As long as you don't expect perfect zones of sharpness every time, the Lensbaby Spark is a fun and educational lens.
Lori Grunin
I've been reviewing hardware and software, devising testing methodology and handed out buying advice for what seems like forever; I'm currently absorbed by computers and gaming hardware, but previously spent many years concentrating on cameras. I've also volunteered with a cat rescue for over 15 years doing adoptions, designing marketing materials, managing volunteers and, of course, photographing cats.
The area of focus can look very sharp when scaled down, but usually it's a bit soft viewed at 100 percent. And it's small, too: I couldn't ever get both eyes in focus, even with tiny little kitten faces.
(1/100 sec, ISO 200, evaluative meter, AWB, Speedlite 580EX flash, Canon EOS 7D)
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Control
Even at f5.6 the depth-of-field is relatively small, so any slight shift of the lens or camera (in this case, the subject) can end up with the incorrect area of focus. Like the bridge of Potter's nose instead of his eyes.
(1/80 sec, ISO 200, spot meter, AWB, Speedlite 580EX flash, Canon EOS 7D)
3 of 7Lori Grunin/CNET
Sharpness
This is the typical level of sharpness I got out of the lens. This is using the T4i's default color and sharpness settings.
(1/100 sec, ISO 100, spot meter, AWB, Canon EOS Rebel T4i)
4 of 7Lori Grunin/CNET
Bokeh
For an $80 f5.6 lens, it has lovely out-of-focus hightlights. That's because it has a round, bladeless aperture. It's great for cases like this, where the background is busy or ugly.
(1/80 sec, ISO 200, spot meter, AWB, Speedlite 580EX flash, Canon EOS 7D)
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Focus
Lensbabies are good for situations like this, where the area of focus you want isn't circular; it's diagonal, vertical, or horizonal.
(1/60 sec, ISO 100, spot meter, AWB, Canon EOS Rebel T4i)
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Focus
Another example of selective focus.
(1/100 sec, ISO 400, -2/3 stop EV, spot meter, AWB, Canon EOS Rebel T4i)
7 of 7Lori Grunin/CNET
Brightness
The lens may be inexpensive, but it's not cheap; it transmits a fair bit of light.
(1/100 sec, ISO 400, -2/3 stop EV, spot meter, AWB, Canon EOS Rebel T4i)