Minolta AF 28-85mm F/3.5-4.5 - Photo Jottings

Minolta AF 28-85mm F/3.5-4.5

Here’s a brief look at the Minolta AF 28-85mm F/3.5-4.5  zoom lens.  Scroll down for the main review.

Minolta AF 28-85mm F3.5-/4.5
Box contents
Front and rear caps, hood, and users manual.
Available on eBay for around $100, depending on condition.
Build quality
Good, to very good
Additional information
This is the original mid 1980s model, the newer (early 90s) version has a different zoom ring pattern and a rubber grip around the focus ring, but optically is the same.
Specifications below
Optical configuration
13 elements in 10 groups
Angle of view
75°-29° full frame, 50°-19° APS-C.
7 blades, straight
Full frame and APS-C
Yes, full frame and APS-C.   APS-C equivalent, 42-127mm
Depth of field and focus scales?
Distance window, and IR marks at 28mm, 35mm, 50mm, 70mm and 85mm.
Minimum focus, image plane to subject
9.8″  (250mm)
Minimum focus, end of lens barrel to subject
3.6″  (91mm)
Hard stop at infinity focus?
Yes, but off on my copy
Length changes when focusing?
Focus ring turns in AF?
Filter size
Filter ring rotates?
Distance encoder?
Max magnification
0.12x, 0.25x with macro switch
Min. F/stop
Sony teleconverter compatible?
Length changes when zooming?
Dimensions WxL  (my measurements)
2.75″ x 3.4″   70mm x 86mm
Maximum  extended length (my measurements)
4.4″  (111mm)  includes 2mm focus extension
Weight bare (my scale)
17.5oz  (495g)  18.2oz (517g) with caps
Requisite product shots.

Side shot, drawn in, included hood not shown.
Front element.
Side view, fully extended
Backside mount.
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.
To view the original owner’s manual, go here.
The Minolta AF 28-85mm F/3.5-4.5 was one of the first few lenses Minolta came out with when they switched over to the AF mount around 1985.  I think it retailed for over $200 when introduced, which was expensive back then.  It’s built mostly of metal, the only plastic visible is the zoom ring, therefore, it’s heavy, more so than the CZ 16-80mm, or Sony 16-105mm, but has the same basic dimensions.
This lens works a little differently than most, in two ways.  It extends out and is longest when set to 28mm, and is fully retracted at 70mm, at 85mm it moves out about 1mm.  This is the same type of action as the old kit lens from Minolta, (35-70mm F/4).  Another rather abnormal feature is the macro switch, (also found on the 35-70mm F/4 just mentioned) which gives a maximum reproduction ratio of 0.25x at 28mm, (instead of the usual long-end 85mm), that’s why you have to get so close to the subject.  Also, there is no auto-focus ability when the macro switch is engaged, that’s by design, and I don’t know why.
The lens color is standard AF Minolta satin black, shinier than the Sony black.  The zoom ring tension is about right in my opinion, and doesn’t want to creep out when you walk.  There’re focal length marks at 28, 35mm, 50mm, 70mm, and 85mm.  It has a focus distance window, with a whopping five(!) infra-red focus index marks corresponding to the focal length index marks.  The EXIF data matches up with the focal length marks.  I can’t find any info about “ED” elements or special coatings used.  This lens is multi-coated and has an uncommon bluish/purple look.
Auto-focusing speed is average.  It seems to be accurate, except for the infinity mark, where it’s off a hair, focus just less than infinity for the sharpest pictures at real infinity, (your copy may vary).  Manual focusing takes just over 1/3 turn from Close-in to infinity, and will extend the barrel about 2mm at close focus.  As usual, the focus ring is very narrow and hard to grip.  These lenses were never really meant to be focused manually.
Lens flare/ghosting.  About average control for a 1980s zoom, but well below average for a twenty-first century zoom.  I see multi-color blobs if the sun is at the edge, or inside the image.  Look below for examples.  Veiling glare seems a little strong, so prepare to block the sun or other super-bright light source to keep the contrast up in your shots.  As usual, the hood really doesn’t help much, use your hand for best control.  This lens comes with a small, kit lens type hood, which is worthless.
Color fringing (CA).  Average control.  I see a very small amount of axial color fringing when using wide apertures all focal lengths, though no big deal as this type of CA goes away as you stop down.  Look for moderate amounts of lateral color fringing, (red) on APS-C cameras.  Full frame coverage yields slightly stronger lateral color fringing results, with a bluish cast in the extreme corners, see samples below.
Bokeh.  Harsh looking at all focal lengths and apertures, and similar to the Minolta 35-70mm F/4 lens.  Look below for sample crops.
Color.   Same as other Minolta lenses.
Close up filter.  Works great, a +4 tested.  Use in macro mode for best results.
Coma.  A slight amount with APS-C cameras at wide angle and F/3.5, one stop down and it’s gone.  It’s much more pronounced with full frame coverage, see photos below.
Regular filters cause no problems on APS-C cameras, but do affect full frame cameras at 28mm, see example at bottom.
Filter size is 55mm.  This is a popular size with Sony, which uses it on the 50mm F/1.4, 35mm F/1.4, 50mm macro, 100mm macro, 75-300mm, 18-70mm, and the 55-200mm.
Distortion.  You’ll notice mild to moderate barrel distortion at the wide end, and mild to moderate pincushion distortion zoomed out to 85mm using an APS-C camera.  Of course, full frame coverage shows more distortion.  Check out the images below.
Distortion examples
28mm, moderate barrel distortion.
Mild to moderate pincushion at 85mm.


Lens flare/ghosting examples


28mm F/5.6, blue and purple ghosts
85mm F/8 big red blob
28mm F/5.6, A900, sun out of picture
28mm F/8 sun centered, with blue outer ring and center smudge
28mm F/3.5
28mm F/5.6
85mm F/4.5
85mm F/5.6
coma 28mm, F/3.5
coma 28mm, F/5.6
I see multi-colored blobs when the sun is close to the edge of the frame, or inside the image. This lens has a somewhat heavy amount of veiling glare when the sun is close, or in the frame.  Shooting the sun when it’s in the center of the image results in a faint ring in the image, near the borders.  Overall, I’d day the results above are strong for todays zooms, but normal for yesterdays zooms.
Bokeh, (cropped) looks harsh at all focal lengths and apertures.
Coma.  Bottom row.  Just a small amount at wide angle, with a wide open aperture.  A stop down or so and things look good.

Aperture/focal length guide for the Minolta AF 28-85mm F/3.5-4.5  This lens has overlapping numbers, for instance; you can get F/3.5 or F/4 at 35mm, depending on tiny movements of the zoom ring, this is quite common.  Look below for guide.


Maximum aperture
Light fall-off.
See the crops below.  Light fall-off or corner shading doesn’t show up at wide angle.  Towards the long end there’s a mild to moderate amount at F/4.5, but it blends nicely towards the middle.  This is not noticeable in actual pictures.

           28mm F/3.5
             28mm F/5.6
           85mm F/4.5 
             85mm F/5.6
Center and corner sharpness.

Below are crops from the image centers at 28mm.

          28mm F/3.5
              28mm F/4.5
           28mm F/5.6
              28mm F/8


Image centers at 28mm, F/3.5 are a little soft, but sharpen up nicely at F/4.5.  I’d say F/5.6 is the sharpest for real pictures, and F/11 starts to soften due to diffraction.


Now the 28mm corner crops.


          28mm F/3.5
              28mm F/4.5
           28mm F/5.6
              28mm F/5.6 from center
           28mm F/8
              28mm F/11
The 28mm corner crops show minor improvement by closing the aperture one stop, and that’s about as good as it gets.  I show a center crop at F/5.6 for comparison.  Overall, not very good results for an APS-C camera.  Also notice the red color fringing along the rock edge.  This kind of color fringing occurs along the image periphery, and doesn’t get better by stopping down.  Notice the center crop has no color fringing.
Below, look at the 85mm centers.
           85mm F/4.5
              85mm F/5.6
           85mm F/8
              85mm F/11


The 85mm center crops show high veiling haze at F/4.5, which is a bit unusual, but improves at F/5.6.  The image sharpens up nicely at F/8-11.  I’d normally expect better results at F/5.6 than what I have here, but oh well.


85mm corners below.


           85mm F/4.5
              85mm F/5.6
           85mm F/8
              85mm F/11
The corners at 85mm aren’t much different than the centers, meaning they’re soft at large apertures, and best at F/8-11.
Let’s check out the macro capabilities of this lens.

Below, check out the 100% cropped portion of the full image.  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 a very short 3.6″ (91mm), measured from the front of the lens barrel to the subject.
This lens has a large reproduction size of 0.25x with the macro switch engaged, and produced a sharp close shot of the usual postage stamp.  F/8 was the sharpest at close focus.  The maximum reproduction size comes at the wide end, 28mm, that’s why you have to get so close to the subject.
As close as you can get. F/8. Click for larger image.


Full frame section next.


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


         28mm F/3.5
          28mm F/3.5 with UV filter attached
march2009/2885ffvigwd35.jpg march2009/2885ffvigwd35flter.jpg
         28mm F/4.5
          28mm F/5.6
march2009/2885ffvigwd45.jpg march2009/2885ffvigwd56.jpg
         85mm F/4.5
          85mm F/5.6


Light fall-off is definitely stronger with full frame coverage.  I see moderate levels at 28mm, with a hard fall-off wide open, diminishing as you stop down.  Check out the sample of additional light fall-off as a result of using a regular type UV filter, It’s a little more noticeable than normal, that’s why I’m showing it.  At the long end, there’s mild to moderate light fall-off, but it blends evenly towards the center and doesn’t show in regular pictures.


Full image from A900 below.




This boring full scene shows light fall-off from 28mm, F/3.5.  It’s noticeable, but not too bad.  In bright sunny conditions like this, you don’t have to use F/3.5, so don’t worry about this.


28mm corner samples next.


          28mm F/3.5
              28mm F/4.5
           28mm F/5.6
              28mm F/5.6 from center
           28mm F/8
              28mm F/11


The 28mm full frame corners look rough wide open, and things don’t change much until F/11.  I threw in a center shot comparison, just to show you how soft the extreme corners are.  The size differences between the center and corners are not from moving in, they were shot from the same spot, that’s just the nature of wide angle lenses, and how they render objects in the corners.  Also notice the strong color fringing, which doesn’t go away as you stop down.


85mm corners below.


march2009/2885fftelcn45.jpg march2009/2885fftelcn56.jpg
          F/5.6 from center


Again, the 85mm corners don’t look much different than the centers, and react about the same to stopping down.  Notice the blueish color fringing along the white wall on the left, and along the top, but nothing in the center crop.  Exposure differences are from light fall-off.


Distortion next.


Odd barrel distortion @28mm on A900
Pincushion distortion @ 85mm on A900


There is moderate to strong barrel distortion at the 28mm end, and moderate to strong pincushion distortion as you zoom in.  The wide angle barrel distortion is complex.  It rises in the center, and falls off quickly about 3/4 of the way out, then is nearly flat at the ends, which makes corrections harder in post processing.  The pincushion distortion is a gradual curve across the frame, and would be easy to correct.


Coma results below.


         28mm F/3.5
          28mm F/5.6
march2009/2885ffcma2835.jpg march2009/2885ffcma2856.jpg
         35mm F/3.5
         35mm  F/5.6
Coma is a problem with a fully open aperture towards the wide end with full frame coverage.  Closing the aperture a stop or so helps greatly.  Don’t worry about this unless you shoot pictures with bright points of light at the corners, in low light.

The Minolta AF 28-85mm F/3.5-4.5 is one of the original Minolta AF lenses from the mid 1980s, and is now over 20 years old.  It’s well built, with a minimum of plastic components, which makes it heavy for its size.  Overall operation is smooth, and accurate, except for the infinity focus issue mentioned earlier.


Optically speaking, this lens is just OK, nothing really stands out as being good or better than other zooms in this range.  The macro shot is sharp, with a large reproduction ratio, but with newer designed lenses, it’s only about average.  This lens shows it’s age, especially in flare and ghosting, where control is poor.  If you keep it out of the sun, and stopped down one or two stops, this lens is actually pretty good, but so are most other lenses.


For APS-C users; I’d pass on this lens, the focal range is not very desirable in my opinion, equalling 42-127mm.  I would much rather carry around the standard Sony kit lens (18-70mm), it’s smaller, lighter and far better at controlling flare and ghosting.  If you have more money, get the CZ 16-80mm, or Sony 16-105mm.  I’d even try a Minolta 24-105mm F/3.5-4.5 which might be a little more money, but will perform better, I reviewed the Sony version here.

Full frame users; the corners are pretty soft, especially at wide angle, color fringing and light fall-off are much more noticeable with the extra coverage.  I’d skip this lens for the Sony or Minolta 24-105mm F/3.5-4.5, which performs better overall, though the macro isn’t as large.
Bottom line; this lens was probably considered pretty good back in the day.  Fortunately, that day has passed and there are better choices out there now.  Although this lens may sell for less than $100 depending on condition, it’s not worth it if you have the lenses mentioned above.
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