Sony E-Mount Lens Guide Here >>

Nex-5n and La-ea2 Lens Adapter w/ A-Mount Lens Vs E-Mount Lenses – Low Light and Low Contrast Testing!! New Nex-7 Book!!

Always curious how the LA-EA2 lens adapter with an A-Mount lens would perform in low light, low contrast situations Vs the standard E-Mount lenses, I put together this really quick test together with results that may surprise you!!

Basically what I did here is compare the Phase detection AF that is built into the LA-EA2 Lens Adapter VS the Contrast Detection AF found natively in the Nex-5n. In theory anyway 😉  I did this test on Sunday in my computer room with the blinds closed and one tungsten light on. I finally got a few minutes to post it up for you guys, so I apologize for the delay!! If you want to get a sneak peak on future videos, you can subscribe to my YouTube Channel, and it will email you when something new is uploaded!! I often put these videos up days before I write the article, as it takes hours for the videos to upload.

HD Video – Low Contrast Low Light Testing

Be sure to click on the little gear icon in the player window once the movie starts playing. You can then select the 720P option for maximum quality!!

All The Gear Used in the Test

Sony Nex-5n
Sony Nex-5n

Sony Nex-5n

I reviewed the Sony Nex-5N already, and I own the Nex-7, but it’s totally disassembled in the Lab! So, I needed a Nex camera body for testing purposes and opted for the Nex-5N again as I love the 16mp sensor!! I would went for the New Nex-F3, but it’s not out yet unfortunatly.

Price: ~$598 @ BHPhoto (Click Here)

Sony A-Mount Lens to NEX Camera Mount Adapter – LA-EA2


The La-Ea2 lens adapter is an amazing piece of camera hardware that pretty much turns your Nex camera into a Phase Detection Autofocus Monster that will except all A-Mount Lenses. That is correct, you can use all A-Mount lenses on your Nex Camera with this adapter, and have killer fast Autofocus!! So needless to say I’m excited about getting it!!
Price: ~$319.95 @ BHPhoto (Click Here)

Sony 50mm F1.8mm lens – SEL50F18

Sony E-Mount 50mm f/1.8 Telephoto Lens

The Sony 50mm f/1.8 is probably the most anticipated and wanted E-mount lens currently. I’ve been trying to get one for months now and I’m sure many of you are in the same boat. Basically what this lens offers is a fast aperture and excellent focal length for Portraits in particular. The F/1.8 aperture will allow for some killer separation from the backgrounds and also allow for extreme low light shooting. With the combination of the f/1.8 aperture and Optical Steadyshot built in, this could be one of the best low light lens on the market in my opinion. For the Money of course, mind you 😉
Key Features:

  • Large f/1.8 Aperture
  • Direct Manual Focus (DMF)
  • Compact and lightweight
  • Image Stabilization
  • Smooth and quiet high-speed focusing
  • Weight (Approx.) : 7.25oz (202g)

Price: ~$299.99 @ BHPhoto (Click Here)

Sigma 30mm f/2.8 EX DN Lens

Sigma 30mm f/2.8 EX DN Lens for Sony E Mount Cameras

The Sigma E-Mount 30mm f/2.8 EX DN Lens is a prime lens designed specifically for mirrorless interchangeable lens cameras. This 30mm lens is equivalent to a 45mm lens in 35mm format and provides a 50.7° angle of view. A very nice fixed focal length to work with on a crop factor sensor like the Sony Nex-5n I might add.
Key Features:

  • 30mm f/2.8 Lens
  • Equivalent to 45mm in 35mm
  • For Sony E Mount Camera
  • Aspherical Design Prevents Distortion
  • Focuses to 11.81″ (30cm)
  • Multi-Coating Reduces Ghosting and Flare
  • Linear AF Motor for Quiet Operation

Price: ~$199 @ BHPhoto (Click Here)

Sigma 19mm f/2.8 EX DN Lens for Sony E Mount Camera

Sigma 19mm f/2.8 EX DN Lens for Sony E Mount Camera

The 19mm f/2.8 EX DN Lens for Sony E Mount Camera from Sigma is a Digital Neo (DN) lens specifically designed for mirrorless interchangeable lens cameras. On a Sony E mount camera (NEX), its focal length is equivalent to 28.5mm. It has a newly developed linear AF motor for swift and accurate autofocus, making it ideal for video as well as still photography. Three glass mold aspherical lenses offer excellent correction for distortion, color aberration and field curvature. The inner focusing system corrects the fluctuation of aberration to maintain image quality regardless of the focal distance. Multi-layer coating reduces flare and ghosting, and provides sharp and contrasty images even at the maximum aperture. The seven blades of the diaphragm produce a pleasing quality in the out-of-focus areas of an image (bokeh).

  • Digital Neo (DN) high performance lens designed exclusively for mirrorless interchangeable lens cameras
  • Ultra compact construction weighing only 4.9 oz and measuring 1.8 inches in length
  • Newly developed linear AF motor ensures accurate and quiet autofocusing, making the lens ideal for video recording as well as still photos

Price: ~$199 @ BHPhoto (Click Here)

Sony DT 35mm f/1.8 SAM Lens

The Sony DT 35mm f/1.8 SAM Lens is designed for D-SLR cameras with DX-format sensors, so the lens has a 52.5mm equivalent focal length. This is perfect for snapshots and portraits under a wide range of shooting conditions. The ultra fast f/1.8 wide-open aperture along with the 7-blade circular diaphragm allows you to work in low light, and with a minimum focus distance of 9.05″ (0.23m) the lens allows you to get in close to your subject.

Price: ~$319.95 @ BHPhoto (Click Here)

The Complete Guide to Sony's NEX-7 Mirrorless Camera by Gary Friedman!
The Complete Guide to Sony’s NEX-7 Mirrorless Camera – by Gary Friedman!

I’ve also been reading, in my limited spare time, my courtesy copy of the Nex-7 book that just came out by Gary Friedman!! It’s excellent, and I can honestly say I learned several things already about the Nex-7 and more. Quite impressed with Gary’s writing style, as it’s like mine in a lot of ways. Except with proper grammar and spelling of course 😉 Seriously though, he comes across like a friend in conversation throwing killer insight, theory, and tips left and right.  I plan on Doing a full review of the book, but in the meantime, you can check it out over on Gary’s website if your curious 😉 Oh yeah, he used one of my images in the book!!

Closing Remarks

Well, in this particular test the Phase detection LA-EA2 lens adapter with the Sony DT 35mm f/1.8 Lens clearly did not do as well as the standard E-Mount lenses tested performed. Mind you, as said in the video the LA-EA2 lens adapter forces the aperture to f/3.5 so that may effect things, and I honestly don’t know for 100% certainty if it does or not. I know the light going in is obviously less, but often this has no effect on the AF performance surprisingly. Depending on a number of factors though it may or may not. I’ve read a few articles on this, but it is so freaking confusing for some reason I can’t yet simplify how it all works. I just need to find a really good article on how it all works with illustrations and stuff. Therefore specific details about how the actual AF sensors work at different apertures, iso, and lenses, is beyond my knowledge base at the moment, but not for long!!

That is about it for now, have a great weekend everybody!!

  1. Hi Jay! I’ve been wondering about the LA-EA2 adapter so I’m loving these reviews! I was wondering why the adapter forced the lens aperture to f/3.5? Does that mean you can’t use an A-mount lens at f/1.8?
    Thanks again!

    1. Hey Brett,
      It has something to do with the Phase detection AF and the fact that it’s easy to blow out the scene when using wide apertures, and its hard to focus with really wide apertures, because the depth of field is narrowed. I think it’s so the movie mode as a whole performs better. I still wish I could get a better more specific answer, but that is what the Sony Engineers told me when I called to find out. This is the same reason.
      This is only in movie mode and 10fps mode as the aperture needs to open and close so fast, they also limited this to f/3.5 as well. Older lenses have slower aperture mechanism’s and won’t be able to go from wide open to say f/8 at 10fps. so the engineers stopped it at f/3.5 for that feature as well.
      I hope that helps and I wish I had a better answer. Perhaps I’ll shoot an email to Gary Friedman, I bet he know the specific reason!!

  2. I have the NEX-5N with the LA-EA2 adapter and I have to say that I’ve fully converted over to a-mount lenses only at this point. I do not do videos so the adapter works very very well. In fact, there’s essentially no difference in focusing speed compared to the A55, A65 or A77 when using the LA-EA2. Yes, I do lose the stabilization on the e-mount lenses but if you have the shutter to a manageable speed, you will not blur any pictures. I currently have the SIGMA 10-20mm f/3.5, Zeiss 24-70mm f/2.8, Minolta G 85mm f/1.4, and the Minolta 80-200mm f/2.8 APO HS lens that I use in combination with my NEX-5N and LA-EA2. It’s a Frankenstein of a combo but it keeps pace with my buddies Canons and Nikons.

    1. Awesome!! Thanks for the sharing the info and your camera combos!! Frankenstein is right, but it does the job 😉 If your always using the LA-EA2 adapter you miles well get the A57/ or a37 and save yourself some ergonomic comfort. Plus you will gain OSS back!!

      1. Hi Jay. Thanks for taking the time to film the test. I have two observations. The first pertains to apertures used. The selected aperture directly affects the camera’s ability to autofocus and it’s speed. Wider apertures will give you faster and more accurate autofocus because more light is hitting the sensor. You may want to replicate the test, but this time use the same aperture for all three lenses. Also bare in mind that the slt approach that sony uses does have a minor impact on sensor performance (about half a stop of sensitivity). The second observation pertains to something you mentioned in the video during the 50mm test and that is minimum focus distance. It is important to keep all lenses further away than the mfd in order to ensure that they are able to autofocus. If you are too close, even by just one inch, the lens will not be able to lock focus on anything. That could have affected some of your results.
        Thanks again for taking the time and keep up the good work.

        1. Thanks for taking the time to comment Andres 😉
          No test is perfect and this test was far from any sort of calibrated test. Just a really quick test using different gear and lenses. I understand how AF will be faster with wider apertures, but the LA-EA2 Lens adapter limits the aperture while in video. What I was really trying to compare was the PDAF AF that is on the LA-AE2 lens adapter vs the on sensor CDAF auto focus. It’s much faster and that was all I was trying to get across. How much better is the PDAF vs the CDAF in a quick and dirty test 😉 I also understand the minimum focus distance and I assure you, that was not the issue with the testing. I know exactly what you mean though!
          Thanks again for the comments and sharing your observations! If I ever do a test like this again I will do a much better job and take your suggestions into account for sure.

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