January 2018 - Digital Group - Raw Files

Meeting Notes March 2009 to 2018.
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January 2018 - Digital Group - Raw Files

Post by spb » Mon Jan 08, 2018 1:42 pm


If you want to sign up for Adobe’s Creative Cloud subscription, it’s not necessary to pay full price (£120pa). Discounted annual subscriptions are available from third parties. On Christmas Day (Sad. So sad. Loser) I found it on Amazon for £74.25. A very useful site for tracking Amazon prices is camelcamelcamel which will tell you the pricing history of a particular product and an automatic tracker can email you when products drop below your target price. This site reveals that the usual price of an annual CC subscription on Amazon is around £100 but it has occasionally fallen as low as £69.99.

Very worrying was the fact that nowhere in the description for Adobe CC does it mention the fact that Lightroom Classic is included and I had to root around at Adobe to satisfy myself that it was. I know that they are pushing the new Cloud version but the writing seems to be on the wall for the traditional product that has become a mainstay of so many photographer’s workflow – although not mine.

The annual statistics for Flickr uploads reveals that 50% originate from smartphones and 32% from DSLRs. Although the demise of point and shoot cameras continues, the statistics hide the fact that 1.5 billion smartphones were shipped last year but only 6 million DSLRs so the latter are still massively dominant among ‘proper’ photographers.

We talked a lot about inkjet printers last month but there are other technologies. Dye Sublimation printers excel at small continuous-tone prints and there are interesting products around which use this technology such as a tiny pocket printer from Lifeprint and a small Mini Shot camera from Kodak that produces prints.

Because my Epson printers are so flaky, we use a laser printer at home for office documents. They just work – well, until they eventually die. I have just replaced my Samsung colour laser with an inexpensive Canon colour laser – eight years later, same price, better build quality, more facilities.

The French are planning to take Epson to court for built-in obsolescence in their printers. This seems to be the same argument that Epson have already lost in the USA regarding ink cartridges being reported as empty with 20% ink still in them. The loss in the USA has resulted in a rethink of their designs with Ink Tank models appearing which have refillable ink bottles. I have another beef with Epson regarding their ongoing firmware updates blocking third party inks whilst disingenuously claiming they are not, and would never do that. Come and make my R3000 work with Permajet ink then.

JPG compressed image files have been dominant since the early days of digital photography and remain an excellent compromise between quality and file size. The camera settings are locked into the image at the taking stage and all further processing in Photoshop negatively impacts quality.

Raw image files can be chosen in enthusiast or professional cameras and contain the image data from the sensor. The genuine advantage of Raw is that under and over-exposure of two stops or more can be recovered. Less convincing are arguments that decisions on colour balance, sharpness etc can be made later when the image is processed, without quality loss and the Raw file is always untouched, remaining available to re-process differently at a later date. Given sufficient skill, a Raw file has the potential to produce a superior quality image to the equivalent JPG. All strictly true but I feel that only the exposure issue is a compelling one. Camera manufacturers put a lot of effort into perfecting their JPGs and getting something as good or better out of a raw file requires considerable skill.

Unfortunately Raw files come with significant disadvantages; each image needs individual attention, online sites and many browsers cannot handle Raws at all, the file size is huge and all previews of Raws are processed in some, often uncertain, way so they can be rather random.

Each camera manufacturer specifies their Raw files differently which necessitates continual, sometimes expensive, updating of software such as Photoshop. The ‘special sauce’ used in-camera to produce the JPG is proprietary, so Adobe etc have to reverse-engineer every new raw file format to try to match it. To overcome this Adobe have specified a universal Raw format called DNG (Digital Negative) and offer a free converter program. A few smaller camera makers output DNG straight from the camera but it has never caught on as a universal standard. Although conversion to DNG would remove the need to constantly update Photoshop, it does require a two-stage process and ongoing support for the format is not assured so it is gradually falling out of favour.

When shooting Raw, you must still pay close attention to aperture, shutter and ISO as these 'hardware' settings impact the image before the Raw is encoded and cannot be changed later. Camera settings such as Colour Space, White Balance, Saturation, Sharpness, Contrast etc are included in the Raw file but can be changed later. The preview image on the back of the camera is actually a processed JPG using all of the camera settings. It's not possible to view the actual Raw in its native form. This JPG is also included in the Raw file and may be used by dedicated image viewers (eg Faststone ) as a preview - hence the rather random nature of Raw previews. A compressed, lossless Raw option on the camera may be chosen to reduce file size without any compromises.

Adobe Camera Raw (ACR) is used by Photoshop CS, Elements and Lightroom to open and adjust Raw images and it's essential to make any big adjustments here, rather than in the subsequent image editor which is destructive to quality. As a general rule, use the various sliders in the order presented to make adjustments for a particular image. Only the camera’s white balance setting is actually used by ACR and then only as a starting point. I want to emphasise that when opening an image in raw processors like ACR we are NOT looking at the raw data. That would be dreadful. We are looking at a processed version of the data that seeks to look as good as, or better than, a camera-processed JPG would have looked.

It should not be necessary to make large Exposure adjustments if the metering in the camera was set correctly. If you find yourself consistently making the same adjustment to Exposure it would be worth considering setting a permanent compensation factor in the camera. Highlights and Whites sliders will rescue overexposed highlights. Shadows and Blacks shadows will rescue shadows. Brightness and Contrast will tweak the mid-tones of the adjusted image. Clarity affects mid-tone contrast and Vibrance boosts less saturated colours. A modest amount of Sharpening is applied here in ACR by default and then further appropriate sharpening should usually be added for final print or screen output. Other tabs lead to excellent noise reduction controls and options to mimic Camera Profiles which may be been set in the camera for JPGs (again – reverse engineered).

The ACR slider settings are saved individually with each image and are the starting point if the image is re-processed. Options allow them to be saved in a separate .XMP file (which requires managing) or in a common database on the computer (my personal preference). If using Photoshop, the image will subsequently be opened with the Open Image button but other options are Done which saves the settings but doesn't open the image and Save Image which offers the chance to save it as a DNG. Settings used repeatedly can be set as the defaults for each camera. Ideally the Bit Depth setting would be set at 16 bits/channel but in Elements, most features don't work at this setting and 8 bits/channel is absolutely fine if the big adjustments have already been made in ACR. As mentioned last month, users of Photoshop Creative Cloud should take advantage of the Shift+Open Image option to open the image into Photoshop CC as a Smart Object offering the opportunity to re-process the raw file at any time. A revelation!

Multiple images can be given the same settings in ACR, if the lighting conditions were consistent, to save spending time on each image individually.

As well as ACR there are many Raw Convertors available. A starting point should be the one that came with the camera. Others include: On 1 Photo Raw, Capture One Pro , Luminar , Affinity Photo and DXO Photo Lab. Each will have a slightly different opinion about what a particular raw image should look like. Try the free trials and see which you like.

A surprising difference that you may see when comparing variously processed raw images and JPGs is that the crop and geometry of the images will differ slightly. This is because the raw file includes information about the lens used and the processors may attempt to correct any known distortions and aberrations using a lens profile. Not all raw processors will have this information. In this respect using a lens, camera and software from the same brand gives it an advantage. Increasingly cameras are doing this automatically to all files (including raw) because it’s easier to do in software than in glass.

My overall conclusion is that Raw is especially good at recovering shadow and highlight detail but there are major downsides too. I strongly recommend that beginners stay with JPG and concentrate on learning good camera technique. Intermediates might consider the Raw + JPG option so that they can practice the skills to extract a better image from the Raw whilst having the JPG for comparison and fallback.

A final point is that JPGs can be sent through a raw convertor (File>Open in Camera Raw for Elements) to gain access to controls that may not otherwise be available such as Clarity, Vibrance and Noise Reduction. Of course there is no additional exposure latitude in a JPG to recover under or over-exposures.

Cheers, Steve

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