Olympus M.Zuiko 12-50mm f/3.5-6.3 in comparison

During this time of year we have not much light even during daytime and the weather in Southern Finland has been quite cloudy and rainy. Because of that I decided to do a traditional test target shoot to compare the new zoom with some of my other lenses. 

Above is my test setup. I used two targets, one in the center and the other in the right upper corner. I shot the same "subject" (marked here as grey area) with different focal lengths. Of course distance varied accordingly to keep (subject) area the same. I used studio flashes and used their power settings to keep exposure on sensor constant in every picture. Accuracy was 1/10 stop. This way the differencies in lens diaphragm did not affect the results. I also focused center and corner targets separately to compensate for possible curvatures in lenses´focal planes. All test pictures were shot at ISO 200. Camera was Olympus E-P3. RAW images were opened in Lightroom 3.6 and I did a basic normalization of tones, correction of chromatic aberration and added sharpening. Those are the same basic tweaks I would do to real pictures. Possible distortions were not corrected as can be seen in corner shots.

Focal Length 12mm

The first comparison shows the center of 12-50mm zoom at full aperture F3.5 and closed at F5.6. Focal length is widest, 12mm. These are 100% crops, like all other target images here. The image quality gets better with smaller aperture as would be expected here.

 

Olympus´4/3 series zoom lens Zuiko D. 12-60mm f/2.8-4.0 is the perfect comparison lens for any lens having the same focal length range. Here we can see center targets. This result is in line with Olympus´MTF curves below: 12-60mm zoom is a great lens, and especially its resolution (orange curves) is higher than with the new zoom. You can find more of these MTF curves at Olympus web sites. They are good tools when comparing lenses.

 

In upper line of this picture we have the corners of 12-50mm zoom at apertures F3.5 and F5.6. Contrast and resolution gets better with smaller aperture, but radial (sagittal) and tangential (meridional) lines have a very different resolution. It can be also seen in MTF curves, where continuous line is sagittal and dashed line is meridional transfer function. For comparison we have corner shots with 12-60mm zoom at F3.5 and and M.Zuiko 12mm f/2 prime at F4.0. 12mm lens is not too good in corners, but it has this reasonable level all ready from F2.

Focal Length 14mm

 

As a further comparison lens we have M.Zuiko 14-42mm f/3.5-5.6 II kit zoom. Above its results at 14mm focal lenght and apertures F3.5 and F5.6. Left side images are from center and right side images are from corner. Now 12mm and 14mm focal lengths are so different that they should not be compared directly. That´s why I have below a common focal length of about 19mm.

Focal Length about 19mm

 

Here I set the shooting distance with Lumix G 20mm f/1.7 prime. After shooting with it, I shot with those three zooms from the same spot while setting zoom or focal length so that the cropping was always equal. Zoom rings did not show 20mm because Lumix actually has not a 20mm focal length. It is maybe close to 18,5mm. These crops are from center. Lumix 20mm and Olympus 12-60mm zoom show almost identical performance. Wide open 12-50mm zoom has a good resolution but its contrast is not up to 14-42mm zoom.

 

Looking at corners, 12-50mm zoom has again nice resolution but contrast performance is very modest. Thus it is practically a draw with kit zoom. Maybe it comes as a surprise for some people but Lumix 20mm is not much better in the corners. Number one from these lenses is quite obvious.

Closing down to F5.6 makes Lumix 20mm markedly better in the corners than these zooms.

Focal Length 42mm

 

This comparison has on the left centers at full aperture and on the right corners, again at full aperture. 12-50mm zoom gets better all the time as focal length grows. 14-42mm zoom on the other hand sees especially contrast dropping at its longest focal length.

Focal Length 50mm

 

Uppermost, on the left, we have 12-50mm zoom´s center at full aperture. All the other crops are from the corner. 12-50mm zoom shows just slightly better contrast in corners when closed to F8. Still contrast performance is lower than resolution. As new lenses I included M.Zuiko 45mm f/1.8 at the same aperture F4 as earlier were Lumix 20mm and M.Zuiko 12mm. 50mm is 4/3 series Zuiko D. 50mm f/2 Macro. 

Macro setting

 

As close up test I did a watch image. At macro setting 12-50mm has a 43mm focal length. It can not be changed as zoom ring does not move when macro setting is engaged. Largest aperture is F6.0. Here we have the closest focusing distance of 200mm.

I tried apertures F8 and F11. The smaller aperture shows already effects of diffractions but on he other hand the better depth of field can be a bigger benefit. How ever, the 12-50mm lens is capable of very nice images with close up subjects. This is a 100% crop.

For comparison once more on the left the new 12-50mm zoom and on the right Zuiko D. 50mm f/2 Macro. Aperture is F8. Focusing differs between these images, please look for the sharpest details in both images. 

Conclusion

Zuiko D. 12-60mm f/2.8-4 is one heck of a lens. I guess that´s old news. The images should tell quite clearly the differencies. However, we must remember that this kind of very precisely made test target comparison is a lot harsher than any normal shooting. The differencies in normal shooting would not be in the same league, there are too many disturbing factors. Even slight differencies in exposure, focus or camera shake could obscure a lot. But, yes this is what you get when everything is optimized.

M. Zuiko 12-50mm f/3.5-6.3 is a very reasonable lens for photography with its longer focal length and especially for close up shooting. Otherwise it fits better for video because of its silent and fast focusing and silent power-zoom. For video it has plenty of quality. You can check this by scaling test shots into 50%. Then they correspond to Full HD quality. 

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Olympus M.Zuiko 12-50mm 1:3.5-6.3

I got a production sample of the new Olympus zoom lens, M. Zuiko 12-50mm 1:3.5-6.3, the other day. It is the first weather sealed lens in Olympus PEN M.Zuiko series. A weather sealed lens among ordinary bodies, well, that means there will be soon a weather sealed body. I would guess that the waiting time is probably not even long. The new lens has attracted some net controversy since it´s release, so it is interesting to see what it is good for.

Above the new zoom in size comparison with 4/3 series 12-60mm 1:2.8-4 and m4/3 series 14-42 kit zoom.

Build

The new lens is slightly larger than the 14-42mm kit zoom in shooting position. The lens has a solid feel, while it´s outer structure is plastic. Both zooming and focusing are internal, so the lens has no external moving parts other than the focusing and zoom rings. The narrow focusing ring is on the front of the lens. The zoom ring is fully electronic. When set for manual, it works like a normal zoom ring. In E-position, it works as power zoom switch. Zoom speed depends on the strength of the twist. Manual and e-mode are selected by moving the zoom ring back and forth. The selected position is shown on the right side of the lens frame. On the left side there are L-Fn and Macro buttons. When the latter is pressed, zoom ring can moved to a third position, which naturally is macro. The closest focusing distance in macro mode is 0.2 m and the minimum image area is 36x48mm. L-Fn in turn, is specially designed as AF lock for video shooting, in situations where you want to prevent the continuous focusing from locking on a wrong subject.

Half of lens elements are of special glass. DSA means Double Super Aspherical, a lens that can substitute a group of lenses in traditional design.

L-Fn and Macro buttons on the left side of lens.

Window on the right side of lens shows now that zoom ring behaves like a traditional zoom ring (while it actually is electronic). Moving zoom ring (on the right) to the right activates power zoom. Pressing Macro button and moving zoom ring another click sets the lens for macro shooting.

On paper

From Olympus provided data I would expect that this lens is in optical quality (contrast and resolution) between the kit zoom 14-42mm and the 4/3 series zoom 12-60mm 1:2.8-4. MTF curves can be found on Olympus' websites. They, too, show a relatively uniform quality throughout the image area. The new lens will not stand up, particularly in resolution, up to the 12-60-millimeter zoom in wide-angle position. However, the longest focal lengths should not differ at all in practice. That in turn means that the new lens should give in practice very visibly better image quality compared to the kit zoom at longer focal lengths.

The first impressions

Finland is not really a wonderland to test such a lens during this darkest time of the year. I shot yesterday the first batch of images  to get an idea of handling and usage in practice. All images were now shot handheld, and then at full aperture out of necessity. ISO sensitivities when shooting outdoors with this kind of lens during the darkest time of the year are too high for verification of previous contrast/resolution estimates. That´s for the next blog. The first impression, however, is in favor of them.

It is noteworthy that the image when opened in Lightroom shows practically no vignetting at any focal length at full aperture. Distortion is notable at 12mm position, and disappears almost entirely by 17mm. Chromatic aberration is also strongest at the widest setting and decreases / disappears when the focal length increases. Distortion, and chromatic aberration are easy to remove with the Lightroom tools, and you can make a specific total correction preset per focal length.

Below are a few pictures, I will return to a more accurate comparison between those previously mentioned zooms after Christmas.

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Focal length 20mm, F4.6, 1/60s, ISO 800

Focal length 50mm, F6.3, 1/100s, ISO 1600.

Focal Length 50mm, F6.3, 1/80s, ISO 1600.

Focal Length 12mm, F3.5, 1/60s, ISO 640.

Update on December 25, 2011 at 11:49 by Pekka Potka

I know the zooming is electronic but when it is set to manual, does it feel like a manual lens?

There are so many versions of the feel of manual zoom among traditional lenses... The feel of movement in 12-50 is smoother and it has a better balanced resistance than in my copy of 12-60. There is a typical "electric scratching" noise while turning the ring on manual mode. End points of zoom range are well defined also with audio. Focal lengths are shown in viewfinder (and in viewfinder only).

Also, can you give the breakdown on aperture/focal length? Where does it hit f/6.3?

This graph shows largest F-numbers at various focal lengths based on viewfinder information:

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Olympus E-P3: AF speed and responsiveness

Olympus E-P3 was introduced on 30th of June. As name says it is the third version in E-P series which I use. I am interested because Olympus promises now to correct the slow AF which hampered previous models. All in all the responsivity of this camera should be at a totally new level.

I created a simple test arrangement to get a real world understanding on E-P3´s AF speed. A sat at a table with my elbows leaning on table. On the others side of table I had a newspaper (at 1m distance) and directly behind there´s a plant across the room at 5m distance. I set both E-P3 and E-P2 to do single-AF at a press of shutter button AND shutter is activated only after focusing is done. Other settings: Program AE, ISO 400, single shot mode, medium JPG, only center focusing spot active. 

Now I aimed focusing spot at newspaper and pressed shutter button until camera focuses and shutter goes, aimed focusing spot at plant and pressed shutter button until camera focuses and shutter goes, aimed focusing spot towards newspaper and pressed… I went on doing this until I counted 75 shots. The number 75 is not important. The point was to make enough shots so that slight differences between each single shots become averaged when shooting with both cameras. I repeated the same drill for four lenses:

  1)  The new Olympus m4/3 kit zoom lens 14-42mm 1:3.5-5.6 II R. Tested at 42mm focal length.

  2)  Olympus m4/3 zoom lens 40-150mm 1:4-5.6. Tested at 50mm focal length.

  3)  Olympus 4/3 zoom lens 12-60mm 1:2.8-4 with Novoflex m4/3 adapter. Tested at 50mm focal length.

  4)  Panasonic Lumix G 20mm 1:1.7

Then I looked into EXIF data of first and last shot of each series to see the time difference between them. I divided this time by number of shots to get the average time for aiming camera and focusing and exposing each shot.

These are my results:

        E-P3     E-P2        E-P3 is faster by

1)    0,82s    1,41s            42%

2)    0,89s    1,46s            39%

3)    1,96s    2,26s            13%

4)    0,87s    1,54s            44%

I have no way to know how long it took to aim the camera between each shot but it was not much. Just turned the camera a few degrees up or down. Olympus gives a shutter response time of ONLY 60ms for E-P3. My conclusion is that E-P3 is in practise twice as responsive camera as E-P2. With older 4/3 system DSLR lenses the lens is the restricting factor. I would guess that these lenses would benefit of a new firmware for m4/3 bodies.  

So how responsive E-P3 is then? Olympus claims it to be the fastest focusing camera of all system cameras. Lets see!

I repeated the same test with Nikon D3x and three Nikon lenses:

  5)   AF-S Micro Nikkor 105mm 1:2.8 G

  6)   AF Nikkor 85mm 1:1.4 D

  7)   AF-S Nikkor 14-24mm 1:2.8 G. Tested at 24mm focal length.

Results:

D3x

5) 0,97s

6) 1,15s

7) 0,70s

Results for differences between these three lenses are logical and should be familiar to everyone who has used them. Wide angle zoom 14-24mm is fast because there the distance to move focusing element is so short. Other than that look at E-P3! E-P3 is faster (with three consumer grade lenses) than Nikon. It´s responsiveness is up (or should I say down) there with a super fast professional DSLR with 10 fold price tag! 

UPDATE: 

Same test with the new Olympus M. Zuiko 12mm 1:2.0 lens. This lens is Olympus´ first lens that which they consider as belonging to the top level in their three level lens grading.

Test result with E-P3 0,74s.  E-P2 was not tested because speed difference is already known.

Already while testing the new kit zoom lens I was somewhat distracted by Live View refresh rate. Live View goes off and back on with each image, as sensor is reseted before and after exposure. (I did not have record view on, just viewfinder image). With this 12mm lens, it is quite obvious that now the restricting factor is not focusing but other functions of camera. Mere focusing back and forth is a lot faster, also faster than Nikon 14-24mm. With this lens focusing is done immediately as you press the button. How ever, this result tells how fast you can take two consecutive images with varying focusing distances. Focusing is very fast but the responsivity of a Live View camera like E-P3 is not yet quite there with a professional reflex camera like D3x.

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