An Idiosyncratic, Unfair and Unscientific Comparison
Having rounded out my Olympus Pen lens kit, I've an excess of choices. I have four primes and two zooms and, as close as often matters, the zooms overlap all the fixed focal length lenses. The zooms themselves overlap at their extremes.
So here's my question: if I'm out photographing in a situation where I could use either a zoom or a prime at the same settings (focal length and aperture) which lens is going to give me the best photograph, technically speaking? E.g., if I have the 14–42mm Olympus kit zoom on the camera and I see a composition which asks for about a 20mm focal length, will I gain anything by switching to the Panasonic 20mm lens?
I don't care about relative size, weight, convenience, maximum aperture, or cost. I just want to know how my lenses perform and which ones I should choose. If that doesn't interest you, skip the rest of this article and come back in two weeks.
Here are the lenses I own:
- 12mm ƒ/2 Olympus M. Zuiko Digital
- 14–42mm ƒ/3.5–5.6 Olympus M. Zuiko Digital (first generation) (NLA)
- 20mm ƒ/1.7 Panasonic Lumix
- 45mm ƒ/1.8 Olympus M. Zuiko Digital
- 45–200mm ƒ/4–5.6 Panasonic Lumix G Vario
- 85mm ƒ/1.4 Rokinon
Simple enough; I'll compare the 12mm to the 14–42mm (lots of the times I don't need the extra coverage of the 12mm), the 14–42 to the 20mm, the 14–42 to the 45mm and the 45–200mm, and the 45–200mm to the 45mm and 85mm.
Then Jeff Goggin, who owns more equipment than is good for me, knowing that I was not totally thrilled with that 12mm, thought maybe I'd be curious to see how it stood up against his wide-angle zooms.
Oh sure, why not. So he sent me:
- 7–14mm ƒ/4 Olympus Zuiko Digital
- 14–35mm ƒ/2 Olympus Zuiko Digital SWD
- 14–50mm ƒ/2.8–3.5 Lumix Leica D Vario Elmarit (NLA)
You can see the assemblage of glass in the accompanying illustration. Suddenly the number of potential comparisons triples, and what was going to be one column is two. Sheesh. Nobody's fault but my own; I could've said no. Well, time to dive in....
How did the 14–42mm Olympus kit zoom compare to the 12mm Olympus lens? At ƒ/4 they were essentially identical in image quality, the zoom being just a touch less contrasty overall. At ƒ/5.6, the zoom was actually better, being sharper on axis. At ƒ/8 the two lenses looked identical.
How did the 20mm Panasonic fare? At ƒ/4, the 20mm had better image quality in the center of the field but the 14–42 zoom was better at the corners. The prime lens was just a touch more contrasty. At ƒ/5.6, though, the two lenses produced almost identical image quality; if one had reason to stop down to ƒ/8, the zoom was actually better.
Understand that there is much nitpicking going on here. In practical reality, what this tells me is that there's no reason to swap out the zoom for the prime (or vice versa) at these focal lengths.
It was quite a different matter at the long end of the 14–42mm's range. The 14–42mm is mushy and smeary in the corners; even stopping it all away down to ƒ/11, where you'd expect diffraction to completely dominate, doesn't clear that up entirely. That superb 45mm Olympus lens wipes the floor with the zoom. It's better in the center of the field, much better in the corners. More importantly, it has much better microcontrast. Overall contrast isn't a big deal in these days of Photoshop; it doesn't really much matter if one lens is a little more contrasty than another. Microcontrast is another matter entirely; if the lens is muddying up tonal distinctions in fine detail, that's hard to recover.
Comparing the two zooms at their extremes, the 45–200mm Panasonic is a lot better in the corners at the 45mm setting than the 14–42mm Olympus is at 42mm, although the Panasonic has pretty serious light falloff in the corners wide open. Not what you'd usually expect in a telephoto. Still, if it's a choice between those two lenses for overall quality, the Olympus loses. But more importantly, that 45mm Olympus prime lens beats them both, although it's only slightly better than the Panasonic zoom at ƒ/8. (That zoom is really quite good; I've made a number of 17x22" portfolio prints with it over its whole range of focal lengths.)
That only leaves me to compare the 85mm Rokinon with the 45–200mm Panasonic. Lenses optimized for ultrafast apertures are frequently not as good as their brethren at more modest apertures. Well, at ƒ/4 the Rokinon is really good, corner to corner. It's noticeably better than the Panasonic zoom, being crisper and sharper over the entire field. By ƒ/8, the two lenses are equally good—the zoom might even be a smidge better, but I'm hairsplitting. Generally, though, I should switch from the Panasonic to the Rokinon if I don't need the autofocus and aperture.
So, there are the answers for my personal lens set. Some predictable results—did anyone really think the 45mm Olympus wouldn't blow everything else away? Some you wouldn't predict at all if you weren't familiar with the lenses. You'd certainly not guess that Olympus's first-generation 14–42mm kit lens would be as good as the much lauded 20mm Panasonic. Or, conversely, that a very inexpensive ultra-fast telephoto would beat out a much better-than-decent zoom.
Next time I'll toss Jeff's wide-angle zooms into the mix and see what rises to the top. Likely we'll find some surprises there, too.
Ctein is anomalously idiosyncratic, unfair and unscientific on Wednesdays here on TOP.
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Original contents copyright 2012 by Michael C. Johnston and/or the bylined author. All Rights Reserved.
Featured Comment by Craig: "My big annoyance with dedicated Micro 4/3 lenses in general is that most of them (even the shorter primes) have excessive barrel distortion that has to be fixed up in software. The difference is obvious if you compare a in-camera JPEG to an uncorrected RAW file (using third-party raw processing software that won't automatically apply a lens profile to straighten the image out). Part of the problem is that correcting distortion requires pixel remapping, which by its nature always reduces sharpness in the regions farthest from the center (where the distortion is worst). Unless I missed something, Ctein doesn't tell us in this article whether he is assessing the lenses' performance based on JPEGs, corrected RAW files, or uncorrected RAW files, which makes it difficult to tell whether he's really judging the lenses as such or the image-processing software."
Featured Comment by Manuel: "You have every reason to be unscientific, Ctein. Using a lens can be a very subjective experience. We often get misled by technical specifications and overlook a lens because of e.g. its narrow maximum aperture, but lenses are hard to judge from specs only.
"Let me advocate a lens that everybody else dismisses: the humble Olympus M.Zuiko Digital 17mm ƒ/2.8 Pancake lens. This is the lens that was bundled with my E-P1 (it was one of those once-in-a-lifetime deals) and was my only lens for two months, save for a rather frustrating two-day experience with the original 14–42mm zoom, which I never got to grips with. (That was when I realized I was a prime man.) Sure, the Pancake has horrendous chromatic aberration and fisheye-like levels of barrel distortion—even if it's unnoticeable with JPEGs due to in-camera correction—but, when I look critically at the 30x40 cm prints of photos made with the 17mm and the E-P1, those issues become completely irrelevant. The levels of detail are simply amazing for such a modest lens and, while I wouldn't exactly call it 'sharp,' it is nonetheless extremely accurate.
"Short of having a top quality wide-angle lens, the Pancake is my loyal companion when I do street photography. Very seldom it lets me down. Even now that I have some nice OM lenses in my backpack (don't even get me started with praising them), I keep turning to the Pancake because of its nimbleness and levels of detail. So here it is: there's nothing like actually using a lens to evaluate it. In my view, printings are the ultimate image quality test—and the 17mm passes it with flying colours. We should never overlook a lens just because it has a bad reputation, and neither should we rush in to buy one just because everybody is raving about it."