Yi Technology -- Yi-M1

Discussion in 'Mirrorless Cameras' started by VidThreeNorth, Aug 25, 2017.

  1. VidThreeNorth

    VidThreeNorth TPF Noob!

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    Yi-M1 Dynamic Range

    There are two specific issues I have been planning on addressing since I started looking into the Yi-M1 JPEG capabilities. One is "dynamic range" and the other is "noise handling v. detail". These are related, but I am trying to address them individually. Looking at "dynamic range" here, I am only looking at the "Natural" finish. If I look at the "Vivid" finish or the others,, the results might turn out to be different.


    "P3030025-1b-rsz1200-C2.jpg"
    The golf course at Eglinton Ave. W. and Jane St.

    My eyesight is pretty bad. Even with my glasses I cannot see a lot of detail. So if I have a camera in my hand, sometimes I take a picture of simply to look at it later. When I was photographing the trees north of the golf course at Eglinton Ave. W & Jane St., I was looking up and wondering if there was anything interesting to see in the shadows. So I took "P3030049" [see also message #34 above]. I chose an EV compensation to get enough exposure into the shadows, expecting that I might lose some highlight areas.


    "P3030049-Crop02-C1.jpg"

    [Crop from 540,2300]

    This crop was all that I was really interested in seeing. After seeing it, I was satisfied that, really, there was not much of interest after all -- just some branches with pine cones and needles. That was going to be the end of that picture. I might even have deleted it at that point, but I decided to keep it for a while.

    As I was thinking about writing a bit about the Yi-M1's current JPEG processing, I looked through the files I had on hand and felt that this file showed a handful of issues I thought I would like to show. In particular, I was interested in the chromatic abberation issues. First, the 12-40mm kit zoom may not be wonderfully sharp but at the telephoto end in particular there was very little chromatic abberation. But there was enough to show the way the Yi-M1 handled it. It also showed a bit of the noise and resharpening issues. So I decided to use it as one of my first examples.

    Having used it for this, I started thinking about the other issues that it demonstrated. "Gee, it sure is too bad I didn't have the highlights covered by the dynamic range." Now that raises a couple of interesting questions. Exactly how much dynamic range does the Yi-M1 have to work with? Did I have enough that I could have "contained" the whole of this scene? Whenever I had the time, over the last few days, I chased after the the answers to those questions, and this is what I can say for now:

    First: If I had paid better attention to this picture, could I have set an exposure that would have covered the whole of the dynamic range in this situation? After trying my best with Corel PaintShop Pro 2018, I can say that no, it was not possible. It was close though. First, we know that I clipped the highlights. It does not look too bad. As I wrote above, I think an uncompensated exposure probably would have been enough to cover the highlights. But what about the darkest parts? I tried compressing the gamma curve using PaintShop Pro's "Histogram Adjust" capability, and then made a further fine adjustment in "Smart Fix".

    What I found was that there were a couple of very small patches of un-correctable "black" in the deepest shadows. Raising the levels of those areas eventually just shows noise. So that answers it. Even with the small patches of overexposed highlights at the top end, there is also unusable "black" at the bottom end. The sensor's dynamic range is exceeded at both ends. Lowering the exposure to bring down the highlights would simply have increased the black areas in the shadows.


    "P3030049-5c-Crop01-C1.jpg"
    [Crop from 540,2300]

    This is the best I could do adjusting the gamma curve to flatten the dynamic range and recover everything possible in the shadow area. Compare this to "P3030049-Crop02-C1.jpg" and yes, I think that I did manage to recover a bit of shadow detail, but not really much. I "think" I recovered detail? Well, if you look at it, the only thing for certain is that the noise is showing up, and there is some "greenish" area that used to be "black" in the original JPEG. I can "guess" that I am seeing more of the needles, but I am simply applying an assumption that it should be more needles. An "unbiased" analysis would conclude that "nothing was proven." But in the end, yes, you will find that there are still some patches that are definitely nothing but "black + noise".


    Still, the camera did pretty well. According to "YI M1 Review" by Mike Tomkins ("Imaging-Resource.com" posted: 09/18/2017)
    "YI M1 Review"

    The Yi-M1 has "... the same image sensor as in the Panasonic GX8". I do not have a reference, but I believe I also read that this is the same sensor which is used in the current Panasonic GH5. It might also be in the G9. Looking further, DXOmark had this to say about the Panasonic GX8:

    DXOmark GX8:
    Overall Score 75
    Portrait (Colour Depth) 23.5 bits
    Landscape (Dynamic Range) 12.6 EVs
    Sports (Low-Light ISO) 806 ISO

    [Compared against Panasonic Lumix DMC-GH4 (16MP), Olympus OM-D E-M1 (16.3MP), Olympus PEN E-P5 (16.1MP), Olympus OM-D EM10 (16.1MP) their review continued as follows:]

    "But the difference between the sensor performance of these Micro-Four-Thirds cameras is so negligible that we can essentially say they offer the same image quality in terms of Color, Dynamic Range and ISO, despite the fact the GX8 benefits from greater resolution."

    I think that the sensor performance of the Yi-M1 would prove to be in this same ballpark, which is still about the same as some cameras which cost much more.


     

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    Last edited: Apr 8, 2018
  2. Braineack

    Braineack Been spending a lot of time on here!

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    My Google Pixel phone performs better...
     
  3. VidThreeNorth

    VidThreeNorth TPF Noob!

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    Well that was an interesting comment, so I took a bit of time to look into it, and came away with a bit of a headache.

    The only source I had time to look up was DXOmark, and I ended up bogged down trying to get a handle on their current testing and reporting method. Put simply, I could not find a specific test of "Dynamic Range". Yet they had no problem knocking the Google Pixel for apparently not being very good in that category for video.

    Here's their link:

    "Google Pixel: Retested with the new DxOMark Mobile protocol - DxOMark"

    Here are some of the things they wrote in summary which I might be related to "dynamic range".

    Photo:
    "Exposure and Contrast 90
    ..."
    - [one of the best cellphone cameras for this]

    Pros:
    "•Very good highlight preservation
    •Very good detail in low light
    •Good noise levels in bright and medium light
    ..."

    Cons:
    "...
    •Very low levels of detail for medium- and long-range zoom
    ..."

    Video:
    "Exposure & Contrast: 83
    ..."
    - [83 does not sound so bad. I need to look at a bunch more to see why they say it lacks dynamic range below.]

    Pros:
    "•Good exposure in almost all light conditions
    ...
    •Good noise reduction and color at all light levels"

    Cons:
    "•Lack of dynamic range
    •Visible color shading in indoor conditions
    ..."


    So it sounds like you are might be right about the "Photo" capabilities of your Google Pixel, but for video it got knocked specifically for dynamic range. In the end, one cannot assume that a smaller sensor in a particular phone camera will be out performed by a particular larger sensor in a camera, and the later technology sensors like in the Google Pixel could be up to the task.
     
  4. VidThreeNorth

    VidThreeNorth TPF Noob!

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    Yi-M1 Noise Reduction:

    First, let me say that I have not used typical "image noise reduction" functions much -- in my whole life. Well that sounds really dramatic, but if you consider that I have only been using image modifying software for maybe three or four years now, you realize that this was mainly a joke. I am excluding "paint" style programs from this because I have done "paint" work for many years, but photo retouching software is something I only really started using recently. Oddly, I had software years ago, yes, legally bought and paid for, but I did not even get around to installing it.

    [2018-0410 BIG Mistake, embarrassing but not really important to anyone but me. I was very tired and in a hurry when I wrote this post so actually, I made 2 big mistakes. This one is not really important.

    What I was thinking about was that I started using "Corel PaintShop Pro" about that long ago. For some reason I discounted my use of another program that came with a "Nero" installation which was a very nice, but not as advanced image manipulation program, which name escapes me right now. But I used that for many year -- over five years? I switched to PaintShop Pro because Nero dropped support of that earlier program. And yes, as I wrote above I had another program, I think by Magix, which I never even installed.]


    But let me get more specific. I have probably only used "image noise reduction" functions about a half dozen times over the last three years. Here is why:

    As most of you who have tried out image processing software fairly thoroughly will know, if you use a "rotation" or a "geometric perspective correction" or a "lens linearity correction" (for "pin-cushion" or "fish-eye" or "barrel" distortions), or a resize downward, then a lot of the noise will be "handled" as a result of those changes. Since almost all my pictures require some combination of these changes, there is usually not much image noise left that requires specific attention.

    The result is that I have very little experience with any of the noise reduction tools that I have had in any of the programs I have used. So likewise I have very little to say about noise reduction for the Yi-M1. It surprised me at first that I read some comments that the Yi-M1 used too much noise reduction which result in loss of detail, BUT others seem to say the opposite, that the Yi-M1 did not apply enough noise reduction. At first I attributed this to the possibility that people were seeing different versions of the firmware, and that may be a part of it. But this comment makes me think that something else might be happening:

    DPreview.com "New kid on the block: YI M1 review" 2018-04-08:

    "The JPEG engine produces JPEGs that are full of nice detail but some of the finer detail tends to get a bit muddled as it appears that they are applying larger radius sharpening during JPEG processing."

    and later:

    "In terms of noise reduction the M1's JPEG engine takes a fairly lazy approach, leaving behind a lot of noise and generally not balancing detail retention and noise reduction as well as the Olympus [PEN E-PL7 specifically] with its context-sensitive approach. Color noise can be problematic with the M1, particularly at and beyond ISO 1600, although it starts to become evident by ISO 800 compared to the Olympus. It's also worth mentioning that the M1's JPEG engine also doesn't completely eliminate all of the color aliasing."

    It is a bit irritating that their review did not make clear which version of the firmware that the above applies to, but their review seems to be up-to-date up to version 1.0.20 Int. and possibly up to version 2.0.0 Int. Moreover, they specifically note for "November 2017" that at least 3.0.0 Int is being tested, which I assume will probably mean that 3.1 Int is probably being tested. I applaud their efforts.

    But first, DPreview.com's comments do sound like what I am seeing, so for now, it appears to me that the JPEG has not changed substantial since around 2.0 Int. If they notice later changes, I will expect them to make a comment about it. Actually, if they saw something significantly different, I would have expected them to re-do their "studio" test shots by now. So I think that their currently posted review probably is the most accurate analysis of the YI-M1's JPEG performance.

    [2018-0410 -- My second BIG Mistake, and this one is important: I think I have made a mistake in my conclusions about the version 3.1-Int JPEG engine, probably because that I managed to get confused about which picture I posted was which. The file I posted below is my DNG raw file conversion and shows "colour aliasing" in a few places. It can be seen in the mortar between the bricks as magenta specks, and especially in the large sign letters which have thin black accent lines running through them which in the DNG conversion come out as a rainbow of coloured pixels but in the crop of the original camera JPEG posted previously, the JPEG engine has rendered them as grey, which is the best that can be done. If this is what the DPreview article is referring to, then it appears that the version 3.1-Int JPEG engine has been improved.]

    [Compare the images posted here with:

    "P3240002b-Crop01-C1.jpg"
    - detail crop of original camera created JPEG.

    "Yi Technology -- Yi-M1"]


    "P3240002 -1c-Crop01-C1.jpg"
    The detail crop.

    I have created a fairly straight forward conversion of the DNG raw file and this is a crop that matches what I previously posted. If you compare the two detail crops, you will see noise specifically in the blacked out windows, and in the Pub's main sign (which includes a lot of the "color aliasing" mentioned in DPreview.com's article).

    How much detail was lost during conversion? Personally, I do not feel that it was much in this sample, so I am fairly satisfied that overall, the Yi-M1 is generally "passable" in that regard. But there is another point that should be understood here. The Yi-M1 was made using a version of an Ambarella chipset. Ambarella probably has not released much information about their DSP circuitry, and decides what capabilities Yi Tech has to work with. It is entirely possible that Yi cannot do better than this because Ambarella has not provided them with information sufficient to have fine enough controls to further correct the problems. So even if their is a further firmware upgrade coming, except for perhaps a better colour balance in the Portrait mode, I am not expecting to see better JPEGs than what I am seeing now.

    "P3240002 -1b-rsz1240-C1.jpg"
    A resized version of the whole DNG converted image. It will not show any noise because it has been reduced so much.
     

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    Last edited: Apr 10, 2018
  5. VidThreeNorth

    VidThreeNorth TPF Noob!

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    I am still exploring the YiM1's new capabilities and testing old capabilities that I did not get around to testing before. In this case I am testing use of adapted lenses, but with a lens I have not tested before. The lens is a Pentax SMC M series 50mm F2.0. This was one of the standard lenses available for the Pentax ME and MX 35mm cameras when they were introduced.

    Back in the "old days" when I was using real film cameras, I did not have a special lens testing setup. I did have a target, but I did not have a large wall space to set it up, so I never got around to trying it. What I did was not much different than what I do today. Mainly I point the camera a brick wall to get an idea of some of the more formal characteristics, and then some good colour and black and white subjects. But back then, because film and development cost money, I was very economical in my approach. These days, I take a lot more pictures because I can afford to delete them. Actually, not only can I afford to delete pictures, it is imperative that I do so because it costs me to store them.

    But back in the old days, I did not have much opportunity to try out a lot of lenses, so I mainly read the most reliable test reports I could find and saw whatever pictures my friends took and compared them to what I knew.

    What I am going to say is my "impression" of the situation back then. There is a good chance that I am wrong about a lot of it. Frankly, I don't really care that much because when it comes down to it, I still cannot afford to buy a whole lot of equipment, and my first problem is to get what I can afford.

    Anyway, my "impression" of Pentax back at that period was like this. The screw mount Super Multi-Coat Takumar lenses really were excellent lenses. That was confirmed by every lens test I ever read by Modern Photography and Popular Photography, and a few other magazines I read. The first K-Mount lenses were as good. In fact mostly they were the same lenses in new bodies. And yes, they were new bodies and not just mount changes. The K-Mount was bigger and I think they tended to make the bodies thicker in diameter.

    When the M-series lenses came out, Pentax re-designed many of them to be smaller. Here I am going to say something that I know many others will disagree with. I think that many of the smaller Pentax M lenses were not as good as their predecessor models. Probably some might have improved. My "impression" was that colours might have been richer, but they might be softer overall or give away a bit of sharpness or vignetting in the far corners.

    It was my "impression" that the older SMC Takumar and Pentax K 55mm F1.8 was a better lens that the M series 50mm F2.0, and moreover, both the 50mm F2 and 50 F1.4 M-series lenses were better than the 40mm F2.8 "Pancake".

    Over the last year I have bought both the 50mm F2 and the 40mm F2.8 M series lenses, intending to use them on Micro 4:3. I got the 50mm F2 at about $40 US. The front element is nicked far off axis. I do not think it is affecting the lens performance, but the lens does appear to be softer than a typical SMC Takumar 55mm F1.8 would be. It is not terrible, but it is a bit under-whelming.

    Buying the 40mm F2.8 was very annoying. I think I paid about $75 US for it, mainly because Kai had recently posted a YouTube clip about how wonderful 40mm pancake lenses were (this time using a Canon for an example). The old M series 40mm F2.8 is not as good a lens as the later "Limited" lens which would be well worth $75 US (or even much more). But I paid the high price because I think the price for this lens is going to be inflated for quite a while. It is legitimately a rare lens, because most people bought the 50mm F2.0 lens, but optically it is just not "wonderful". I class it as "good". Not better than that because it has severe vignetting when used on a full size sensor (or 35mm film). I bought it as a manual version backup lens for my M4:3 version 42.5mm F1.8 Yi portrait-macro lens.

    When the "first colours" of Spring, began to show, I had the 50mm F2.0 lens on a Pentax K100D, but without my monopod and had a terrible time trying to take very small early flowers. I eventually went back to the park with the Yi-M1, first with the Yi 42.5mm F1.8 lens, and then again later with the Yi-M1 with this Pentax 50mm F2.0 lens. The reason for using the 50mm F2.0 lens was because I did not like using manual focus on the Yi 42.5mm lens (which has no focussing control ring), but the Yi-M1 camera does work really well when using adapted, properly designed manual lenses. Also, the slightly longer focal length was a bit easier to work with in a park where I did not want to step into the flower bed to get closer to plants.
    [2018-05-12 above 4 paragraphs have minor changes.]

    Why is The Yi-M1 So Good For Real Manual Lenses?

    The Yi-M1 has really good screen magnification, and in the Version 3.0 - 3.1 firmware that magnification goes beyond 4x to 6x, 8x and 10x. It works like this:

    On the back of the camera, the bottom most button is called the "Q" button, and its function varies sometimes. During still and video recording it controls magnification. Each time one clicks that button the screen magnification advances to the next setting and after it reaches 10x, then it re-cycles back to 1x. So the screen magnification cycles like this: (starting from 1x), 2x, 4x, 6x, 8x, 10x, then back to 1x.
    [2018-05-12 minor edit for clarification.]

    The cycling can be over-ridden at any time by touching the shutter release 1/2 way. The magnification immediately reverts to 1x.

    I have found that I generally use 3 quick clicks to get to 6x and do my focussing, and then touch the shutter release back to 1x and compose and take the picture (or abort). I can do this very quickly.

    NOTE: Some people prefer "focus peaking" and the Yi-M1 supports this capability. I have tried "focus peaking" on the Yi-M1, the Sony a5000 and the Pentax Q-S1 and on all these cameras I did not find it helpful. In fact, it confuses me and I end up making mistakes.

    Before the Yi-M1 with 3.1 firmware, my favorite camera for manual focus was the Pentax Q-S1. Now I prefer the Yi-M1. So the Yi-M1 has my favorite manual focus control, and it also is also arguably, capable of taking the best pictures of any of my cameras, when used this way. My Sony a5000 still has some advantages for still photography, but I won't go into the fine differences right now.


    This Set of Pictures:

    This set is really just three variations of the same picture and I should start by mentioning that almost all the in-camera JPEG pictures that I have taken with the Yi-M1 have been with AdobeRGB instead of StandardRGB. I made a set of tests (only a couple of pictures of each) comparing StandardRGB against AdobeRGB early when I started testing Firmware version 3.0. What I found was that when using AdobeRGB colour saturation turns out a bit higher. I have not decided that it is necessarily "better" but rather, I am looking at it as a long term experiment. I know that really, AdobeRGB was intended for print output rather than "on screen", but for now I have decided to leave this Yi-M1 as my only AdobeRGB camera. This goes along with the fact that I do not really intend to use it as a still camera anyway. Part of the "test" was to see if it made any difference to videos, and apparently it does not. It seems to only affect still pictures.
    [2018-05-12 clarification]

    With this set of pictures, two of the files are based on the AdobeRGB output of the in-camera JPEG render. The third image was made from the DNG (raw) file using Corel PaintShop Pro X9, and despite the fact that the colours have been adjusted and "brightened", the Yi AdobeRGB JPEG version is noticeably more saturated.


    "P5040013b-rsz1640-C1.jpg"

    Partial EXIF (from JPEG)
    Date taken 2018-05-04 13:41
    Program name ASDK-00141
    Dimensions 5184 x 3888
    Resolution unit 2
    Color representation "Uncalibrated" (AdobeRGB)
    F-stop f/0 [probably F16]
    Exposure time 1/125 sec.
    ISO speed ISO-200
    Exposure bias +0.3 step
    Focal length 0mm [50mm]
    Max aperture 0 [2.0]
    Metering mode Center Weighted Average
    35mm focal length 0 [100]
    [Finish is "Standard"]

    - resized version of in-camera JPEG


    "P5040013a-Crop01-C1.jpg"

    Detail crop from in-camera JPEG
    - Start 940,2200 (lower left)
    1640 x 1230


    "P5040013-2a-SmartFix-C1.jpg"

    From DNG:
    Temperature 5090
    Tint 23
    - crop from 950,2210 (almost a match for crop from in-camera JPEG)

    - One Step Noise Removal (this function is not defined in my documentation)

    - SmartFix:
    Brightness
    Overall 28
    Shadows -50
    Highlights 20
    Focus 78
    Black 12
    White 18

    NOTE: The recommended "focus" (sharpening) for the DNG without noise removal was "75". Noise removal only increased it to "78". Most images taken on the Yi-M1 using the Yi lenses have used sharpening in the range from "35" to "50". I take this as an indication that this Pentax lens is not as sharp. The only other pictures I have taken with it so far -- on the Pentax K100D, do seem to indicate this as well.

    [2018-05-12]
    Recently I posted three pictures of flowers taken with the Yi-M1 using the Pentax SMC M-Series 50mm F2.0 lens at:

    "Spring, Finally . . . ."

    I did not have a chance to pay attention to these pictures earlier. Looking at them, the lens looks a bit better -- closer to the older 55mm F1.8 . If you look at "P5040057-1c-rsz1240-C1.jpg" in particular, the sharpness and detail level look much better. When I checked my processing
    notes I found that the recommended sharpening was only "focus 31" which is roughly in the usual range of my Yi 42.5mm F1.8 lens. So it seems to be about as sharp as that lens. I have a couple of other pictures that show good to excellent performance at around F8, which is also typical of the 50mm F1.4. The following are from my processing notes for that picture:

    "P5040057"
    - unidentified blue flowers

    Partial EXIF from JPEG:
    Date taken 2018-05-04 14:03
    Program name ASKD-00141
    Dimensions 5184 x 3888
    Resolution unit 2
    Color representation Uncalibrated [the JPEG was AdobeRGB, but
    the version I uploaded was from the DNG raw file processed i
    Corel PaintShop Pro X9]
    F-stop f/0 [I was trying to use between F4.0 and F16.0
    and I think this was probably F16.0]
    Exposure time 1/250 sec.
    ISO speed ISO-200
    Exposure bias 0 step
    Focal length 0 mm [actually 50mm]
    Max aperture 0 [actually F2.0]
    Metering mode Center Weighted Average
    35mm focal length 0 [actually 100mm]

    - Conversion from DNG
    Temperature 4282
    Tint 21

    - SmartFix:
    Brightness
    Overall 28
    Highlights 10
    Focus 31
    White balance Yes
    Black 4

    - Vibrancy 20


    Which Picture is More "Realistic"?

    Actually neither version looks quite the same as I remember the original scene, but I think the AdobeRGB version based images are closer to reality.
     

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    Last edited: May 12, 2018
  6. VidThreeNorth

    VidThreeNorth TPF Noob!

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    Revisiting files taken this Spring.

    YiM1
    42.5mm F1.8 Lens
    Monopod

    I planned this post weeks ago, but then I covered the issues in another post elsewhere. I think that was a mistake because where it is possible, all this YiM1 information should be keep in a single topic where people can find it later. The number of other people who might buy this camera later is going to be small, but I should still finish what I started properly. The final incentive to get this done is to remove a lot of files from my computer. All these Spring files will be difficult for me to access later.

    I think I have better cameras than the YiM1 to take this particular picture. The problem I had was the auto-focus. My first pictures focussed on the background (ignoring the roses which were nearer). So I decided to use the "touch focus". But the touch focus does not track movement and the branches, including the flowers were in constant motion. I set the lens to Macro which in this case limited the aperture to F3.5 and allows closer focussing, but as far as I know, makes no other adjustments. So the aperture at F7.1 was not affected by the setting. I increased the exposure 1/3 stop because a lot of the flowers were in shadows. After that, all I could do after selecting the focus point was watch the branches waving around in the air and try to take a picture when my actual target was moving into the focus box. The bumble bee came into the area after I was set up, but I decided not to make any changes (or try to chase the bee around). This picture caught the bee, but not in a bloom that was well lighted, so there has been a further adjustment of around another 1/2 stop. I did make a couple of versions using noise reductions, but in the end, neither of these uploads uses any noise reduction.

    Yes, it would have been nice if I had gotten closer. Maybe next time. . . .

    "P5020041.DNG"
    - Bumble bee on rose

    Partial EXIF from DNG: (PaintShop Pro X9)
    Software ASDK-00141
    FlashPix version 01.00
    Date and Time May 2, 2018, 17:21:19
    Image width 5200
    Image height 3902
    Components per pixel 1
    X resolution 72.0 dpi
    Pixel height 3888
    Pixel width 5184
    Component configuration YCbCr
    Color space Uncalibrated (AdobeRGB -- irrelevant)
    Exposure Program Normal program
    Scene capture type Standard
    Exposure mode Manual exposure
    Exposure bias 0.30 ev
    Exposure time 1/250 sec.
    F number f/7.1
    Max aperture f/3.5
    Focal length 43.0
    Focal length in 35mm 86 mm
    ISO speed 200
    Metering mode Center weighted average
    Custom rendered Normal processing
    Gain control Low gain up

    "P5020041-1-rsz1440-C1.jpg"
    [The whole frame re-sized.]

    Corel PaintShop Pro X9 on Gateway dx4375,
    AMD A6-5200 APU, Windows 8.1

    Temperature 4610
    Tint 11
    Brightness +1.0

    "P5020041-2b-SmartFix-C1.jpg"
    [Detail crop.]

    Crop X=1280, Y = 960
    Start @ 1872,1410

    Smartfix
    Brightness
    Overall 24
    Shadows -50
    Highlights 20
    Focus 68
    White balance [yes]
    Black 12
    White 16


    Detail crop
    No Noise reduction.
     

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    Last edited: Jun 20, 2018 at 1:58 AM
  7. VidThreeNorth

    VidThreeNorth TPF Noob!

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    HDR for Architectural

    YiM1 w/12 - 40 mm F3.5 - 5.6 zoom, tripod
    and wide rubber lens hood

    When I tried the YiM1 "HDR" capability earlier this year, the first thing I thought of was Toronto City Hall. I have not taken many still pictures of City Hall. It is a very dramatic building, and world famous, and it is easy to get a "nice" picture of it, but hard to get a really good picture of it. Part of the reason is that the shapes cause complex, unavoidable shadows on its internal faces. As far as dynamic range is concerned, it is a nightmare. The result of my first test of the YiM1 HDR capability gave me a very nice result I wanted to see what it could do for this situation.

    Unfortunately, I have a problem when it comes to Micro 4:3 wide angle lenses. I do not have one that is "really good". I have two zooms that reach 12mm (eq 24mm). The YiM1 12-40 zoom was known to be poor at the wide angle end. Likewise the Panasonic 12-32 zoom is also not so good at full wide angle. Which is worse? I do not know. I do not have comparable lens test results. All the tests for the Panasonic lens are old and at best, done on 16MP sensors. In fact, I think some were tests on 12MP sensors. My experience with the Pansonic 12-32 seems to indicate that it might be a bit sharper in the middle, but I think it falls off worse in the corners.

    This has not concerned me up till now because for video, I have the Git2 which does a fairly usable 21mm eq. view in "near-UHD" at 24 fps, and my Sony Z3c phone which seems to be around 24mm eq, at 30 fps. Unfortunately, it looks like the "SLR Magic 8mm F4" is not going to be useful, but I have not totally given up on it yet. For still pictures, I am only "well covered" out to around 14mm (28mm eq), where both the above mentioned zooms are much better.

    Setting Up:

    If you look at the reduced version of the first picture you will see that in theory, I could have zoomed out to 14mm (28mm eq), but if I decide to correct perspective I will already lose a lot of the left and right sides, and the bottom level of the building will be need to be cropped. I think that bottom level is a part of the whole and should be kept. So really, I would have preferred to start from a 20mm lens' view. The camera is on a tripod which extended to about 5' 6". The wind was a strong gusting breeze which causes some vibration on the tripod, so some motion blurring might also be a factor. The Vivitar Wide Angle rubber lens hood is minimal, but probably helps a bit. At this distance, atmosphere can also start to interfere with sharpness, though I do not think that happened in this picture. Does the HDR processing result in loss of image sharpness and detail? From my earlier test using the Yi 42.5mm prime lens, I think there might be a very slight reduction in quality, but I do not think it had much effect on this picture.

    Technical Results:

    The results in terms of exposure and colours was very good. But the sharpness and detail were not very good. I think the lack of sharpness was subsstantially the result of the lens, with other factors having neglibible affect. The question I am left with is how interested I am in pursuing this type of HDR photography in the near future? If so, I need to buy another lens.

    Getting back to the exposure, I like the result overall. I will probably make some small adjustments, but I got a level of shadow detail that I think is nice, without clipping the top end highlights. I used 1 EV "jumps" in my bracketting. I think that there is a benefit in "filling in" the exposures by using every one of the 1/3 EV increments. I might even have gotten a "perfect" result without any further adjustments. There is also a benefit in taking more pictures because the tourists were wandering around without regard to my preference, creating different "found" compositions. The more pictures taken, the more chances one has of getting a "better" picture.

    Miscellaneous:

    Slowly but unavoidably, developers are filling in the backdrop of this view with typical urban clutter. It looks like the view down the middle is in the process of going away.

    The Flower:

    This is the same camera equipment with the lens zoomed out to 37 mm. As I have written before, the lens actually performs quite well, except at its wide angle limit.


    "P6140042.jpg"
    [original JPEG not uploaded.]
    City Hall HDR

    Partial EXIF [original JPEG]
    Date and time June 14, 2018 10:28:13
    Program name ASDK-00141
    Dimensions 5184 x 3888
    Bit depth 24
    Resolution unit 2
    Color representation Uncalibrated [AdobeRGB]
    F-stop f/7.1
    Exposure time 1/320 sec.
    ISO speed ISO-200
    Exposure bias +1 step
    Focal length 12mm
    Max aperture 3.64
    Metering mode Spot
    35mm focal length 24
    Exposure program Normal (HDR)

    P6140042a-rsz1936-C1.jpg
    - resized, but no other changes.

    P6140042b-Crop01-C1.jpg
    - detail crop, no other changes.

    "P6140068.JPG"
    [original JPEG not uploaded.]
    - flower

    Partial EXIF (original JPEG):
    Date taken 2018-0614 10:43
    Program name ASDK-00141
    Dimensions 5184 x 3888
    Bit depth 24
    Resolution unit 2
    Color representation Uncalibrated [AdobeRGB]
    F-stop f/8
    Exposure time 1/400 sec.
    ISO speed ISO-200
    Exposure bias 0 step
    Focal length 37 mm
    Max aperture 4.93
    Metering mode Spot
    35mm focal length 74

    "P6140068-1a-rsz1980-C1.jpg"
    - processing: Corel PhotoShop Pro X9

    SmartFix
    Overall 28
    Focus 37
    White Balance [yes]
    Black 12

    ---
    [2018-06-19 20:04]

    This picture is being uploaded later because I needed to alter faces. In fact, I almost decided to skip this picture because it does not really add much real information beyond the earlier pictures. It was taken about 3/4 of the distance of the earlier picture (to the center "dome") and from a lower angle. About the only thing to see is that by adding more elements so the picture is "busier", and completing the post processing (adjustments for gamma and sharpening) one gets an illusion of better image quality. If you look closely though, the level of "fine" detail has not really changed.

    Another lesson is that this HDR capability does actually keep up with motion to an extent. There are people who were walking around and the plants were being moved the breeze, but they do not seem to show motion blurring more than the concrete planter and arches over the reflecting pool. It makes me curious about how this actually works. Put simply, this picture could not have been done with traditional sequential bracketing shots.

    Lastly, I guess I will say that I consider these "nice" pictures. So, at least for now, I am still stuck in the "nice" zone, at least unless or until I get a better lens. . . .

    "P6140044.JPG"

    Partial EXIF:
    ASDK-00141
    Date and time Jun 14, 2018, 10:32:21
    Pixel height 3888
    Pixel width 5184
    Color space Uncalibrated [AdobeRGB}
    Primary chromaticities 0.64 0.33 0.21 0.71 0.15 0.06
    Exposure Normal program
    Scene capture type Standard
    Exposure mode Manual exposure
    Exposure bias 1.00 ev
    Exposure time 1/400 sec.
    F number f/7.1
    Max aperture f/3.5
    Focal length 12.0 mm
    Focal length in 35mm 24 mm
    ISO speed 200
    Metering mode Spot
    Gain control Low gain up

    "P6140044c-rsz1840-C1.jpg"

    - Manually obscured faces

    Smartfix:
    Brightness
    Overall 0 [Recommended 4]
    Shadows -10
    Saturation 7
    Focus 41
    White balance [yes]
    Black 10
    White 4
     

    Attached Files:

    Last edited: Jun 20, 2018 at 1:53 AM
  8. VidThreeNorth

    VidThreeNorth TPF Noob!

    Joined:
    Oct 21, 2016
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    Can others edit my Photos:
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    John Kuna v. YiM1

    This is a continuation of my test of the various colour choices in the YiM1 and also an update on my pictures of the "Village of Islington" murals. As I noted, the "Vivid" finish worked much better than the "Portrait" finish. I posted the "Vivid" set in:

    "Yi Technology -- Yi-M1" (see #36)

    As I wrote before, I am quite pleased with that set of pictures. They are "scouting" pictures where I am mainly interested in making a record of "what is there". In particular, I felt that due to the building orientations I would need to plan the time of day when lighting and shadows were optimal.

    Lately I was checking the internet researching the artist (John Kuna). There was nothing in Wikipedia(yet) but I did eventually find articles about him, and also his own website.

    On his website, there are pictures of a number of his works. What I found most interesting is that there is a strong similarity in the color rendering to what I got from the YiM1 in AdobeRGB and "Vivid" finish. Have a look and compare them. Certainly the pictures on his site are better, but the colour sets are very similar. You can see them at (his website):

    "John Kuna Murals"
     

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