Minolta AF 70-210mm F/4 Review - Photo Jottings

Minolta AF 70-210mm F/4 Review

Here’s a brief look at the Minolta AF 70-210mm F/4 telephoto zoom lens.  Scroll down for the main review.

Lens
Minolta AF 70-210mm F/4
Box contents
Front and rear caps, hood, nice hardcase and users manual.
Cost
$229 retail in the 1980s, now hundreds available on eBay for less or more than that depending on condition.
Build quality
Very good
Additional information
Well built and cheap eBay prices for this F/4 zoom
Specifications below
Optical configuration
12 elements in 9 groups
Angle of view
34°-12° full frame, 23°-8° APS-C.
Aperture
7 blades, straight
Full frame and APS-C
Yes, full frame and APS-C.   APS-C equivalent, 105-315mm
Depth of field and focus scales?
Distance window, and IR marks at 70mm, 100mm, and 210mm.
Minimum focus, image plane to subject
42″  (1.07m)
Minimum focus, end of lens barrel to subject
34.5″  (876mm)
Hard stop at infinity focus?
Yes
Length changes when focusing?
Yes
Focus ring turns in AF?
Yes
Filter size
55mm
Filter ring rotates?
Yes
Distance encoder?
No
Max magnification
0.25x
Min. F/stop
F/32
Sony teleconverter compatible?
No
Length changes when zooming?
No
Dimensions WxL  (my measurements)
2.8″ x 6″   72mm x 152mm
Maximum  extended length (my measurements)
6.6″  (168mm)
Weight bare (my scale)
24.5oz  (693g)  25.2oz (715g) with caps
Requisite product shots.

Aug08/70210box5.jpg
Box contents with no box
Aug08/70210ft2.jpg
Front element.
Aug08/70210sdex2.jpg
Side view, with focus extention
Aug08/70210bk2.jpg
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 the review methods and terminology, go here.
To view the original owner’s manual, go here.
The Minolta AF 70-210mm was very popular with the old Maxxum film users, and now, thanks to eBay, Sony users.   This telephoto zoom is long, but doesn’t extend out when zooming, and has a constant fast aperture of F/4.  Currently, Sony has no equivalent lens, the closest lens in the Sony lineup would be the very inexpensive DT 55-200 F/4-5.6, which isn’t for full frame cameras.  I’d say the best lens to compare the Minolta to is the Sony 75-300mm F/4.5-5.6.  Look for a few comparisons in the review.  The color is satin black, shinier than the Sony black.  The zoom ring tension is about right to slightly loose in my opinion, and my copy has seen little use, so it’s not worn out.  It was purchased in 1986 and used once up until a couple of years ago.  I’ve used it several times recently.  It has a focus distance window, with three infra-red focus index marks at 70mm, 100mm, and 210mm, you don’t see this much anymore.  The EXIF data doesn’t match up with the focal length marks.  At 70mm, data reads 75mm, 100mm reads 105mm, 150mm reads 160mm, and 210 reads a correct 210mm.  This is no big deal if you check your lens, and record it.  Maybe other copies of this lens reads differently.  I can’t find any info about “ED” elements or special coatings used.  This lens is multi-coated and has the typical older-style magenta cast.
Auto-focusing is a little slow and loud, but seems accurate.  Manual focusing takes just over 1/3 turn from Close-in to infinity.  The focus ring extends as you turn it, which is part of the lens barrel, so it makes manual focusing a little awkward, but it still works well.
Lens flare/ghosting.  Average to below average control, just as distracting (but different) as the Sony 75-300mm.  Check out the boring shots below.  You normally don’t need to shoot into the sun with a telephoto lens, unless taking pictures of the (rising or setting) sun, in which case if it’s dead center, there’s not much of a problem.  The hood that came with this lens is plastic.  Some online reviewers are stating metal, but I think only a few very early copies had a metal hood.  My plastic hood is original to the lens when purchased in 1986.
Color fringing.  Strong near the end of the zoom looking at white roof tops against dark A/C units enlarged on my computer screen.  Less at 70mm.  About the same as the Sony 75-300mm.  I also see some Longitudinal color fringing at all focal lengths, and fortunately this type of CA goes away as you stop down.  It’s almost all gone by F/8-11.
Bokeh.  Smooth over the full range, but a little less so around 70mm, much the same as Sony telephoto zooms.
Color.  Similar to Sony lenses.
Close-up filter use is limited to 70mm or slightly longer with a +4.
Regular filters cause no problems on full frame or APS-C cameras.
Filter size is 55mm.  Sony uses this size on many lenses such as the: 75-300mm, 50mm F/2.8 macro, 100mm F/2.8 macro, 35mm F/1.4, 50mm F/1.4, 18-70mm kit lens and the 55-200mm zoom.
Distortion.  Barrel at 70mm, but very mild, then towards the long end it turns to mild pincushion.  If you like looking at your pictures with a grid overlay you might see it on the outer portions of the image containing straight lines.  It’s not a big deal, and you don’t see it in regular pictures.  Distortion performance is nearly the same as the Sony 75-300mm F/4.5-5.6.  Look below for examples.
Distortion examples
Aug08/70210brl.jpg
70mm, very mild barrel distortion.
70210pin.jpg
Mild pincushion at 210mm.

 

Lens flare/ghosting examples

 

70mm F/5.6
70mm F/4.5
october08/70210gstoff.jpg
october08/70210gstoff2.jpg
210mm F/4
210mm F/5.6
September2009/5670210tel40z.jpg
September2009/5770210tel56z.jpg
70mm F/4
70mm F/5.6
october08/70210ffbokw40.jpg
october08/70210ffbokw56.jpg
70mm F/4 “swirling” bokeh
70mm F/5.6 “swirling” gone
october08/70210ffswlboktel40.jpg
october08/70210ffswlboktel56.jpg
Sun flare and ghosting occurs when a bright light or the sun is off-center in the image.  I see the usual amount of veiling glare when the sun is just out of the frame.  You can help control this problem by using your hand to shield the lens.  When the sun is in the image, you’ll get multi-colored blobs towards the 70mm end, and a large blob at the long end.  Shooting the sun when it’s in the center of the image results in a faint haze around the sun.  Dark backgrounds and foregrounds exacerbate problems with flare and ghosting, such as the examples above.
Bokeh, middle rows, (cropped) looks smooth, but not the smoothest I’ve seen.  I like the look of F/5.6 near 70mm, and F/4 near 210mm, heptagons show up at F/5.6 at 70mm.  The last row (full images) shows a “swirling” bokeh at the long end and F/4.  This is caused by a flattening of the highlights around the image periphery, where the flat, long side is always facing the center.  Think of the shape of an American football instead of circles.  Stopping down gets rid of this look.
Light fall-off.
See the crops below.  Light fall-off or corner shading is mild at F/4 and 70mm, what little there is blends nicely towards the middle, at the long end it’s moderate, but one stop down and there’s nothing to worry about.

           70mm F/4
             70mm F/5.6
Aug08/70210f4lfw.jpg
Aug08/70210f56lfw.jpg
           210mm F/4 
             210mm F/5.6
Aug08/70210f4lfL.jpg
Aug08/70210f56lfL.jpg
Center and corner sharpness.

Below are crops from the image centers at 70mm.

              70mm F/4
           70mm F/5.6
Aug08/7021040actrw.jpg
Aug08/7021056actrw.jpg

 

Now the 70mm corner crops.

 

           70mm F/4
              70mm F/8
Aug08/70210cn40w.jpg
Aug08/70210cn80w.jpg
The 70mm center and corner crops show very little improvement by stopping down, that’s not necessarily good or bad.  I see some axial color fringing present in the center crops.  Stopping down will help eliminate axial color fringing; it’s mostly gone by F/5.6-8.  The F/8 centers looked about the same as F/5.6, however, F/11 was a little soft.
Below, look at the 210mm centers.
 F/4
Aug08/70210ctr40L.jpg
F/5.6
Aug08/70210ctr56L.jpg
F/8
Aug08/70210ctr80L.jpg
F/11
Aug08/70210ctr11L.jpg

 

210mm corners below.

 

           210mm F/4
              210mm F/8
Aug08/70210cn40L.jpg
Aug08/70210cn80L.jpg
Obvious here is the difference in sharpness in the centers between F/5.6 and F/8.  Also notice the color fringing disappears as you stop down, but only in the centers.  F/8-11 is the sharpest at 210mm, including the close macro shot below.  In the corners, directly above, we don’t see any change in sharpness by stopping down, but at 210mm, color fringing is strong, and stopping down doesn’t do anything with color fringing along the sides and corners.  The F/4 corner crop is darker because of light fall-off, which can make the image appear sharper.
Let’s check out the macro capabilities of this lens.

Below, check out the sample and click the picture to see a 100% cropped portion of the full image, (314kb file).  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 horrendously long 34.5″ (876m), measured from the front of the lens barrel to the subject.
The macro (F/8) is pretty sharp and detailed with 0.25x magnification.
As close as you can get macro, at F/8.

 

Now the full frame results.

 

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

 

         70mm F/4
          70mm F/5.6
october08/70210ffvigw40.jpg october08/70210ffvigw56.jpg
         210mm F/4
          210mm F/5.6
october08/70210ffvigtel40.jpg
october08/70210ffvigtel56.jpg

 

Light fall-off is worse than the APS-C crops shown earlier.  At 210mm, F/4 shows a little heavy, but extends evenly towards the center, and isn’t all that noticeable in real shots, see image below.

 

Full image from A900 below.

 

october08/70210fffnover.jpg

 

This boring full scene shows how the light fall-off from 210mm, F/4 isn’t really an issue, contrary to what the crops above show.

 

70mm corner samples next.

 

         F/4
          F/5.6
october08/70210ffcn40wb.jpg october08/70210ffcn56wb.jpg
         F/8
          F/5.6 at center
october08/70210ffcn80wb.jpg
october08/70210ffcn56wctrb.jpg

 

The 70mm corners suffer from a small loss of contrast, but have plenty of detail.  Contrast is lacking, but not as bad as the super expensive Sony 70-200mm F/2.8 G full frame corner crops.  These crops are from the extreme corners, only 250-350 pixels in.  I threw in a center shot at the lower right to show you what I’m talking about.  The exposure differences are from light fall-off.  Don’t compare these corner crops with the center crops in the APS-C section.

 

210mm corners below.

 

         F/4
          F/5.6
october08/70210ffcn40b.jpg october08/70210ffcn56b.jpg
         F/8
          F/5.6 at center
october08/70210ffcn80b.jpg
october08/70210ffcn56ctrb.jpg

 

The 210mm corners don’t change much as you stop down, again, they look similar to the 70mm crops by way of contrast, and they’re not quite as sharp overall.  I threw in the same center image for comparison.  Don’t sweat this as things look much better a little farther away from the corners.  No doubt you’ve noticed the lateral color fringing in the corner crops, which makes things seem less sharp.  Exposure differences are from light fall-off.

 

Distortion next.

 

october08/70210ffbrl.jpg
Barrel distortion @70mm on A900
october08/70210ffpin.jpg
Pincushion distortion @ 210mm on A900

 

There is moderate barrel distortion at the wide end, and moderate pincushion distortion as you zoom in.  The results are a little stronger than the APS-C crops, but not by much.

 

 

Conclusion. 
For APS-C users; this is a good lens, and can be had for about the same amount of money as Sony telephoto zoom lenses in this category, but not with a constant F/4 aperture, because Sony doesn’t offer one at the time of this review.  The Minolta AF 70-210mm F/4 is well built, reasonably sharp at all apertures, and considering the constant F/4 aperture; very inexpensive.  The main reason you would buy this lens is the use of F/4 at 210mm.  If you don’t need the extra stop, buy the smaller and lighter Sony 75-300mm F/4.5-5.6, or the real diminutive (APS-C only) DT Sony 55-200mm, all for about the same amount of money.  Many people in chat rooms claim this is the greatest telephoto zoom lens Minolta ever made, unfortunately, that’s not true, it’s good, but not that good.  Again, if you really need the extra stop for low light shooting, go for it, if not, get the more useful Sony models, which have distance encoding, (used mostly for flash), and are much more portable.  See the review of the excellent Minolta AF 100-200mm F/4.5, which is just as good as the 70-210mm F/4 lens.
For full frame users; this lens performs much the same as the far more expensive Sony 70-200mm F/2.8 G.  The only real difference other than the extra stop of light is the Minolta has more color fringing at full zoom, and axial color fringing at the centers, though this type disappears as you stop down.  The Sony 70-200mm F/2.8 is sharper in the centers, but not by much, in fact you probably wouldn’t notice it unless you examine your images at 100% on your computer screen.  The corners are slightly soft, and have a lack of contrast at 210mm, but the results are typical–to above average for full frame coverage.  Most people would be hard pressed to ever really need F/2.8 in a zoom lens, unless you enjoy available light, hand-held photography or fast action shooting, like sports.
As I’ve said before, if you’re a fair weather photographer, you probably don’t need F/2.8 or F/4, and can live at F/5.6 where the lenses are less-expensive, smaller, lighter and just as good at that aperture.
For those of you with $900, get the much more useful Sony 70-300mm F/4.5-5.6 G SSM, or the way less expensive Tamron 70-300mm F/4-5.6 also reviewed here.
More sample crops with the Minolta AF 70-210mm F/4:
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