Minolta AF 24-105mm F3.5-4.5 D A-mount lens review by artuk
|artuk#2548 date: Jul-15-2007|
flare control: 4
|ownership:||I own this lens|
|compared to:||Sigma 24-70 f2.8 EX|
Minolta 24-85 f3.5-4.5
|positive:||Very good sharpness|
Good range (full frame)
|comment:||Origianlly launched at around the same time as the Dynax 7 film camera, I believe this was the first Minolta lens to support the "D" chip for ADI ("Advanced Distance Integration") flash. Although this lens replaced the previous 24-85 from the early-mid 1990s, it was not a "stretch" of the existing lens but in fact a complete redesign. Minolta appeared to throw the optical book at it, incorporating multiple moulded compound aspheric elements. It is alleged that the design is also protected by one or more patents, though for what I do not know - presumably to stop some aspect of it's design being "copied". It is certainly more compact that the 24-85 it replaced, and few other zooms of the same range have been as small, so it is possible the patents relate this this element of it's design.|
On full frame at 24mm, sharpness at centre is very good even from full aperture. Corners are understandably softer than centre at full aperture, a reflection that this is a zoom lens with a wide angle of coverage. Stoping down 1-2 stops improves things, and sharpness more or less reaches parity from centre to edge. The performance is fairly consistent across it's range - 105mm is also very good. Technical tests of the lens at the time of launch showed an overall very good performance. Stopped down, it is certainly capable of very sharp results on full frame.
Colour is good, neutral and well saturated, and whilst there are traces of the fabled 1970s/80s saturated "liquid" colour, this is a much more modern design. Contrast is quite high, fairly typical for a modern zoom lens. This lens is much more contrasty than earlier Minolta AF zooms (such as the 28-135 f4-4.5 or 24-50 f4), and in my opinion this sometimes sacrifices highlight detail, which can blow out. I would say the lens definately uses the design technique of high edge contrast to improve the appearance of "sharpness". This is quite common in mid-range zooms, and a technique used by Nikon is some of their lenses for many years. High edge contrast makes details (which are resolved from contrast of light and shade) appear very well defined - that is "sharp" - even though the underlying resolution of the lens may not be that high. Ultimately, as contrast is reduced (e.g. poor light) the detail will remain until it just disappears as the lens is no longer able to create edge contrast. This is not a criticism, just an observation.
One of the benefits of "slower" variable aperture zooms such as this is that it gives the designers some freedom to improve other aspects of performance such as distortion and vignetting. Lens design must be a trade off between speed (maximum aperture), distortion and vignetting, amoungst other things. Fast constant aperture zooms must be significantly more complex in design (and therefore expensive, bigger, heavier etc) to correct issues such as distortion because the optic required become that much more complex.
The build is very good, typical late 1990s Dynax finish with rubberised controls and satin black barrel made from a mix of polycarbonate and metal. The lens feels quite sturdy when extended to its maximum 105mm length. AF performance is good. The only criticism is that being so compact, the controls are made quite small, and manual focusing is with the typical near useless thin ring with almost no resistance. However, zoom is light but well weighted, and controls and smooth. Overall very good.
Distortion is surprisingly good for a zoom of this range. There is the inevitable barreling at the 24mm end and some pin-cushion at the 105mm end, but it is not the worst I have seen on a wide angle standard zoom. It is about on par with the 24-85 it replaced. For general photography it is unlikely the rectalinear distortion at edges would be noticed, though for architectural an other critical work it may prove problematic. It would rate as very good for this type of zoom.
Flare control seems good. The lens is supplied with a proper "petal" shaped hood, and whilst this gives limited protection at the 105mm long end, flare seems well controlled. Overall, very good.
Overall, on full frame a very good lens. Whilst absolute performance at maximum aperture may be limited when compared to prime lenses of the same focal length, overall the optical balance is good, and performance stopped down leaves little significant criticism. Clearly, at 24mm a prime lens will out-perform it.
There is little to choose between this lens and the 24-85 it replaced. I would suggest, based on personal experience and comparative technical tests I have seen, that the 24-85 is marginally better, but it is so close and potentially subjective that to all intents and purposes there is no difference in their performance.