Image Circle of Olympus Digital 50mm 1:2 Macro ED

Discussion in 'Olympus' started by harold_gough, Oct 13, 2016.

  1. Does anyone know the actual size in mm of the image circle? I can't find it in the specs or in any review.
    I know it was made for 4/3 sensors but I would like to at least consider any merits of adapting it to full frame (Sony Alpha A7R). Even if it did not give a usable full-width, full frame image, it might give a larger one (to be cropped) than on 4/3 or m4/3 and the perspective would be different.
    As the lens is operated totally "by wire", even in manual mode, it would have to be via a rather expensive adapter.
  2. It is a fine lens. Still, I cannot imagine it would be in any way adaptable to a full frame camera. Which is why I do not see a mount to mount adapter made for this lens to the Sony mount. The image circle, depends on distance to the plane of imaging sensor and is dependent on that distance. Unless I am totally misinformed. I await other comments. Many other full frame lenses adapt by spacing them outward. Rather than the reverse. And that does not include focusing, which you correctly describe as improbable. Many good FD macros out there by the way. I got one.
  3. The image circle is a feature of the lens design and is not a matter of distance. For example, the image circle of a shift or tilt lens will be something like 50% wider than than (43mm) of other lenses for the same format e.g. OM 35mm. The distance is a matter of infinity focus and reducing it loses that but gains closer focus.
    The question is whether this lens, marketed for 4/3 has an image circle too small for a larger format.
    "Many good FD macros out there by the way". Yes. I use an FD mount Kiron 105mm for most of my macro. I have a 35mm 4/3 macro AF but the working distance is too short. A 50mm macro could be interesting on FF.
  4. I have seen M43 to NEX adapters, which are extremely thin due to the fact that M43 flange distance /
    registration distance is only 1.25 mm longer than NEX. I have seen a 4/3 to NEX adaptor (which has a much
    longer registration distance than M43), but it had no electronic connections. I can't see how useful that lens
    would be on a Sony A system camera since it was designed to cover a sensor 1/4 the size of FF. As Gerry
    pointed out, there are lots of adaptable vintage macro lenses to choose from.
  5. I did a little checking of this image circle thing. Near as I can tell, the image circle of a lens will be close to the circle obtained by measuring the X and Y sides of the sensor and the hypotenuse of the two to get the circle of design circumference and diameter. I do understand that some lenses have a wider circle to embrace a larger sensor as well. Probably we are dealing in this case with ANGLE OF VIEW of the lens vice design image circle..? I could be wrong and likely am incomplete in analysis. All kinda hypothetical it seems , ya know,, as one would like both infinity focus and full clarity in THE CORNERS where one might see distortion from distance to plane of the lens center. I did have a Tessar field camera lens that allowed shifts and still within the tolerable coverage, that is so.....Phooey, I had to give up after the trig and formulas busted my little brain cells. So, I would guess why not empirical testing as my high school Physics guy Mr Webster used to say. :)
  6. Here's a thought. Get a used old 55mm Nikkor f3.5 or f2.8 manual focus lens and a couple of cheap adaptors. That lens works AMAZING and is real cheap.
    For real macro use, manual focus is a must anyway.
  7. Even better, back in the days of the original Series One lenses, when Vivitar was making super lenses, they produced a 55mm f2.8 Macro lens in every mount imaginable and it was super, super nice. Here's one that's new, old stock, in an Olympus OM mount..
    I would find one of these in whatever mount you happen to have an adapter for. It's a high quality, low cost, macro-capable lens. Optically I believe it's as good as most anything out there
  8. I asked a simple question and did not require anything other than a direct answer. I am not surprised that I did not get it, as I asked the same question of Olympus UK technical department. They told me that Olympus did not have that information. So, they built the lens and took a chance on the image circle?
    I projected the image (infinity focus) onto a piece of paper. It measured around 40mm. I also lashed up a way of focusing the lens (set at infinity) onto the sensor of the full frame A7R. The image covers the frame. I cannot say what the edge of the image is like but there are clear macro possibilites with this lens on full frame, should an adapter be available.
  9. Image circle doesn't answer the whole question.

    Because sometimes the edges of the image circle are not usable because of light falloff, distortion, or other aberrations. If a lens is made for ยต43 sensors, they most certainly didn't design it with a wide USABLE image circle as a goal in mind.

    An expensive adaptor would be money NOT well spent on a lens like this imho.
  10. You shell out bucks for a full-frame Sony, then cheap out on the lens end by trying to fit something made for a format half the size and get upset when you don't get a straight answer about something probably no one else would ever think to try?
    Go buy a Sony 50mm f2.8 or 90mm f2.8 Macro that's MADE FOR YOUR CAMERA. There. the most direct, sensible response you'll get.
  11. Who is upset?
    I don't need to "go by", whatever that means, any macro lens. I have a Printing-Nikkor 105mm which covers full frame. I like to try all sorts of new ideas, many of which pay off.
  12. I have obtained a basic adapter. I have no control over the lens aperture, which remains on f2 but I can prefocus the lens on my EM-1. I have done some quickie shots to get the general idea of what vignetting, if any there is.
    No image has been cropped. Essentially, there is a small amount at infinity but none close in (FOV ca 90mm, 42mm with 25mm tube). The small dark area top right of the second image is the background.
    My interest would be in the macro possibilities. (I have Kiron 105mm macro as my go-to one for this camera).
    A very relevant issue is the amount of hardware I can carry around.
  13. That looks like evidence of the uselessness of using this lens in this fashion... jus' sayin'...
  14. Technical correction: I said I had no control of the lens aperture. It would be more accurate to say that I had no control of its diaphragm settings. I can control the effective aperture quite easily. That is for another day.
  15. Even so, even at low resolution, the first image you put up proves that the corners, maybe even as much as a third of the image or more, is totally useless in regular photography.
  16. The 4/3 70-300mm covers the frame at all focal lengths, with no darkening in the corners, at distance and at about 8 feet and 300mm. As the A7R shutter shake is a problem at longer focal lengths, it is not worthwhile investing in new telephoto lenses but the tele-macro will be useful on occasion. Motion blur can be taken out with my software for those few images.
  17. No darkening in the corners, but what about blur, distortion, coma...?
  18. None of that.
  19. Really? Love to see that.
  20. Here are a couple of shots, for my own satisfaction, and not to prove anything to anyone else. They were both handheld at 300mm (maximum aperture) and a proper test would have used a tripod. One is of a house across the road and another at about 8 feet, inside a sunlit window.
    I have a system x 1.4 TC, should I want to use a smaller aperture.
    Having seen what the 50mm would do, I tried the 70-300mm. That is all there is to it.
    The images are uncropped and have had no in-camera adjustments. I have processed them as I would any other "keeper" images. (My images are currently only for posting on websites). These are hosted by this blog.
  21. I have just be advised, in another Olympus forum, that the Olympus 4/3 70-300 was a modified Sigma full frame macro lens.

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