Dpreview's OM-D E-M5 Review, Second thread

Started Apr 30, 2012 | Discussions
rrr_hhh
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Re: IBIS *does* work at 9 fps...
In reply to Andy Westlake, May 1, 2012

Andy Westlake wrote:

kenw wrote:

The review says IS was disabled above 4 fps. This seemed odd because I recall testing it at 9 fps with no problems.

It seems that in Sequential High IS works just fine even at 9 fps, but perhaps in Sequential Low if you set the frame rate above 3.5 it is disabled as the review states?

We'll look into this again just as soon as Richard gets back into the office in Seattle this morning, and correct the review if necessary.

The manual is very explicit about IS being unavailable in L at 4fps, which presumably is why 3.5fps is the default. So as you say there's a chance that IS is only unavailable at 4fp, which would be odd but far from impossible.

There is something which may interfere : aka if the camera was alo in continuous AF mode or not ?

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kenw
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No IBIS in video with adapted lenses?
In reply to Aleo Veuliah, May 1, 2012

Sorry, meant to post this earlier.

A bunch of us seem to have discovered that IBIS does not work in video mode when we use adapted "legacy" lenses. Works just fine for stills, but doesn't seem to work with video. I've tried an adapted 85/1.8 Canon FD and others have had similar problems.

I don't know if DPR has any such lenses to test with, or really the time to do so, but it seems like an important point for a camera that does IBIS in video. I know adapted lenses are really popular with video and if IBIS doesn't in fact work that might be an important review point.
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Bob Meyer
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Really? REALLY?
In reply to Aleo Veuliah, May 1, 2012

Oh, puleeze. The OMD got a score of 80, the GH2 a score of 79. Yeah, that's a dramatic improvement all right, especially considering Oly's had two years to come up with something newer and better. Yawn.

Aside from that, the concept of an overall numeric score that somehow encapsulates the essence of a camera's "goodness" is more than a little bit stupid. Any scoring system like this assumes every photographer's priorities are the same, which is clearly not the case. If weather sealing really matters to you (as in you frequently shoot in the rain, or standing in the surf, as opposed to thinking this somehow makes it a "pro" camera), then the OMD is clearly better for you. But if you routinely shoot at 16:9, the GH2 may be better for you because of the multi-aspect sensor. No single number, or label (e.g., Gold) can possibly provide this kind of meaningful information.

But if knowing your camera is a single point "better" than a GH2 makes you happy, then by all means pat yourself on the back and use the gold rating to validate your self worth.

hahaha wrote:
Relax
Really?? Would you be happy if your GH2 get "Gold"?
Of course you would LOL
I have GH2 and 2 Pens, so I'm happy for Oly

Now, since you are a Panasonic fan, ambassador, or whatever, just tell them to > not to make another boring G camera. The only not boring Lumix G is GH2. > Period.
"LC1" m4/3 would get 'Gold', believe me LOL

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Richard Butler
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Re: After going through 8 series of shots
In reply to ppotka, May 1, 2012

ppotka wrote:

Tweak them out??? Was meant to mean that I tried to emphasize differencies by contrast and sharpening.
-p-

I've re-tested and I am seeing an improvement with IS on at 9fps. I wouldn't have found this without your feedback, so thanks a lot for that.

http://forums.dpreview.com/forums/read.asp?forum=1041&message=41390275

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Richard Butler
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Re: IBIS *does* work at 9 fps...
In reply to rrr_hhh, May 1, 2012

I've found my error (and worked out how I drew the wrong conclusion). I've now re-tested and have updated the review accordingly.

http://forums.dpreview.com/forums/read.asp?forum=1041&message=41390275

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Richard Butler
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Re: Question on Auto Gradation
In reply to assaft, May 1, 2012

assaft wrote:

A related question I have is whether you noticed a significant difference between (a) - applying Auto gradation at exposure time; and (b) - applying Normal gradation at exposure time and then changing the setting to Auto in the development of a raw file using the Oly Viewer 2 developer. I know that option (a) sets a higher shutter speed in order to protect the highlights, so as far as I understand, this option has more lifting work to do and probably introduces more noise. But regarding DR - does the tonal range scale you published for the Auto setting on page 18 is approximately the same for both option (a) and option (b)?

Thanks!
Assaf

The difference between (a) and (b) is that you'll get more highlight detail in (a) than (b), but also more shadow noise. This should only happen if the camera detects high contrast in the scene (Grad Auto is relatively clever about whether it uses a different shutter speed). I've not shot the two back-to-back, so I don't know how significant that difference is (I'll have a go later).

The example shot given, at ISO 800, was exposed with Grad Normal and then re-converted in-camera so, as you say, the shadows might not have been pushed as much as if it were natively shot with Grad Auto (depending on what exposure it chose).

The tonal range seen on page 18 is based on allowing the camera to change the shutter speed - that's where the extra highlight range comes from. The fact that the tail of the curve goes on further than for Grad Normal suggests noise isn't excessive, but I'll look into it.

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Richard Butler
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Re: 4/3 lenses not tested with OMD?
In reply to J R R S, May 1, 2012

J R R S wrote:

I thought you would include a bit about focus speed and usability with the old 4/3 lenses?

Sorry if this has been covered in this thred...

It hasn't. And I didn't go into it (because there are already too many features on the camera to go into detail on all of them. I tried, but I couldn't keep extending and delaying the review forever).

My initial experiences seemed positive but testing side-by-side with an E-PL3, there's no significant improvement. It's slow enough that I wouldn't recommend using Four Thirds lenses on the E-M5 (it varies between lenses, of course). That said, with some lenses, including the 12-60mm, it's workable if you already have the lens and are aware of the limitations.

Overall, they work, but this isn't the camera Four Thirds lens owners have been waiting for, and there's no comparison between their behavior and the latest M.Zuikos, which are stunningly fast.

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Macx
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Re: 4/3 lenses not tested with OMD?
In reply to Richard Butler, May 1, 2012

Richard, can I please ask you to clarify for me the point about the output images being slightly darker than expected for a given set of exposure values, indicating to me that the exposure index ("iso") is equally slightly shifted. Don't worry, I'm not the kind who believes this is some sort of conspiracy.

What I'm wondering is if this behaviour was only seen when using an independent meter, or if it also happened when using the camera meter?

If it's the latter I can adjust the camera meter, but on the other hand if the camera metered images turns out the expected level of brightness, I must conclude that the minor discrepancy in the exposure index is already being adjusted for by the meter, but that I'll have to remember to give the camera an extra 1/3 EV in situations where I use an independent meter (and really need that kind of precision).

I'm sorry if this was unclear, I suspect I might be confusing myself about this.

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ppotka
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Re: After going through 8 series of shots
In reply to Richard Butler, May 1, 2012

Glad to be of help! Testing these modern cameras is such a bitch, variables after variables, hour after hour... I really don't envy you in that jungle.
-p-
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PeterNMIF
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Andy, Guess that is why high ISO is important
In reply to Andy Westlake, May 1, 2012

Since I am not usuallyusing a tripod for macro work (bugs, insects, etc) perhaps better hight ISO performance is more important than better IBIS. This is one reason I like auto ISO in manual exposure mode on EM5 (something my GH2 lacks). Just set desired Fstop for DOF, set shutter to eliminate cam and insect movement, and let ISO go where it needs to go!

I am looking forward to experimenting as I use both nikkor 55mm micro and 105mm micro on the GH2 without problem, so any extra from the EM5's IBIS will be gravy.

Peter F.
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Aleo Veuliah
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Re: IBIS *does* work at 9 fps...
In reply to Andy Westlake, May 2, 2012

Andy Westlake wrote:

kenw wrote:

The review says IS was disabled above 4 fps. This seemed odd because I recall testing it at 9 fps with no problems.

It seems that in Sequential High IS works just fine even at 9 fps, but perhaps in Sequential Low if you set the frame rate above 3.5 it is disabled as the review states?

We'll look into this again just as soon as Richard gets back into the office in Seattle this morning, and correct the review if necessary.

The manual is very explicit about IS being unavailable in L at 4fps, which presumably is why 3.5fps is the default. So as you say there's a chance that IS is only unavailable at 4fp, which would be odd but far from impossible.

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Andy Westlake
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I think does not matter if we are using such high FPS, we must be using high speed shutter speeds

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Aleo Veuliah
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Re: Wait, they will answer, maybe they are not ...
In reply to Detail Man, May 2, 2012

Detail Man wrote:

Aleo Veuliah wrote:

Wait, they will answer, maybe they are not online now,

It's around 8:15 PM here in Seattle. Perhaps Richard actually eats dinner, or something ? ...

... and today is already 1st of May, an Holiday, at least here it is.

Not in the "I've got mine, Jack" USA, where International Worker's Day is often considered to be a paganistic Marxist holiday that "Libertarian Jesus" would most certainly decry (tongue in cheek)

Did not knew about that, tanks

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Aleo Veuliah
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Re: Andy, Guess that is why high ISO is important
In reply to PeterNMIF, May 2, 2012

PeterNMIF wrote:

Since I am not usuallyusing a tripod for macro work (bugs, insects, etc) perhaps better hight ISO performance is more important than better IBIS. This is one reason I like auto ISO in manual exposure mode on EM5 (something my GH2 lacks). Just set desired Fstop for DOF, set shutter to eliminate cam and insect movement, and let ISO go where it needs to go!

I am looking forward to experimenting as I use both nikkor 55mm micro and 105mm micro on the GH2 without problem, so any extra from the EM5's IBIS will be gravy.

Peter F.

True, for that is really important and good, but I try to use always the lowest ISO possible and tripod

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Frank B
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Re: Dpreview's OM-D E-M5 Review, Second thread
In reply to Aleo Veuliah, May 2, 2012

How does the stabilization in the M5 compare to PEN cameras? The review of the E-PM1 said it could be good for up to 3 stops and the review of the M5 seems to have gotten about the same result. Is the M5 more consistent in getting results? I don't care about video, howver I understand that others could are. Thanks.
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bg2b
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Re: No IBIS in video with adapted lenses?
In reply to kenw, May 2, 2012

And if you (dpreview guys) have any contact within Olympus, could you ask them if there's a technical reason it's not done, or is it just a firmware oversight?

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StevenN
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Well said, Bob
In reply to Bob Meyer, May 2, 2012

I am a new GH2 owner, and am very happy with it. I could've purchased an OM-D , but its features and price difference didn't make it worth it to me.

Many years ago I sold my Nikon F2 and several lenses to purchase a Olympus OM-1n and several lenses (which I still own), so I am a big fan of Olympus.

But whether I own an OM-D, a GH2 ... or Nikon D4, for that matter, it is not going to measurably affect my picture taking. The world's most expensive and feature-packed camera is not going to produce great photos without a good photographer behind the lens.

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Aleo Veuliah
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Re: Well said, Bob - Plus 1 (nt)
In reply to StevenN, May 5, 2012

StevenN wrote:

I am a new GH2 owner, and am very happy with it. I could've purchased an OM-D , but its features and price difference didn't make it worth it to me.

Many years ago I sold my Nikon F2 and several lenses to purchase a Olympus OM-1n and several lenses (which I still own), so I am a big fan of Olympus.

But whether I own an OM-D, a GH2 ... or Nikon D4, for that matter, it is not going to measurably affect my picture taking. The world's most expensive and feature-packed camera is not going to produce great photos without a good photographer behind the lens.

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StevenN

GH2, GH1, D70, ZS3

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J C Brown
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Re: Sensor Resolution - for R Butler et al.
In reply to Richard Butler, May 6, 2012

R Butler wrote:

All I'm saying is that if you look at the test chart image, a cursory glance makes it look like it's correctly rendering 2800 lines, but if you look closely, it's not able to differentiate between 9 distinct lines after all. In fact they start to merge together at around 2600.

And what does it mean in terms of sharpness when looking at photos? Not a tremendous amount. There's a risk that you end up over-analysing how well a camera resolves black and white converging lines. The main thing is that it comfortably gives the resolution that you'd expect of a sensor with 3456 vertical pixels. At which point, it's far more relevant to worry about sharpening and image processing.

My attention was drawn to this thread by Detail Man who kindly referred to my FZ50 paper in his response to Kikl. From the range of comments on this topic it is clear that there is some concern about the subjective interpretation of the test images obtained from the DPR test chart and its effect on the accuracy of the resolution measurements.

To illustrate the appearance of the vertical resolution area of the Olympus OM-D E-M5 test chart under close examination I took an 1100 x 300 pixel crop from the DPReview test image and marked vertical lines on it at positions which correspond to 3456 (N), 2800, 2600, 2444(N/root 2), 2304(N/1.5) and 1728(N/2) where N is the image height in pixels.

To represent the test chart accurately the thickness of the lines and spaces should remain equal as it increases along the length of the chart.

If you examine the above image at high magnification you will see that at 3456(N) where the lines and spaces should each have a thickness of 1 pixel, with the exception of a couple of darker grey lines, the image is almost entirely the same shade of grey.

At the 2800, 2600 and 2444(N/root 2) positions the lines and spaces consist of a mixture of black, white and grey pixels and their relative thicknesses vary.

At 2304(N/1.5), all of the lines are black with a thickness of 1 pixel while all the spaces are white with a thickness of 2 pixels resulting in an area of high contrast.

At 1728(N/2), both the lines and the spaces have a thickness of 2 pixels. Each of the lines has a black and a dark grey pixel while each of the spaces has a white and a light grey pixel.

It is more than 5 years since I noticed significant variations in the appearance of the DPR vertical resolution test charts at the measured resolution values, as can be seen in the following image which shows crops from the DPR test charts for FZ30 and FZ50 both with an assessed resolution of 1800 LPH.

Having concluded that the way in which tapered lines are represented in a digital image could lead to somewhat subjective results, I decided to try to design a test chart which would be better suited to digital images.

From the arrangement of the Bayer matrix it seemed likely that for coloured images in which the colour of each pixel is obtained by combining the signal for each pixel with those from several adjacent pixels the resolution would be lower than for a black and white image. That led me to design a test chart in which the thickness of the lines in the smallest recognisable E is used to assess the limit of resolution for each colour. The chart is available for download from my DPR gallery.

Below are a full frame FZ50 image and a screen capture comparing a crop with the original test chart.

Although intended for use only by private individuals I believe that the use of my test chart by DP Review to compare the colour resolution of cameras would be of interest to DPR members.

Jimmy
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Detail Man
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Re: Sensor Resolution - for R Butler et al.
In reply to J C Brown, May 7, 2012

J C Brown wrote:

R Butler wrote:

All I'm saying is that if you look at the test chart image, a cursory glance makes it look like it's correctly rendering 2800 lines, but if you look closely, it's not able to differentiate between 9 distinct lines after all. In fact they start to merge together at around 2600.

And what does it mean in terms of sharpness when looking at photos? Not a tremendous amount. There's a risk that you end up over-analysing how well a camera resolves black and white converging lines. The main thing is that it comfortably gives the resolution that you'd expect of a sensor with 3456 vertical pixels. At which point, it's far more relevant to worry about sharpening and image processing.

My attention was drawn to this thread by Detail Man who kindly referred to my FZ50 paper in his response to Kikl. From the range of comments on this topic it is clear that there is some concern about the subjective interpretation of the test images obtained from the DPR test chart and its effect on the accuracy of the resolution measurements.

An excellent and a very informative post, Jimmy ! The in-camera sharpening that in-camera JPG "engines" perform tends to (artifically, using edge-enhancement techniques) "disguise" such things

Although intended for use only by private individuals I believe that the use of my test chart by DP Review to compare the colour resolution of cameras would be of interest to DPR members.

This is a truly useful test-chart. I wonder if DPReview, or any E-M5 owners/users, will endeavor to utilize your test-chart in order to assess it's "chroma-resolution" (as opposed to "luma-resolution") ?

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J C Brown
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Re: Sensor Resolution - for R Butler et al.
In reply to Detail Man, May 11, 2012

Detail Man wrote:

J C Brown wrote:

My attention was drawn to this thread by Detail Man who kindly referred to my FZ50 paper in his response to Kikl. From the range of comments on this topic it is clear that there is some concern about the subjective interpretation of the test images obtained from the DPR test chart and its effect on the accuracy of the resolution measurements.

An excellent and a very informative post, Jimmy ! The in-camera sharpening that in-camera JPG "engines" perform tends to (artifically, using edge-enhancement techniques) "disguise" such things

Although intended for use only by private individuals I believe that the use of my test chart by DP Review to compare the colour resolution of cameras would be of interest to DPR members.

This is a truly useful test-chart. I wonder if DPReview, or any E-M5 owners/users, will endeavor to utilize your test-chart in order to assess it's "chroma-resolution" (as opposed to "luma-resolution") ?

Thanks for your very complimentary remarks Detail Man.

For the benefit of anyone who, suitably encouraged by Detail Man’s recommendations, might be interested in experimenting with my test chart, I feel that I should provide some more detailed information about its design, use and potential benefits.

The coloured Es chart is similar in design to the visual acuity charts used by opticians in that it uses rows of letters of different sizes to assess the limit of resolution but differs in that the letters are all Es, the incremental increase in size from row to row is just 10% of the size of the bottom row and to allow the resolution to be assessed for a range of colours the Es are printed in red, green, blue, black, magenta, cyan and yellow.

To measure the vertical resolution in lines per picture height, LPH, the distance between the camera and the chart is carefully adjusted until the length of the scale line in the recorded image is 400 pixels within one or two per cent. Then with the white balance set manually a shot is taken for each desired condition, e.g. aperture, ISO rating, etc.

As the thickness of the lines in the bottom row of Es corresponds to the height of a single pixel the vertical resolution for each colour can be calculated by dividing the number of pixels in the height of the sensor by the thickness in pixels of the lines of the smallest E of each colour which can be easily recognised as consisting of three lines and two spaces.

For example for a 12 MP sensor with a sensor height of 3000 pixels, if the smallest easily recognisable blue E has a line thickness of 1.5 pixels then the vertical resolution for blue is 2000 LPH.

As illustrated in the following image when examined at high magnification, by clicking on the image, the individual pixels which make up the lines of the Es can be very easily recognised allowing the resolution limit to be determined with acceptable accuracy.

In addition to the benefit of allowing the resolution to be assessed in six colours as well as black, experience with several users has shown that the consistency with which the resolution can be assessed using the coloured Es chart is considerably better than for charts consisting of tapered black lines for which the ability to locate the position at which it is possible to distinguish 9 lines and 8 spaces is much more varied and subjective. The edge and corner resolution can also be easily assessed by placing additional copies of the test chart in the appropriate positions on the test board.

As can be seen from the above Panasonic FZ50 image there is a significant variation in the resolution for different colours, with the green, cyan and yellow Es being considerably less well defined. These differences may be explained in part by the arrangement of the red, green and blue filters in the Bayer matrix and the in camera demozaicing process and in part by the effect of the edges of the image partially overlapping adjacent pixels.

To demonstrate that effect I designed the stepped Es test chart shown above. In that chart each successive E in a row is displaced upwards by 10% of the thickness of the lines of which the Es are constructed. When an image of the chart is recorded from the distance at which the thickness of the lines in the smallest E is one pixel, each successive E in each row of Es in the resulting image will overlap the pixels on the sensor by an increment of 10% of the thickness of the lines used to construct them.

The above images show part of the test chart and the corresponding part of an FZ50 image. As may be readily seen by clicking on these images the accuracy with which successive Es are recorded and the ease with which they can be recognised varies with the amount by which the edges of the lines overlap the adjacent pixels.

These results lead me to conclude that the appearance of images recorded using charts constructed of tapered black lines is susceptible to variation due to the overlapping pixel effect described above making it more difficult to obtain consistent measurements of the limit of resolution.

In addition to providing images for which the resolution is relatively easy to assess, the colour test chart gives the advantage of allowing the resolution to be measured for six colours and of facilitating assessment of the variation of colour resolution with various settings such as aperture and ISO rating.

Jimmy

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