Olympus 12-100 v. Panasonic 35-100 v. a Brick Wall

This is basically a continuation of the testing I am doing on the new Olympus 12-100 F4 lens.  In a previous post I compared it with the Olympus 12-40 F2.8 zoom.

On the Olympus E-M1, I shot with the Olympus 12-100mm F4 zoom and the Panasonic 35-100mm F2.8 zoom at 35, 50, 70 and 100mm, using F4 and F8. That’s eight images with each lens. I then compared the four corners and the center of the comparable 12-100 and 35-100 images. I shot in raw and did not use a tripod.  Shutters speeds were fast, about 1/400s for those shot at F8 and 1/800s for those shot at F4. 

Because this was a brick wall experiment at about 50 feet, some might criticize it as a less-than-useful experiment because it is not a "real world" situation. I understand this argument. After all, how often in real life is one interested in only one two-dimensional plane within a three-dimensional image. Nevertheless, primarily to be sure a new lens is working properly, I most often conduct a brick wall experiment during the 30-day return period available when purchasing from Adorama or BH Photo (and perhaps others).

So you can visualize the experiment, here is the brick wall at 35mm:

Below is 50mm:

Below is 70mm:

Below is at 100mm:

I downloaded all of the photos to Lightroom and compared them side-by-side using the X:Y tool.  At 1:1 magnification I could see no difference in sharpness in the center or corners! Since the 35-100 is already known as a very sharp lens, by association this suggests that the 12-100 is likewise sharp over the 35 to 100mm range.  (And I already know —see prior post— that the 12-100 goes head to head with the very sharp Olympus 12-40 over the 12 to 40mm range.)  

This is all good news for the 12-100. But I wanted to check it out with additional magnification to see if I could then see a difference.

So, I compared the images at 2:1.  This did allow me to see some differences.  The overall result is that the Olympus did better most of the time, but the results were very close and were not consistent. In the real world, I am confident that the differences will not make a difference.  Here is what I found with the two lenses:

Centers:  

In total I compared 8 image centers for each lens.  That images were at four focal lengths and at two F stops.  As far as I could tell, the lenses were equally sharp in the center.

Corners: 

The 32 corners were a different story. At 35mm, 50mm and 70mm, and at both F4 and F8, I compared 24 corners and the Olympus corners were generally sharper.  My tally shows that Olympus had 15 sharper corners (screen shot below is typical); the Panasonic had 4 sharper corners (but it is impossible to see the difference on a blog-published jpeg compressed screen shot so I am not showing any); and 5 corners were “tied”. 

Lower right corners viewed at 2:1.  They do not exactly line up, as I did not use a tripod.
However, as I mentioned, centers were equally sharp throughout these comparisons and I
don't believe therefore there was any camera shake.  These two images were taken at 1/800s,
so again I don't think camera shake was a factor.

The story changed again at 100mm. Here, Panasonic was the winner, as it was sharper (marginally) in 5 of the 8 corners.

Summary:

Centers: Equal

Edges: Olympus 18.  Panasonic 9.  Tied 5.

Thoughts on Purchasing:

There is really no clear winner.  If there were, only one would be selling and the other would stay on the shelves.  To me the disadvantages of the 12-100 are worth the cost. But of course I can only speak for myself.  I would choose the 12-100 over the 12-40/35-100 or 12-35/35-100 combo if I were starting fresh.

On the negative side, the 12-100 is more expensive, larger, and heavier.  I don’t like the fact that it telescopes when zooming, where the Panasonic 35-100 zooms internally.  But on the other hand, I believe this telescoping design is what allows it to provide a 1:2.5 close up magnification. I also like that the 12-100 combines two useful focal lengths  (either the 12-40/35-100 or 12-35/35-100) into one lens. I find changing lenses a real hassle.

Overall I think the 12-100 wins on sharpness, being equal to the 12-40 and being sharper overall than the 35-100. But the differences were only seen at 2:1 magnification.  This should not make a difference in real world photography. Assuming proper technique, no one will ever say your images aren't sharp enough, with whichever lens you use.  On the other hand, with the 12-100 you give up the F2.8 aperture. F2.8 is so nice when working indoors when only ambient light is available. However, since I am mostly a landscape and travel photographer, F4 as the largest aperture is perfectly fine with me. For depth of field purposes I usually shoot mFT cameras at F4 to F8. Indoors I can switch to an F1.8 Olympus prime which does more than one stop better than F2.8 and more than two stops better than F4 in bringing light to the sensor.

After landscapes and travel, close up photography is a favorite.  Like the 12-40, the 12-100 has a very nice close up capability, making it quite handy for flowers, butterflies and food, for example.  At the closest focusing distance at focal lengths from 25mm to 100mm, I can fill the frame with a subject 3-3.5" wide.  This represents an approximate magnification (35mm equivalent) of 1:2.5. The pull-back "clutch" style manual focus ring is gorgeous.  It turns the focus ring into a mechanical style manual ring with hard stops at both ends of the 90° range of movement. This feature works very well with focus peaking. 

For closeup work the 35-100 is lacking (comparatively). It's advertised magnification is  1:5 (35mm equivalent). The smallest subject that can fill the viewfinder with this magnification is approximately 6-7" wide.