A good 70-200mm is a go-to for pro photographers. The Lumix S Pro 70-200mm F4 O.I.S. ($1,699.99) is Panasonic's first full-frame telezoom lens. It's quick to focus and does a fine job on 24MP cameras, but falls short of what we've seen others do on high-resolution sensors. For the high price we expect a bit more.

Compact, Internal Zoom

The Lumix S Pro 70-200mm certainly looks and feels like a top-end lens. It measures 7.1 by 3.3 inches (HD) and boasts an internal zoom design so there's no extension of the barrel as you adjust the focal length. It weighs in at 2.2 pounds and supports 77mm front filters. The lens ships with front and rear caps, a reversible hood, and a carrying pouch.

A removable tripod collar is included. The lens isn't too heavy or long, so you may opt not to use it. I found it useful with a sling strap, as it better centered the connection point. The foot is compatible with Arca-Swiss equipment, so you can use it in compatible tripod heads without the need for an additional quick release plate.

Like the S1 and S1R cameras, the S Pro 70-200mm is sealed to protect it from dust and moisture. Panasonic has opted not to include a fluorine coat on the exposed glass, as it does with the 24-105mm F4.

The zoom ring turns smoothly and has marks to show the 70, 100, 135, and 200mm positions. (The S1 and S1R show focal length in the viewfinder if you want a more exact figure.) The focus ring, which is placed farther ahead, uses a clutch system. This gives it a linear response to manual adjustments, with hard stops at both ends of the focus range.

Focus is available to just about 3 feet (92cm), giving the lens a 1:4 macro capability at the 200mm setting. It's not close enough for Panasonic to bill the lens as a macro, as it does with the 24-105mm F4 with its 1:2 magnification.

The lens is optically stabilized. It works in conjunction with the in-body stabilization offered by the S1 and S1R bodies. The system can be turned on or off via a switch on the side of the barrel.

Focus is driven via dual motors and is quite fast. It's one of the big advantages the lens offers over using a non-native zoom via an adapter. The 70-200mm is also compatible with the two teleconverters Panasonic is offering for the system, the Lumix S 1.4x ($499.99) and Lumix S 2x ($599.99). We didn't have the opportunity to test the lens with either converter.

Disappointing Resolution

I used the 70-200mm with both the S1 and S1R, and ran resolution tests using the 47MP S1R and Imatest software. At 70mm f/4 it puts up resolution that's decent, but not noteworthy. It notches 2,776 lines on average, with the sharpest results in the central third of the frame (3,420 lines). Resolution drops as you move off-center, eventually softening noticeably at the edges of the frame (1,712 lines).

There isn't a huge improvement at f/5.6. The average score climbs to just 2,881 lines. The center doesn't get noticeably sharper, but the mid parts of the frame climb to exceed the average, and the edges get a very modest bump (1,810 lines). Likewise, at f/8, the average is up to 2,898 lines, and edges to climb to about 2,000.

See How We Test Digital Cameras

Absolute sharpest performance is at f/11—3,046 lines averaged across the frame. We consider this to be a good result on a high-resolution image sensor. Edges are just about as good as they get with this lens, 2,549 lines. Diffraction enters the picture and cuts into resolution slightly at f/16 (2,715 lines) and f/22 (2,348 lines).

We've not yet had the opportunity to test the only other telezoom available for the L-mount system at this time, the $6,395 Leica APO-Vario-Elmarit-SL 90-280mm f/2.8-4, but its price puts it out of reach of most photographers; we've seen similar zooms that put up more resolution for less money. Results are not directly cross-comparable from camera to camera, but the $800 Tamron SP 70-210mm f/4 Di VC USD showed 3,625 lines at 70mm f/4 when tested on the 50MP Canon EOS 5DS R.

At 135mm f/4 the lens shows 2,512 lines, which is slightly soft. The center is better (2,821 lines), but it drops as you move toward the edges, averaging 2,364 lines in the mid parts and 2,116 lines at the periphery.

There isn't much shift in the average at f/5.6 and f/8—we see about 2,550 lines at both settings. Edges do get better, hitting 2,220 lines. Resolution is steady at f/11, with about 2,545 lines and performance that's very close from center to edge. The story is about the same at f/16, and there's an expected drop at f/22 (2,262 lines).

At 200mm the resolution drops more. We see 2,135 lines at f/4—edge quality isn't a concern, as the periphery is just as sharp (or soft, in this case) as the center. There's a bit of an uptick at f/5.6 (2,295 lines) and resolution holds just about steady through f/16. There's a slight drop at f/22 (2,118 lines).

Overall, these are disappointing figures for resolution. It is only one aspect of lens performance. The 70-200mm does a wonderful job controlling distortion, showing basically none throughout the range. There is a very slight vignette at f/4, about -1.5EV at the corners when working in Raw format, but it goes away at f/5.6. If you shoot in JPG format, in-camera corrections remove the vignette completely.

A Pro Lens?

Expectations for the Panasonic Lumix S Pro 70-200mm F4 O.I.S. are understandably high. The company slapped the Pro moniker on it, for one, and it's the most expensive 70-200mm f/4 zoom on the market for any system by a couple of hundred bucks.

On the outside, it lives up to the promise. It looks good and is fairly compact and light given its zoom power. The tripod collar is easily removed and compatible with Arca-Swiss equipment, the focus clutch works well, autofocus is very fast, and the lens is sealed to protect it from dust and moisture. But it falls short in some respects—there's no fluorine coat, now expected on a serious lens, and you don't get the physical aperture control ring like you do with the Lumix S Pro 50mm F1.4.

It's ultimately the disappointing resolution, coupled with the high price, that keep the 70-200mm from getting higher marks. Panasonic's L-mount cameras are on the pricey side, so it's not surprising to see its lenses creep up in cost as well. But for $1,700, this is a lens that needs to deliver absolute crackerjack image quality, and it falls a little short.

Thanks to Lensrentals for providing the 70-200mm for review.

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