Panasonic GH4 User review Part 5, 100-300mm lens compatibility problems

GH4 with 100-300mm , hand held.  f8, 1/1600 sec. It was a hazy warm day, not really good for long distance photography however the 100-300mm lens has handled the conditions well. The buildings in the foreground and the old crane which is being dismantled by the men from Marrs are about 1.5 kilometres from the camera. The buildings in the background are about 3 k away.

 

The Panasonic Lumix 100-300mm lens was announced in September 2010 along with the GH2 camera body. Since then Panasonic has introduced the G3, 5, and 6, then the GH3 and now the GH4. With each new model comes an increase in performance especially when using burst Mode and AF-C for follow focus on moving subjects.

Unfortunately the performance capability of the 100-300mm lens has not been able to keep up with the camera bodies. The GH4's frame rate in Burst Mode M (7fps) is almost double that of the GH3 (4fps).  Even on the GH3 the 100-300mm lens was unable to run at 4 fps, giving on average about 3 fps.  Unfortunately the 100-300mm lens is not able to match the performance of the GH4 at all.

This is a particular problem because in the GH4 we have for the first time a Panasonic Lumix camera which can genuinely claim to be usable for follow focus on sport/action/wildlife with a high frame rate and on my tests with the 35-100mm lens a very high rate of frames in sharp focus.

For many sports, action, wildlife and similar subjects the 100-300mm lens has the ideal focal length range and is very good optically.

But many users reporting on forums are expressing frustration that the 100-300mm lens does not allow the GH4 to express it's potential.  I have had the same problem.

Crop of the top photo. It appears the Navy has parked a ship in the middle of the city, which it has, more or less.  The 100-300mm is great for single shot photos, when it focusses correctly which is about 90% of the time.

Timings

I ran some timings on the 100-300mm lens mounted on the GH4. I used a SanDisk Extreme Pro 95 MB/sec card, Burst Mode M (which allows AF, AE and live view on each frame), 1 Area center AF Mode, AF-C and AF-S  Focus Mode, RAW capture. I timed bursts of 40 frames. The GH4 will deliver 48 RAW frames before the frame rate slows due to the buffer filling.

At f4: AF-S gave 7fps,  AF-C gave 4 fps.

At f8:  AF-S gave 3fps,  AF-C gave 2.3 fps.

When the lens did not have to focus or close down the aperture diaphragm for each shot it ran at 7fps which is the same rate as the 35-100mm lens.

Forcing the lens to focus on each frame slowed it considerably. Forcing it in addition to close the aperture diaphragm made the lens slow even further.

In addition I found that when using the lens on moving subjects in AF-C the hit rate of sharply focussed frames was significantly less (variable but about 70%) than that delivered by the 35-100mm (around 95% with many types of subject).

Other issues  I have been using the 100-300mm a lot lately and have found two other problems on the GH4.

* Even in AF-S Focus Mode, the hit rate of perfectly focussed frames is lower than I get with most other lenses. With the 12-35mm, 35-100mm and 14-140mm which are the lenses I most often use, I see about 1% of frames not in perfect focus provided I use the camera thoughtfully,  don't expect the impossible and don't expect the camera to read my mind.

But with the 100-300mm I am seeing 5-10% of frames not quite in perfect focus. Furthermore I can see no particular reason why the slightly off focus  frames should be so.

* The last one is that the EVF on my GH4 flickers intermittently when the 100-300mm is mounted.  At first I thought I had a faulty camera but it appears to work fine with other lenses. I think the problem is one of partial incompatibility between the GH4 and the 100-300mm lens.

I would very much like Panasonic to update this lens very soon as it has become  obvious that it is not a good match for the GH4 camera body and is holding back the performance capability of the GH4 for sport/action/wildlife photography.