Here's a brief look at the Sony 50mm F/2.8 macro lens.  Scroll down for the review. . Lens SAL-50M28  Sony 50mm F/2.8 macro Box contents Front and rear caps, and a users manual. Cost $624 retail Build quality Very good Additional information Has focus hold button and focus limiter switch.  Less money, smaller and lighter than the 100mm macro, but has a shorter working distance, which some folks may not like. Specifications below   Optical configuration 7 elements in 6 groups Angle of view 47° (full frame)  32° (APS-C) Aperture 7 blades, circular Full frame and APS-C Yes, made for full frame.   APS-C equivalent, 75mm Depth of field and focus scales? Yes and yes Minimum focus, image plane to subject 7.8"  (198mm) Minimum focus, end of lens barrel to subject 1.9"  (48mm) Hard stop at infinity focus? No Length changes when focusing? Yes Focus ring turns in AF? Yes, but has clutch. Filter size 55mm Filter ring rotates? No Distance encoder? Yes Max magnification 1:1 Min. F/stop F/32 Sony teleconverter compatible? No Dimensions W x L (my measurements) 2.9" x 2.4"   73mm x 60mm, protrusions add an extra 2mm to width Maximum  extended length (my measurements) 4.2"  (106mm)                                                       Weight bare (my scale) 10.1oz  (288g)  11oz (312g) with caps Requisite product shots. Box and contents. Fully extended. Deep front element. Backside. Focus limiter and focus hold buttons. Sony X-ray view and MTF chart The Sony A700, and A900 were used for this review.  For full frame results, go to the bottom of the page.  For a better understanding of my review methods and terminology, go here.   The Sony 50mm F/2.8 macro lens (made in Japan) is very compact, but extends out another 1.9" (46mm) at full macro.  It's nicely made, but lots of plastic.  The finish is satin black.  Filters are 55mm.  The lens is multi-coated, with the usual green/magenta look.  It has a 7 blade circular aperture as opposed to the 9 blades of the Sony 100mm macro lens. The lens has the focus distance window with standard markings for FT/M, and DOF marks at F/16-32.  It has magnification levels from 1:1 to 1:4 written on the extended lens barrel.  Other useful items include a focus hold button, which can be changed to DOF preview on select Sony camera bodies, and a focus limiter switch, full, for focusing over the full range, and limited, which has two ranges: close range is about 2" to 5.5" (51mm-140mm), far range is about 6" (152mm) to infinity.  This helps speed up focus, but don't use auto focus for extreme close ups, manually focus on the subject and move the camera back and forth until you've got a sharp subject.  The figures above are for end of lens barrel to subject distances.   The Sony focuses quickly and accurately, though plan on using manual focus for super macros, read above.  The lens has a focus ring clutch, which means the ring turns as it focuses, but if you hold it, it won't turn.  It takes about a manual half turn from close-in to infinity focus. It has the usual loud focusing sound typical of Minolta/Sony which has the focus motor in the camera body, unless it's an SSM, this one isn't.  The Sony 50mm macro has a short 1.9" (48mm) distance from the front of the lens barrel to the subject at close macro.  That's about 4.2" (105mm) closer than the Sony 100mm macro.  The extra distance is good to keep shadows out of the frame, but that's at maximum macro, and not everyone will need to be that close.   Lens flare/ghosting.  No real problems here, although there is a pesky green blob that shows up when the sun is in the image, but not in the center.  Center shots look fine.  There's an average amount of veiling glare when the sun is just outside the frame.  Use your hand to eliminate this.  Additionally, the lens has plenty of recess for the front element, acting as a built-in hood.    Color.  Looks the same as other Sony lenses.   Coma.  None.    Filter size 55mm.  This is the most popular size for Sony, other lenses using it are: 35mm F/1.4, 50mm F/1.4, 100mm F/2.8 macro, 18-70mm, 75-300mm and the 55-200mm.   Filter use.  No additional vignetting using a regular filter, even on full frame.    Color fringing is very light, and poses no real problems.  At F/2.8 in very harsh dark/bright flanking conditions, it has some purple color fringing at F/2.8, but that goes away about one stop down.  This lens is one of Sony's best for controlling color fringing.     Bokeh.  Nice and smooth, and very similar to the Sony 100mm F/2.8 macro.   Random samples below.           Sun in shot, F/5.6          Sun centered, F/5.6         Bokeh,  F/2.8          Bokeh,  F/4   On top we have some ghosting, but it's very light, with a green blob showing up at certain angles.  With the sun centered, everything looks fine.    Lower crops show bokeh, which looks decent here, and seems about the same at both apertures.    Distortion.  Very good job, so there's nothing here.  If you like to look at your pictures with a grid overlay, you'll see very slight pincushion distortion.   Very minor pincushion distortion. Light fall-off, (directly below) is not noticeable with APS-C sensor cameras.                   F/2.8             F/4   Light loss at high magnification.    Here are the approximate F-numbers you will get as you increase the magnification, the table below is from the Sigma 105mm F/2.8 DG macro, but is close to the Sony model.  I modified it slightly for this lens.  Sony lists exposure compensation in the owners manual, but it's not nearly as clear as the Sigma table.  These numbers will not be indicated on the camera, and will still read F/2.8 even at 1:1 magnification, but look at your shutter speeds and you'll notice the loss.  This is for your information only, so just shoot away, the camera will adjust your exposure automatically.  I'm simply providing this in case you're wondering why your shutter speeds are so low when the LCD says F/2.8.   Magnification F-number 1:22 2.8 1:4 3.3 1:3 3.8 1:2 4.2 1:1.5 4.7 1:1.2 5.1 1:1 5.5   Below, check out the corner softness, lower left. You'll see a little corner softness at wide apertures, but it's doesn't show in regular pictures.  It gradually sharpens up 'till F/8.               F/2.8             F/4             F/5.6             F/8 Here are some center crops for comparison.  Look below for an explanation.              F/2.8             F/4 The two shots above are from the center of the image.  The Sony 50mm F/2.8 macro is darn sharp, even at F/2.8.  It does sharpen up at F/4, but it's no sharper at F/5.6 or F/8 when looking at regular pictures.  It softens at F/11 due to diffraction.  Look at the dumb shot at F/2.8 in broad daylight, 1/1250s ISO 100!  In low light F/2.8 looks great.   Maximum sharpness for close objects like the stamp below is F/8.  Requisite macro paragraph.  As with all 1:1 life size macros, sometimes it can be a little tough to focus, and a tripod is highly recommended, especially if you go full size.  Hand held macro field shooting is limited to 1:2 in my opinion, any more and you'll likely fill up a 16GB memory card trying to get a decent shot.  At F/4 the depth of field is razor thin, at F/16 you  lose your shutter speed, so some extra though is required before your photo session begins.  I often have to bump up the ISO to get a sharp picture with hand-held shooting.  Even on a bright sunny day you'll be surprised at how low your shutter speeds are, and with jittery hands it's all the worse.  If you like to compare shots from other lenses and cameras, don't be too critical about it at 100% screen size.  Getting a uniformly sharp image from a flat object like my stamp is very difficult, especially when it's a full 1:1 macro.  I use the stamp so you will know about how big an area is covered, and get an idea of the sharpness.  Keep this in mind when viewing the macros. Macro shot.   Below, check out the sample and click the picture to see it full size (1.9mb, large file) it may have been cropped or straightened to reduce size.  The sample shot was taken with the Sony A 700 12.2mp camera.  The subject is a standard US stamp, 1"x 3/4" or 25.4mm x 19mm.  Also, note the macro shot was taken as close to the subject as focusing allowed; In this case, about 1.9" or about 48mm, measured from the front of the lens barrel to the subject. Full 1:1 macro shot 1.9mb F/8   The Sony 50mm F/2.8 macro produced a very nice macro shot, coming in sharpest at F/8, but there was little difference between F/5.6-11.     Full frame results using the Sony A900 below.   Check out the differences when using a film or full frame camera below.  I'm only pointing out the noticeable issues as compared to the APS-C bodies, so if I don't show it here, the results are not significantly different enough to warrant posting an additional set of images in this section.   Light fall-off             F/2.8           F/4   Light fall-off is a reality with full frame coverage.  At F/2.8 it's heavy, and noticeable in real shots, but one stop down and things change dramatically for the better.  The corners don't lighten up any further by stopping down past F/5.6.   Full image from A900 below.     The dark corners are noticeable here, and as usual, the perceived severity depends on subject placement and background.  This shot was F2.8, ISO 200, 1/5000sec.  As always, don't shoot normal landscape scenes at F/2.8.  I think this scene looks just fine as it is, even though it isn't all that interesting.   Corner samples next.            F/2.8           F/4          F/5.6           F/8   The corner sharpness is about the same as the APS-C crops show.  The corners are their absolute best at F/8, but look fine wide open.  The exposure differences are from light fall-off.   Distortion.   Mild pincushion distortion on A900   This lens produces a small amount of pincushion distortion, and results are similar to the APS-C image.    .   Conclusion. The Sony 50mm F/2.8 macro is a very good lens.  It's sharp through F/2.8 to F/11, very sharp from F/4-8.  Color fringing is basically non-existent.  It focuses good, though keep it on manual up close.  The main differences in the Sony 100mm F/2.8 macro and the Sony 50mm F/2.8 macro are; the 50mm is smaller, lighter, less expensive, sharper at F/2.8 and has much better CA control.  The 50mm has a lens barrel to subject distance at maximum macro of only 1.9" (48mm) as opposed to the 100mm macro at 6.2" (157mm) distance.  Normally, close working distances will bring you problems with shadows on your subject from the lens, although some people won't get that close so they won't be bothered by this.  If you shoot a lot of really close macros, you might want to get the 100mm.  In my opinion, for most people, the 50mm macro makes more sense when factoring in all the previously mentioned items, and considering you'll save a lot of money over the 100mm macro.  The Sony 50mm F/2.8 macro is a good lens to put in a bag or your pocket when you're on a hike or vacation.     APS-C users;  also consider the Tamron 60mm F/2 macro, which offers more working distance (4" or 101mm), and a wider aperture for hand-held available light shots.  If you want something real small for your pocket, check out the Sony DT 30mm Macro lens.   For full frame users; this lens performs about the same as APS-C coverage, just factor in more light fall-off wide open.