A7.mod

Discussion in 'Leica M Camera Forum' started by uhoh7, Feb 9, 2015.

  1. uhoh7

    uhoh7 Leica Place Regular

    163
    Oct 14, 2014
    Kolarivision offers a thin cover glass for the A7 and A7r cameras and they move the sensor forward to compensate. It costs 400USD. Fast turn around. I've had mine back a week, and while I of course still prefer M9 for many reasons, the A7.mod is a vast improvement for RF glass and considering the A7 can be found used for 900 USD, you have a real FF alternative to M240 or M9 for about 1300USD. I'll make a thread here so everyone can see some results.

    So, I had a short weather break and managed to get some shots with two lenses I consider "worst case", the tiny CV 21 and 35 Skopars. I had no expectations, but I thought I might as well see what they would do.

    Since there is big copy variation and many of these lenses are decentered, not to mention the variable of adapters, these should not be seen as definitive, but these lenses can at least do this well.

    15867344933_9a361e5d4e_b.
    a7M_CV21_11 by unoh7, on Flickr

    16486505042_f8466b5955_b.
    a7M_CV21_8 by unoh7, on Flickr

    16300033890_ccc66d20d8_b.
    a7M_CV35_56 by unoh7, on Flickr

    16301196969_5b9bd416fd_b.
    a7M_CV35_8 by unoh7, on Flickr

    For me, these lenses were totally unusable with heavy smearing at all apertures with infinity shots like this on the A7 and A7r. Here a close look will reveal considerable strangeness, but I'd say they are way better. I would not use them, I don't even use them on the M9, although they are much better than this with that camera.
     
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  2. uhoh7

    uhoh7 Leica Place Regular

    163
    Oct 14, 2014
  3. uhoh7

    uhoh7 Leica Place Regular

    163
    Oct 14, 2014
    • Like Like x 1
  4. uhoh7

    uhoh7 Leica Place Regular

    163
    Oct 14, 2014
    SEM 21 actually has corners wide open at infinity and is also a very good lens on the A7.mod

    16260988327_082ea54e9d_b. Skis and tables by unoh7, on Flickr
     
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  5. Brian

    Brian Super Moderator Subscribing Member

    Apr 3, 2013
    Thankyou for posting these. It's an interesting alternative, and inexpensive compared with the alternatives.

    Feel free to post links to the company that did the work, and to post more pictures.

    And. Most Important.

    How did it do with the 1930s Sonnar?
     
  6. uhoh7

    uhoh7 Leica Place Regular

    163
    Oct 14, 2014
    LOL I will get on that :)
     
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  7. raid

    raid Leica Place All-Pro

    Apr 12, 2013
    USA
    Raid
    I like the idea that we have an (approx) $1300 option that can give us reliable cameras with FF and excellent results with RF lenses.
     
  8. uhoh7

    uhoh7 Leica Place Regular

    163
    Oct 14, 2014
    • Like Like x 1
  9. uhoh7

    uhoh7 Leica Place Regular

    163
    Oct 14, 2014
  10. uhoh7

    uhoh7 Leica Place Regular

    163
    Oct 14, 2014
    Last edited: Mar 5, 2015
  11. uhoh7

    uhoh7 Leica Place Regular

    163
    Oct 14, 2014
  12. brusby

    brusby Leica Place Regular Subscribing Member

    96
    Mar 1, 2014
    What's the proposed benefit? It seems moving the sensor closer toward the lens would exacerbate the problems of color shifts and smeary details in the corners caused by sub-optimal angles of incidence.
     
  13. Brian

    Brian Super Moderator Subscribing Member

    Apr 3, 2013
    The IR cover glass is very thick, light at high angles of illumination travels through more of it. Using a thin IR cover glass cuts down on the difference in travel distance through the IR absorbing glass. The image plane of the sensor would have to be moved enough to compensate for the deifferent thickness of the new filter and change in index of refraction. So- not a lot of movement.
     
  14. brusby

    brusby Leica Place Regular Subscribing Member

    96
    Mar 1, 2014
    Thanks for your reply Brian. I understand what you're saying about the thinner glass and less IR absorption, but I'm still a little unclear about exactly what benefits that is supposed to bring -- truer colors? sharper image? better saturation? less dispersion of light from not having to travel through the extra glass? Maybe I just need to research the issue of the effect of IR absorption on other photographic properties.

    There would still be refraction on the two glass surfaces -- leading and trailing edges -- so nothing gained there. And the sensor would be closer to the lens, which could be detrimental to any color shift issues that are caused by a small rear-element-to-sensor distance, although as you correctly state, the sensor would't be much closer.

    Are they removing or reducing the low pass (anti-aliasing) filter?

    Not trying to be argumentative, I'm just very curious.
     
  15. raid

    raid Leica Place All-Pro

    Apr 12, 2013
    USA
    Raid
    I also want to know more details about it. Thanks.