The Lensbaby Sweet 50 is a manually-focused 50mm f/2.5 lens with the interesting ability to restrict the sharpness in an image to a localized portion of the frame. Most lenses are designed to have good sharpness from the center out to the edges and corners of the frame; those that don’t tend to get punished in online reviews (even though many images don’t really benefit from corner-to-corner sharpness). The Sweet 50, however, is designed with a different goal in mind: it is deliberately blurry away from the center. Although I’ve seen a lot of Lensbaby images that seem maliciously crafted to induce eyestrain, there are some nice images out there, too. Recently I decided I would like to give one a try. My wife thoughtfully obliged me with the Lensbaby Sweet 50 (and a Composer Pro II mount) as an anniversary gift this past August.
All lenses have a depth of field that decreases as the aperture is increased (i.e., smaller f-numbers). Sometimes this is desired to isolate a subject; sometimes this gets in the way of having enough of the scene in focus. This isn’t good or bad, it’s just reality. Well, the Lensbaby Sweet 50 takes this one step further and has what I will call width of field. At wide apertures, there is a small circle of sharpness. Whatever is within both the depth of field and the width of field will be sharp. And at the other extreme, whatever is not in either of them will be really blurred out. In addition, the blur pattern radiates outward from the central area of sharpness. Finally, this “central” area can actually be steered around the image by bending the Composer Pro II mount. That’s a lot of words; time for some examples.
I used the Lensbaby Sweet 50 with a relatively wide aperture to isolate the central flower within this cluster on a Mexican Bird of Paradise. In isolating this particular flower, it does help that it is predominantly yellow while many of its neighbors are orange. And it is also helpful that it is out in front of the others so the normal depth-of-field limits help to blur out the background. But the real keys are selecting the right aperture to give a circle of sharpness that matches the size of the flower and positioning that circle with the articulating Composer Pro II lens mount.
(Note that I will only list the aperture f-numbers approximately for this lens; since it is set manually and the lens is not electronic, the camera cannot record the aperture used in the EXIF data for any image taken with this lens. Since I don’t write the apertures down separately, I’m just taking my best guesses based on looking at the images.)
For the hanging planter image, I tilted the Composer Pro II mount so that the central spot of sharpness was near the top of the frame right where the three chains converge. The wide aperture (likely f/2.5 or f/2.8) then shrinks the sharpness zone into a tight circle. This image also highlights the radial blur pattern of the lens; notice how the lower portions of the three chains are each blurred along their length in a direction that radiates out from the focus point at the top of the frame.
I’ll wrap this post up with two more quick examples along a similar vein. There is nothing dramatically obvious about the effect in the cactus image, but the radial blur pattern gives a bit of bursting effect to the bucket image. If anything, the effect may be a bit strong here; anything more and it might start to induce a headache. That’s a good reason to always take the same image two or three times with different apertures; it can be little hard to judge the effect well in-camera.
Overall, I really enjoy the Lensbaby Sweet 50 for close details; tilting the lens to position the central spot of sharpness anywhere in the frame gives a lot of compositional freedom, which is nice. I am also looking forward to using it for portraits, too. I haven’t been too happy with anything along the lines of a landscape image, yet, although I have only tried a few exposures before giving up. I will have to be more persistent, but other tools seem more suited to that job.
One final tip. One of the Lensbaby reviews I found online complained that the aperture markings were inconveniently located on the bottom of the lens as you held the camera normally. Since the Composer Pro II has a ball and socket joint, just grab the front of the unit and twist it around the lens axis until the markings are where you want them.