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A7r samples with adapted lenses

Discussion in 'Adapted Lenses' started by NightBird, Aug 10, 2014.

  1. NightBird

    NightBird TalkEmount Regular

    50
    Jun 13, 2014
    I posted this over at SC, but thought it might be of interest here as well...

    I took these images on the weekend to try a couple of inexpensive legacy lenses at night, namely a Minolta MD 50mm f2.0 which was about $35, and a Sigma Mini Wide II 28mm I picked up for comparatively less of a bargain price of $85, albeit it is in absolutely minty condition. I was pleasantly surprised overall with the older lenses except for a little flat colours (or perhaps a colour cast) from the Minolta MD 50mm. Unfortunately I didn't have my Rokkor MC 50mm f1.4 with me, I would like to see how it compares to the MD 50mm f2.0.

    I also took an image using the Zeiss 35mm 2.8 and the Sony FE 28-70mm @ 50mm. Unsurprisingly I thought the colours were nicer from the modern lenses, however the Sigma did pretty well, and the Minolta MD 50mm was unsurprisingly a little sharper than the Sony 28-70mm.

    All images except the one from the Zeiss had the same exposure settings, default Lightroom sharpening only, and identical Lightroom processing, so differences in those three images should come down to focal length and lens. The Zeiss 35mm I adjusted a little further, but still with default sharpening.

    I hope it's of interest to someone. Larger images are in Flickr. I'm looking forward to picking up some further old lenses in the future.

    Sony FE 28-70mm
    14869418804_4831e74f11_b.
    Harbour Bridge from Observatory Hill
    by Darren.Nightingale, on Flickr

    Minolta MD 50mm f2.8
    14685210529_a441700a2c_b.
    Harbour Bridge from Observatory Hill
    by Darren.Nightingale, on Flickr

    Sigma Mini Wide II f2.8
    14881136885_6e8956598d_b.
    Harbour Bridge from Observatory Hill
    by Darren.Nightingale, on Flickr

    Sony Sonnar T* 35mm f2.8

    14878157411_18e1184b8c_b.
    Harbour Bridge from Observatory Hill
    by Darren.Nightingale, on Flickr
     

    Attached Files:

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  2. Dan Euritt

    Dan Euritt TalkEmount Regular

    191
    Jan 11, 2014
    nice pics!

    i tested that sigma 28mm superwide II on my a7r, i really liked the way that it handled, but it had too much field curvature... great choice for crop sensor, tho, and it would work fine for non-landscape uses on full-frame.

    i've been thru several 28mm primes on the a7r... lately i'm thinking that the minolta celtic 28mm f/2.8 has potential.

    28mm is a great focal length for this camera, much better than 24mm.
     
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  3. addieleman

    addieleman Passionate amateur

    Nov 13, 2012
    Netherlands
    Ad Dieleman
    The Minolta Celtic 28/2.8 has the same optical design as the Rokkor version; it is believed that Rokkors have better coatings than the Celtics, but apart from that and a few cosmetic differences the lenses are the same. All Minolta 28mm lenses in SR-mount (MD/MC/Auto) are troubled with field curvature. The best one is the plain MD 28mm 1:2 (no Rokkor designation), but it is relatively hard to find and can be quite expensive. For landscape work I prefer my Olympus OM Zuiko 28mm 1:3.5 over any Minolta 28mm lens.

    In general I'd say that the Minolta wide-angle lenses (28mm and below) aren't great, they almost universally suffer from more or less pronounced field curvature. Only notable exceptions are the Minolta plain MD (non-Rokkor) 24/2.8 and the Minolta 17/4 (any version).
     
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  4. Dan Euritt

    Dan Euritt TalkEmount Regular

    191
    Jan 11, 2014
    well, i did a bunch of comparative cityscape type shots, on the a7r.

    the 28/3.5 lenses were not usable wide open, due to excessive vignetting... imatest corner measurement averages for exposure:

    pentax 28/3.5: -3.6 stops down wide open
    oly 28/3.5: -4.0 stops down wide open
    celtic 28/2.8: -2.77 stops down at f/4
    viv 28/2.0: -1.67 stops down at f/4

    at ~f/10 the corners had nearly equal vignetting on all lenses; the 28/3.5 lenses only gave up maybe a quarter-stop to the brighter lenses.

    pq at ~f10:
    viv 28/2.0, but it's only usable at ~f/8-f/10, the field curvature at f/5.6 and wider is bad, and the image field had slight oof spots in it.
    pentax 28/3.5: barely beats the oly in the center, but it only has five aperture blades, so the bokeh can get really weird.
    oly 28/3.5: decentered on one side, but neither the center nor the good side could match the top two.
    celtic 28/2.8: worst overall sharpness of the bunch, slightly decentered one side.

    what's the take home? my konica 28/3.5 is just as dark as those two 28/3.5 lenses, so i won't be getting any more 28/3.5's, and i won't be getting any minota 28's, unless addi says that the 28/2.5 is different than the rest of the minolta 28's :)

    it looks like all pentax 28's might have five aperture blades, so they are only usable where there won't be a bokeh situation.

    copy quality makes a big difference, but it won't change the characteristics of the lens.
     
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  5. addieleman

    addieleman Passionate amateur

    Nov 13, 2012
    Netherlands
    Ad Dieleman
    Thanks for the write-up. And the Minolta 28/2.5's are generally unuseable because almost all of them suffer from a strong brown-yellow discoloration of one of the glass elements due to radioactive elements in it.
     
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  6. tomme

    tomme TalkEmount Regular

    56
    Apr 9, 2014
    Norway
    Tom Erik Sivertsen
    I think the zeiss 35 have the best starburst effect from those images, nice images btw.
     
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