M43 Practice, Diffraction, Unsharpness caused by reducing lens aperture

 

Why post about this ?  I am moved to write this by a post which is running currently on the DP Review M43 Forum, titled "Diffraction Limit". It has generated 142 responses thus far. Some contain such deep questions as ..."are you inebriated with the exuberance of your own verbosity ?"

I have to confess that I could not bring myself to read all the erudite contributions and further have to confess that I did not understand several of them. There is a lot of material about Airy disks and pixel dimensions and all kinds of technical and theoretical stuff.

Numerous contestable assertions are offered.  Much of the "discussion" would, I think be described by Australia's former Prime Minister Ms Julia Gillard as "Argy Bargy".

The Test  My own approach to the evaluation of contestable assertions is to test them. In this case a useful test can easily be designed and carried out in a few minutes.

I set up a simple test chart and photographed it at f2.8 - 22 in 1/3 stop increments. I made all the usual precautions to prevent camera shake: tripod, E-Shutter to 1 second then Shutter delay, 2 sec timer delay, manual focus, ISO 125. I used a Lumix GH3 with Lumix 35-100mm f2.8  lens at 42mm.

The Test Chart. This photo has been reduced and compressed for the net so it is difficult to appreciate the detail. Many Lumix zoom lenses, even some of the budget ones can resolve all the words all over the frame at their optimum aperture.

 The Results  I enlarged a small part of the frame, near the center, 330x343 pixels [0.11 Mpx] from each exposure and viewed these on screen at 200%.

On this particular test with this particular lens I found sharpness/resolution was the same from f2.8 through to about f8, with the first sign of slight softening becoming evident from f9. The image gets progressively softer from there to f22.

F2.8

F4

F5.6

F8

F11

F16

F22

Comment on the test photos  These have suffered somewhat from their compression for publication. The originals appeared sharper. Despite this I think you can see things are definitely softer at f11.

Conclusion  On this test closing down the lens aperture smaller than f8 did have a deleterious effect on image sharpness. I estimate the effect would be apparent in ordinary photographs by f10. By the way, with this particular lens, image sharpness in a large central area (not the corners, which sharpened up by f4) was just as good at f2.8 as f4 or F5.6 or f8.

It has certainly been my experience when photographing out and about that image sharpness/resolution is adversely affected in M43 camera/lens systems when the aperture reaches the f9-f10 range.  

Note on close ups, 30 August  I made some flower photos this morning, trying various apertures. The ones at f11 were the best. The gain in depth of field achieved by stopping down outweighed the slight loss of sharpness from diffraction.

Lumix GH3, 12-35mm f2.8 lens at 35mm and f11, tripod.

 

3 Way Shootout Part 9, Final Comments and Predictions for the Future



On the left, Nikon 1, V2, Center, Nikon D5200, Right Panasonic Lumix G6

 

The questions At the beginning of this 9 part 3 Way shootout, I put several questions.  Let us come back to these, with the results of testing in hand.

Q.  Do DSLR's make better pictures than MILC's ?

A. No. Picture quality is determined by many things, the distinction between DSLR and MILC not being one of them.

Q. Do larger/more expensive cameras make better pictures than smaller cameras ? This question goes to the selling message long promoted by CanoNikon in particular.

A. Sometimes but it depends on many things. Some large cameras make great photos in certain circumstances but, for instance, long distance hiking would not be the best circumstance for a large heavy camera. Even with large and small cameras on location together, you cannot always expect the larger one to make better pictures.

Q. Do larger sensor make better pictures than smaller sensors ?

A. Sometimes, but again it depends on many other attributes of the imaging system.

Q. Does Phase Detect AF work faster or better in some way  than Contrast Detect AF ?

A. In some cases.  However not all PD or CD autofocus systems are made equal. In fact the performance of each varies markedly with manufacturer, system and model of camera and lens. Even with the demands of predictive autofocus on moving subjects, recent advances in CD autofocus have brought CDAF up to or even in some cases surpassing the performance of some PDAF systems.

Best kit of the three on test ?

Taking into account all the findings of the previous 8 posts, my pick for the one which best fulfilled the brief for a family/holiday/all-in-one/beginner to enthusiast camera kit is:

1. G6/14-140mm, followed by

2. V2/10-100mm, and

3. D5200/18-200mm

Best Camera type ?

When mirrorless interchangeable lens cameras were first introduced they were a distinctly underwhelming, overpriced, underperforming bunch which DSLR users generally ignored.

But in the last two years or so, the balance of capabilities between the two types has changed.

In the mid range, upper entry,  consumer level of the market which has been explored in this 3 Way shootout, MILC's now have the upper hand.

Future Prospects

DSLR    My considered view, with which others are free to differ, is that the DSLR as a camera type has no future at all. I am not alone in this view. Panasonic and  Fuji are no longer in the DSLR business. Olympus' latest, the EM-1 is likely to be a mirrorless offering with on chip PDAF which can effectively drive lenses originally designed for the 4/3 DSLR system. Sony is strongly rumored to be exiting DSLR and SLT technologies altogether.

While the makers of DSLR's were engaged in making small, incremental improvements with each "new" but actually not very new, model, the makers of MILC's were re-inventing the camera with a series of disruptive innovations.

Research and development in the MILC world is racing along at a great pace while that in the DSLR world has almost come to a halt. The main reason for this is that the DSLR as a type of device is nearly at the end of it's evolutionary journey.

MILC  I believe that in a few years MILC's will be the dominant interchangeable lens camera type.

M43  If the makers of M43 camera can eliminate the problem of shutter shock, perhaps by developing a global shutter and speed up their EVF refresh rate, then I believe M43 is best placed to become  the dominant interchangeable lens system. M43 sits in the sweet spot between larger and smaller formats. The sensor is large enough to deliver excellent picture quality, but small enough to allow the design of very compact lenses.

Nikon 1 SystemWhen Nikon introduced it's oddly named "1" system it was greeted with derision by reviewers and commentators alike.

Nikon's engineers developed a photographic rocket, with the fastest still and continuous frame rates, fastest EVF refresh rate and biggest RAW buffer ever seen. The V1 and now the V2  have the guts of a product line capable of outperforming every other camera in existence and transforming the entire  industry.

In the event, Nikon's product development people slipped this potential industry hero  operating system  inside a series of small, point-and -shoot style compact ILC's with atrocious ergonomics and childish gimmicks like Motion Snapshot Mode. The critics were rightly critical.

BUT.  Watch this space. IF Nikon's execs wake from their current torpor and stop trying to make dumb cameras aimed at a possibly non existent target buyer group (one blogger has coined the phrase "teenage facebook girl"), give the 1 series a better sensor and improved ergonomics, then watch out camera world.   Of course Nikon and all the others will have to completely restructure their entire product line and I guess they don't want to do that. But I believe it is just a matter of time before they are pushed into doing so, ironically by the invention of their own engineers. The genie will not go back in the bottle.

 

 

 

 

 

 

3 Way Holiday Camera Shootout Part 8, Video User Experience

D5200 with 18-200mm lens at 200mm

 

Brief Report    My interest is in still photos. I rarely make a video.  However each of the three cameras in this 3 Way shootout is capable of motion picture capture.  So I made some videos with the purpose of comparing the user experience provided by each. I make no comment about the technical details or output quality of the video. There are numerous websites which cover this aspect of camera function in great detail.

I was interested to discover how each kit managed inexpert hand held panning in varied light plus moving from near to far subjects to test the autofocus.

I made the video clips indoors, in reasonably bright light, with some parts of the room in sunlight, others in deep shade. I panned slowly from people to furniture in the room. I set each camera to it's fully auto mode then pressed the motion picture start button. Each camera has one of these located behind the shutter button.

Holding and Viewing  When the operator is standing,  a convenient camera height for video is about waist level. This usually allows the camera to be held level to prevent distortion.  This camera position is greatly facilitated by a fully articulated monitor, which the D5200 and G6 have but the V2 does not have.

Both the MILC's enable viewing with motion picture capture via either the EVF (useful in sunny conditions) or the monitor. The D5200 can only use the monitor.

Panning  My subjective impression is that the V2 was smoother but they each managed well enough.

Continuous Focussing  The D5200/18-200mm  exercised itself with much whirring and clicking but was slow to catch up when the camera was required to focus from near to far or vice versa.  The MILC's were smoother and quieter. They managed near-far-near-far focus transitions more quickly and smoothly.

As was the case with still photos in monitor view, I wondered if the D5200 might work better with manual focus set by scale for motion picture capture.  

Face Detect  Each has face detect. That on the G6 and V2 were more reliable. The D5200 picked up a plate (plate detect, anyone ?) near the edge of the frame then kept focus at that location for many seconds after the camera was panned to a different part of the room.

Summary The G6 has been designed for fully integrated stills and motion picture capture and it shows in the user experience.

Ranking

1. G6/14-140mm

2. V2/10-100mm

3. D5200/18-200mm

Next, and last: Summary and final ranking

 

 

3 Way Holiday Camera Shootout Part 7, Ergonomics

Lumix G6 with 14-140mm lens

 

Summary of ergonomic concepts applicable to cameras   Ergonomics is the study of designing equipment and devices that fit the human body, it's movements and it's cognitive abilities.

Camera operation can be considered in four Phases, Setup,  Prepare, Capture and Review. Ergonomics devolves to Holding, Viewing and Operating in each of these Phases but particularly Capture Phase in which there is the highest requirement to carry out specific actions in a limited time.

General Observations  Each of these cameras offers at least acceptable ergonomics and none is without fault.

Holding  The lighter cameras are easier to hold than the D5200.  They require less constant support under the lens by the left hand and less gripping force by the right hand.  The D5200 and V2 each have a reasonable handle but a poorly located and shaped thumb support. The G6 allows the right hand to adopt a holding posture which is closer to the ideal "half closed, relaxed" position which I described in the post on functional anatomy of the human hand. There is enough space on the D5200 for a better thumb support which could be like that typically seen on Canon DSLR's. This would mean re-arranging control modules but that would not be difficult. I have also designed and built a mockup with the same dimensions as the V2 but with a much more user friendly layout.
Overall the most comfortable and secure kit to hold is the G6 followed by the V2 then the D5200.

Viewing  The modern electronic camera has complex viewing requirements. The user has to preview/review the image in the eye level viewfinder and also on the Monitor. In addition a user selectable menu of camera data must be visible on or beneath the eye level and monitor image. It is desirable that the viewfinder and monitor be configured to look the same and present the same data in the same format. This makes for a seamless segue from one to the other. In this regard, the mirrorless cameras have an advantage.

In my experience a fully articulating monitor (as found on the G6 and D5200) can be very useful. But performance with D5200 monitor view is sluggish.

In bright sunny conditions the D5200 optical viewfinder (OVF) provides the most appealing subject preview with the best shadow detail but the camera data can be almost invisible. Image playback is not available on an OVF.

In bright sun the G6 EVF is rather contrasty with blocked up shadows but the camera data are always easy to read.

The V2 EVF presents a slightly soft blue tinted image which is adjustable for brightness but nothing else. The V2 eyecup is a bit small, allowing light to impinge on the viewing eye, making clear preview difficult.

In Low light levels  The D5200 OVF gets quite dark. The EVF's on the two MILC's gain up in low ambient light to present a steady bright view in all conditions. In extremely dark conditions the G6 EVF is subject to jitter when panning but that is uncommonly seen in regular photographic practice.

In any conditions the very functional and fully articulated monitor of the G6 is  useful and practical. I have found that having become accustomed to this type of monitor on several Lumix cameras over the last two years I do not want to go back to a camera with less functional monitor live view or a non articulated or just pivoting monitor.

So the D5200 and V2 each have their viewing strengths but overall the G6 provides the best viewing experience, followed by the V2 then the D5200.

On the left, Nikon 1 V2. On the right my wooden mockup with the same dimensions.  This has raised shoulders and a completely revised user interface with JOG lever, providing excellent ergonomics.

Operating  Modern electronic or hybrid mechanical/electronic cameras (like DSLR's) are very complex machines. This poses a challenge to designers. How can they pack into the device the multitude of functions and capabilities which are expected these days while maintaining a user interface which ordinary humans can understand and operate efficiently ?

I will just mention some of the highlights and problems with each camera as a full discussion of operating characteristics would be too complex for this blog post. I have posted detailed discussion about analysis of camera operation in early posts on this blog.

 D5200  In eye level view operates reasonably efficiently.

ISO can be adjustable via the Fn button if it is so tasked. But the Fn button is difficult to locate by feel. The D5200 implements ISO/Auto ISO in a fashion which I find strange and frustrating. In the Shooting Menu, or My Menu if so allocated, you can select to switch Auto ISO On or Off.  If  set  On then you cannot set a specific ISO via the Fn button or the menu.  You have to switch Auto ISO Off.

In the other two cameras the Auto ISO setting is contiguous with specific ISO settings which is a much more coherent arrangement.

Exposure Compensation is available via the +/- button behind the shutter button. With some practice this is easy enough to find by feel.

Direct Focus Area control is available on the Multi Selector. This is easily accessible to the right thumb and this function works well, except that the active AF area is confined to the central part of the frame. MILC's can use the whole frame.

AF start can be allocated to the AE-L/AF-L back button in proper DSLR fashion. But this capability is oddly implemented. If AF start is allocated to the back button, it is disabled from the shutter button. I can more or less see the logic of this but in practice I find it irritating and I don't like cameras which irritate me.

If you want to adjust Image Quality, AEB, WB, Focus Mode, AF Area Mode, Meter Pattern or Flash Mode you have to stop using the OVF, lower the camera, open the monitor (if it was closed) press the [i] button, press the [i] button again then scroll around to your desired setting with the Multi Selector, make the adjustment then return to eye level viewing. This workaround is partly a consequence of operational constraints built into the basic SLR design and partly a result of the "semi-beginner-style" user interface of the D5200.

 Compare this to the G6  which can be user configured to be able to make a comprehensive list of adjustments by feel, while continuously viewing through the EVF.

Nikon 1 "V3" mockup being held in the right hand. I needed my left hand to make the photo. I rate this as being the smallest camera size which can accommodate a fully ergonomic shape and control module layout.

V2  The designers of the V2 have deliberately restricted the number and range of features, functions and adjustments available. This is not such a bad approach as it makes the camera the easiest of the three to set up and learn to operate effectively. It can manage most of the requirements of most beginner to enthusiast users. The dials are well designed and turn with the right amount of  resistance and clicky feel. The V2 is a vast improvement over the incomprehensibly crippled V1. The F button could be implemented much better if it was configured like the Q Menu on current Lumix cameras.

I have designed and built a wooden mockup camera having the same dimensions as the V2. This is a proof of concept exercise which shows that within the dimensional envelope of the V2 it is possible to design a fully featured pro style camera with excellent ergonomic efficiency.

G6  My interest in ergonomics was provoked by Panasonic's first "G-Micro" camera, the G1, which superficially looks like and is aimed at the same user demographic as the G6.  But I found the G1 to be a really frustrating thing to operate with many ergonomic deficiencies. The G6 shows that the details of user interface implementation are of the utmost importance. The G1 was, in my view, an ergonomic kludge while the G6 is a pleasure to use for the snapshooter or expert alike. Press the [iA]  button for  a simple point-and-shoot user experience. Or switch to one of the user control modes, access the Fn button options and build a camera with a sophisticated user interface designed to individual requirements.

All the functions which need to be adjusted in Capture Phase can be made with the eye to the viewfinder, by feel, without breaking the flow of image capture activity.

The downside of this sophistication is that the G6 is more daunting for the novice at the Setup phase of use.

So the G6 is the most efficient camera to operate, followed by the V2 then the D5200.

Comment about ergonomics, DSLR-vs-MILC  A well designed and implemented MILC can provide a streamlined, integrated user interface which no DSLR can match due to the presence of the flipping mirror. This was one of the very best ideas of mid 20th century mechanical camera design but it is unable to seamlessly integrate the complex requirements of a modern, multi view, multi function electronic camera device.

Sony tried to deal with this problem with it's SLT (Single Lens Translucent) range of DSLR style cameras. These cameras have a fixed mirror which allows about 60% of the incoming light to reach the sensor and the remainder to reflect up to the PDAF module in the hump. This technology does provide operational and ergonomic benefits over the standard DSLR type. However these cameras are forever stuck with a mirror sitting between the lens and sensor, blocking a substantial part of the light, gathering dust and preventing reduction of the flangeback distance. It appears from rumor sites that Sony will probably move it's entire interchangeable lens camera lineup to MILC type quite soon.

Ergonomics, ranking

1. G6/14-140mm

2. V2/10-100mm

3. D5200/18-200mm

Next, Video User Experience

 

3 Way Holiday Camera Shootout Part 6, Performance and Speed

D5200, 18-200mm lens. You can see the orange in this photo is bolder than in the photo below. The one below is probably more accurate.

G6, 14-140mm lens. Different aspect ratio from the M43 camera. Apart from this and the different color rendition I see little substantial difference between these photos.

 

Published Camera Tests  Many published camera tests just regurgitate manufacturer specifications and present this as an evaluation of camera performance. For instance I was recently reading a comparison between two cameras, one of which could shoot continuously at 9 fps, the other at 5.3 fps. The faster one was declared "better". But the reviewer just got this information from the spec sheets without testing to discover if 9 fps actually delivered any benefit over 5.3 fps.  Delving further in to the specs, it appears that both cameras claim to be able to do continuous AF, Continuous Drive at 4.2 fps. But again we have no idea how effective either camera might be in terms of the data which really matters, namely the percentage of frames in sharp focus.

Real World Performance Testing  I subjected all three kits to a series of tests, evaluating the relevant ones by checking the resulting photos at 100% on screen.

General remarks  All three cameras (Except the D5200 in Live View Mode)  delivered very good performance. I think most users would be well pleased with any of them. They each switch on and operate in a brisk and responsive fashion. A missed shot will rarely be due to any deficiency in the equipment.

Autofocus Speed  For this test I focussed back and forth between a near object and a far object, acquiring focus with a half press of the shutter button and waiting for the beep plus green AF area. I used the central area in each case. I did not fire the shutter.

Camera	Outdoors, dull overcast focus actions per second	Indoors low light Focus actions per second
D5200, OVF View	1.5	1.1
D5200, Monitor (Live) View	0.3	0.2
G6	2.2	1.3
V2	2.5	1.0

 Comment on Autofocus Speed   Outdoors the V2 is the AF speed champ, just beating the G6 by a small margin. The D5200 is by no means slow and will please most users but it can't keep up with the two MILC's.

Each camera slowed indoors but the V2 was slowed the most by low light. I believe this is because it switches from PDAF to CDAF in low light and Nikon CDAF is slower than Nikon PDAF.

Of the three the G6 was almost fastest outdoors and was the fastest indoors.

Turning to the D5200 in Monitor (Live) view mode we discover that the word "speed" does not apply in any sense at all. The camera switches from Phase Detect (PD) to Contrast Detect (CD) which does the "5 step dance" on every shot even when the subject distance has not altered. It goes eee...errr...eee...errr...beep (Yay! look at me, I did it !!) Presumably exhausted by this effort, the screen goes black for 2-4 seconds before the camera is finally ready to make the next shot. That might be just acceptable for landscape and similar work but the Monitor AF is error prone as well as slow. If this sounds bad it is better than the last DSLR which I owned which was a Canon EOS 60D. This thing did an eight step dance to achieve Live View focus and still made mistakes. I suspect that in most cases pre-setting focus distance by scale would be more satisfactory for Live View photography.

You may read opinions on the net by various photo sages that DSLR's focus faster than MILC's as if this were a statement of indisputable fact. My testing shows this is not so.

You may also read that CD autofocus is slower than PD autofocus. This is only true to the extent that CD AF in current model DSLR's  is slower than PDAF in those same cameras. CDAF in current model M43 cameras is very fast indeed, faster in fact than the PDAF in many DSLR's. It is also in my experience and testing, more consistently accurate.

D5200 with 18-200mm lens

G6 with 14-140mm lens

 

Shot to Shot Times  For this test I pointed the camera at a fixed target and in Single AF, Single Drive Mode, center AF Area, repeatedly pressed the shutter to make an exposure. The camera did not have to refocus between shots but it did have to confirm correct focus.

Camera	Shot to Shot time, seconds
D5200, OVF View	0.65
D5200, Live View	4.1
G6	0.5
V2	0.25

 

Comment on Shot to Shot Times  Like it's namesake in Peenemunde in 1944, the V2 goes like a rocket.  The G6 and D5200 in OVF Mode are by no means disgraced however and will suit most purposes just fine. The D5200 in Live View Mode is best suited to subjects firmly bolted down and immobile.

Continuous AF, Continuous Drive, Predictive Autofocus  For this round of tests I used cars driving along a suburban road and a person walking towards the camera at close range. The cars were in mixed light varying from sunny to shaded. The walker was in partly open shade  requiring a high ISO for adequate shutter speed.

The task for each camera/lens kit was to hold focus on the moving subject at 4 or 5 frames per second, and in the case of the V2, 15 frames per second.  The V2 has a huge buffer of 72 RAW frames at 5 fps. The G6 can manage 6 RAW frames before slowing, the D5200, 4 frames. So I used Fine JPG capture for all tests. With JPG files the G6 and D5200 could run off 50+ frames per run, more than enough for my purposes. I used single center AF Area, AF Continuous and a 95 MB/Sec card.  The D5200 and V2 were set at 5 fps, the G6 at M Burst which gave 4 fps. I ran the V2 at 15 fps in a separate test. The V2 is as far as I am aware the only camera at any price which can do predictive AF at 15 fps.

I set each lens at or near it's longest zoom position. I used the eye level viewfinder for all shots.

I used cars and the walker to be reasonably sure that each camera had the same task to perform in the same conditions, making the test fair. I did not test sports as this would introduce many uncontrolled variables.

I downloaded the resulting many hundreds of files and inspected each at 100% on the computer screen. I rated each as being Sharply in focus, Just out or Unsharp.

The User Experience  In reasonably bright light outdoors, the most pleasing camera to use in Continuous AF is the V2.  It has a muted shutter sound. The EVF appearance is that of continuous streaming video even though the camera is actually making stills. There is no perceptible EVF blackout. The image preview appears steady in the EVF.   The RAW buffer is huge. If you want, the camera can run silently at 5 or 15 fps with AF on every frame.

Next best to use is the D5200 which operates just like other DSLR's with a short blackout between each shot as the mirror flips up and down.

The G6 has the longest viewfinder blackout after each frame. It is usable and with practice the subject can be maintained in frame easily enough. It would be nice however if the Panasonic guys got the system in the V2.

Results 

Camera	Cars, Frames sharply in focus average over several runs	Walker, Frames sharply in focus. Average over several runs
D5200, 5fps	86%	95%
G6, 4fps	85%	93%
V2, 5fps	66%	76%
V2, 15 fps	65%	Not tested

 Comment on Predictive AF Results  Each of these consumer level cameras performed surprisingly well at predictive AF. All three cameras got a majority of frames in sharp focus.

The V2 is the absolute speed king however when we look at the percentage of frames in focus the other two perform a little better.

I found no significant difference between the D5200 and the G6 both of which performed at a level which would have been considered excellent in an expensive professional DSLR just a few years ago, and maybe even today.

You may read in the online photographic commentariat that

a) DSLR's do predictive AF better  than MILC's

b) MILC's are useless for predictive AF

c) Phase Detect AF is better for predictive AF than Contrast Detect AF

Each of these assertions is incorrect as to fact.

I think what is correct is that

a) Contrast Detect AF in DSLR's with PDAF optimised lenses is unsatisfactory for predictive AF. These lenses have  helical focussing mechanisms which were once considered fast but are really very slow compared to the direct drive AF mechanisms in modern M43 lenses.

b) The latest MILC cameras and lenses, particularly those for the M43 system can do predictive AF very well indeed. However M43  EVF refresh technology needs to be upgraded  to match that of the Nikon 1 system.

Performance Ranking  This is a bit difficult to determine due to the mixed results achieved.

The V2 is the nicest to use and is capable of the fastest shot to shot times and frame rates in good light outdoors where most predictive AF work will be done. But the percentage of sharp frames is not up to the other two.  In addition its speed drops substantially in low light indoors.

The D5200 works well and delivers a good result in all the test conditions (with eye level viewing).

The G6 does predictive AF  much better than some commentators and testers would have you believe. Some of these testers may have set the Autofocus  Mode on M43 cameras to "AF Tracking" which does NOT produce effective predictive AF.  Continuous AF is available with the monitor swung out, a handy feature not available on the other two.

In the end I have decided not to call a winner of the Performance /Speed criterion. Each does a good job but each has a different spectrum of capabilities.

The very fact that I am not able to call a winner with any confidence is actually very significant. Two years ago any mid range DSLR from Canon or Nikon would have easily outperformed any MILC.  It is intriguing to see how the march of technology has altered the balance between DSLR's and MILC's, or at least the Nikon 1 and M43 systems.

I have little doubt that MILC technology and performance/speed will continue to advance. But the DSLR has just about come to the end of it's evolutionary journey.  The main arena for performance advances in DSLR's lies in the Live View side of their operation. But any advances in that direction will potentially be of even more use to MILC's. I am thinking of Canon's incorporation of PDAF on every pixel of the imaging sensor, being introduced in Australia as I write on the EOS 70D. Canon wants it to improve smooth continuous AF during motion picture recording. But if the idea really works well why bother with all the mechanical paraphenalia of a DSLR ?  It might be even more suitable for a MILC.  

Next: Ergonomics

 

3 Way Holiday Camera Shootout Part 5, Picture Quality

G6 with 14-140mm lens

D5200 with 18-200mm lens

 

Technical Image Quality vs Picture Quality   There are several internet sites which publish data about camera image quality using technical terminology. A well known one is DXO Mark (dxomark.com). DXO reports overall image quality, Color Depth, Dynamic Range and Low Light ISO. DXO also reports a range of other technical measurements such as signal to noise ratios at various ISO levels. These measurements are made in highly controlled conditions in a laboratory style environment using test targets designed to reveal specific imaging characteristics.  I have no doubt these results form a useful part of an overall evaluation of the capability of a camera.  For want of a better term, I refer to the figures produced by this type of testing as "Technical Image Quality".

But when we use a camera it is never in a highly controlled environment. Real world use introduces many variables which intervene between the technical capability of a sensor and the final picture. I call this final result "Picture Quality".

Factors Influencing Picture Quality   Some of the factors which might and in fact often do influence actual output picture quality include:

* Camera Movement. Some users can hold a camera steady, others don't do so well. Some camera/lens kits are easier to hold steady than others.

Some cameras have Auto ISO algorithms which keep shutter speeds in the acceptable range for hand held use, others allow shutter speed to fall to levels which can cause unsharpness.

Some users watch their shutter speed readout and increase ISO setting if the shutter speed falls too low.

Some cameras/lenses have some kind of image stabiliser which can help steady the camera/lens unit.

* Lens quality.

* Exposure. Some cameras have exposure metering systems which allow highlights to become overexposed (blown out), others protect highlights assiduously.

* Color rendition. Cameras differ in the way they render colors.

* Focus accuracy.

* Aperture and depth of field. A camera with a large sensor will have to use a smaller lens aperture to achieve the same depth of field as a camera with a smaller sensor. This in turn requires a higher ISO setting and/or slower shutter speed both of which could have a negative impact on picture quality.

Real World test procedure  I made hundreds of photos of a wide range of subjects, shooting the same subject in the same light at the same time with the three kits. I used both the Auto setting and one of the P,A,S,M settings, usually Aperture priority. I used Auto ISO most of the time as that is what I and I suspect most users do. I noticed that each camera typically used a different Auto ISO setting and therefore  a different shutter speed.

Subjects were in bright sun, front lit and back lit, shady bright light, outdoors, indoors, in medium and low level lighting, natural and artificial. I shot people, single and groups,  landscapes and  buildings inside and out. I shot JPG and RAW files. I uploaded selected shots to the computer and compared images side by side on screen. I looked at JPG's, unmodified RAW's and RAW's processed to "best result" in Adobe Camera RAW 8.1.

G6 with 14-140mm lens

D5200 with 18-200mm lens

 

Defining Picture Quality 

* Color rendition    Some people like saturated colors, others prefer a more natural rendition which may be less saturated.  Cameras often differ in the way they place output colors in the spectrum. For instance one camera might render blues slightly cyan, another might render blues slightly violet. The accuracy of each can be measured with suitable test materials but the individual photographer might not be overly concerned with accuracy. The cameras in this test do render colors differently but I had a hard time deciding if any one of those representations was better than another.

* Highlight and shadow detail  It is easy enough to evaluate the amount of highlight and shadow detail in a JPG or RAW file on screen or in print. This is not the same as technical Dynamic Range which is measured in a specific way, generally by photographing a transilluminated step wedge.  I found that although the D5200 has a higher technical Dynamic Range, this was not reflected in actual pictures.

* Resolution/sharpness  I looked at resolution and sharpness in the center, at the edges and corners of test shots. I found that lens quality, focus accuracy and auto selected shutter speed had a big influence on sharpness.

* Noise  I looked at noise levels in each of the comparison photos.

The cameras on test, real world results  If you review the technical image quality data in Part 2 of this comparison series you will see that the D5200 scores best, followed by the G6 with the V2 scoring lowest on DXO Mark ratings.

You might expect the D5200 would easily beat the G6 for picture quality but that is not the case in the many hundreds of photos which I made for this comparison test.  However both the G6 and D5200 made better pictures than the V2 in almost all comparisons.

* Color:  There are differences in color rendition between the three cameras but I could not say one is better than the other. Another observer might have a preference for one or the other. For instance the D5200 typically delivers more saturated colors than the other two.

* Highlight and shadow detail: the D5200 and G6 are both very good and very similar. Even in subjects with a high brightness range I could not proclaim one to be better than the other.  By comparison the V2 suffers from less highlight and shadow detail than the other two when subject brightness range is high.

* Resolution/sharpness:  In the  frame center there was not much difference between the three kits. One might have expected the D5200 with a lot more pixels to excel here but that was not often  the case when actual photos were examined.  At the edges and corners the 18-200mm lens let the D5200 down,  producing consistently softer peripheral resolution than the other two lenses. The V2 in lower light levels often selected a low Auto ISO level presumably to keep noise levels in check. But this also produced a low shutter speed which fairly often led to unsharpness due to camera shake.

 I don't understand why the D5200 did not deliver better sharpness/resolution in the frame center. The 18-200mm lens works well in the center and the camera has more pixels than the others so one might expect it to beat the others easily. I did not have the time, money or motivation to test the D5200 with a better lens.

* Noise: The D5200 produces less noise at high ISO levels than the G6 which in turn is less noisy than the V2, which exhibits noise even at base ISO.  In actual photos the D5200 would typically set the highest Auto ISO level, followed by the G6 then the V2.  As a result the noise superiority of the D5200 was often countered by the higher ISO setting. With the camera on a tripod and with matched ISO settings the D5200 was able to demonstrate it's superiority. V2 pictures were always more noisy than the other two.

Summary My overall ranking for picture quality taking into account all the real world factors is:

1. G6/14-140mm.

2. D5200/18-200mm. With a better lens the D5200 would be the winner.

3. V2/10-100mm

Next: Performance

 

 

 

 

3 Way Holiday Camera Shootout Part 4, User Experience

Nikon 1 V2, 10-100mm lens at 100mm

 

Camera Reviews  Many camera reviews provide a long list of specifications and features. Several also provide a detailed description of all the various User Interface Modules (UIM, meaning buttons, dials levers, touchscreens etc), describing the location and function of each.  No doubt this "shopping list" approach to evaluation has it's uses but reviews like this leave the reader with very little insight as to whether the device is user friendly or not.

User Experience  In my family and I suspect many others, devices of all  kinds which do not work in harmony with the user get left in the drawer depreciating in value. If a camera is not user friendly it will not be used and so it's real world image quality and performance will be nil.

Notes on the single lens reflex camera  (SLR)     For 50 years SLR's  used film as the recording medium. There was no hint of digital capture, monitor viewing or motion picture capability.  With the advent of the digital era the SLR morphed into the DSLR but retained it's basic architecture and flipping mirror operation. Still  image and motion picture preview on the monitor require the mirror to be flipped up and locked. This blocks the optical viewfinder and exposure metering unit. It also disables the phase detect autofocus module beneath the mirror. So in monitor view the DSLR has to use a completely different system for exposure and autofocus, taking data from the imaging sensor itself, just like a MILC. In effect the modern DSLR is two cameras in one.

Notes on the MILC  Mirrorless interchangeable lens cameras were designed for all electronic operation from the start. Focussing, exposure and capture all use the imaging sensor. The camera works the same way with eye level or monitor viewing. This enables a seamless transition between these two viewing modes, either of which can be used for still and motion picture capture.

Monitor viewing and motion picture are fully integrated electronic functions of the MILC but are an afterthought to the SLR's basically mechanical operation.

In addition MILC's, having dispensed with the flipping mirror, mirror box and pentaprism  can be much more compact than DSLR's with the same sized sensor.

Price  Before  using a camera one has to buy it. The D5200/18-200mm  is sufficiently more expensive than the other two kits to give one pause about buying. If this camera had markedly better picture quality or performance than the other two kits this extra cost might feel justified.  The G6/14-140mm costs more than the V2/10-100mm but it does deliver better image quality.

Size, Mass   Although it is not terribly evident from the product comparison photographs, the D5200/18-200mm feels significantly more massive in use than the MILC's, which feel very similar.

Features  I have to confess being rather skeptical about many of the features which festoon modern cameras. This trio has some which could be useful and others the appeal of which eludes me. The G6 has touch screen operation, focus peaking and Wi-Fi connectivity to name just a few from the long list available. The V2 can shoot with predictive autofocus on every frame at 5 or 15 frames per second, a huge buffer and continuous streaming EVF view.  On the other hand the V2 has some faddish features which I suspect will be three day wonders for many users. These include Motion Snapshot Mode and Best Moment Capture Mode.

User Interface  For the novice or snapshooter each camera has an Auto mode. The D5200 has an additional Auto [No flash] mode. Auto Mode works well in each case, allowing easy point and shoot operation.
The D5200 allows user set function of the Fn button on the front of the camera. In practice this will likely be allocated to ISO as there is no other place for direct access to ISO adjustment. Unfortunately the Fn button is difficult to locate by feel as it is immediately adjacent to the lens mounting index marker and close to the identical flash pop up button.

The V2 offers a user interface with reduced content compared with the other two cameras. This might suit the less adventurous user quite well but could be frustrating for an experienced user. The V2 offers no control modules with user selectable function.

The G6 has by far the most user configurable control interface with 6 hard buttons and one lever all enabled for user selectable function. In effect the moderately advanced user can build the  interface to suit personal requirements, then change it as those requirements evolve over time. In addition the G6 has three Custom Modes where a group of user configured settings can be saved and reused at any time. This high level of user control does make the G6 appear somewhat intimidating for the novice wanting to move beyond iA mode. Making best use of  all that user control does  require some thoughtful consideration about how a camera works and how the individual user wants it to function.

Holding, Handling  The D5200 feels unbalanced, with a relatively heavy lens on one side and a somewhat inadequate thumb support on the other side. I found it always necessary to apply substantial gripping force with my right hand and also fully support the lens with my left hand. There is enough space on the back of this camera to fit a more prominent thumb support which would allow the right thumb to lie diagonally across the back of the camera for easier holding  with less gripping force.  The G6 achieves this with a smaller body, showing that it can be done. The V2 has a prominent handle and gets away with the poor thumb rest by being so small and light.

Operating  Both the MILC's offer seamless integration of stills and video, eye level and monitor viewing. The G6 allows the monitor view and EVF view to be configured to the same layout so the transition from one to the other involves no cognitive disconnect. The MILCs allow an extensive and user selectable list of camera data to be displayed on or beneath the EVF/Monitor preview/review image. The G6 offers the most options.

Both the MILC's operate smoothly and quietly. The mechanical shutter of the V2 is particularly unobtrusive. Both can be set for silent operation using an electronic shutter. The D5200 operates with audible whirring and clunking as the AF motor, shutter  and flipping mirror do their thing.

Family appeal  Part of my testing process has been to give each of the cameras to various family members to hold and use. None of them selected the D5200 as the camera they would like to take on a family holiday. Of the two MILC's, my pick for user experience is the G6 as it has the best ergonomics. But others selected the V2 for various reasons. It is the smallest and (just) lightest, it is the most quietly unobtrusive in operation and (this is not a joke) the shiny white surface is not easily marked by ladies' makeup.

My ranking for user experience is

1. G6/14-140mm

2. V2/10-100mm

3. D5200/18-200mm

Next:  Picture Quality