Minolta AF 24-85mm F3.5-4.5 RS A-mount lens review by artuk

reviewer#2522 date: Jul-7-2007
sharpness: 4
color: 4
build: 4
distortion: 4
flare control: 4
overall: 4
tested on:
  • film camera:Film camera
  • APS-C: 6MP6 MP; 10MP10 MP; 12MP12 MP; 14MP14 MP; 16MP16 MP; 20MP20 MP; 24MP24 MP
  • full frame: 12MP12 MP; 24MP24 MP; 36MP36 MP; 42MP42 MP; 61MP61 MP
ownership:I used to own this lens
compared to:Minolta 24-105mm f3.5-4.5
Minolta 25-50 f4
Sigma 24-70mm EX f2.8
price paid:30000 Yen
positive:Compact
Good resolution and colour

negative:No serious complaints
comment:The Minolta 24-85mm variable aperture zoom was a useful extension of the previously common 28-xx zooms, in fact the original version was probably the first "standard" zoom to offer 24mm when it was launched.

Sharpness at centre is very good. In fact, technical tests revealed that resolution at the very centre measures around 600 line per milimetre, much more than would ever be recorded on film or sensor. Corners are somewhat lower resoltion, especially at 24mm and full aperture. Wide open, centre sharpness is still very good, but corners less so on full frame. Stopping down improves things and resolution at centre and edge becomes very good.

It is important with this type of lens to consider the fact that the variable maximum aperture, and modest overall "speed", gives the designers some freedom to tackle other aspects of the design such as resolution and distortion control. Fixed fast aperture zooms may have the benfit of being stopped down half or one stop to match the speed of a lens such as this, but their higher maximum aperture means the designers were wrestling with greater challenges over vignetting and distortion. Often absolute resolution on equal aperture with vairable zooms such as this offers little benefit beyond slightly better corners. Full frame corners are clearly this lenses greatest weakness at 24mm, wide open or stopped down. However, you must bear in mind that this is part of the limitation of a 24-xx zoom lens design. Clearly, a 24mm prime lens will out-perform it.

This lens appears to use a technique used by lens designers to increase the apparent sharpness, where high edge contrast gives the impression of very high resoltion, even where that resolution does not exist. Image contrast and edge contrast are very good, and combined with very high central image resolution, results appear sharp. (This technique has certianly been used by other Minolta designs such as some generations of the 100-300mm f4.5-5.6 zoom). Overall resoltion would rate as very good.

The colour and contrast are very good. Colours are well saturated, and the lens has some similarities with some of the "classic" Minolta lenses of the 1970s and 80s which gave a very fluid, water-like colour. This was rumoured to be similar to the look of some Leica lens designs which favoured micro-contrast (the ability to record minute changes in contrast, colour and shading) rather than absolute resoltion. It tended to give a very "3D" effect to pictures that look very "real", as if the viewer could step into. Overall colour would rate easily as very good.

Bukeh isn't bad for a zoom. It has a circular aperture (which typically works from full aperture down by about 2 stops, after which the aperture starts to become geometric), therefore background highlights can be rendered as circular highlights when out of focus.

The build is engineering grade plastic and some metal. It is neither very light not very heavy, and balances well on the camera. Overall build quality would rate as very good to very good "plus".

Distortion is well controlled for a zoom, with some barrelling and pin-cushioning at the wide and long ends respectively. Distortion compares favourably to many "standard" zooms, and rates as very good.

I have never had a problem with flare with this lens. It was one of the first Minolta lenses I saw that has proper "petal" shaped lens hood, rather than the designs previously used by Minolta where the hood was the same width all the way around that the widest end of the lens allowed, which as hoods were almost useless. (See the hood for the lovely 35-200mm Xi as an example). Flare control therefore rates as very good or "plus".

Overall, a very sharp, arguably ever so sligthly better than the 24-105mm that replaced it.

rating summary

lens image
  • total reviews: 53
  • sharpness: 4.41
  • color: 4.68
  • build: 4.34
  • distortion: 4.19
  • flare control: 4.11
  • overall: 4.35
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