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The "Piazze die Miracoli" ("Square of Wonders") in Pisa |
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During ten days in October 2008 I had the opportunity to test the 24MP full frame Sony alpha 900 simultaneously with all the six classical professional zooms from the Sony / Minolta system (3.5/17-35mm G, 2.8/24-70mm Zeiss, 2.8/28-70mm G, 4-4.5/28-135mm, 2.8/80-200mm APO, and 2.8/70-200mm SSM - thanks to J. Nemecek for providing the 17-35mm G and the 28-70mm G, and thanks to Sony Overseas AG, Schlieren/Switzerland, for providing the Zeiss 24-70mm). In this section you will find test images of the following zooms at f=70mm: Minolta AF 4-4.5/28-135mm (1985), Minolta AF 2.8/28-70mm G (1993), Minolta (Sony) AF 2.8/70-200mm APO G (D) SSM (2003), and Zeiss Vario Sonnar 2.8/24-70mm ZA (2008).
At f=70mm the Minolta AF 4-4.5/28-135mm delivers at f8 clearly the best image quality of any zooms tested here - at a second hand price of 1/10 of the Zeiss. The contrast wide open is a bit low, but stopping down just 1/2 - 1 stop solves the problem. Be aware that some of the Minolta 28-135mm lenses were used heavily by professionals; their zoom mechanisms may be worn out.
If you need a lens with perfect center resolution, high detail contrast and virtually no koma at f2.8 (!), or if you need the 24mm wide angle, the Zeiss Vario Sonnar 2.8/24-70mm will be appropriate - at least as long as you don't mind its weight and size;). And: the Zeiss T* coating is outstanding.
If you are looking for a well balanced f2.8 "normal zoom", the Minolta 2.8/28-70mm G may be right. Its design and size fit perfectly to the Alpha 900, it's smaller and lighter than the Zeiss ZA 2.8/24-70mm, it offers slightly more tele range, and it is sold second hand at roughly 1/3 of the Zeiss' price. Due to it's softer image characteristics it may be more useful for portraits than the Zeiss.
All images shown here are 100% from the 24 MP full frame sensor of the Sony Alpha 900. The Alpha 900 settings were set to standard values. Previous to the test, all lenses were individually and carefully calibrated using the "Micro AF" feature of the Sony A900. Originally, the 28-135mm lens could not focus to infinity on the a700/a900 DSLRs. Therefore prior to the test its "infinity" setting had to be adjusted as well.
The RAW files were converted with Photoshop CS5. Sharpening radius was 0.5 px, Sharpening was set to 50, and Detail was set to 50.
The color aberrations (CA) were NOT removed by the software (be aware that all Nikon FF bodies do automatically correct the CAs!).
The A900 was set on a professional Manfrotto 055CB tripod equipped with a 3-way-head Manfrotto 410. Its image stabilizer ("steady shot") was turned off, and 2s mirror lock-up was used to minimize vibrations.
Minolta AF 4-4.5/28-135mm @ 70mm
The professional "normal range" zoom from 1985 has a remarkable performance even wide open. Minoltas first professional mid-range zoom is meanwhile thirty years old, but it still has clearly the best image quality: Best detail resolution, virtually no CA's, and a very good contrast even in the extreme corners of the 24MP full frame sensor.
Wide open the contrast is a bit low, the 28-135mm displays a lots of details even in the extreme corners of the alpha 900 full frame 24MP sensor. It has much less CA's than the 70-200mm SSM and less CA's than the Zeiss 24-70mm. Remarkable indeed.
Minolta AF 2.8/28-70mm G @ 70mm
Not at all comparable to the performance of the elder 28-135mm (but one stop faster, of course). The corners of the AF 2.8/28-70mm G never become really crisp and sharp.
In 1993 the professional Minolta zoom was "state of the art" - but on the high resolution sensors of both the a700 and the a900 it has some weaknesses. While its size and weight are more agreable compared to the Zeiss ZA 2.8/24-70mm, its detail resolution and contrast are worse. The images shown here reflect the general impression one can read in several internet forums: "Never completely sharp". Ruggedness, and bokeh are on par (or even better) than the current Zeiss.
These are not slightly mis-focused images!! The Minolta AF 2.8/28-70mm G behaves like that, even when stopped down.
Minolta AF 2.8/70-200mm APO G (D) SSM @ 70mm
In 2003 Minolta introduced the new professional f2.8 tele zoom. This lens - at atht time widely recognized as one of the best f2.8 tele zooms - has its optimal performance at f=200mm. While at f=200mm virtually no CA's are visible, at f=70mm the lens has stronger color aberrations (CAs) than any of the other lenses tested here. The CAs can be removed easily using "Photoshop", but it's less than perfect, of course.
The detail resolution is clearly better than the 2.8/28-70mm G and at least on par with the Zeiss Vario Sonnar 2.8/24-70mm.
Sony Zeiss Vario Sonnar 2.8/24-70mm @ 70mm
In the corners the detail resolution reaches neither the level of the AF 4-4.5/28-135mm nor of the AF 2.8/70-200mm SSM. Yet it is slightly better than the Minolta AF 2.8/28-70mm G.
There are virtually no CA's (yet both the 28-135mm and the 28-70mm G are slightly better).
100% CROPS FROM THE IMAGE CENTER:
Minolta AF 4-4.5/28-135mm @ 70mm
Minolta AF 2.8/28-70mm G @ 70mm
Again - these are not slightly mis-focused images! The Minolta AF 2.8/28-70mm G behaves like that. Obviously there's slight focus shift when stopping down.
Minolta AF 2.8/70-200mm APO G (D) SSM @ 70mm
In the center the image si nearly perfect, even at f2.8.
Sony Zeiss Vario Sonnar 2.8/24-70mm @ 70mm
The image center has perfect detail resolution and contrast even wide open.