reduction. Demosaic implementations are continually being researched and written about, and there is always scope to do better here.
 
 
As far as advantages of SerifLabs go, there is one that I can strongly point out: because betas are made available in-between major releases (either for bug fixes or to introduce new features), new raw camera support is added frequently - so if you invest in a new camera, chances are you could grab a beta and be able to open raw images sooner rather than having to wait for an official update. For example, 1.5 was released in December and supported the new Olympus E-M1 mk2 camera which also shipped that month. It also opened images shot with the camera's high res mode (sensor shifting to produce 80MP raw files) - a feature that's still yet to be supported in some raw converters.
 
At the end of the day, the best advice is to experiment and find which raw converter's results you like the most based on what you shoot; e.g. if you do a lot of high ISO urban photography you'll want some fairly robust noise reduction and, perhaps more importantly, good colour handling. If you're into landscape photography with difficult dynamic ranges perhaps you'd find the ability to remove the tone curve more useful. And so on and so forth...
 
Hope that helps!