Jumat, 29 Maret 2013

Lumix GH3 Review Part 2 Viewfinder Problems ?


LUMIX GH3 CAMERA USER REPORT
Part 2,  Viewfinder Problems ?
Author AndrewS  March  2013
GH3 Eyepiece with plastic/rubber eyecup removed  
GH2 Eyepiece
The ergonomics of camera use   I like to consider camera ergonomics under the general headings  Holding, Viewing and Operating. This post describes one aspect of Viewing, namely the Lumix GH3 Electronic Viewfinder.  Specifically it is a user report about my personal experience with the particular GH3 which I bought and have been using frequently for a month.
Reports of EVF problems  The GH3 has been in the market place long enough for there to be many reviews, blog commentaries and user reports available. Most of these are strongly favourable but some reviewers have expressed adverse comment about the EVF. The strange thing is that while some reviewers are strongly critical of the EVF to the point they feel the camera is unusable, the majority find no fault with it at all. So what is going on ?  Is there some kind of drastic sample variation ? Is there a batch of bad copies ? Are some user's viewing practices different from others ?  Having only one sample to test and just myself to do the testing I have no answer to these questions.  The best I can do is describe my own experience over the last month of use.
What problems have been reported ?   The most frequent  one is a visual perception usually described as "smearing" of some part of the preview image in the EVF particularly when the viewing eye is moved slightly from side to side. Other reports describe a lack of perceived sharpness compared with other EVFs in M43 and other mirrorless cameras.

Viewfinders Compared, GH3 vs GH2  The EVF in the GH2 [that in the G5 appears to be similar but has a lower resolution as specified by Panasonic] has a 4:3 aspect ratio.   The eyepiece lens is flat and angled down presumably to reduce the likelihood of reflections into the viewing eye. The rubber eyecup is fixed in place and  the eye sensor for monitor/EVF switching is on the right side of the eyepiece. The GH3  EVF is clearly different. It has a 16:9 aspect ratio, presumably to optimise motion picture viewing. The eyepiece lens has a strongly convex curvature. The plastic/rubber eyecup is removable. The eye sensor is below the eyepiece.  When set up for still photos at 4:3 aspect ratio and  the EVF [which Panasonic calls LVF, Live View Finder] is set to display camera data beneath, not overlaid on the preview image, the GH3 preview image occupies, at a guesstimate,  approximately 60% of the total EVF frame. The GH2 image preview set up the same way occupies about 80% of the total EVF frame. The GH3  EVF resolution is stated by Panasonic to be 1744000 dots equivalent, the GH2  EVF  1533600 dots equivalent and the G5  EVF 1440000 dots equivalent.   So on my rough calculations the actual 4:3 preview image will have: GH3  1046400 dots,  GH2  1226880 dots, G5  1152000 dots.  If these calculations are  approximately correct you would expect the GH2 to have the best resolution, followed by the G5 then the GH3.  In fact that is exactly what I find when looking through the viewfinders of each camera using matched lenses.
Sydney Easter Show. The GH3 can do a decent job as sport/action camera. A faster EVF refresh rate would make it even better. Usually the way to shoot horse jumps like this is to pre focus manually on the bar, but this time I used CAF which kept up with the action.
My own experience  The arrival of a new camera is always an anticipated event especially when the wait to acquire that particular model has been many months as was the case with my GH3.  I had, of course, read several negative comments on user forums about the GH3 EVF  so I was feeling a little anxious when I looked through the viwfinder for the very first time. And what did I see ?  Really bad smearing !!  One was not amused, to put it mildly. I was very agitated indeed.  I use the EVF for about 90% of my photos which meant that the whole GH3 enterprise was under threat from the start.  Anyway I calmed down after a while and adjusted the eyepiece diopter to suit my right eye. I found this more difficult than has been the case with other cameras as, for some reason, still not entirely clear to me, the optimum setting was hard to find.  Some eyepieces snap in and out of sharpness when the diopter wheel is turned so finding the best position is easy. But the GH3  EVF showed  a more gradual transition from unsharp to "best possible". It took  me several days of adjusting and re-adjusting the diopter wheel until I was confident I had gotten the optimum position. That improved the overall EVF appearance greatly and markedly reduced the smearing.
The next thing I did was to adjust the LVF Display Style and the Monitor Display Style to match. These are found in the Custom Menu, Page 5/8.  Then I adjusted the Viewfinder Display. This adjustment should logically be grouped with the LVF/Monitor Display Style, but just to keep you guessing it's down  in the Setup Menu, Page 2/6,  and to keep you guessing even  more it is labelled [Monitor Display].  When you look through the EVF the label on the field changes to [Viewfinder] and you can adjust the settings with the Control Dial.    The settings which I use are given below. It is highly likely that your personal eye/brain/visual perception physiology will prefer different settings.  Many  people differ in their  color balance perception. It took me two weeks of repeatedly making small changes to the settings in different conditions till I was satisfied I had found the best match for my right eye [the left eye has different color balance].
Brightness +1.  Brightness and Contrast interact with each other. When one is altered it will probably be necessary to change the other.
Contrast/Saturation +3.  I found colors, particularly reds, very desaturated in the mid position. Even with the +3 setting I found some inaccurate color in the reds, which tend to orange.
Green/Red [Red Tint]  Neutral.  
Yellow/Blue [Blue Tint] --3.
While this adjustment process was ongoing I was using the camera to make thousands of photos over several weeks. Somewhere along the way I realised that I no longer noticed any problem with smearing, or indeed any problem with the viewfinder at all. In other words, I adjusted to the camera and found it working well for me.
Comfort    The GH2 has a rubber eyecup which compared to that on the GH3 is larger, thicker and softer.  I find it more comfortable. The GH3 eyecup is removable. I would like to see Panasonic make a softer, more comfortable version.
Summary of EVF characteristics and differences GH3/GH2/G5
Sharpness  GH2 [best] >G5 >GH3   In use the GH3 does the job quite adequately. The EVF does not give me an  impression of unsharpness or softness such as might interfere with the process of making photos.  It is a bit disappointing however to discover that on direct comparison an older model delivers slightly better sharpness/resolution with still photography in 4:3 picture format.
Color saturation/accuracy  Overall I rate the GH3 as delivering more natural colors across the spectrum and in a variety of conditions,  than either of the other two cameras. I can adjust the GH3 until the EVF colors appear mostly natural in bright light, low light, high and low  levels of subject brightness range. That is not possible with either the GH2 or G5. 
Highlight/Shadow detail   The EVF in the GH3 reveals substantially better highlight/shadow detail than the other two cameras. This is particularly noticeable in the dark tones where the GH3 shows more gradation, color and detail.
Panning  All three EVF's manage panning well without skipping, except in very low light levels where panning becomes jerky.
Refresh rate  I am not in a position to test this scientifically and in single shot mode the GH3 EVF refreshes quickly enough that it is not an issue. However when following a moving subject in M Burst Mode and Continuous AF,  EVF refresh rate becomes very important. As it stands, M  Burst Rate with the Lumix 35-100mm f2.8 lens is 4.6 frames per second.  This is just but only just, usable. The issue is the proportion of time with live view active  versus the proportion of time with the EVF blacked out. A faster refresh rate would be very welcome and would enhance this camera's sport/action capability.
Olympus EM5  I did not have an EM5 to hand for comparison testing but in my time with the EM5 I was very pleased with it's EVF, finding no problems with it's appearance. The only things I recall not liking were  1. The tendency of the eyecup to dig into the tissues around  my eye in portrait orientation and   2. That I couldn't set up the EVF and Monitor both to DSLR style, with  camera data beneath the image preview.
Summary  Compared to previous models the Lumix GH3  EVF  has improved color accuracy, improved gradation, color and detail in the dark tones, slightly less resolution/sharpness and in my personal estimation, slightly less comfort in use.
The smearing issue which I initially encountered was eliminated by accurate diopter adjustment, display adjustment and practice using this particular piece of equipment.

 

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