Figure 7-26: Chromatic Aberration is what happens when the optics don’t bend all wavelengths of light by the same degree. Usually this effects telephoto lenses above 200 mm.
Figure 7-26: Chromatic Aberration is what happens when the optics don’t bend all wavelengths of light by the same degree. Usually this effects telephoto lenses above 200 mm. |
The next setting usually occurs only in telephoto lenses. As you know, optics are designed to bend light. And as you also may know, optics might also have the ability to bend light like a prism does – that is, different wavelengths get bent by different amounts (Figure 7-26). To combat this, many expensive telephoto lenses employ something called “apochromatic” glass which is designed to bend visible wavelengths by the same amount, resulting in very sharp pictures at long focal lengths. The good news is that if you don't have such a fancy lens, it is now possible to correct for this in-camera by understanding the lens' CA characteristics extremely well. And I can think of no good reason to ever turn this feature off.
The third lens correction is formally referred to as either “Pincushion Distortion” or “Barrel Distortion” (but Sony likes to just call it “Distortion”). Essentially it means that a lens will start to curve straight lines at different focal lengths. If you understand the characteristics of a specific lens (at each focal length) you can correct for it in-camera, which is what the LENS COMP.: DISTORTION mode does when it’s set to AUTO.
Interestingly, this option doesn't seem to be available for the lenses that REALLY need this feature. For example, Figure 7-27a shows the "distortion" option being greyed out for the 16-50 PZ OSS lens which all the experts say really distorts at the wide end. And yet images from the camera appear to have no significant distortion. What's going on?
Figure 7-27: Some lenses have distortion so strong that the camera forbids you from turning off in-camera distortion correction. Sony has gone one further by insisting that all Adobe products correct for it too when opening RAW files. Opening a RAW file in 3rd party raw processors let you see the lens you really paid for. |
The answer is "The camera always applies Distortion Correction to lenses like these, and you can't turn it off. What's more, Sony and Adobe have an agreement that whenever an Adobe product like Photoshop or Lightroom opens a RAW file taken with a lens with such strong known distortions, Adobe will automatically apply distortion correction to the RAW file too, and you can't disable that either.
How do I know this? Have a look at Figure 7-27c and d – these were taken with the lens zoomed out all the way, and the "brick wall" test pattern looks pretty straight via both the in-camera .jpg and the .arw file processed by Adobe Camera RAW. Now look at Figure 7-27e, which was opened with a free program called RawTherapee (www.RawTherapee.com) which has no such agreement with Sony and therefore will show you the uncorrected RAW file in all of its distortion-laden glory.
Like the other lens correction functions, I can think of no good reason to turn this feature off. (Ever.)
TIP: And speaking of the kit lens, have you ever had a hankerin’ to disassemble it and see just how complex it is? There’s a youtube video for that: https://www.youtube.com/watch?v=g9umAQ1-an4 . |
Menu Position MENU --> 
6 --> AF System
What it Does Lets you specify what kind of autofocus technology to use when an LA-EA1 or LA-EA3 A-mount adapter is attached
Recommended Setting: Phase Detect
While it’s true that the A6300 employs what’s called a Hybrid AF system (which utilizes both the older Contrast Detect AF and the newer on-chip Phase Detect AF), when you attach a Sony or Minolta A-mount lens using either the LA-EA1 (for APS-C bodies) or LA-EA3 (for APS-C or full-frame bodies) adapter, you can only choose one type of AF or the other. (This applies to other "smart" adapters as well, such as the Sigma MC-11 or the Metabones IV for the Canon EF lenses.)
Even so, when you are allowed to choose only one or the other, there are certain trade-offs you should know about:
Benefits to choosing Phase-Detect AF:
Benefits to choosing Contrast Detect AF:
TIP: When “Phase Detect” is chosen, Priority Set in AF-S mode (Section 7.22) is fixed to “AF”. That means it will only take a picture when the camera thinks it’s in focus. |
I think the main reason this feature is here is so you can see for yourself the superiority of the new on-chip Phase Detect autofocus system is compared to the older contrast-detect AF. :-)
As you might expect with a complex and nuanced feature such as autofocus, there will be some caveats and restrictions when trying to be backwards-compatible with older lenses. Here's a short list:
