Lens Test Lumix 35-100 mm f2.8 Premium Tele Zoom for M43

Introduction  This constant f2.8 lens completes a trio of premium zooms for the M43 System. The first was the 7-14mm f4, the second was the 12-35mm f2.8. I have reported on my experience with both on this blog.

Test Procedure    I bought my 35-100 mm lens in February and have been using it on a Lumix GH3 over the last 2 months in a wide variety of photographic situations, allowing me to test it thoroughly in real world use involving several thousand exposures. I have photographed a test chart, a grove of casuarina trees with fine foliage, landscapes on and off  tripod, portraits indoors and out, sport/action, day and  night shots, OIS tests, AF tests and shutter shock tests. I gave the lens a thorough workout. I shoot RAW and inspect the images post capture in Adobe Camera RAW.  Both the GH3 and 35-100 mm were  running firmware version 1.1

Place in the M43 System  For many years professional photographers using DSLR's with a 24x36 mm sensor [a.k.a. Full Frame] have relied on two constant f2.8 zooms for much of their work. These are the 24-70 mm f2.8 and the 70-200 mm f2.8.  Canon regards the 70-200 mm focal length as sufficiently important to offer 4 versions; f2.8 with and without OIS and f4 with and without OIS.       If  the  M43 System is  to seriously challenge CaNikon's hegemony of the interchangeable lens camera market there needs to be a M43 version of  the fast mid range pro level zoom.

The 35-100 mm f2.8 is that lens.

Features  The most obvious visible feature of this lens is it's compact size. When the M43 system was inroduced much of the marketing message emphasized how losing the DSLR mirror and prism could reduce camera body size.   All this is still true of course, but the greatest opportunity for size reduction is to be found with the lenses.  Moreover, longer focal lengths mean more opportunity for size reduction. The difference between the M43  35-100 mm f2.8  and the full frame 70-200 mm f2.8  is dramatic, as you can see in the photographs.

35-100 mm on m43 provides the same diagonal angle of view [34-12 degrees] as 70-200 mm on full frame, although the native aspect ratio of M43 [4:3]  is different from that of DSLR's [3:2].

The Lumix 35-100 mm is weather sealed with a thin gasket around the mount. The lens does not extend  with zoom or focus, both  actions taking place internally.   This feature makes the lens a pleasure to handle.

The front element  does not rotate with zoom or focus.  There is an OIS ON/OFF switch on the lens barrel, but no distance or depth of  focus marks and no AF/MF switch. The lens is of varifocal type, which means that it has to be refocussed after zooming.

As with the 12-35mm,  the rear element is as far back in the optical pathway as possible. It is a fixed double element about 21 mm in diameter, almost that of the sensor diagonal measurement. Care is required when handling the lens as the rear element is very close to the outside world. If you try, as I have done several times, to quickly mount a body cap on the lens instead of the correct lens cap, damage to the rear element is possible.

A reversible hood is supplied with the lens. I use it all the time.

Measured length with UV  filter, front and rear lens caps is 120 mm.

Measured diameter with the lens hood reversed on the lens is 78 mm.

The bare lens without filter, caps or hood is 103 mm long and 67 mm in diameter.

Mass is  350 grams bare, 440 grams with front and rear caps, filter and hood.

Prices vary with country, vendor and time. However for comparison I checked prices listed at the time of writing by a Sydney vendor, Digi Direct.

Lumix 35-100 mm f2.8 OIS                     $1459

Canon 70-200 mm f2.8 L IS 2                  $2375

AF- S Nikon 70-200 mm f2.8 ED VR 2  $2868

In most markets the 35-100 mm is the most expensive M43 lens, leading to  adverse comment from some contributors to M43 user forums.  However when compared to the full frame equivalents it looks quite a bargain. I bought mine from the camera shop mentioned above together with the GH3 body for a significant discount on the listed price for both. I expect that over time the price will come down a bit.

When reviewing models and prices I noticed that Canon does not offer an EFS 46.6-133 mm f2.8 lens and Nikon does not offer a 44-125 mm f2.8, either. These would be the equivalent lenses for the Canon EFS and Nikon DX camera lines. It would appear that neither Canon nor Nikon is supporting their APS-C model lines as alternatives for the professional photographer.

Panasonic, having no other line of interchangeable lens camera to support, can offer the 35-100 mm without taking sales from itself.

Like other M43 lenses with OIS, the unpowered 35-100 mm rattles when shaken side to side, due to movement of the OIS unit. 

With one's ear right on a powered lens noises can be heard from the OIS unit, AF motor and aperture diaphragm operation.

The zoom action is very smooth.

Single autofocus is very fast and accurate on the GH3.  Continuous AF also works well making the lens quite suitable for many types of moving subject.

If pointed at a bright light source, the lens sometimes behaves like the 12-35 mm in that the aperture diaphragm can open and close without user input. This makes a  noise which is audible in a quiet place. Some contributors to user forums have reported this as a fault, but it appears to be the normal behaviour of the lens. It may possibly serve the function of protecting the sensor from excessive light, I don't know.  

Manual focus operates the usual way,  by rotating the focus ring which triggers an electronic mechanism. This works without problem however I personally would prefer a little more drag on the focus ring for more feel.

The Optical Image Stabiliser works well to stabilise the preview image in the EVF, an effect most noticeable at the long end of the zoom range. Some reviewers have stated the OIS allows sharp handheld photos up to 4 shutter speed steps slower than without OIS.   My tests found the difference to be about 1.5 steps. The difference may lie in the test procedure. Many reviewers measure the percentage of unsharp shots with OIS on vs OIS off.  But I want to know the shutter speed at which every shot is sharp which may be a more stringent test.

Note that one reviewer, Jordan Steele (Admiring Light),  found that photos with OIS  On,  were less sharp at very fast shutter speeds [1/3200, 1/4000]  than at more frequently used shutter speeds.  I have not observed this issue but that may be because I rarely use such fast shutter speeds.

Shutter Shock  This is a well known potential source of unsharpness in photos made with M43 equipment, about which I have written elsewhere on this blog. I ran formal tests using a test chart and tripod, then many hundreds of real world photos in the shutter speed range 1/80 -1/100 sec with E-Shutter on and off.  My conclusion is that I could not find any convincing evidence of softness or blurring which might be attributable to shutter shock with the 35-100 mm lens on a GH3 body.

Sharpness/resolution  For comparison I used the Lumix 12-35 mm, 14-45 mm, 45-150 mm and 100-300 mm lenses.

At 35mm focal length, the 35-100 mm and 12-35 mm gave the same level of sharpness/resolution. Without the EXIF data I could not distinguish one from the other on any test.

At the longer focal lengths the 35-100 mm was better at f2.8 than any of the other zooms at any aperture.

Image definition in a broad area covering most of the frame is excellent from f2.8 at all focal lengths, with excellent resolution of fine surface texture and faithful  rendition of all skin blemishes in people pictures.  Ladies will hate portraits made with this lens. Stopping down to f4 sharpens the corners perceptibly. My copy delivers very even performance right across the focal length and aperture range. Best overall aperture appears to be in the f4-5.6 range but f2.8 gives really excellent results except for slight softness in the corners.

Roger Cicala of Lens Rentals reported his tests on  7 copies of this lens in October 2012. He found generally excellent results but resolution below expectations at the 100 mmm focal length and f2.8 on all 7 copies. My experience with a lens presumably from a later production run has been that I did not notice this issue at all even though  I was looking for it having read Roger's review prior to doing my own tests. In fact my copy is notable for it's ability to deliver excellent resolution at all focal lengths and aperures.

Chromatic aberration  This is corrected in camera in Panasonic RW2 files and was not evident in any of my photos. It may be an issue on Olympus cameras which do not correct for CA.

Some Corner shading  is  present at f2.8 but not to a degree which I thought required correction on any of the thousands of photos I have made with this lens.

Distortion  is corrected in camera such that it is not evident in general photography, even where this includes buildings. Some reviewers have  examined uncorrected RAW files and discovered substantial barrel distortion at the short end of the zoom range.

Bokeh  Out of focus rendition is generally pleasing and smooth, without tramlining or other jarring intrusions into the viewer's awareness.

Contrast/microcontrast  is excellent.

Flare  The lens is supplied with a deep hood, which I use for all outdoor photographs. This prevents the sun 's direct rays falling onto the protective filter and as a result flare is an infrequently encountered issue with this lens. If the lens is pointed directly at the sun flares of various types are readily induced, to the detriment of image integrity.

Close focussing capability  appears not to have been a priority for the designers of this lens.   Minimum focus distances, measured from the subject to the sensor plane are

At 35 mm focal length,   630 mm

At 100 mm focal length,  780 mm

At 100 mm with +2 diopter Close Up lens,  420 mm.  Horizontal subject field at this distance is 70 mm.

The main advantage of the 35-100 mm is the constant f2.8 aperture, which does not reduce with zooming out. This allows the lens to be used at wider apertures in all conditions than the more consumer oriented optics. This in turn allows for lower ISO settings or faster shutter speeds or both. The consequence is better potential image quality.

The absolute resolution available with the 35-100 mm is slightly better than the less expensive zooms but I had to look hard at 100% and 200% enlargement of test photos to see the difference.

Value for money  I would have to rate lenses like the Olympus 40-150 mm [occasionally on sale for the astoundingly low price of $99] and the Lumix 45-150 mm [at around $300] as the best value tele zooms in the M43 system. Their performance to price ratio is remarkable. The extra 1-2 stops of aperture available in the 35-100 mm comes at a premium price. For M43 users who prioritise small size and low cost, the 35-100 mm is overkill. But for those who want the best performing tele zoom lens and can afford it, the 35-100 mm is perfect.

Comparison with Canon EF 70-200 mm f4 L IS USM      I bought  this lens for use on a Canon EOS 60D two years ago and at the time rated it the sharpest lens I had ever used. I sold off the Canon gear mainly because the camera would not reliably focus the 70-200 or the 15-85 mm lenses which I was using at the time. The size and weight of the Canon kit didn't help much either. I did not have the opportunity to test the Lumix and Canon lenses side by side but I shot several favourite scenes with both and was able to make a reasonably useful comparison based on viewing the photos. My impression is that the Lumix 35-100 mm lens gives slightly better sharpness and resolution across the frame.  This should be no surprise, by the way. The Canon lens is designed for full frame so cannot deliver it's best performance on the reduced frame of the 60D. The Lumix lens is being used on the imaging sensor for which it was specifically designed.

Focussing   Depth of focus at f2.8 is quite shallow. In consequence the user needs to tell the lens exactly where to focus. If the camera is left to select a focus point, results are out of the user's control and may not be as intended.   Please refer to my discussion about this with illustrative photographs in "Lumix GH3 Review Part 4, Single Shot Focus" on this blog. The user needs to make a conscious decision as to the best point of focus. The size and position of the active AF area need to be precisely specified.

Camera movement  There is nothing new here. However the lens is capable of very high sharpness if the camera is held perfectly still at the point of exposure or the shutter speed is high enough to negate the ill effects of camera shake. Some users  might think the lens' performance is nothing special when the problem is lack of attention to optimal technique. For more discussion about this please see "Lumix GH3 Review Part 9, Stop the Shakes" on this blog.

Summary  The Lumix 35-100 mm f2.8  and the  12-35 mm f2.8  are the best zooms available for the M43 system and in my experience two of the best zoom lenses I have ever used for any camera system. Used with care the 35-100 is capable of excellent results in a wide variety of photographic situations.