Sony A7 & Contax G primes

Disclaimer: All you ‘re about to read does not rely on scientific tests. It’s all about conclusions, feelings, thoughts, second thoughts and decisions based primarily on experience out in the fields…

Sony A7 with Contax G lenses

Sony A7 with Contax G lenses

Recently I was pulled from the hair to enter the realm of mirrorless freshness. Long before A7 was released, I was dreaming of a full frame little camera, so little that it could just enclose the sensor. After reading Falk Lumo’s post back in 2010 I was convinced that it was all about marketing and the dream camera would surely find its way to the shelves in the coming years. I ‘d love to become a  stealth street photographer! I was seeking for a camera that has

  • quiet shutter
  • fastest & sure AF (preferably on eyes)
  • lightest possible with a 35mm lens (23mm on aps) so I can carry it 24/7
  • very little with a 35mm lens (23mm on aps) so I can hide it or carry it 24/7
  • can accept old Nikon glass that I own
  • no visible noise in high ISO so I can photograph during night
  • good bokeh so I can isolate my subjects

Most friends showed me Olympus EM-1 as the fastest and lightest. The main reason I got A7 was i) to test all my lenses and ii) to push street photography to the limits i.e.speedy subjects in dim light I was coming from the D4 world so there would be no forgives

the father and the kid

father and kid

Unfortunately I could not get the new Sony CZ FE35mm so I stuck with Nikon glass and some wonderful Contax Zeiss rangefinder lenses. I will only review the A7 with these lenses as I found myself using them in everyday basis. First things first, some things about the A7 are astonishing

  • Really small, can fit in hand easily but not feather light, gives a metal sensation shouting “I am a serious camera”
  • 1st electronic shutter curtain (or mechanical selectable!) meaning quiet operation
  • bright viewfinder, big, sharp,without lag. It has nothing to be jealous of the optical viewfinder of the D4.
  • focus peaking and focus magnification also during video recording, perfect combination for manual focusing mainly with the eye glued on the viewfinder. These advantages are not to be overlooked, a new era in video rises, no need of external monitor, just a tiny camera in your eye and you get a spectacular, isolated, detailed view
  • auto-ISO in manual mode !! Yeah, I don’t have it in D4, D800 during video
  • exposure compensation when auto-ISO in M-mode !!! Yeah, I don’t have it in D4, D800 during video
  • Clean 1080/50p signal via HDMI when simultaneously recording 1080/50p in card !! So the question is: Do really  D4 and D800 have an incapable processor that can only output via HDMI 720/25p when simultaneously recording ?
  • ClearImage zoom up to 2X during recording !!! Yes it is smooth, stepless AND of great quality, meaning you can use a prime and pretend you have a zoom.

Now let’s move on with the downsides

  • – little and light body with huge sensor, means body and thus handheld video are constantly in motion, IBIS or OSS lenses are an important miss
  • – AF is at least bad. Slow, and uncertain. I hope Sony FE lenses focus better and faster
  • – Really poor battery (1080mAh). I need 3-4 batteries to get along the whole day, not even shooting a lot, just playing with the menus.
    Actual recording time is 107 minutes in 1080/50p mode. Not to mention almost 4 hours of charging !! Only plus point is it’s a tiny battery, like a little sweet so I can carry many of them in my pockets.
  • – Rich menu although it doesn’t offer much 🙁 e.g. no straight AF point selection (2 buttons at least), no straight Focus Magnification (2 buttons at least).
    Offering direct upload to Facebook means nothing to me, while nail-sharp focus means everything.
  • – Very wide Focus Peaking meaning you think you have a focused subject but you end up with a blurry one.
  • – Over 2sec of startup time, meaning important moments are gone.

When searching for lenses for A7 I was confused since Sony offers were too limited.
The only AF solutions were
LA-EA4 &Sony A-lenses, big SLR lenses with alien adapter (with translucent mirror inside)
Metabones EF-NEX adapter (again Canon has huge lens which become huger with the adapter)
and Deo-Tech Contax-G to NEX “Eagle” adapter & Contax G lenses.

Contax G lenses make perfect companion to A7 as they were built for a rangefinder system preserving size and weight low but retaining image quality equal or superior to that of SLR lenses.
Colors are great, resolution is comparable to expensive Leica lens, vignetting is non-existent, distortion too.

But, in terms of handling, these lenses are 20 years old and cannot compare to modern AF solutions. The adapter actually couples the electrical pins from body to lens letting it to focus on the subject (after a while!).
At the end it fails to satisfy my needs:

  • – I have to check twice the f/stop BUT NOT SET IT TWICE! if I accidentally set f/4 in camera and set the lens at f/4 then the camera will think that it could close the aperture 2 stops at the time of click. The lens will not allow that, so the image will be overexposed for two stops.The solution is to set in camera the most open f/stop of EACH lens.
  • – pdAF not working with these lens ! Yeah, but this is the main reason I preferred A7 versus A7R. pdAF if accomplished correctly is the ultimate tool for street photography
  • – MF very confusing, especially when shooting in portrait orientation. I have to search for the little dial on the adapter with my finger. This is not always easy, it is very little dial and lacated on the upper left side of the adapter.
  • – MF is accomplished by wire, meaning it forces the AF system to turn the little screw on the lens. That means it cannot work without battery and it cannot work away from the body. Odd decision, I reckon.
feels great in hands

feels great in hands

Final thoughts about the adapter:
Does its job, it CAN make Contax G lenses AF again, it is elegant and slim but out in the fields its much easier (and faster) to use the lenses with another adapter that just MFs with traditional wide ring.


Now check out some photos taken with this combination of lens/adapter on the Sony A7. RAW in LR5.3 .All settings at default.
Under each photo you can see lens used. Mostly wide open at f/2.0 or f/2.8 (since you cannot see aperture setting in EXIF)



Some comments about some samples:
01.  Check the sharpness, great in the center, good in the corners
11. check the flare , remember these are simply constructed lenses, beware of light reflections. (it’s produced by the light strip in next photo)
16. Great bokeh, even with the 35mm. That’s the beauty of FF
17. Light leakage produces haziness. Beware of side light entering the lens
37. the 45mm is the sharpest and faster
41. beware of the light ghosts
42. iso 12800. Dare to capture motion during the night.
46. colored bokeh? No they’re stickers.
62. dare to shoot against the sky. This camera has exceptional DR when using low ISO.
63. the 90mm is a very clever approach to surveillance. It is the littlest and lightest tele lens I’ve ever used.
71. magenta strip before the focus level. This is LoCA
72. Non-circular bokeh due to only 6 blades of diaphragm
78. Although this shutter is fast enough to capture quick motion, the viewfinder goes dark just about the decisive moment. Is this malfunction?
79-80. Lens Whacking. I was holding the lens with my hand, interesting (and easy) project


That’s for now.

pretty little beauty

pretty little beauty


lens weight comparison

lens weight comparison


Thanks for reading


19 Responses to “Sony A7 & Contax G primes”

  • Sony A7-A7r SAR readers tests and samples! | sonyalpharumors Says:

    […] George: “Some thoughts about the A7+ AF adapter + Contax lenses on my blog” […]

    • Hans Says:

      The A7 can work in auto mode with this adapter also (for example in modes A / M)- you only have to release AF/AE-lock, then the A7’s auto mode will do well.


  • Andy Says:

    Thank you for sharing these photos. Back in the day of film, my main camera was a Contax G2. I took a lot of very nice photos with it and its 28, 45, and 90mm Zeiss lenses. I wanted to bring them back to life and bought an NEX-6 last summer to use the lenses with the Techart adapter. Results can be really quite good, but as you note: the G1/G2 cameras had only aperture-preferred automation. There is no mechanism for the camera body to set the diaphragm. On the other hand, the Techart adapter does report the max aperture of the lens correctly to the camera body (if not the actual aperture). Consequently, the only way to insure correct exposure in A mode is to force the camera body to use max aperture.

    Two thoughts occur to me here:

    1) You /could/ use the camera in M mode and twiddle both the shutter and aperture settings until you get the histogram you want. Like using an ancient, non-AI Nikkor lens on your D4 body.

    2) In theory, if Sony were to publish the programming interface, you /could/ write an app to tell a Wi-Fi capable E-mount camera you are using a manual diaphragm lens. Apps must be able to take full control of the exposure system; see the High ISO Noise Reduction app from the Sony store. This makes me say hmm….

    In any case, thanks again for the post. Street shooting with a highly portable camera is a noble calling!

  • Iullian Says:

    I have the Sony A7 and Zeiss Contax G 28/2.8 and 90/2.8. I use them via Metabones (MF) adapter. This is the best MF adapter for these lenses. I would like to know what is the hit/miss rate for autofocus with your adapter. Trusting the focus is the major concern to me. How about the speed of autofocus? Can you, for example, take a portrait of a child who poses, but has the patience of a … child? Looking forward for your answer.

  • George Kalogeris Says:

    Guys as I mentioned this adapter is OK but the lenses aren’t made for modern AF systems. Even in bright light it takes 1-2 sec to focus on stationary subject. If the subject is moving (i.e. kids) just forget it. It is impossible to focus, that simple. Even in MF mode the little dial isn’t long enough to turn the whole barrel at once.
    I already own the Metabones adapter but 1. it is ugly 2. big 3. heavy 4. very stiff focus ring 5. uncertain lock lever 6. it takes hours to fix the lens right on it
    Conclusion is, all adapters are crap for these marvelous lenses. The image quality is really impressive, I would pay a lot to buy a decent “PRO” adapter like Sony or Oly.
    Please guys share with me photos with the Contax 28mm I was afraid vignetting is an issue. Also is the protrusion on the rear of lens a problem ?

    • Joel Says:

      I’m sorry you’ve had such a bad experience with the metabones adapters. I have several and find them a great solution. In my experience you need a separate MF adapter for EACH Contax G lens. Set it and forget it. Yes, it can take a while to properly mate the lens to the adapter (and I have a Kipon-style adapter that never worked well with my 28mm) but once you do you don’t have to worry about it.

      I wish the AF performance with the Deo adapter was just a hair faster. I’m still on the edge about buying one. It is a pity that Sony does not make the PDAF routine available for third party lenses/accessories.

      Check out my website & Flickr for more shots taken with the Contax G lenses and the A7.

    • Hans Says:

      The Contax G 28mm does not work on the A7, because of smearing, even at F11 (color and vignetting are moderate).


    • Andy Says:

      I will post a link shortly for photos with the Techart and 28mm Zeiss, but remember, I am shooting with an NEX-6, having not yet made the leap to A7(r). There are no mechanical issues with clearance of the rear element on the 28mm Biogon and, given the 1.6x crop factor of an APS-C camera, no real problems with vignetting. You lucky FF owners may possibly have an issue.

      I also have a 35mm F2 Contax C/Y SLR lens on a $20US Fotodiox adapter (you can tell I was a Contax junkie in the day). This combo is manual everything (no chip to transmit info to the camera body), but strangely satisfying to use. MF assist makes manual focusing a snap, and the M setting on the PASM dial is there for a reason. It’s just big.

      Anyway. Based on my experience so far, I wouldn’t say all adapters are crap, but I would agree they all have distinct limitations. At the end of the day, they are stopgap measures. They can help bridge you from one system to another. They can fill in the gaps in the native lens product line. What they aren’t is they are not a long-term substitute for a proper native lens purpose-designed for your system. With that in mind, they do have a legitimate, if limited role.

  • Pierre-Yves THOMAS (Belgium) Says:

    Very interesting review and great pictures, from great lenses, sure!
    Personally, I have since few years the Zeiss/Contax G lenses and I have already tried them on my Nex 7 and Nex 6 with a Kipon adapter (the first I can find on the market at the beginning of my experience). The 35/45/90 gives great results on these APS sensors but the 28 is special. This lens produce a important magenta vignetting and a loss of sharpness in the corners on the Nex 7, but works fine with the Nex 6 (and also on an old Nex 3). For me it was a mystery because the lens was in front of sensors having the same size… Since a few weeks now I have an A7R and (of course) I tried the CZ lenses on it. The problem with the 28 is even more important compared with the Nex 7. The magenta vignetting is stronger and more extended and the losses in the corners are more marked. With some tools and a lot of patience, you can resolve (not totally) the magenta problem but you can do nothing against the smearing. I an user of DXO Optics Pro 9 for my pictures and I always apply some corrections in batch on a lot of images but this software is useless on the problems of the 28 CZ. And I can’t imagine making a special treatment on each picture one by one! In comparison, I also tried an other 28 Zeiss lens in Leica mount and also a Voigtlander 28 VM but the same problem appears in different proportions. The Zeiss produce less magenta vignetting, is very sharp on a larger part of the image field than his cousin Contax Zeiss, but basically it is the same problem. The Voigtlander is clearly behind in sharpness but has very minor vignetting.
    For comparison, I also tried very old Minolta MF lenses (28/2,8 and 28/2,5). The sharpness is good, but also behind the Zeiss ZM but I have never a problem with vignetting (normal darker corners but no color vignetting) or smearing. I think we must accept the A7/A7R are not ready for marriage with every wide lens. They are very selective with the optical design and unfortunately (for us) they are not in good relationship with compact and symmetric designs. I will send some pictures in a moment.

    • George Kalogeris Says:

      Thanks for your reply, very informative.I was just ready to purchase an 28mm Contax G when you wrote this.
      Let’s hope Sony/Zeiss makes wide and ultra-wide lenses small and light as the Contax G lenses. And faster ofcourse.
      It’s true, the advantages of a brand lens are many. But I cannot understand their practice of charging a fortune for a 2.8/35 lens. If they ever make an 1.4/35 or 2/28 should it cost millions?

  • Andy Says:

    Pierre-Yves, I, too, have had good results with the 28mm Contax G Biogon on the NEX-6. As you note, NEX-7 and NEX-6 sensors are the same physical size (APS-C). However, NEX-7 is 24 megapixels, NEX-6 is 16. This means individual pixel sites are smaller on the 7’s sensor, of course. {Pure speculation on my part} I wonder if Sony applies a different microlens array on the higher resolution sensors (NEX-7 and FF) to increase the low light sensitivity? If the magenta shift is intrinsic to the sensor and its microlenses, even very clever software such as DxO is unlikely to correct it. 🙁

    • Pierre-Yves THOMAS (Belgium) Says:

      Hi Andy,
      A few month ago, I asked DXO about this question. Since two years now, I take part to the poll of “customers/developers” and I like to send them my impressions about their product, and sometimes launching a possible direction for new developments. They answer me they are working on ideas regarding better corrections of vignetting, especially in case of color shifts, but this question appears very difficult for them. So, wait and see! (and hope)

  • Greg Tselepidis Says:

    great test George, I’ve tested A7 & A7r when they came out. Serious problem the small battery time and maybe warming up too soon in video mode. I will stick to to Nex for the moment and try the Pentax 50mm 1,7 on it. It is one of the best 50mm lences and with the cropped sencor it should be very good..

    • George Kalogeris Says:

      I am an ex-Pentaxian and so, Very interested in your results. I have several Takumar and Pentax lenses but never tried on the a7. Instead, I am going back to what I neglected! MEsuper! Thanks!

      • Chris Huang Says:

        Hi George, I am a Leicontaxian (Leica, Contax, Pentax). I can ensure you Pentax lenses works wonder on A7. Contax G I get mixed results. The AF adapter it’s hard to make manual focus, while on autofocus, there is slightly focus shift on 45mm G. To me I went back to non-AF G adapter.

        As for Contax G, I would say stay on 45 and 90. Others are hit and misses. I have both Nex-5n and A7.. Majority of my work pretty much came out from Pentax 43mm LE instead.

        The way I see it is that Contax made G tiny enough. However, Contax G + hood + UV filter + adapter is equal to the length of Pentax 43mm LE + hood + UV filter + adapter. Only difference is Pentax lenses are much easier to focus when you are on manual focus.

        Contax G 90mm also is the case.. It’s actually longer than Pentax 77mm Limited. Since I have both sets.. I am much favorable to Pentax lineup. << my flickr page.. You can see a lot of examples from these lenses.

        • George Kalogeris Says:

          How would you consider SMC Pentax-M 28mm f/2 instead of the expensive 31mm f/1.8 Limited ? Do you think it could serve as an everyday shooting lens on A7 ?
          Also could you recommend a decent adapter ?

  • Joel Says:

    The Contax G 28mm is not perfect on the A7 but much better on the A7 then on the A7R. This has been documented in many places on the web. Only occasionally to I see smearing or color casts on the A7.

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