The Battle of the 85mm's
 
 
Minolta's Top Portrait Lenses Compared
 
 
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Performance at Standard Distances
 
 
The lenses have been tested for sharpness at differing apertures, as well as bokeh, light falloff, and flare. As a result, the information below should provide a good indication of performance.
 
 
 
   

85mm f/1.7 MD @ f/5.6

   
 
Above you can see the image that I used for the following tests. On the map you can see three small red squares that indicate the areas I have cropped for the resolution samples below. Unfortunately, because the edges of the map curled up I was not able to go to the true corners to evaluate the sharpness, however I feel that the side and corner sites provide an excellent indication of the performance of the lens.
 
 
 
 
In the 100% crops shown below, the top image is from the centre of the frame, the centre image is from the right hand edge of the frame, and the bottom crop is from the top-right corner. The samples below are actually approximately 0.5mm x 0.7mm on the original negative. No sharpening has been used for these scans, which were conducted at 5400 dpi, no multipass, 16 bit.
 
 
Performance wide open
 
 

MC f/1.7 @ f/1.7

MD f/1.7 @ f/1.7
 
MF f/2 @ f/2
Varisoft @ f/2.8
 
 
 

 
 

Looking at the above scans it is apparent that of the four lenses, the two MD series lenses have the best performance wide open (excluding the Varisoft, which after all is at f/2.8 wide open). The MC has very good centre sharpness (given it is wide open), but falls away somewhat at the side and corner. The newer design of the f/1.7 MD lens has evidenced an improvement in resolution in the sides and corners while still retaining acceptable centre sharpness, providing support for Minolta's decision to change the optical formula.

The f/1.7 MD model also appears to marginally outperform the f/2 lens in terms of centre resolution, but once we move away from the centre the later model appears to perform better. The performance of the f/2 lens wide open is really very impressive.

 
 
Performance at f/2.8
 
 

MC f/1.7 @ f/2.8

MD f/1.7 @ f/2.8
 
MF f/2 @ f/2.8
Varisoft @ f/2.8
 
 
 

 
 

At f/2.8 the MC and Varisoft lenses really stand out from the crowd in terms of centre sharpness. Despite this, their performance lags behind the MD f/1.7 and f/2 in terms of side and corner resolution. Why would a lens perform in this manner?

When designing a lens, the manufacturer can choose to optimise the design for centre sharpness, or to sacrifice some centre sharpness in order to achieve better overall resolution. Minolta chose to do this when replacing the 300mm MC with the new MD model, and it appears that they may have made the same decision here.

Certainly the MD f/1.7 and f/2 lenses have considerably better overall resolution when compared to the other designs. The f/2 particularly shines in this test, showing outstanding sharpness at side and corner for a lens only closed down one stop.

 
 
Performance at f/4
 
 

MC f/1.7 @ f/4

MD f/1.7 @ f/4
 
MF f/2 @ f/4
Varisoft @ f/4
 
 
 

 
 
At f/4 the performance of all of the lenses continues to improve, but the f/2 still stands out from the crowd. Corner sharpness is excellent, and is demonstrably better than its peers. Interestingly, at f/4 the Varisoft's performance has improved to the point where it is almost identical to that of the f/1.7 MC.
 
 
Performance at f/5.6
 
 

MC f/1.7 @ f/5.6

MD f/1.7 @ f/5.6
 
MF f/2 @ f/5.6
Varisoft @ f/5.6
 
 
 

 
 
At f/5.6 all of the lenses are performing well, albeit the f/1.7 MD and the f/2 remain a little ahead of their fellows.
 
 
Performance at f/8
 
 

MC f/1.7 @ f/8

MD f/1.7 @ f/8
 
MF f/2 @ f/8
Varisoft @ f/8
 
 
 

 
 
At f/8 all of the lenses perform well at centre side and corner, however the 85mm f/2 MD continues to stand out as an excellent performer. In my opinion, based upon the resolution tests detailed above I find the 85mm f/2 to be the best performer, followed by the MD f/1.7, then the MC f/1.7 and the Varisoft very close.
 
     
 
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