Thursday, July 24, 2014

Do All 24mm (equivalent) Kit Lens Vignette?

For those that don't know, what is vignette or vignetting?

"In photography and optics, vignetting (/vɪnˈjɛtɪŋ/; French: "vignette") is a reduction of an image's brightness or saturation at the periphery compared to the image center.

Vignetting is often an unintended and undesired effect caused by camera settings or lens limitations. However, it is sometimes deliberately introduced for creative effect, such as to draw attention to the center of the frame."  - Wikipedia

In general, a good lens should not vignette or at least show minimum darkening of the image corners.

The picture above with heavy vignetting was taken with a Sony A6000 and kit lens at it's widest zoom setting of 24mm (equivalent).

This APS-C format large sensor compact came with a16-50mm (24-75mm eqv) kit lens.

That picture sure showed very heavy vignetting, luckily, if necessary, the darkened corners can be corrected with many graphics program.

 As a consolation; this optical deficiency is invisible in most outdoor shots.

Canon, however; I found out by accident, did her trick differently...

To satisfy her grumbling G1X fanboys, Canon up the ante and equipped their Mk2 with a much wider 24-120mm f/2-3.9 zoom lens.

While testing the Canon G1X Mk2, I took a 24mm (eqv) shot of this busy "yum cha" scene at the Dragons Restaurant in downtown Wellington.

I remember, after previewing my result on the LCD rear screen; I was cursing myself that I should have shifted my composition more to my left to include the other "trolly girl".

Once home, at my iMac; I "quick view" (by selecting the thumbnail and hitting the space bar, eat your heart out, PC!) my shots one by one.

When I got to the shot above, the JPEG version looks exactly like what you see above.  The RAW (I always shoot both), however; was a different story! See below...

WOW! The D1X Mk2 24mm lens setting actually can cover a wider view!

I estimated at least a 20mm lens coverage!

No doubt there are vignetting on the corners, but they are NOT unpleasant. As a matter of fact, they actually made the composition better!

The moment I saw that composition in quick view, I double click and launch the file in Adobe Camera Raw and guess what...

The file opened to the composition just like the JPEG version, MINUS the left trolly girl!

Why can't I open it like I see it, in quick view?

My conclusion was that, Canon has build in some instructions to all images produced by G1X Mk2, (RAW and JPEG) at the instance when the files open; to automatically getting rid of the vignettes by cropping, !

More out of the box thinking and I reckon I will be able to open the "un crop" RAW file by using Preview (OSX application) and IT DID!

I export the unadulterated RAW image to a 16 bit TIFF file without problem!

Eat your heart out Canon ;)

 This is the adjusted version, the dark vignettes have been lightened and more details appear overall. I like it!

My little Lumix GM1 with 24mm setting on its kit zoom has no vignetting problem in RAW format, or did the camera correct the light fall off in-camera?
This is from the Canon G1X Mk2 RAW file, open in Preview, retaining the heavy vignetting.
The same G1X Mk2 file, open with ACR, the vignettes are automatically cropped.
Famous Last Words...

Optical vignetting occurs in all lenses, it is an optical phenomenon; nothing wrong with the lens!

Depending on the optical design of the lens, vignetting  can be quite strong on some lenses, while hardly noticeable on others.

There is an excellent article on this subject, here; good read!

But then not every photographers accept that fact, Sony and Canon should have hide the light drop off of their kit lens better ;)

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