Minolta AF 50mm F/1.7 Review - Photo Jottings

Minolta AF 50mm F/1.7 Review

Here’s a brief look at the Minolta AF 50mm F/1.7 lens.  Scroll down for the review.

Minolta AF 50mm F/1 .7
Box contents
Front and rear caps and a users manual.
Find ’em on eBay for about $90-$150 as of 9/09
Build quality
OK to good
Additional information
Has neat built-in hood, .3″ (8mm) deep fully extended, but it does no good
Specifications below
Optical configuration
6 elements in 5 groups
Angle of view
47° full frame, 32° APS-C.
7 blades, straight
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
18″  (450mm)
Minimum focus, end of lens barrel to subject
13.75″  (349mm)
Hard stop at infinity focus?
Length changes when focusing?
Focus ring turns in AF?
Filter size
Filter ring rotates?
Distance encoder?
Max magnification
Min. F/stop
Sony teleconverter compatible?
Dimensions W x L (my measurements)
2.6″ x 1.5″   66mm x 39mm
Maximum  extended length (my measurements)
1.8″  (47mm), add .3″ (8mm) for hood extension.
Weight bare (my scale)
5.8oz  (165g)  6.4oz (183g) with caps
Requisite product shots.
Front with hood extended
Side shot fully drawn in
Left 50mm F/1.4, right 50mm F/1.7
Left 50mm F/1.4, right 50mm F/1.7
All testing done with the Sony A 700, and A900.  For full frame results, go to the bottom of the page.  For a better understanding of my review methods and terminology, go here.
This page has a copy of the original owner’s manual.
The Minolta AF 50mm F/1.7 is a very compact lens, the smallest Minolta made in the day.  This particular lens is a restyled version from the 1990s.  It’s a “kit” type lens, and feels like it, meaning super light-weight.  It doesn’t feel nearly as nice as the Sony 50mm F/1.4 lens, which costs over double the price of this one.  Fit and finish are good, but plastic is used for everything but the glass it seems.  It has a rather shiny black finish with rubber grip areas around the barrel and focus rings, and also sports a nifty built-in hood, which works by pulling on the plastic barrel around the front after you turn the focus to close-in, which allows you to grab it.  The 28mm F/2.8 lens has the same feature.  On top it has a focus distance window with ft/m in white, along with DOF hash marks.  The lens is made in Japan.  Filter size is 49mm.
Focusing.  The little Minolta AF 50mm F/1.7 has a short focus throw, and auto-focuses quickly and accurately.  Manual focusing is easy, and quick too, with a 1/4 turn from close-in to infinity.  This lens has a sticky focus ring when near close focus, and from what I’ve been told from other sources, is a common problem.  I think it has something to do with the built-in hood tolerances.  Most people probably won’t be manually focusing with this lens anyways, so it’s not a deal killer.
Multi-coatings.  It has the older Magenta/blue look.  See comparison shot above.
Flare/ghosting.  Flare, or veiling glare is similar to the Sony 50mm F/1.4, which is good, but watch the sun when it’s real close to, but not in the image.  This lens has an odd, blue looking ghost, like half of a 7 blade aperture that shows up opposite of the sun when the sun is at the edge of, or in the image.  It’s large and will mess up your shot, so pay attention.  The ghosting control is not as good as the Sony 50mm F/1.4.  This Minolta lens has a very small built-in lens hood that you slide out from around the front element, as described, and seen above, but it doesn’t do anything.  Use your hand for keeping the sun out of the shot if possible.
Filter size, 49mm.  Sony uses this size on the 28mm F/2.8 only.
Filter use.  No noticeable additional vignetting using a regular filter.
Coma.  Strong at F/1.7, good at F/2.5, gone by F/2.8.
Color looks the same as other Sony/Minolta lenses.
Close-up filter.  works great, tested with a +4.
Bokeh is neutral to just so-so in my opinion.  Not as good as the Sony 50mm F/1.4, see comps below.
Color fringing is light and poses no problems, it looks better wide open than the Sony 50mm F/1.4 does, but from F/1.7 and down, it’s about the same.
Distortion below.
No distortion.


Distortion is flat, which is good, so nothing to report here.  About the same, or slightly less distortion than the Sony 50mm F/1.4.


Light fall-off.


Aug08/m1717lf2.JPG Aug08/m1728lf.JPG
Light fall-off is not a problem on an APS-C camera.  It’s not noticeable in real pictures.
Random shots.
Sun in shot,  F/5.6
Sun centered,  F/5.6
october08/5017ffsunof.jpg october08/5017sunb.jpg
Minolta AF 50mm F/1.7 @ F/1.7
Sony 50mm F/1.4 @ F/1.7
Aug08/m17a17bok.jpg Aug08/s14a17bok.jpg


The top shots show how the lens handles the sun when inside the image.  There always seems to be some purple somewhere in the image, even when the sun is centered.  Veiling glare is strong when the sun is just outside the frame, use your hand to block the light, and you won’t have problems.  The two shots at the bottom are comparisons of “Bokeh” or background blurbetween the Minolta AF 50mm F/1.7, and the Sony 50mm F/1.4.  I like the look of the Sony better.


Veiling haze and CA wide open.


Aug08/m17sa17.jpg Aug08/m17sa20.jpg
The images above are cropped from the centers.  This lens is better wide open than the Sony 50mm F/1.4, but they even out at F/2.  Just 1/3 of a stop makes a big difference.  Don’t shoot at F/1.7 in broad daylight, save the large apertures for low light, where you won’t notice this stuff.
How sharp are the corners?
Aug08/m17cn17.jpg Aug08/m17cn28.jpg


These crops are from the extreme bottom left corner.  Things look rough here at F/1.7-2.8, then sharpen up gradually, peaking around F/8.  They never really get sharp.  See the comparison shots with the Sony 50mm F/1.4 towards the bottom.


How sharp are the centers if the image is enlarged to a staggering size?


Aug08/m17ctr17.jpg Aug08/m17ctr20.jpg
The center sample crops above show F/1.7 to be soft, with veiling haze, but sharpens up with plenty of contrast at F/2.  It appears the lens is at its sharpest at F/4-5.6.  There isn’t a whole lot of change as you can see after F/2, and it’s only noticeable cropped and displayed side-by-side.  This lens is pretty sharp at F/2-8, and is similar to the Sony 50mm F/1.4 in the centers, see comparison crops towards the bottom of the page.
Bonus section!   
Corner comparison crops.  Read carefully.  The Minolta 50mm F/1.7 lens crops are on the left, the Sony 50mm F/1.4 crops on the right.
Minolta AF 50mm F/1.7 @ F/2.8
Sony 50mm F/1.4 @ F/2.8
Aug08/m17cn28.jpg Aug08/s14cn28.jpg
Minolta AF 50mm F/1.7 @ F/5.6
Sony 50mm F/1.4 @ F/5.6
Aug08/m17cn56.jpg Aug08/s14cn56.jpg


It’s pretty clear the more expensive Sony 50mm F/1.4 lens is much sharper in the corners, at all apertures.  I wouldn’t worry too much about it though, since it’s not very noticeable if you have an interesting subject.


Center comparison crops.


Minolta AF 50mm F/1.7 @ F/1.7
Sony 50mm F/1.4 @ F/1.7
Aug08/m17ctr17.jpg Aug08/s14ctr17.jpg
The Minolta 50mm F/1/7 is showing loss of contrast wide open, much the same as the Sony 50mm F/1.4 does at F/1.4.  These two lenses are about equally sharp in the centers at F/2.8 and beyond.
Close focus sample.
Below, check out the close focus shot, click for a 100% cropped portion of the full image.  The sample 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, 13.75″ or 349mm, measured from the front of the lens barrel to the subject.
Click for larger image (154kb) F/5.6
This maximum magnification shot is sharp from F/4-8.  This one was taken at F/5.6.  It’s small, so if you want to get a little closer, screw on a +4 close up lens, like I did in this review.

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


october08/5017ffvig17.jpg october08/5017ffvig20.jpg


Light fall-off is worse than the APS-C crops shown earlier.  At F/1.4 it’s moderate to heavy, and slightly noticeable in real shots, but don’t shoot at this aperture in daylight.


Full image from A900 below.




The dark corners visible in the gray crops above aren’t really noticeable here, but this is the wrong thing to do with a F/1.7 aperture.  Save F/1.7 for low-light shots. This picture was taken at F/1.7 at +1/8000sec.


Corner samples next.


october08/5017ffcn17.jpg october08/5017ffcn28.jpg


At wide apertures, the corners are soft, with a lack of contrast.  Things look good at F/5.6, but F/8-11 seems the sharpest.  The contrast looks poor for some reason in these crops, but it’s really good by F/5.6.  The exposure differences are from light fall-off.


Distortion on A900


The distortion (or lack thereof) is about the same as the APS-C images I showed earlier.  It’s still flat when using the A900 and has noticeably less distortion than the Sony 50mm F/1.4 on a full frame camera.   For you nitpickers, a grid overlay will reveal slight barrel distortion.


Coma results with full frame.


october08/5017cmaff17.jpg october08/5017cmaff22.jpg
october08/5017cmaff28.jpg october08/5017cmaff40.jpg


This is coma on the A900.  At F/1.7 it looks bad, and doesn’t change at F/2.  By F/2.2, things lighten up significantly, and F/2.8 results aren’t noticeable in normal sized images.  This lens produces roughly the same size coma as the Sony 50mm F/1.4, but looks “backwards” as in the “antennae” location.


My final thoughts.
The Minolta AF 50mm F/1.7 lens turned in a good performance.  The good points are: compact, lightweight, low distortion, quick focusing, low color fringing, and is often found on eBay for just over a hundred bucks for a good copy, (original version), mine is a restyled version, but they’re the same optically according to the specs.  The not-so-good points are; very soft corners with a wide aperture, and a sticky focus ring, neither one is a deal killer for the price.
This lens is a little long for an APS-C camera, so you’ll have to decide if you can live with an equivalent focal length of 75mm.
For full frame users; this lens performs mostly the same as the APS-C coverage, except for light fall-off.  See paragraph below.
If you can afford to pay the extra money for the 50mm F/1.4, I’d just get that one, it’s sharper at the same apertures, from F/1.7-2.8, and offers 2/3 of a stop more light.  If you’re strapped for cash, and just want a good low-light lens, this is a bargain.  Don’t worry about the soft corners, you won’t notice them with good subjects.
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