2014年10月22日 星期三

Olympus M.Zuiko 25mm F1.8 Test and Review (English Version)


中文版請點及這裡.

Since the M4/3 system has been published for 6 years, Olympus announced the first standard prime lens “M.Zuiko 25mm F1.8” finally. We are eager to know the appearance, build quality and performance of this lens.





First Impression:
The size of this lens is larger than M.Zuiko 45mm F1.8(right of the picture is 45mm). Metal mount and plastic focal ring are just as the other M.Zuiko low cost prime lens. Although the color of the silver one is a little different to E-PL6 silver camera body but the build quality is very good. Unlike the most low cost lens of Olympus made in China, this one made in Japan. It fells a little tight when I screw it to my E-PL6, the focal ring is well damped, auto focusing is quite. But It is pity for no iris ring. Actually all of the M4/3 lens from Olympus have no iris ring.








Start test:
This test is for Olympus M.Zuiko 25mm F1.8 lens on Olympus E-PL6 camera body. Some of the test result will be compare with the other lenses with similar focal length. If you want to know about the detail of test procedure please refer “Basic of lens test on Olympus E-PL6”.

 
Vignetting:
At maximum iris the light loss of corner is around 1EV. After F/5.6 the vignetting disappear. It is pretty good.

F/1.8

F/2.8

F/5.6

F/11

Distortion:
Regarding the distortion of this lens just has a little barrel distortion. We rank it “Good”.

Distortion of Olympus M.Zuiko 25mm F1.8


 Distortion of Panasonic Leica DG 25mm F1.4

Resolution:
Here is the sample chart for the resolution test.


 Sample chart of resolution test


Here is the center resolution on F/1.8  F/2.8  F/4  F/8  F/16. The optimum resolution is at F/4. After F/8 the detail loss show up. The resolution is consistent from F/1.8 to F/8. If it’s not for the depth of field the iris above F/16 must be avoid due to the resolution degradation serious.


 Center sagittal resolution on F/1.8 F/2.8 F/4 F8 F/22

 
 Center tangential resolution on F/1.8 F/2.8 F/4 F/8 F/22


Here is the tangential(right) and sagittal(left) resolution at 1/4  2/4  3/4 of center on F/5.6(from up to down). Tangential is a little worse than sagittal. Sagitall is very good from center to border.

 1/4 from center on F/4


  2/4 from center on F/4
 

 3/4 from center on F/4 


 Corner resolution of Olympus M.Zuiko 25mm F1.8 at F/4


Corner resolution of Panasonic Leica DG 25mm F1.4 at F/4


To sum up the resolution crops we rank it “Good”.



Chromatic:
Here is the chromatic at corner on F1/8  F/2.8  F/5.6  F/11(from left to right). We rank it “Good”.
      
 Chromatic at corner on F1/8 F/2.8 F/5.6 F/11of Olympus M.Zuiko 25mm F1.8



Chromatic at corner on F/2.8 F/5.6 of Panasonic Leica DG 25mm F1.4 


Flare:
Here is the flare we rank it “Average”.

 Flare of Olympus M.Zuiko 25mm mF1.8 at F/5.6


 Flare of Panasonic Leica DG 25mm F1.4 at F/5.6


Sun Star:
Here is the sun star at indoor simulation light source. Very good all over the frame. We rank it “Good”.


 
 
Sun star of Olympus M.Zuiko 25mm F1.8 at indoor simulation


 

  Center sun star of Panasonic Leica DG 25mm F1.4 at F/8


Magnification:
The magnification of this lens is (17.3mm/105mm)=0.165, higher than the specification.



Coma Aberration:
Here is the coma at center(left) and corner(right). We rank it “Excellent”.



Detail of pictures:
There are a very little detail loss at maximum iris. The detail loss at maximum iris of this lens is the best we ever test.

F/1.8

F/5.6

F/22

Defocus Aberration or Bokeh:
The bokeh is very good at maximum iris. The shape of bokeh keep circle even the iris is small.

F/1.8

F/2.8

F/5.6

F/11


Conclusion:
Today we can buy M4/3 standard prime lenses at market included:

Olympus M.Zuiko 25mm F1.8
Panasonic Leica DG 25mm F1.4
Voigtlander 25mm F0.95

The retail prices are US$400  US$500  US$1000. Olympus is the lowest price, smallest size and weight least of them. To reference the ranking of each item on test :

Vignetting: “Good”
Distortion: “Good”
Resolution: “Good”
Chromatic: “Good”
Sun star: “Good”
Coma: “Excellent”

To sum up we rank this lens performance in “Good”. Considering the cost size weight and performance we recommend it is the best buy lens in M4/3 standare prime lens.

Regarding the more sample pictures please hit "Olympus M.Zuiko 25mm F1.8 Sample Pictures".


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