Panasonic 100-300mm lens reappraisal, Part 1, specifications and operation

100-300mm at 300mm, hand held shot by the roadside. 1/500sec at f5.6. Sharpness is adequate for this type of shot  even though the shutter speed is quite slow for this lens.

 

Panasonic's first and the world's first electronic mirrorless interchangeable lens camera the G1 was introduced in 2008. Two years later the 100-300mm tele zoom arrived. This gives the M43 system a full range of zooms from the ultrawide 7-14mm to the super tele 100-300mm.

Review history I bought a 100-300mm three years ago, used it for over a year then sold it. I had become dissatisfied with pictures taken at the long end of the zoom range, many of which were not sharp. Several reports on user forums confirmed my own experience, namely that the lens was sharp at the short end but soft at the long end. Then I read some more reports suggesting the problems at the long end might be more about operator technique than outright optical capability.

So I bought another one and carried out a more comprehensive set of tests than I had done previously.

Picture courtesy of camerasize.com  Sometimes the picture tells the story. On the left Canon EF 200-400 f4 [with inbuilt 1.4xconverter] on 5D3. On the right 100-300mm on GH3. Same angle of view range, same aperture range.

Specifications The 100-300mm f4-5.6 OIS lens [H-FS100300] is compatible with the Micro Four Thirds format and works on both Panasonic and Olympus M43 cameras. With 67mm UV filter, front and rear lens caps fitted it is 145mm long. With the supplied lens hood reverse bayonet mounted the diameter is 88mm. These are the dimensions you need to fit into a camera bag. Mass with UV filter, front and rear caps and hood is 605 grams. The lens comes boxed with a soft pouch and operating instructions.

On the outer barrel are a focus ring towards the front and a wide zoom ring in the mid section. At the rear is an OIS on/off switch. There are no other user interface modules on the lens.

No tripod collar/mount comes with the lens and none is available from Panasonic.

Panasonic does not reveal in it's literature whether the lens is parfocal (stays in focus when zoomed) or varifocal (has to be refocussed after zooming). On my informal testing it appears to stay in focus on the monitor when zoomed however at the long end focus accuracy is very critical to sharpness so I always refocus after zooming. The lens is not weather sealed.

Closest focus distance is 1420 mm at the short end and 1485 mm at the long end. This enables one to zoom in on small subjects like little birds from a not-too-threatening distance,

The lens mount is metal as you would expect.

Diagonal angle of view is 12 degrees at the short end and 4.1 degrees at the long end. This is the same as a 200-600mm lens on a full frame (sensor 24x36mm, 43mm diagonal) camera.

GH3 with 100-300mm on Roesch tripod collar.

Comparison with full frame You can see in the photograph that although the 100-300mm is the largest lens in the M43 system it is dramatically smaller than its full frame equivalent. The closest full frame lens I could find for comparison is the Canon EF 200-400mm f4 [With inbuilt 1.4x converter] This gives effectively a 200mm f4 to 560mm f5.6 range which is a little short of the Panasonic lens but close. You can see them side by side in the photograph. The Canon lens is 3x as long, 7x as heavy and ...........19x as expensive. It had better be good.

Mechanical properties As the lens zooms the inner barrel extends by up to 57mm. Zoom action is a little uneven and slightly stiff although I notice this is improving with use. Autofocus is quick and accurate on the GH3, although AF is a little slower at the long end. OIS effectively holds the EVF preview steady for composition. I did not systematically test it's effectiveness at producing sharp pictures but see my comments about this in the next post.

Follow focus on moving subjects is effective on the GH3, using AF Continuous (not focus tracking), 1 Area center focus point and Burst Mode M which provides AF and live view on each shot. I have noted that with any M43 camera which I have used the 100-300mm gives a lower frame rate than other tele zooms, including the 35-100mm, 45-150mm and 14-140mm. In addition the shutter sound has a different cadence when the 100-300mm is used. I have no idea why this might be so. I have read that the aperture mechanism on the 100-300mm is slow but the frame rate is still slow even at maximum aperture. So, it's a mystery.

On the GH3 or G6 unsharpness due to shutter shock is readily produced with the mechanical shutter especially at the long end. For this reason I recommend use of the E-Shutter and a sturdy tripod for speeds slower than about 1/400 second.

I found when using the lens at the long end that it is very important to keep my fingers or any other source of pressure off the inner barrel. Pressure on the inner barrel deflects it out of proper alignment leading to softness along one edge of the frame. This could be a significant issue when handholding or with the lens placed on a bean bag or similar soft support.

After market tripod collar/mount Rudolf Rosch (with an umlaut on the o) in Germany, contact at info@roesch-feinmechanik.de makes a very nice aftermarket tripod collar/mount. It is beautifully made to very close tolerances and fits on the lens nicely. I paid E75 delivered to Australia. Payment is by PayPal. I think the 100-300mm really does need a tripod collar/mount as the body/lens combination is rather unbalanced on tripod using the camera tripod socket. On the GH3 this is 19mm from the front edge of the camera base but on the G6 the center of the tripod socket is only 10mm from the front, placing a lot of strain on the socket.

Although the Rosch product is as well engineered as you could wish there are still problems resulting from the fact that it is aftermarket and not incorporated into the original design. When handholding it impedes the left hand's grip on the lens and the ability to rotate the zoom ring. If you try to deal with this by rotating the collar, it bumps into either the handle or flash housing. So for hand held use, I leave it off.

The collar is at its most useful when shooting in portrait orientation. If the camera is mounted to the tripod via the tripod socket then flipped over for portrait orientation, substantial twisting force is applied to the camera base by the weight of the lens and the screw has to be tightened hard to counteract this. The aftermarket collar allows the camera and lens to be rotated while the collar and tripod mount stay in place, with all the weight balanced nicely over the top of the mounting point.

100-300mm on GH3 at 100mm, hand held, 1/1000 sec f4.5, OIS on. This picture has been reduced and compressed for the internet so some loss of original detail rendering will be inevitable. The houses are about 200 meters from the camera.  In the original file individual leaves on trees and blades of grass are rendered quite clearly. Apart from some explicit commercial, strategic or scientific purpose, I am not sure why anybody would want more information in a photograph. 

Next Post, optical performance