This page points to all recent articles published on dslrbodies.com, sansmirror.com, gearophile.com, and filmbodies.com, and is updated as new articles appear (most recent on top). For articles from previous months, check the Articles Index Archive.
Thom takes the month of August off from the Internet and email to rejuvenate, to spend some time shooting, and to get rid of some of his snarl. byThom and the other sites will be silent from August 7th through September 8th this year. All product announcements and other news that occurs during that time will be caught up to when I return to the office after Labor Day.
August 6, 2015
Nikon Q1 Financial Results. t’s a new fiscal year, so how’s Nikon doing so far? Surprisingly good according to Nikon. Article on dslrbodies.com
August 4, 2015
Three More Nikkors You’ll Be Interested In. Nikon today introduced three new F-mount lenses, two of which are likely to be of some interest even to DX users. Article on dslrbodies.com. 24mm f/1.8G data page. 24-70mm f/2.8E data page. 200-500mm f/5.6E data page.
Fujifilm Returns to Forensics. Back in the days when Fujifilm had (Nikon-based) DSLRs, they targeted the forensic photography niche with cameras that had wide, unfiltered spectral abilities, from UV to visible to near-infrared light. Today Fujifilm announced the X-T1 IR, which is a version of its top-end mirrorless camera that does the same thing. Article on sansmirror.com
August 3, 2015
Note: Since a number of people don’t fully understand E-type lens compatibility, I have added a section on it in my Making Sense of Nikon Lens Acronyms article and notes about compatibility in each of the database entries for E-type lenses. E-compatible is not a new thing. We’ve had such lenses for seven years now, but because the 16-80mm f/2.8-4E DX and 300mm f/4E lenses are targeted at a broader, more general, and often consumer audience, a lot of folk using older cameras missed the compatibility story when it first appeared. Short version: pro cameras since the D3 and consumer cameras after 2009 are fully compatible with E-type lenses, older cameras won’t let you set the aperture (aperture is stuck at maximum aperture). Update: I made a few small clarifications and corrections on the Acronyms page.
What We Learned from the Latest Nikon Owner Survey. Last week NikonUSA sent a survey to an n sample of people for which they had email addresses. The survey itself was a strange concoction: a set of poorly chosen either/or statements, most of which weren’t actually opposites, followed by a “what are you going to buy” hammer at the end. Article on dslrbodies.com
New Nikon Lens Rebates. As always when Nikon offers lens-only rebates, I go lens by lens with an analysis of whether these are deals you should be interested in or not. These new rebates are in effect already and last until August 28th. Article on dslrbodies.com
July 29, 2015
CS6? The End is Nigh. Adobe quietly posted an “update to policy” about Photoshop CS6 in the Lightroom Journal (sic ;~). Article on dslrbodies.com
Previous articles can be found in the Articles Index.
Thom's Teaching Point — Selecting Sky
How about a software teaching point this month?
One of the toughest things you sometimes encounter in processing landscape photographs is selecting just the sky. The reason generally has to do with tree limbs, bushes, and other things projecting up into the sky and making selection tough. Worse still is when you have gaps in vegetation that lets some sky through.
The good news is that sky is mostly blue spectrum light, so we’re going to take advantage of that. We’ll work with an image you’ve seen before on this site:
I’m not making much of a change to the image in ACR, basically just grabbing the white and black sliders and adjusting them to maximize the histogram. I don’t want you to get confused by other settings along the way. We’re just interested in that sky at the moment (and conversely, the hoodoo and foreground). I would suggest, however, that you remove any chromatic aberration, if you can, as it can impact the boundaries of the objects we’d be selecting against.
In Photoshop, go to Channels and select only the Blue channel:
You can probably already see that the lines of the hoodoo and horizon are pretty distinct, but we’re going to go further. We going to drag the Blue channel to the New channel icon at the bottom to duplicate it. Your new layer will be called "Blue copy", but you can rename this to something useful, such as “Sky Selection”, as I’ve done here:
Next, we’re going to do something specifically to that new channel: make sure that new channel is the only one active, then select Levels from the Adjustment menu. Bring the Black slider up until the land and hoodoo go completely black, and the White slider down until the sky goes completely white:
You probably now know why I selected this image: it’s got clouds in it that are going to be a problem, and the hoodoo itself doesn’t really go completely black. That’s okay. We’re trying to simplify selecting the sky, and sometimes we won’t get exactly what we want on one pass. (*)
I’ll quickly clean these things up by using a white brush, then a black brush:
All the above only took me a few seconds from hitting the Open Image button in ACR to getting a clean black/white mask.
We now want the white area here to be our “selection,” so hold the Command (Mac) or Control (Windows) key and click the Channel to load its white areas as a selection. You should see the cursor change as you hold the key when you’re hovering over the Channel list, and when you click you should see the crawling ants now define your selection. (Bonus point: you might find that the Refine Edge item in the Selection menu is very helpful at disguising the actual edge. But that’s a lesson for another day.)
At this point, you’ll want to click the RGB Channel to activate it, delete the Sky Selection channel you created, and move to the Layers panel. Apply whatever layer effect you want on the sky. Invert your selection and apply whatever layer effect you want on the foreground. You’re done.
Here I’ve done a bit of over processing on the foreground and background so that you can see that I was indeed able to get this image quickly processed based upon the quick selection I made. This is not the way I’d normally process this image, as the light cues are now screwed up. But it should be obvious that I’ve touched both the foreground and sky in different ways:
I made no attempt to refine my selection other than the bit of brush painting I did. Normally I’d take the time to look closely at every edge very carefully and be tweaking pixel level decisions. But I wanted to show you that you can make what’s otherwise a tough selection with just a simple use of the channel information, and do so quickly. In fact, really quickly if you take the steps I noted up through the (*) and made them into a Photoshop Action. I’d probably also create a second Action that took everything after the brush touchup through to my final “ready for adjustment” selection. In other words, to select sky you’d activate Sky Action 1, touch up the selection with brushes, then activate Sky Action 2. That makes for a pretty simple and quick method to get your selection dialed in.
Note that here we’re working with sky, and thus the Blue channel is the thing we normally find the most useful. If you were shooting a subject with a green screen behind them, guess which channel you’d use for selection? So you could also create actions for each of the channels to use in different lighting cases.
Why does the hoodoo look like it’s glowing at the edge? Guess where the sun is. You’re seeing a bit of the diffractive properties of light.
If you're wondering where the previous Teaching Points went, they're here.