Minolta AF 50mm F/3.5 Macro Review - Photo Jottings

Minolta AF 50mm F/3.5 Macro Review

Here’s a brief look at the Minolta AF 50mm F/3.5 macro lens.  Scroll down for the main review.

Lens
Minolta AF 50mm F3.5 macro
Box contents
Front and rear caps, users manual, no hood came with this lens.
Cost

Prices on eBay run about $200 as of this review.

Build quality
Good
Additional information
This lens has a reproduction ratio of only 1:2, or half life size.  Retail price was around $279 in 1999.
Specifications below
Optical configuration
5 elements in 5 groups
Angle of view
47° full frame, 32° APS-C.
Aperture
7 blades, circular
Full frame and APS-C
Yes, full frame and APS-C.   APS-C equivalent, 75mm
Depth of field and focus scales?
Distance window, and magnification scale.
Minimum focus, image plane to subject
9.1″  (231mm)
Minimum focus, end of lens barrel to subject
4.1″  (105mm)
Hard stop at infinity focus?
Yes
Length changes when focusing?
Yes
Focus ring turns in AF?
Yes
Filter size
55mm
Filter ring rotates?
No
Distance encoder?
No
Max magnification
1:2 or 0.50x
Min. F/stop
F/32
Sony teleconverter compatible?
No
Dimensions WxL  (my measurements)
2.6″ x 2.2″   66mm x 55mm
Maximum  extended length (my measurements)
3.2″  (81mm)
Weight bare (my scale)
8.4oz  (240g)  9.2oz (261g) with caps
Requisite product shots.

September2009/5035boxzm.jpg
Box and contents
September2009/5035sd2.jpg
Side shot fully drawn in
September2009/5035sdexzm.jpg
Side view, fully extended
September2009/5035ftzm.jpg
Deep front element.
September2009/5035bk22.jpg
Rear mount and contacts.
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 terms and methods used in this review, go here.
The Minolta AF 50mm F/3.5 macro was introduced in the mid 1990s, and was a less-expensive alternative to the Minolta AF 50mm F/2.8.  What made it less expensive was the smaller maximum aperture, maximum reproduction ratio of half life size (1:2) instead of full life size (1:1), and lighter build quality, meaning lots of plastic.  It’s put together well though, and functions properly, as it should.
This lens has the typical look of Minolta AF restyled lenses all through the 1990s.  It’s satin black, similar to the original Sony black, with a wider rubber focus grip ring, and also a different type of rubber barrel grip.  It has the standard prime lens focus distance window, with two depth of field hash marks at F/32 and F/16.  The blue numbers around the focusing ring indicate the level of magnification, 1:2 is half, 4 is 1:4, 7 is 1:7 etc.  The EXIF data reads the proper 50mm.  I can’t find any info about “ED” elements or special coatings used.  Official information from Konica Minolta states this lens has a circular aperture, but heptagons (seven bladed aperture) show up in bokeh about one stop down, which indicates the blades do not form a very good circle.  True circular apertures should be round at least one stop down.  Oh well, this is not something to lose sleep over, the bokeh, or background blur is not very smooth anyways.  This lens is multi-coated and has the common for the era purple/green look.
Focusing.  Manual focusing is easy and properly dampened.   Manual focusing takes just over 1/4 turn from Close-in to infinity, but does add about 1″ or 26mm to the length of the lens.  Auto-focusing is not very fast, but adequate, and accurate.  Note; don’t use auto-focus when shooting things up-close, use manual focus and move the camera back and forth to get the proper focus.
Lens flare/ghosting.  Odd blue/green ghost when sun is in shot, otherwise good control.  See sample images below.
Color fringing (CA).  Excellent control.  In normal pictures there is none to be found.
Bokeh.  Fairly harsh looking.  The aperture shape starts to show up about a stop down.  Look below for sample crops.
Color.   Same as other Minolta lenses.
Coma.  No Coma on either APS-C or full frame cameras.
Regular filters cause no additional light fall-off problems on APS-C cameras, but do affect full frame cameras at F/3.5, see example farther down in review.
Filter size is 55mm.  This is the most popular with Sony, and allows you to swap filters with both Sony macro lenses, the Sony 50mm F/1.4, 35mm F/1.4, DT 18-55mm, DT 18-70mm, 55-200mm and the 75-300mm.
Distortion.  Excellent control, and flat with both APS-C and full frame cameras.
Distortion example directly below.
September2009/5035dis.jpg
50mm, flat.

 

Lens flare/ghosting examples

 

F/5.6, unusual color ghost
F/5.6 sun centered, no problems
September2009/5035gst1.jpg
September2009/5035gst2.jpg
50mm F/3.5 bokeh
50mm F/5.6 bokeh
September2009/5035bok35.jpg
September2009/5035bok56.jpg
I see a funny blue/green blob when the sun is inside the image. I’ve never seen this color before, weird!  Other than that, flare and ghosting are controlled quite well, and would not be a concern in normal shooting.
Bokeh, (cropped) looks harsh even wide open.  Heptagons are clearly visible at F/5-5.6.  Sony macros show a somewhat smoother bokeh, see comparisons below the stamp shot.

 

Light loss at high magnification.

 

Here are the approximate F-numbers or light loss you will get as you increase the magnification, assuming the same exposures at each setting in the table below.  The numbers in the table come from simple observation, they will not be indicated on the camera LCD, and will still read F/3.5 even at 1:2 magnification, though when you look at your shutter speeds you’ll notice the loss.  This is for your information only, so just shoot away, the camera will adjust your exposures automatically.  I’m simply providing this in case you’re wondering why your shutter speeds are so low when the LCD says F/3.5.  For instance, if you’re shooting at infinity focus, F/3.5, with a shutter speed of 1/250sec, at full 1:2 magnification your shutter speed would decrease to around 1/100sec, or an equivalent of one and a third stops of light loss.

 

 

Magnification
F-number
3.5
1:10
4.0
1:4
4.5
1:2
5.6
Light fall-off.
See the images below.  Light fall-off or corner shading is not noticeable in real pictures at any focal length or aperture using an APS-C camera.

           50mm F/3.5
             50mm F/5.0
September2009/5035vigf35.jpg
September2009/5035vigf50.jpg
Center and corner sharpness.

Below are crops from the image centers and corners.

         F/3.5 center
          F/3.5 corner
September2009/m5035ctr35.jpg
September2009/m5035cn35.jpg
         F/4.5 center
          F/4.5 corner
September2009/m5035ctr45.jpg
September2009/m5035cn45.jpg
         F/5.6 center
          F/5.6 corner
September2009/m5035ctr56.jpg
September2009/m5035cn56.jpg
         F/8 center
          F/8 corner
September2009/m5035ctr80.jpg
September2009/m5035cn80.jpg
         F/11 center
          F/11 corner
September2009/m5035ctr11.jpg
September2009/m5035cn11.jpg
         F/16 center
          F/16 corner
September2009/m5035ctr16.jpg
September2009/m5035cn16.jpg
The center crops show slight veiling haze wide open at F/3.5, though sharpen up nicely at F/4.5, and stay sharp almost to F/11, then diffraction shows at F/16, which is normal.  The corners are a different story.  At F/3.5, they’re quite soft, but improve much a little over one stop down, at F/5.6.  Corner sharpness improves up to F/8, where the centers and corners are nearly the same in sharpness.
Let’s check out the macro capabilities of this lens.

Below, check out the 100% cropped portion (1.1mb) of the full image.  The sample shot was taken with the Sony A 700 12.2MP camera.  The subject is a standard US stamp, 0.87″x 1.0″ or 22mm x 25mm.  Also, note the macro shot was taken as close to the subject as focusing allowed; in this case a short 4.1″ (105mm), measured from the front of the lens barrel to the subject.
This lens has a large reproduction size of 0.50x or 1:2 (half macro), and produced a very sharp close shot of the new postage stamp.  F/5.6 was the sharpest at close focus, but F/8 looked very good also.  As a side note; the “1996” on the bottom left of the stamp measures a mere 1mm wide.
As close as you can get. F/5.6 Click for larger image.

 

 

 

Special bonus section with comparisons to the Sony 50mm F/2.8 macro

 

 

     Sony 50mm F/2.8 @F/3.5 center
     Minolta AF 50mm F/3.5  @F/3.5 center
September2009/5028ctr35cmp.jpg
September2009/5035ctr35cmp.jpg
     Sony 50mm F/2.8 @F/3.5 corner
     Minolta AF 50mm F/3.5  @F/3.5 corner
September2009/5028cn35cmp.jpg
September2009/5035cn35cmp.jpg
     Sony 50mm F/2.8 @F/5.6 center
     Minolta AF 50mm F/3.5  @F/5.6 center
September2009/5028ctr56cmp.jpg
September2009/5035ctr56cmp.jpg
     Sony 50mm F/2.8 @F/5.6 corner
     Minolta AF 50mm F/3.5  @F/5.6 corner
September2009/5028cn56cmp.jpg
September2009/5035cn56cmp.jpg

 

The Sony 50mm F/2.8 macro lens is on the left, the Minolta AF 50mm F/3.5 on the right.  The centers and corners are clearly sharper on the Sony at F/3.5, but are much closer in comparison at F/5.6.  This is to be expected, as the Minolta was intended as a less expensive alternative to the fast F/2.8 macro available at the time.  When they make a cheaper or slower version, they usually have to compromise optical and mechanical quality at some point.  The Minolta does a good job, and the sharpness differences would not be noticeable unless cropped and displayed side-by-side at huge sizes as you see here.  In the film days, this lens’ optical quality was probably indistinguishable from the more expensive F/2.8 model, that’s just the predicament with digital.  Test shots done with the Sony A700.

 

Bokeh comparisons next.

 

     Sony 50mm F/2.8 @F/3.5 bokeh
     Minolta AF 50mm F/3.5  @F/3.5 bokeh
September2009/5028bokcmp35.jpg
September2009/5035bokcmp35.jpg
     Sony 50mm F/2.8 @F/5.6 bokeh
     Minolta AF 50mm F/3.5  @F/5.6 bokeh
September2009/5028bokcmp56.jpg
September2009/5035bokcmp56.jpg

 

The bokeh characteristics are similar, but the Sony is slightly smoother at the same apertures.  Also, the Sony is a little smoother yet at F/2.8, which is obviously not available on the Minolta.  I thought the Sony bokeh would be much better before I made a direct comparison with the Minolta, and found the differences small.

 

 

Full frame section below.

 

 

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

 

         50mm F/3.5
          50mm F/3.5 with regular filter
September2009/5035ffvig352.jpg September2009/5035ffvig35flt.jpg
         50mm F/5.0
          50mm F/5.6
September2009/5035ffvig50.jpg September2009/5035ffvig56.jpg

 

Light fall-off is stronger with full frame coverage.  I see moderate levels wide open, diminishing greatly just one stop down.  Check out the sample of additional light fall-off as a result of using a regular type UV filter, just stop down a little more to get rid of this.

 

Full image from A900 below.

 

September2009/5035ffoverz.jpg

 

This full frame F/3.5 full shot illustrates the disparity between test charts and real world results.  I don’t see any light fall-off here, I’m only admiring the Orange King Bougainvillea.

 

Corner samples next.

 

     F/3.5
     F/5.6
September2009/5035ffcn35.jpg
September2009/5035ffcn56.jpg
     F/8
     F/5.6 from center
September2009/5035ffcn80.jpg
September2009/5035ffctrcn56.jpg
     F/11
     F/16
September2009/5035ffcn11.jpg
September2009/5035ffcn16.jpg

 

The corners show very soft with full frame coverage, and don’t sharpen up even close in comparison to the centers.  F/8-16 corners seem to be the sharpest, F/11 best.  Exposure differences are from light fall-off.

 

Distortion next.

 

September2009/5035ffdis.jpg
No distortion on A900

 

There is no noticeable distortion, even with full frame coverage.  This lens has excellent control of distortion, and is about as flat as you’re going to get.

 

Conclusion. 

This little inexpensive macro lens is pretty darn good.  It has very good control of distortion, color fringing and coma.  Average items include ghosting, bokeh, and wide open center sharpness.  Sub-par characteristics only show themselves using full frame coverage, and include very soft corners and light fall-off, though not really noticeable in normal shooting as seen above.  Back in the film days when this lens was designed, it probably produced the same results as the more expensive F/2.8 version because people didn’t blow their pictures up to poster size like they do now on the computer screen and compare image crops side-by-side.  The only real down side to this lens is the current eBay selling price, which is quite high, around $200.  I guess some people are drawn to the somewhat scarcity of the lens, or they’re suckered into thinking this lens is the best macro Minolta ever produced, as a result of dubious review methods from lens forum members.  Also consider the late model Minolta AF or Sony 50mm F/2.8 macro which are more expensive, but are full life size, and include a focus hold button and focus limiter switch.

 

For APS-C users; this lens performs very well, and would be especially useful as a pocket field macro, where half life size is about all you can reasonable get without a tripod or other means of camera support, and gives a decent 4.1″ or 105mm of working distance.  Consider the newSony DT 30mm F/2.8 macro, which I like better.

 

Full frame users; I’d pass on this lens and go for the slightly more expensive, later model Minolta AF 50mm F/2.8 full size macro (or more expensive Sony version here), where the corners are much sharper, and light fall-off using filters isn’t much of a problem.

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