Mẹo vặt đồ gia dụng

Author  AndrewS  November 2012

Introduction    The G5 is Panasonic's seventh Micro Four Thirds Lumix G-with -EVF camera [the GH3 when released will be the eighth] and the fourth that I have bought and used.    My first was  the G1, then the G3, GH2 and now G5. This year I also bought and used for several months an Olympus OMD-EM-5.  I have posted ergonomic reviews of the GH2 and EM5 on this blog.  My main interest in writing about cameras and the purpose of this blog, is to draw attention to ergonomic issues in the design and use of photographic equipment so this report will concentrate on ergonomics with some reference to image quality and performance as these have a substantial influence on the user experience. 

The G5 had a low key market release with most of the Micro Four Thirds headlines being grabbed by the Olympus EM5 and the soon to be released Panasonic GH3.  However the G5 is a quiet achiever with  small but significant improvements in features, image quality, performance and ergonomics compared to previous Panasonic M43 cameras.

Description and Features  The G5 sits in the mid range of Panasonic's M43 lineup with features designed to appeal to both beginner and expert users.  The beginner/snapshooter can push the iA button with it's glowing blue ring and enjoy fully automatic camera operation. But this camera has a great deal more to offer  the photographer prepared to take control of the image capture process.  It is smaller in all dimensions than the GH2 but slightly easier to hold and operate due to improved ergonomic design. The G5 provides much better ergonomics than the  G3, in particular related to holding the camera and operating the scroll wheel.

Right hand grip on the G5. A comfortable hold without cramping

G5 Rear.  Compact but well designed user interface

Scroll Wheel serrations need more projection and sharpness

Surfer. Captured with G5,  Panasonic 100-300mm lens at 300mm and 1.4x Ex Tele Conv

Introduction   This is the third article I have published on this blog about the effects of shutter shock on image sharpness in mirrorless interchangeable lens cameras and Micro Four Thirds cameras in particular.

In my previous report of the issue, I predicted that the eShutter now available on the Panasonic G5 camera would solve the problem.  It does.

Test   I repeated the previous test protocol. Panasonic G5 camera, Panasonic 100-300 mm lens at 300 mm, tripod mounted, 2 second timer delay, Shutter Priority mode, AF on each frame, OIS off.  Shutter speeds ranged from 1/5 sec to 1/800 sec. I made one series with the mechanical shutter, a second series with eShutter.

Results  With the mechanical shutter slight softness began at 1/40 sec, becoming more marked at 1/50 sec. Worst results with blurring and image doubling ocurred at 1/125 and 1/160 sec, just as previously reported with the GH2 and EM5 cameras.

With the eShutter all the frames were sharp. In the range from 1/20 to 1/40 sec the eShutter files were slightly sharper than those made with the mechanical shutter.

Conclusion  eShutter works as expected.  I recommend use of the eShutter for shutter speeds between 1/20 and 1/200 second. I use the eShutter whenever the camera is on a tripod.

Disadvantages of the eShutter  The eShutter works by scanning the frame, a process taking 0.1 second. As a result any subject which moves in relation to the camera during the 0.1 sec scan may exhibit shape distortion. For the same reason electronic flash cannot be used. [flash duration is much shorter than scan time]. In addition for reasons unknown to me maximum ISO is limited to 1600 and  the slowest shutter speed available is 1 sec.  

This article was originally published on the Digital Photography Review website in December 2011, in the section for user created articles, under my DPR  user name axlotl.

It is a speculative opinion piece created to explore some issues not often discussed on photography blogs and websites.

Here is a brief excerpt from a recent interview with a Canon representative about the company's position on mirrorless interchangeable lens cameras:  From Impressjapan magazine, via mirrorlessrumors.com  dated 19 December 2011.
Canon appears to believe  the Mirrorless Interchangeable Lens Camera (MILC)  is a "Gap Filler", something inbetween  compact and  DSLR.

In a recent edition of  the Australian magazine ProPhoto the editor, Paul Burrows commented......" we've been seeing a steady dumbing down of  CSC's, partly as a result of making them smaller and partly because the idea persists that snap- shooters really hanker after interchangeable lenses, but apparently little else of what comes with an entry level D-SLR".
In the same magazine, Mr Burrows also wrote.   "There seems to have been quite a bit of confusion among the manufacturers - or more accurately, the marketers- of compact camera systems about who exactly is the target customer".
I agree with this and would add  that in it's current form the MILC appears to be an answer without a clearly expressed question.

My perception is that there are, in the operational sense, two main types of camera user. The majority are snapshooterswho are too busy enjoying life to bother about changing lenses or wondering what an f stop might be. Many of these people take photos with a phone cam. Some still like to use a compact camera. Some  use a DSLR  or MILC  set to one of the fully automatic modes.
The other camera user group is the controllers. These people do like to change lenses, fiddle with shutter speeds, adjust f stops and experiment with all the interesting options available on an advanced camera.
So what does this mean for the mirrorless interchangeable lens camera ?  What follows is my reading of the situation, others will have their own views. In due course the market will decide. 
The MILC may look like a "Gap Filler" right now.  But with further development it has the potential to become a genuinely disruptive innovation leading to real change in the market for interchangeable lens cameras.

So, which segments of the market are in line to be disrupted ?  Basically, all those with interchangeable lenses.
Medium format  DSLR   The larger the sensor, the  greater the  potential for size and weight reduction by removing the mirror box, prism, etc..  etc of a DSLR.  So I think that if some maker has enough courage to make the investment and if they get the product right, then mirrorless will become the preferred option for medium format, using a square sensor, live view monitor and touch screen controls for use on a tripod, which is the way these cameras are usually supported.
DSLR with full frame sensor,   43 mm diagonal  Same argument as above. This type of camera would handle even better with a 36 x 36 mm sensor and electronic selection of  landscape/portrait framing, so there is no need to flip the body over for portrait framing. This would be a hand held camera for reasonably still subjects, requiring a high quality EVF and a sufficiency, but not a profusion,  of hard controls.
DSLR  with 27-28 mm (diagonal) sensor  Most DSLR's have a sensor this size.                 At present the MILC offers some things not managed very well by the DSLR,  such as full time live view, the benefits of EVF and accurate contrast detect AF.  But most of them take away other things like predictive AF and the benefits of OVF.  The MILC can be smaller than a DSLR  but the size difference with lens mounted is not compelling and in any event, cameras which are too small usually suffer from compromised handling and control.
Compact    I think that if  mirrorless ILC's continue their present attempts to compete with compacts, they will fail.    I think that when snapshooters get over the  newness of the MILC they will revert back to compacts or abandon cameras altogether in favour of phone cams.   Why ? Because, for any given box size (width x height x depth)  a compact with a fixed, collapsing zoom lens can have more zoom range or greater aperture or both, than a body with mounted interchangeable zoom lens and a smart phone trumps most cameras for compact size and "always ready" availability.

I believe the MILC has to tackle the DSLR  category  head on and win or become a lost cause.   In order to succeed in this task the MILC has to do everything  better than the DSLR.
Everything  means everything.  Image quality, operating speed,  responsiveness, EVF appearance and refresh rate, single frame AF,  predictive AF,  handling qualities, controls,  lens selection and more. To really disrupt the market all this has to be available to consumers at an attractive price point.

This is one of my wooden MILC mockups.  The shape, size, handle design and UIM layout have all been designed  by working directly with wooden pieces to provide an ergonomically eficient device with compact dimensions. This mockup's box size [Width x Height x Depth] is 605 cc which is actually smaller than the Panasonic G5 shown above [box size 722 cc] Yet the mockup has a larger handle and larger UIM's throughout. I would like to see the makers of MILC's use this camera body shape in preference to the mini DSLR shape for it's greater ergonomic efficiency and ease of holding, viewing and operating.

Responding to the challenge   To generate interest from the snapshooter crowd seeking better image quality than a phone cam, camera makers could make large sensor compacts with fixed zoom lenses. The Micro Four Thirds or Nikon CX size sensor could form the guts of a category killer advanced compact. Sony has already entered this arena with the RX100 compact, recently voted one of the best 50 inventions of 2012 by Time Magazine.
 To keep the controller group happy and push DSLR's off center stage in the interchangeable lens market MILC's  need  to develop a multi tier product line.   At the bottom are the very compact ILC's without EVF, at the top there are pro style high performance cams with the ergonomics, capabilities and lenses required for professional use.   These have an ergonomic handle, thumb rest and control modules  for users who elect to operate the device with their hands. Oh........right.........that would be all of them........ 

Canon and Nikon will keep  selling boatloads of  DSLR's, in the process competing with each other within the envelope of sustaining innovation until the day someone delivers to the market an MILC which beats the DSLR at everything, for the same price or a bit less.  At that point the game will change forever.
The problem for the DSLR as a species is that it has  reached the end of it's evolutionary journey. DSLR's  can benefit from sustaining innovation  but the MILC brings the potential for disruptive innovation. I think that if the makers of MILC's  bring their technology, ergonomics and marketing up to speed, they will prevail.

Postscript, November 2012
The biggest disruptive innovation to hit the camera world turned out to be the phone cam which has encouraged snapshooters to abandon entry level compacts  en masse.  I still think there is a role for advanced compacts, superzooms and similar cameras which offer features and/or performance not available from phone cams.    

Canon finally released it's MILC in the form of the underwhelming, "me-too" EOS-M.  It looks and operates just like the many "no EVF"  ILC's from Panasonic, Olympus, Sony and Samsung, but  according to many reviews, focusses more slowly than any of them. Canon is promoting the EOS-M to the  customer who is urged  to  "Lose yourself in the moment, not the Manual.  Be  a PLAY- Fessional"  whatever those words might mean.  From my perspective as a consumer it appears Canon still regards the MILC as a gap filler and is slow to fully embrace the MILC as a disruptive innovation.

This is my large mockup with box volume of 882 cc which is midway between the GH2 [808 cc] and GH3 [1014 cc] It would be suitable for professional use with handling characteristics similar to medium/large DSLR's but in a much more compact package.

There has been some discussion on blogs and user forums recently about the camera market and in particular the rate at which MILC's are, or are not, encroaching on DSLR sales. It appears MILC sales have flatlined or even declined in 2012. One possible explanation for this might be the recent aggressive discounting of entry and lower mid level DSLR's.  For instance in a popular electronics discount store in Australia today you can buy a Nikon D5100 Twin Lens kit for $847 or Nikon D3100 Twin Lens kit for $746.  But the Olympus EM5 single Lens Kit is  $1396 and  Sony NEX6 Twin Lens Kit sells for $1498. To be fair the DSLR's  are superseded models and the MILC's are the latest and presumably best of the breed.  Do the customers care ? I don't know.  But I can see that it could be difficult for the sales staff to explain why the available mirrorless cams are more expensive than DSLR's with similar specification.  I have read opinions by people who appear to know about such things that a MILC should be less expensive to produce than a DSLR as it contains fewer parts. If that is true perhaps there will come a day when the price difference operates in favour of the MILC.

 

Excellent photos,  puzzles included

Announcement and reaction   Olympus announced the EM-5 in February 2012 and quickly generated a very positive response from reviewers and early adopters.  It provoked  renewed  interest in the M43 system and in Olympus cameras at a time when Olympus really needed a good news story. For many months after it's release the camera was difficult to obtain, indicating strong takeup from buyers.

Author's background  I have discovered from my photographic experience over the last 50 years that the only way for me to really appreciate the capabilities of a camera is to buy and use it over a period of several months, making many exposures in a wide variety of conditions.  Earlier this year I bought a Panasonic GH2 then an Olympus EM5 then a Samsung NX20, each with a selection of lenses, mostly zooms as I prefer their versatility. I have been using them often side by side and often with the same subject matter. The intention was always to keep one and let the others go, as I do not care to clutter up the house with underutilised camera gear and there are budget issues to consider. By the way, I decided to keep the GH2, for reasons which I will discuss in another post on this blog. This article is a review of the EM5, with an emphasis on ergonomic issues,  but also referring to image quality and performance which obviously influence the user experience.

Market position, target user group and buyer expectations  The EM5 is Olympus' flagship ILC. It has an extensive feature set, a complex user interface and is priced with mid level DSLR's at the upper end of the ILC range.  It would be possible for snapshooters to manage the EM5 with the Mode dial set to iAuto.  But the expert/enthusiast camera user will make better use of the many features and user interface options available. Such a user will expect very good image quality and performance from the EM5 and in large measure it delivers. It also delivers a few challenges which have made my time with the camera a mixed experience.

Review priorities This review is written for the expert/enthusiast photographer who likes to take control of the photographic process and who uses a camera frequently.  I have not reviewed video operation or the touch screen function as I do not use either of these features. You can read about these and a list of the camera's specifications and features in great detail elsewhere. I have nothing to say about scene modes or art filters. 

Image Quality  IQ is excellent, easily the best of the M43 cameras at the time of this report. You can read all about it  in technical reviews.  Resolution, Dynamic Range and noise are all very good.  JPG and RAW files are both very good.  To quote dpreview's assessment.............."moving up to......... full frame is the only way of gaining a significant step up [in image quality] from the EM-5". DXO Mark recently scored the EM5 at 71 with a Dynamic Range of 12.3 which places it in the middle of the APS-C sensor group.

Autofocus, single shot:  This is very fast and sensitive, latching onto the slightest hint of texture including brush strokes in paint. The downside  is a significant rate of slight misfocussing. The degree of misfocus might not be noticed with many photographs, but can become an issue with big enlargements or prints.  Sometimes the camera signals it cannot focus but more often it indicates focus has been achieved when that is not quite the case. Misfocussing appears more frequent in conditions of low light level and/or low subject brightness range, but also when there are many bright light sources in frame. It appears to me more frequent with Panasonic lenses than Olympus lenses, particularly the 7-14mm zoom. It is more frequent at the long end of the 12-50mm, 40-150mm and 75-300mm zooms and more frequent at long distance from the camera, possibly related to the lowered subject contrast inherent in that situation.  The actual rate of misfocus varies widely with circumstances. There have been days when all the frames were sharply in focus, but on other days with different lens/light conditions, as many as 50% of frames have been slightly unsharp with no evidence of camera shake (no doubling). 

Manual Focus, single shot: With focus assist enabled MF is readily achieved although the EVF's on both the GH2 and NX20 snap in and out of focus more clearly.

Autofocus, Continuous, Sequential drive, moving subject:  The EM5 with Olympus M 75-300mm lens will follow focus on a moving subject at 3.3 frames per second  with  IS operating, AF and live view on each frame even when the subject is a motor vehicle travelling at 60 kph. It has the best performance of any M43 camera to date with sport/action type subjects. It works best in bright sunlight with subjects moving at a steady speed. I discuss this in more detail in another post on this blog.

In normal single shot use the camera will refocus and shoot almost as fast as I can press the shutter button again after each shot even with RAW capture, an excellent performance. With image review off, monitor and EVF blackout is very brief to the point I don't notice it. Shutter lag is virtually nil.  In general the camera operates in a very brisk and responsive fashion. Note that if you activate copyright information [Custom Menu >H >Record/Erase >Copyright Settings >Copyright Info>On] the camera slows down markedly.

Image Stabiliser  The EM5 has the much advertised "Five Axis" In Body Image Stabiliser, which appears to work very well. I found it possible to get sharp pictures at very slow shutter speeds. There have been numerous questions in user forums online about the reliability of this system. The camera which I bought had no IBIS problems that I could detect. I suspect that some user's experience of image doubling may have been due to shutter shock rather than IBIS problems. Please see my aticles on shutter shock elsewhere on this blog.

Flash  I have only used the supplied, detachable unit and then only to a limited extent. I have read elsewhere that the EM5 has sophisticated off camera flash capabilities but I have not tested this aspect of performance.

Ergonomics  This discourse follows my usual approach, looking at each of the four phases of use in turn then investigating viewing, holding and operating in Capture Phase.

Setup Phase  The main task of this phase is making selections in the Menu. Many modern cameras have a complex menu system which can be hard to follow, even with the instruction manual to hand.  The Panasonic GH2 which I tested alongside the EM5 is no paragon of menu clarity.  But the EM5 menu system takes complexity to the next level which many people myself included find difficult to negotiate. Experienced Olympophiles on user forums scoff at people like me,  insisting the menus are perfectly simple and easy to negotiate.

Button Function   The EM5 allows extensive user configuration of button function. It even allows some buttons to be assigned single function or multifunction. This allows the expert  user to customise camera operation to personal preference, but, compared with most other cameras,  does require more choices to be made at the setup phase.

Dial Function     I am a great advocate of user selectable interface module function in electronic cameras but the EM5 takes the concept to extremes.  For instance in Custom Menu >B >Button/Dial >Dial Function, you can assign a different function to the dials in each of the P, A, S, M, Menu and Review modes, plus you can choose the dial direction in the same menu. Perhaps I lack the requisite imagination or aptitude for cognitive challenges but I simply don't understand why one would want the dials to change function on switching from one shooting mode to another.

Picture Mode Settings A long list of these appears in Camera 1 Menu >Picture Mode, but there is another not quite identical list in Custom Menu D >Disp/Sound/PC >Picture Mode Settings. Presumably there is a reason for this but I never figured it out.

Mysets  Many electronic cameras have positions on the Main Mode Dial usually labelled C1, C2.....etc. This allows groups of settings to be stored and recalled as required to streamline preparation for different photographic tasks.      There is room on the EM5 Mode dial for some presets but Olympus does things differently.  Mysets can only be accessed via the main menu which requires 9-12 button presses depending on which Myset you want. The active myset is not indicated anywhere at all. When the camera is switched on it will return to the settings in place at switch off  but does not inform you which set is active. There is also an option for a "quick myset" which can be allocated to a button but you must hold the button down while pressing the shutter for this to function. While the allocated button is being pressed there is a myset indicator in the lower left corner of the monitor. This is another example of a useful function which other camera makers provide in a reasonably straightforward fashion but which Olympus delivers in a manner which I find more opaque. Once registered and set, the Mysets work just fine.

Flash settings  There are five  places you can make settings for flash operation, two in the main menu, Camera Menu 2 >flash +/- and Custom Menu >F >Flash, two in the Super Control Panel and one on a scroll wheel if you have preset a  wheel to change flash output level. Some of these duplicate each other, some do not. Some of the help guides are difficult to understand.  Again we see complex arrangements when more direct ones would have served better. The other problem for flash use on this camera is that it lacks one built in.  You have to remove the hotshoe cover then a little plastic cover from the connection port, then take the (supplied) flash out of it's pouch and remove the  plastic protective cover, then put the three little bits of plastic in the pouch so they don't get lost, then push the flash unit into the hotshoe and connection port together, lift the flash head up and you are ready to go. Fortunately the camera has good  high ISO image quality so the flash is not often required in general photography.

IS Operation  There are several different places where settings affecting IS operation can be made.   In the Super Control Panel or Camera Menu 2, IS can be set to Off, 1, 2 or 3.

In Custom Menu C > Release/Drive, there are two settings: Halfway Rls with IS,  [which I suspect most users will set to On and wonder why the choice was provided]  and Sequential+IS Off  [which you have to set to Off  in order to make the IS On  with sequential drive] Go figure.

Then In Custom Menu D >Disp/sound/PC >LV closeup Mode, you can set Mode 1 or Mode 2, which I read on user forums has an influence on IS operation but I have to confess I never figured out how this relationship works.

Some cameras such as the GH2 have several set and see dials and levers on the top plate together with several maker and user configured buttons, for direct user control of Prepare Phase adjustments. But the EM5 has only one set and see dial (the Mode dial). If  the 4 way controller buttons are allocated to changing AF area position then Prepare Phase adjustments will involve a trip to the Super Control Panel.

Super Control Panel   This is generally well implemented with a few caveats. There are five different sub panel sizes the logic of which escapes me. It's not a big problem but scrolling around the screen is not as quick as it could be if each element was the same size.  The panel is approximately divided into a selection of Prepare Phase items on the left side and a few Setup items on the right side. Overall the appearance is somewhat that of a work in progress, with some items which should be on the SCP missing and others included unnecessarily, cluttering the panel.  One solution  would be to allow the operator  to move  user selected items from the main menu across to the SCP. That way each owner could have their own preferred items and no others on the SCP.   The Fn screen on the Samsung NX20 is  better implemented,  the Q Menu on the GH2 is  worse, with it's non user selectable items arranged around the periphery of the frame.

Auto Exposure Bracketing  Some cameras have a drive mode dial, lever or button on which you can select AEB, having previously set up the number, EV step and sequence in a main menu. Easy. But the Olympus is different. There is no drive mode dial, lever or button. No problem you might think, just put AEB  on the Super Control Panel. But it's not there. You have to go into Camera Menu 2 >Bracketing >Select an option. This takes 10-21 button presses depending on which option you want.  You have to repeat the whole sequence to turn AEB off. Alternatively you can include AEB in a Myset.  But you still have to go to the main menu to activate the myset.

Capture Phase

Capture Phase, Holding   As part of my voyage of exploration into camera ergonomics, I have made several wooden mockup cameras. This has given me some insight into the process of design. Early in that process come basic decisions about dimensions, layout, control systems and style. These early decisions limit the range of options available at later stages of the detail design process. I am just an ordinary consumer with no knowlege of the people who design  cameras or their decision making activities. However one can make some inference about these things from the product itself and the maker's promotional material. Olympus makes much of the EM5's homage to their 1980's OM series film SLR's. One Olympus spokesman referred to the EM5 as  having "the beautiful shape".   I don't care to comment on whether the shape is beautiful or not but it has a substantial effect on the ergonomic capabilities of the device.  

OM series film cameras established the leitmotif  for the OM digital cameras, however there are substantial  differences in their shape and form with ergonomic consequences.  The OM series film cameras (and many similar designs such as the Pentax ME series which I used for many years) were easy to hold and operate with the "no handle" design because they were, compared to the EM5, wider, deeper and devoid of any screen or interface modules on the rear. You could get ahold of them.

This is not the case with the EM5 which in standard configuration provides the user with a tenuous hold on the camera, particularly if a telephoto lens is mounted.  It feels much less secure than the GH2 or  NX20. 

An  accessory handle provides a more secure grip.  The first part of the Olympus HLD-6 is suitable. There are also several independent makers of accessory handles for the EM5. This arrangement may be a marketing triumph but is an ergonomic kludge.  With the grip attached there are two shutter buttons and three scroll wheels on the top plate, cluttering up high priority camera real estate with redundant user interface modules (UIM).  Worse, for my average sized adult hands none of the scroll wheels is optimally positioned or angled. My index finger keeps wanting to find a front scroll wheel between the two which are actually there and the same finger wants the axis of rotation of  that scroll wheel to be tilted 80 degrees so it matches the natural movement of the finger. The HLD-6  grip costs  an extra $300 over the initial price and you have to remove it to change a battery. Oh, yes, and try not to lose the little plastic contact cluster cover piece from the grip, and the little black rubber cover thingy from the contact cluster on the camera base. While I am complaining I note the accessory grip has a sharp corner which digs into the palm of my right hand. 

If Olympus had simply incorporated a properly designed handle in the first place,  the EM5 could have delivered a more effective ergonomic layout at lower cost.

Capture Phase, Viewing   The monitor is very nice, with plenty of user selectable options for content and characteristics of the  display. One of the most useful of these options is the orange/blue indication of highlight/shadow clipping, available on preview and review in both the monitor and EVF.  The level which activates the clipping indicator is also adjustable, a very sophisticated feature.   The monitor is of the swing up/down type which is good for waist level or over the head shooting in landscape (horizontal) format. Some people prefer the swing-out-and-swivel type, which is more versatile in some ways, not least the ability to turn it face in to the camera body.  I guess you can't have both.  Likewise the EVF is excellent, providing a natural looking view of the subject in all conditions and plenty of options for the display. I have just two ergonomic grumbles about the viewing experience. I like to set up the monitor and EVF to look the same so when I switch from one to the other the cognitive experience is continuous. This is possible on the EM5 but only using "Monitor" style with camera data overlaid on the image area. The EVF will, but the monitor will not allow the "DSLR style" with camera data in a strip beneath the image. The other grumble is about the eyepiece shape. This is short and wide which is comfortable in landscape orientation but in portrait orientation the ends of the eyepiece dig uncomfortably into the the upper and lower margins of the eye socket.

Capture Phase, Operating    This camera's operation is highly dependent on user configured setup which determines the function of most of the UIM's.  This level of user selectable UIM function is very welcome however the option to select functions is also an imperative which requires a longer familiarisation period than many less sophisticated cameras.  In general the camera operates quickly and efficiently in Capture Phase with some exceptions described below.

Autofocus Start  Several pro style cameras have a dedicated AF start/lock button on the upper rear of the body. There is no room for such a button but  the EM5 enables AF start to be activated by half press on the shutter button and thereby separated from AE and Capture which take place at full press. This works well and represents an  efficient  use of the shutter button.

Changing AF area position and size:    There is a set of features described on Page 45 of the Instruction Manual under the heading "Zoom Frame AF/Zoom AF".    This set of features, I have to confess, continues to baffle me completely despite reading the instructions many times, playing with the camera for many hours and trawling through the numerous posts and responses (literally hundreds of them, I am not the only one  having trouble with this) about it on multiple user forums and independent blogs. Some contributors to those user forums say they  have figured out how to make sense of this set of  focus functions. Maybe those  people are able to adapt more readily to the Olympus way of doing things.

Auto ISO  Is well implemented. The camera will increase ISO up to the preset maximum to ensure the shutter speed does not fall into camera shake territory.

Buttons  The Play and Fn1 buttons are very recessed, making them awkward to activate in any Phase of use and almost impossible in Capture Phase with one's eye to the EVF.   However if you are going to operate the rear scroll wheel with the thumb, which appears to be the designer's intention, then those buttons must be recessed or they will be pressed inadvertently.     The buttons generally are small because the body panels which accommodate them are also small. Panasonic M43 cameras have the same problem. One could be philosophical about this and say small buttons come with the territory of ILC's but I know this is not true because I have designed and built mockups which are even smaller than the EM5 yet have larger body panels with  larger buttons, better positioned for ease of operation. The size issue is in play but design decisions are the main determinants of the effectiveness of the user interface.

Review Phase  The EM5 has one of the best image review systems I have encountered.  One scroll wheel magnifies the review image centered on the AF area used to make that image. The other scroll wheel can advance to the next image at the same level of magnification. Very neat, very convenient, well implemented.

Conclusion   This camera's oficial name, Olympus OM-D- EM-5 sets the theme for the whole package: a convoluted  course to it's realisation when a more straightforward  pathway could have been provided.  This is no "safe",  middle of the  road product.  It's best features are very appealing but some aspects of the user interface can be either challenging or baffling depending on your aptitude for puzzles.  I suspect this camera will polarise users with some enjoying it's impressive capabilities while others become frustrated by it's sometimes obtuse user interface.  You pays your money and makes your choice. Good luck.

Introduction  I recently bought and have been testing a Panasonic GH2, Olympus EM5 and Samsung NX20 each with a range of zoom lenses.  Panasonic and Olympus each make a range of standard zoom lenses. The entry level offerings are the Panasonic 14-42 mm OIS (non collapsing), Panasonic PZ 14-42 mm Power OIS and Olympus 14-42 mm (collapsing).  Next up in the price/performance scale we have the Panasonic 14-45 mm OIS and Olympus 12-50 mm with e- zoom and macro features. The Olympus is often bundled with the EM5 body in a kit. At the top of the price/performance tree we have the Pro level Panasonic 12-35 mm f2.8 zoom. There are plenty of rumors circulating on the net that Olympus will also produce a pro standard zoom.

This article reports my tests of the Panasonic Lumix G Vario 14-45 mm f 3.5-5.6 Asph Mega  OIS and Olympus M.Zuiko ED 12-50 mm f 3.5-6.3 EZ.  Lenses in this price/performance range are attractive to enthusiast photographers as they deliver most of the performance of pro level optics at a fraction the price.

 

 

 

 

Test method  I find that photographing test charts in controlled conditions  provides me with less than half the information I want to know about a lens. So in addition to charts I make many hundreds of photos in a variety of conditions to challenge the camera/lens combination. This includes low contrast, high contrast, closeup and distant shots with many different types of subject. I often find that a lens which performs quite decently well on a test chart can be markedly less well behaved in more difficult conditions.

Testing consistency   Part of my test procedure is to make several shots of the same subject, refocussing for each. I do this to determine if the camera/lens combination will give the same image quality every time. With the Panasonic 14-45 mm that was almost always the case. But with the Olympus 12-50 mm I often  found a small variation in sharpness from one frame to the next.   Some possible reasons for this are discussed below.

Body/lens compatibility  As I gain experience with the M43 system I am finding that in many cases Pansonic lenses work best on Panasonic cameras and Olympus lenses work best on Olympus cameras.  Autofocus accuracy, stabiliser type  and in camera correction of lens aberrations are some of the factors determining compatibility.  So for this comparison I used the Panasonic 14-45 mm lens on the GH2 body and the Olympus 12-50 mm lens on the EM5 body.

Specifications  As I have found several times when comparing M43 lenses from Olympus and Panasonic, these two have a different feature set. The Olympus goes for versatility with a 4.2 x zoom range, manual and power zoom operation plus an inbuilt macro facility.  The Olympus is a modern design with internal zoom and focus so it's length remains constant. There is no focal length scale on the lens barrel. Instead the current focal length is displayed in the monitor or EVF but only on Olympus cameras.  The Panasonic was the first ever M43 lens released with the G1 in 2008 and is still in production.  The Panasonic is more conventional in design with 3.2 x zoom range, standard mechanical zoom ring and extending barrel. The Pana 14-45 mm has an optical image stabiliser in the lens. The Oly 12-50 relies on  Olympus IBIS.

 

Mechanical Operation and autofocus  The Pana 14-45 zooms smoothly and focusses quickly on the GH2, but not as fast as the 12-50 on the EM5.  The Oly 12-50 has a smooth power zoom for video. Manual zoom is faster with a slightly rough feel. The macro facility is very effective allowing the front of the lens to be brought to within a few centimeters of the subject. The 12-50 focusses extremely fast on the EM5 but speed and accuracy do not necessarily travel together. I discovered after many hundreds of test photos in a variety of conditions  that there was a significant misfocussing rate with the EM5/12-50 mm combination particularly at the long end in soft light.  What is "significant" ? I found that with bright sunlight and good  subject contrast the misfocus rate was negligible. But with low subject brightness range, the long end of the zoom and a subject distance over about 20 meters, some frames would be sharp and others slightly soft. I attribute this to slight misfocussing, as it occurs at shutter speeds faster than those affected by shutter shock (see below).

Shutter Shock  The Oly 12-50 mm lens can exhibit unsharpness caused by shutter shock in the shutter speed range about 1/40s --1/125s. This specific cause of unsharpness can be eliminated by setting [Anti Shock 1/8sec] in the EM5 Menu. Please see my article "M43 Shutter Shock Revisited (OMD-EM-5)"in a separate post on this blog for more information and discussion about this topic.

Manual focus  This works just fine with both lenses using focus assist in each case.  I did note however that using the EVF,  the image snaps in and out of focus more clearly on the GH2 than the EM5. That is a camera issue of course, not a lens feature but it does affect the user experience.  My ongoing complaint with all ILC's including M43 is the absence of any way to manually preset a focus distance by scale.  

Resolution  The Pana 14-45 mm has been favourably reviewed by users and technical testers over a four year period, building up a solid reputation in the process.   I have owned two of these lenses over the last three years and found both to deliver very good  resolution at all focal lengths and apertures up to about f 11 after which diffraction effects start to erode resolution.

When the Oly 12-50 mm lens was introduced, numerous reviewers complained that it was a bit soft.  Then technical lens test results started to come out with more favourable assessments, mostly from test chart analysis.   My own testing leads me to the view that both these evaluations are correct, but they are measuring different parameters of lens capability. When presented to a test chart the lens resolves fine details very well at all focal lengths and apertures up to f 11, with some softness and chromatic aberration in the corners at the shorter focal lengths and loss of contrast at the long end.  

But on side by side testing against the Pana 14-45 mm out in the real world a different picture emerged. Time after time, over  hundreds of  matched photos I found the  Pana 14-45 gave pictures which looked crisper, had more "snap" and overall appeared sharper.  I spent considerable time trying to understand the reason for this. I considered  AF errors, IS malfunction and eventually decided that in those cases which were definitely in focus and the shutter speed (faster than about 1/160sec) precluded shutter shock,  the difference between the two lenses may have been due to higher microcontrast achieved by the Pana14-45 mm. 

Aberrations  Both lenses are subject to chromatic aberration paticularly towards the corners at the shorter focal lengths. With the Pana 14-45, CA is automatically corrected in Panasonic but not Olympus cameras. CA from the Oly 12-50 is not corrected in Pana or Oly cameras.

Color fringing  In addition to chromatic aberration both lenses exhibit purple fringing most marked in the corners with subjects having adjacent bright and dark elements. Purple fringing is more prominent with the  Oly12-50 mm. I have read many different explanations for purple fringing in digital cameras and am still not sure I understand why it occurs.  Whatever the cause, it can usually be corrected or greatly reduced with the "Defringe" sliders in ACR 7.1/LR 4.1.

Flare  I find it useful to identify two kinds of flare. The first is general, affecting  the whole or most of the frame and occurs when the sun or other bright light source is in or just outside the frame. The second kind is local, usually revealed by light spilling over from a bright part of the subject to an adjacent dark part. Foliage against a cloudy/bright sky will often reveal this type of flare. The Oly 12-50 mm is more prone to both types of flare than the Pana 14-45.

The combination of  lower microcontrast, more uncorrected chromatic aberration and more local flare means that in general photographic use the Oly 12-50 mm lens, even when correctly focussed,  will often deliver less satisfying image quality than the Pana 14-45 mm. 

Drawing(distortion)  Distortion from both lenses may be corrected in camera to some extent. The net result for the Oly 12-50 is mild barrel at the wide end and virtually nil in the mid range and long end. The 14-45 mm produces moderate barrel distortion at the wide end reducing to mild in the middle focal lengths and slight at the long end.  The distortion from both lenses is circular in type, easily corrected in Adobe Camera Raw/Lightroom.

Conclusion  I am not a lens designer, just a user. However it is clear enough even to my untutored eye that there must be a technical envelope which constrains lens design. This could be visualised as a hexagon of constant area with six points representing Focal length range, Aperture, Features, Size, Price and Optical quality.   If  one of these qualities is increased the others must be reduced.      With the 12-50 mm, Olympus has opted to maximise focal length range and features with a consequent reduction in aperture at the long end and real world  image quality. The Pansonic 14-45 has a shorter focal length range and fewer features but is slightly smaller (at 14 mm) and has better image quality.  In addition that quality is more evenly distributed across the frame and focal length range. The Oly 12-50 mm is best in the central region of the frame and the middle of the focal length range.  With reservations about shutter shock and autofocus issues affecting the Oly 12-50mm, each lens does what it appears to have been designed to do.   You pays your money and makes your choice. [And remember to set Anti Shock with the EM-5/12-50mm combination].