Konica Minolta 28-100mm f/3.5-5.6 D AF Zoom

Discussion in 'Sony Lenses' started by VidThreeNorth, Dec 9, 2017.

  1. VidThreeNorth

    VidThreeNorth TPF Noob!

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    Konica Minolta 28-100mm f/3.5-5.6 D AF Zoom
    Reference Material:
    Imaging Resources [no review]

    Used with: LA-EA3 Lens Adapter, Sony a5000 body

    I bought this lens to test the LA-EA3 Lens adapter on my a5000, and hopefully, to use thereafter if it showed good performance. On the LA-EA3 adapter there is no "auto-focus", but "auto-aperture" is supported, as well as some EXIF data.

    The lens has only two control rings, the Focus and the "Zoom". There is no aperture ring. The focus ring is at the very front of the lens and seems to be intentionally small so one does not accidentally affect the auto focus. Focusing turns the front lens element, including the filter mount (bad for polarizers).

    Using the LA-EA3 Lens Adapter

    The adapter is well made with an apparently strong tripod mount. It controls the aperture for exposure, but there is no support for depth of field preview. I think the only way I can preview the depth of field is to record a video clip.

    My first tests were taken at about 2' - 3'. I mounted the camera on a monopod but as I was moving around I decided to just take it hand-held, so the monopod was just dangling in the air.


    First Sample Images:

    "DSC00293.JPG"
    Partial EXIF:
    Width 5456
    Height 3632
    Bit depth 24
    Colour representation sRGB
    F-stop f/5.6
    Exposure 1/80 sec.
    ISO-200
    Exposure Bias -1 step
    Focal length 50mm
    Max aperture 4.640625
    Metering Center Weighted Average
    35mm focal length 75
    Brightness 3.97421875
    Original file size 5,865,472 bytes

    I have the RAW file for this picture, but I am using the camera created JPEG.

    "DSC00293a-rsz1640-C1.jpg"
    - no adjustments except for resize to 1640
    - compression is JPEG minimum to preserve detail.

    "DSC00293b-Detail01-C1.jpg"
    - no adjustments except for the crop
    - compression is JPEG minimum to preserve detail

    The detail crop does not start in the far corner. I started it a bit lower at "0,900" because there are points along the bottom rim of the upside-down cup on the far left and the cup on the upper right, and the rim of the red lid below that cup which are in proper focus and are the best places to judge the sharpness.

    Note that at 1/80th sec. (hand held) it is possible that some sharpness might have been lost to motion blurring.


     

    Attached Files:

  2. VidThreeNorth

    VidThreeNorth TPF Noob!

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    I think that most people will find this project less interesting than I did, and as sample images for an equipment test it is going to be hard for people to see the lens characteristics through the unusual subject matter characteristics.

    This is a complete re-do of the earlier picture set. The cups are in a box and I emptied it and re=loaded it. There was more light this time, and I used the monopod properly (with it actually on the ground), so it is no surprise that it whole picture is a bit sharper, but these are only early tests. This will probably be the last set from this particular setup. I will probably re-do it with other cameras and lenses, but I think I have learned all I want from this one.

    So what is there to see? The first thing you can see is that in both the earlier test image and this one, there is no colour fringing, all the way out to the corners. These are in the "middle" focal lengths (50mm and 60mm) and the earlier F-stop was almost "fully open". The F8.0 of the second image is within the typical working range of the lens. I might work down to F11, and occasionally F16, but I would expect that F16 is as small as I would use since I expect refraction issues below that point. Since the sides of the cups are close to straight, it appears that there is little or no distortion in these middle focal lengths. In the second image set, the higher 1/200 sec. exposure time and properly used monopod eliminate motion blurring, so the sharpness is as good as it is going to get. I would call it "quite good" in the F8, but borderline at F5.6.

    I would say that so far, the lens seems "passable to good" from center to corner for this APS-C sensor. My research indicates that in general, most of the low cost "normal" range Minolta zooms tended to be soft in the corners when used with for real full-frame film photography, and I expect that this is probably true for full-frame digital cameras. Whether the 28-100 was a generally better performer than some of the other similar lens Minolta produced is going to be the interesting question.

    Hopefully I will test the far ends of the zoom later, with different, less difficult to analyze subject matter.


    "DSC00297.jpg"

    Partial EXIF
    Width 5456
    Height 3632
    Bit depth 24
    Colour representation sRGB
    F-stop f/8
    Exposure 1/200 sec.
    ISO speed ISO-200
    Exposure Bias -1 step
    Focal length 60mm
    Max aperture 4.96875
    Metering mode Center Weighted Average
    Brightness 6.57578125
    Windows File size: (JPEG) 6,488,064 bytes

    "DSC00297a-rsz1640-C1.jpg"
    This is file is based on the JPEG image created by the camera and has not been altered except for resizing and re-compression. The compression is the highest detail that JPEG allows.

    "DSC00297b-Crop01-1640-C1"
    This is file is based on the JPEG image created by the camera and has not been altered except for cropping and re-compression. The compression is the highest detail that JPEG allows.

    [Added 2017-12-12]
    "DSC00297c-Crop02-1640-C1.jpg"
    I am posting one last detail crop. I wanted one in the corner (which I had on the first picture) and one in the center (which was the second picture), but that "center crop" in the second picture was disappointing from a technical analysis standpoint. So this second detail crop is roughly top center (shifted to the right a bit), but it has a good look at the edge of a cup rim that can be used to judge sharpness, which is quite good. It also shows that I was not focussed where I thought I was. I had originally focussed a bit deeper in the cups. I must have changed it.

    That brings up an interesting point. The focus on this lens really is touchy. The ratio of the lens barrel turn to focus is very fast. I remember over-correcting back and forth a few times before getting it right.
     

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    Last edited: Dec 12, 2017
  3. jcdeboever

    jcdeboever TPF Supporters Supporting Member

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    I think it was neat. It really goes to show how nice those Minolta's render color.
     
  4. VidThreeNorth

    VidThreeNorth TPF Noob!

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    Much thanks! I started with the idea for the pictures and then decided to take them with this new camera/lens setup. Most of my pictures tend to have enough "technical aspects" that you can evaluate the equipment. Actually these pictures do have enough, but it turned out harder to find this time. And yes, when all colours are perfectly balanced, then you get black, greys and white. As I mentioned you can see absolutely no "chromatic-aberration"! The camera and lens really did do a nice job in the second picture with rich dark greys.

    Anyway, I seemed to be having an Andy Warhol period lately. There are probably people hoping it's over.
    :)
     
  5. jcdeboever

    jcdeboever TPF Supporters Supporting Member

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    Yeah, Andy Warhol period is not a good idea.
     
  6. Derrel

    Derrel Mr. Rain Cloud

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    Looks pretty good. Yes, there likely will be some sharpness lost due to diffraction at the smaller f/stops (like f/11,f/13,f/16,etc)--and YET, even with diffraction, on many close-up scenes, the increased depth of field from using say, f/22, or even f/32, can often make for a better picture, by, well, getting more stuff in-focus.

    I do not worry about diffraction at small f/stops nearly as much as I worry about the way sensor dust becomes so,so crisp and defined, like pepper flecks on the image area!
     
  7. VidThreeNorth

    VidThreeNorth TPF Noob!

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    Overall, I agree. I have seen many large format film architectural pictures in particular done at f/22 and smaller and clearly diffraction issues can be compensated. But in the back of my mind, I do still get a twinge if I see the aperture numbers trending higher.

    I have been very lucky about that. I had noticeable sensor dust only once. I generally avoid changing lenses in the field. Actually, on camcorders I have a worse problem with autofocus. Dirt of any kind on the lens can make the lens focus on the front of the lens. On my cheap camcorders there is no manual override to fix it quickly. The only thing I can do is zoom wide and try to find something to grab a usable focus lock.
     
  8. VidThreeNorth

    VidThreeNorth TPF Noob!

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    Sony a5000
    Sony LA-EA3 adapter
    Minolta 28-100 3.5-5.6 D Autofocus zoom


    I decided that I would use more typical pictures for samples of this zoom and I think these are much better. These are sunset pictures. The backlighted trees and light fixtures give good references for analyzing sharpness. And there are structures that indicate linearity. I should warn however, that the road in the distance is not horizontal. It has a slight grade. So do not use it for a level horizon reference.

    About the focus: I used the magnification but no "focus peaking". Focus is on the trees in the middle of the picture. These are very far away, but were not at "infinity". There are definitely trees further away within the pictures which are falling out of the depth of field -- even in the 28 mm wide angle picture, and even at this small an F8.0 aperture.

    Wind was light to moderate. The camera was mounted on a tripod, sitting on grass, which was somewhat compressible. I used a 2 sec. delay to allow the camera to settle. Combined with the 1/400 sec. exposure times, there should be no appreciable motion blurring.

    The uploaded files were made from the camera created JPEGs. Aside from re-sizing or cropping, no alterations were made. Re-compressing in all cases is the "least compressed" possible from JPEG, preserving the most detail.

    "DSC00311.JPG"

    Partial EXIF
    Program name ILCE-5000 v.1.10

    Width 5456 pixels
    Height 3632 pixels
    Color space sRGB
    F-stop f/9
    Exposure time 1/400 sec.
    ISO speed ISO-200
    Exposure bias +1 step
    Focal length 100 mm
    Max aperture 4.96875
    Metering mode Center Weighted Average
    35mm focal length 150
    Brightness 7.82578125

    I do not think there is any distortion. If there is, then it is very slight. The lighting fixture on the left is relatively close and is starting to blur, so will take a detail crop from the right side and one from the center. At 100mm focal length I see no colour fringing. Sharpness is well maintained within the APS-C coverage.

    DSC00311a-Rsz1640-C1.jpg
    - resize and recompressed

    DSC00311b-CropRt1640-C1.jpg
    - right side crop and recompressed

    DSC00311c-CropCtr1640-C1
    - center crop and recompressed

    "DSC00312.JPG"

    Partial EXIF
    Program name ILCE-5000 v.1.10

    Width 5456 pixels
    Height 3632 pixels
    Color representation sRGB
    F-stop f/8
    Exposure time 1/400 sec.
    ISO speed ISO-200
    Exposure bias +1 step
    Focal length 28 mm
    Max aperture 3.6171875
    Metering mode Center Weighted Average
    35mm focal length 42
    Brightness 7.34140625

    There is color fringing on the posts at the far right side of the image (and the corresponding trees on the far left, though it is hidden by apparent depth of field loss), but sharpness seems quite good for the telephone wires running through the middle of the image. There is just an hint of barrel distortion. Sharpness decreases more noticeably towards the corners, but is acceptable.

    DSC00312a-Rsz1640-C1.jpg
    - resize and recompressed

    DSC00312b-CropRt1640-C1.jpg
    - right side crop and recompressed

    DSC00312c-CropCtr1640-C1.jpg
    - center crop and recompressed


    Other notes:

    There is some focus shift during zooming. I think it would take about F11 to cover it.

    As previously noted, focus is very quick which results in a bit of overcorrection, but it was more controllable in this set of pictures where everything is very far away.
     

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  9. VidThreeNorth

    VidThreeNorth TPF Noob!

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    Sony a5000 w/LA-EA3 adapter
    Konica Minolta 28-100mm f/3.5-5.6 D AF Zoom
    on Slik tripod

    Not one of my nicest looking setups

    This is the setup I have been testing: The Sony a5000 with the Konica Minolta 28-100mm f/3.5-5.6 D AF Zoom using the Sony LA-EA3 adapter. Let me say that this is not the "prettiest" camera setup I use. Despite all three pieces being made by the same company at various times the combination of styles ends up looking awkward. The best I can say about the pieces is that they would all look better if
    I had bought a black lens. But I did not have that option.


    APS-C Performance:

    Looking back over the test images, I can say without hesitation that the lens performed very well, from around 50 mm out to 100 mm. At 60 mm, it rivalled a good prime lens. Out at 100 mm, it was still pretty good, but with just a bit of sharpness loss, particularly off axis.

    At the other end, the image is starting to fall apart at 28mm with off-axis chromatic aberration, even at around F8. It might still go away by F16, but I think I would avoid going wide in general. I think eventually I will want to test the lens at around 35 - 40 mm and see where the limit actually is, but from this much, I would probably trust it down to around 35 mm.

    This lens fits nicely with my current equipment array. If I want to use a single body and two lenses then the 16 - 50 mm E-Mount zoom that came with the camera combines well with it by covering wide angle to short tele, with a comfortable overlap, and with the addition of optical stabilization.

    Realistically, that is not how I work. I prefer to take two complete cameras, and my primary camera is not even for still pictures. My primary camera would usually be a camcorder, and if I took a still camera, it would be as my secondary camera (either an "alternate approach" camera or an overlapping
    backup camera).


    About Focussing:

    If the focussing is typical of the Maxxum lenses generally, it seems that manual focussing is usable, though touchy. If one can afford the extra cost, I think I might suggest that the LA-EA4 which supports full Auto-Focus might be worth the prices (about $200 US more than the LE-EA3).


    Final Thoughts:

    For now, I will refrain from speculating how this lens would work on a Full Frame camera. I am just happy that it turned out as well as it did on an APS-C.

    If you have existing Maxxum or Sony "A-Mount" lenses, then these mounts provide an excellent bridge for moving onto E-Mount, or even just expanding ones system in that direction.

    What about people with no previous "A-Mount" lenses? While the "A-Mount" was never as popular as the Canon or Nikon mounts, there does seem to be a good number of old lenses available. Just do not expect to find as many of the more esoteric products. But there are some attractive pieces out there. I have seen Maxxum 28-135mm zooms available for around $80 US. That lens would have been more of a premium lens and I expect, a fairly good performer. There is not real equivalent in the current Sony line-up. The only lens that is similar "on paper" is a particularly expensive cinema lens. The combination of the LA-EA4 adapter and a used Maxxum 28-135 lens would be about 1/4 the price of the current Sony. So yes, getting one of these adapters can be worth considering.


    Future:

    I will not be in a hurry to add to this collection of images. I might add some more tests next year -- particularly at around 35 - 40 mm, as I mentioned above, but I think I know all that I need for now.


    About These Pictures:

    Camera Used: Yi-M1 w/42.5mm lens on Slik monopod

    This turned out to be one of my harder recent projects. On the one hand, I should have expected problems with dynamic range due to the dark blacks and shiny metal and silver paint surfaces, but I was using very flat lighting, so I underestimated it. I left my metering unadjusted. In retrospect, since most of the gear was black, I think I should have used EV = +1.0. I ended up having to substantially "re-tool" the RAW files to get images worth posting.
     

    Attached Files:

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