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Here's a brief look at the Minolta AF 100mm F/2 lens.  Scroll down for the review.

Lens

Minolta AF 100mm F/2 

Box contents

Front and rear caps, hood, and a users manual.

Cost

No longer available, but check used prices here.  At the time of this review, used prices are around $600-$900.

Build quality

Very good

Additional information

At the time of this review, Sony offers the Carl Zeiss 135mm F/1.8, which is more expensive, but performs better.

Specifications below

 

Optical configuration

7 elements in 6 groups

Angle of view

24° full frame, 16° APS-C.

Aperture

9 blades, circular.

Full frame and APS-C

Yes, made for full frame.   APS-C equivalent, 150mm

Depth of field and focus scales?

Yes and yes

Minimum focus, image plane to subject

40.5"  (1029mm)

Minimum focus, end of lens barrel to subject

35"  (889mm)

Hard stop at infinity focus?

Yes, but off slightly

Length changes when focusing?

Yes

Focus ring turns in AF?

Yes

Filter size

55mm

Filter ring rotates?

No

Distance encoder?

No

Max magnification

0.13x

Min. F/stop

F/32

Sony teleconverter compatible?

No

Dimensions W x L (my measurements)

2.65" x 2.95"   68mm x 75mm 

Maximum  extended length (my measurements)

3.6"  (91mm)                                                    

Weight bare (my scale)

16.7oz  (473g)  17.4oz (494g) with caps


Requisite product shots.

April2009/100f2sd.jpg
Side shot
April2009/100f2sdex.jpg
Side shot with full focus extension
April2009/100f2bk.jpg
Backside
April2009/100f2ft.jpg
Front

 
 
All testing done with the Sony A700 12.2MP and Sony A900 24.6mp cameras.  See full frame results at the bottom of the review.  For information on my lens review methods and terminology, go here.
 
This page has a copy of the original owner's manual.
 
The Minolta AF 100mm F/2 is a compact lens, about the same size (but a little heavier) as the Sony 24-105mm F/3.5-4.5 lens.  Build quality is very good.  It has a gloss black finish with ribbed rubber inserts around most of the circumference.  It has a focus distance window with ft and m in different colors along with DOF hash marks.  It also has an infra-red focus index mark, the red dot on the aperture scale.  The lens is made in Japan, and dates to the late 1980s.  Filter size is 55mm. 
 
This lens has a normal to long focus throw, and focuses a little slow, but mostly accurately using the A700 or A900.  There seems to be a bit of front-focus at long distances, and back-focus at short distances, but not noticeable past F/2.8.  There's a tiny bit of slop on the focus ring if you wiggle it by hand when engaged, and none in actual MF use.  Manually, the ring is pretty easy to manipulate with a finger and thumb.  Over a third of a turn gets you from close focus to infinity, with the overall length of the lens increasing and extra 16mm for focus extension.  The focus ring turns in auto-focus mode, but thankfully, not the filter ring.
 
My copy of this lens is pretty scratched up, so instead of spending days in photoshop re-doing the images pixel-by-pixel, I darkened them up to hide the damage.  Optically though, it's in great shape.
 
This lens has the typical  multi-coatings from the 1980s, and the color is predominately golden.  You'll see a lot of green/magenta blobs and/or arcs depending on angle and aperture.  The sun doesn't have to be in the image to cause heavy veiling glare, so be sure and block any intense light sources which can cause havoc with your pictures.  This lens came with a hood originally, but my sample is missing that part.  I tried a few modern Sony 55mm hoods, and found the best fit was the hood from the Sony 50mm F/1.4 lens.  I don't think is has the correct flanges, but it holds tight.  Also try the Sony 75-300mm F/4.5-5.6 hood.  It fits ok.
 
Filter size is 55mm.  This is also Sony's most popular size. 
 
Filter use.  A regular filter causes no additional vignetting on a full frame, or APS-C camera. 
 
Coma.  None on an APS-C camera, but full frame has a very small amount at F/2. See sample crops below.
 
Color looks the same as other Sony/Minolta lenses. 
 
Close-up filter.  Works ok, with a little contrast loss.  A +2 or +4 would help out if you want a better close focus shot since this lens has a small reproduction ration of 0.13x.  See results here of a Minolta 28mm F/2.8 lens using a +4. 
 
Bokeh looks somewhat busy when the background is close to the subject at medium distances.  Overall, I found (in most images) the background blur to be fairly smooth, and very similar to the Sony 100mm F/2.8 macro lens.  See crops below.
 
Axial color fringing is present, especially at F/2, (and typical of 1980s lens designs), but not very apparent unless you shoot bright white subjects flanked by dark areas--and--look at your images greatly enlarged on your computer screen.  I mostly came upon magenta and cyan, though magenta is usually more noticeable.  Stopping down gets rid of this type of CA.  Lateral color fringing (occurring along the sides) is not very noticeable, and control seems above average here.  See the sample images below. 
 
Random samples below.
 

Big green blob,  F/5.6

Magenta blobs at F/5.6

April2009/100mmf2ght2.jpg

April2009/100mmght3.jpg

 

Ghosting examples using the full image. The left sunset shot shows a large, bright green blob, which is obviously very noticeable.  There're also some red arcs/arrows which are not so noticeable.  The right shot shows a more intense sun, with different colored ghosts.  This is typical of first generation Minolta AF lens ghosting performance.  There are no problems with the sun centered in the image.  Veiling glare is strong anywhere close to the sun.  Use your hand as a hood, which will eliminate most of this problem.


Comparison to the Sony 100mm F/2.8 macro.

 

Minolta AF 100mm F/2, @F/2

Sony 100mm F/2.8 macro, @F/2.8

April2009/100mmf2atf2.jpg

April2009/100mmf28at28.jpg

Minolta AF 100mm F/2, @F/2.8

Sony 100mm F/2.8 macro, @F/2.8

April2009/100mmf2at28.jpg

April2009/100mmf28at28.jpg

 
I thought I'd throw in a comparison of the Minolta 100mm F/2, and the one stop slower Sony 100mm F/2.8 macro.  The Minolta is clearly the sharpest at F/2.8, bottom row.  I'd also say the Minolta 100mm is about as sharp at F/2 as the Sony 100mm macro is at F/2.8, though with obvious axial color fringing, the Sony has almost none, (top row).  If you want a fast medium telephoto lens, the Minolta AF 100mm F/2 is better, although the close focus ability is poor.  All exposure values are the same.  The top and bottom Sony 100mm F/2.8 shots are the same.
 
Distortion below.
 

April2009/100mmdisz.jpg
Minor pincushion distortion.

 

Distortion isn't bad at all, and only shows slight pincushion if you look closely.

 

Light fall-off.

 

F/2

F/2.8

April2009/100mmvigf2.jpg

April2009/100mmvigf2.8jpg.jpg


Light fall-off or corner darkening is moderate at F/2.  It blends well into the center of the image so it's not distracting in real pictures.  By F/2.8 it's gone.
 
Bokeh examples below.
 

F/2

F/2.8

April2009/100mmbokf2.jpg

April2009/100mmbokf2.8.jpg

 

Bokeh is fairly smooth, nothing special.  I thought it would be a little smoother for some reason.  Images are 100% cropped samples from the center.

 

Veiling haze and color fringing.

 

April2009/100mmcfa.jpg
Center crop from F/2

April2009/100mmcfb.jpg
center crop at F/2.8

 

You can see from the top image that color fringing and haze are noticeable at F/2.  Luckily, the image clears up nicely at F/2.8.  All axial CA is gone at F/5.6.

 

Center and corner crops side-by-side.

 

F/2 from center

F/2 from corner

April2009/100mmctrf2b.jpg

April2009/100mmcnf2700.jpg

F/2.8 from center

F/2.8 from corner

April2009/100mmctrf2.8b.jpg
April2009/100mmcnf2.8700.jpg

F/4 from center

F/4 from corner

April2009/100mmctrf4b.jpg
April2009/100mmcnf4700.jpg

F/5.6 from center

F/5.6 from corner

April2009/100mmctrf5.6b.jpg
April2009/100mmcnf5.6700.jpg

 

I've put the center and corner crops side-by-side this time, and the lens produces sharp corners, as expected with an APS-C camera.  It looks like the centers sharpen up fully at F/4, and the corners at F/5.6.  The F/2 crops look a little fuzzy, due to veiling haze, but they're showing quite a bit of detail, I'd say about as much as the Sony 100mm Macro lens shows at F/2.8, see crops above.  I see some lateral color fringing in the corner crops, which doesn't go away as you stop down.  It's not bad at all, and only noticeable with huge enlargements.

 

Close focus sample.
 
Below, check out the close focus shot, a 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 long 35" or 889mm, measured from the front of the lens barrel to the subject.
 

April2009/100mmac987.jpg
Maximum reproduction, no larger image, F/5.6


This maximum magnification shot is sharp, but quite small, with a ratio of 0.13x.  I chose the F/5.6 shot.  The F/2.8 shot was just as sharp, but didn't look as good due to the axial color fringing.
 
 

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

          F/2.8

April2009/100mmf2vig.jpg

April2009/100mmf2.8vig.jpg

 

Light fall-off is handled well, and isn't much of a problem wide open; one stop down and the corners brighten up to nearly match the central area. 

 

Full image from A900 below.

 

April2009/100mmf2ffvigover.jpg

 

The slightly dark corners visible in the gray shot at F/2 are hardly noticeable in a real picture.  The image above with a slim DOF was taken at F/2, 1/6400 sec at ISO 200.

 

Corner samples next.

 

         F/2

          F/2.8

April2009/100mmffcnf2.jpg

April2009/100mmffcnf2.8.jpg

         F/4

          F/5.6 from center

April2009/100mmffcnf4.jpg
April2009/100mmffcnctrf5.6.jpg

 

The corners are pretty sharp, and don't look any different from the centers at each aperture.  I show a F/5.6 shot from the center on the bottom right crop.

 

April2009/100mmdis.jpg
Very mild pincushion distortion on A900

 

There is minor pincushion distortion, about the same as the APS-C crop shows, which suggests the lens is producing less distortion at closer focusing distances: I had to take the A900 shot at a closer distance to fit the window in the frame than the A700 due to the crop factor.

 

Coma results with full frame.

 

F/2

F/2.8

April2009/100mmcmaf2.jpg

April2009/100mmcmaf2.8.jpg

 

This is coma on the A900.  It's not bad at all, and wouldn't be noticeable unless viewed at huge sizes.  One stop down to F/2.8, and coma disappears.

 

 
My final thoughts. 
 
The Minolta AF 100mm F/2 lens turned in a very good performance.  Good points are: compact, low distortion, and very sharp from F/2.8 to F/11.  The corners are about as sharp as the centers.  Color fringing is strong wide open, but looks much better one stop down.  Flare and ghosting can be strong when the sun is near (or in) the image, as I've said above, use your hand to block stray light, that's easy to do on a small telephoto lens.   
 
Used prices for the Minolta AF 100mm F/2 run roughly the same as the Sony 100mm F/2.8 macro, which is a stop slower.  I'd definitely buy the Minolta F/2 if I wanted a good medium telephoto lens, and available light, hand-held shooting was the primary purpose.  This lens is very impressive from F/2 to F/2.8, and would make a good portrait lens.  I would actually prefer this lens to the much more expensive, but one stop faster CZ 85mm f/1.4, the main reason being; I prefer moving subjects, and the DOF is too thin at F/1.4 for reliable sharp focus points.  If you don't think you'll be needing to shoot at those apertures, stick to the slower, less expensive and more useful zoom models.
 
For you people with a fistful of cash, buy the better Carl Zeiss 135mm F/1.8, which focuses quicker and more accurately, and is better at controlling flare and ghosting.  It also has less color fringing and haze wide open, and produces great shots at F/1.8.