Saturday, April 18, 2015

A-Mount and E-mount Focusing Differences

In This Issue:

I try to keep this blog very general most of the time, knowing that many readers shoot with a wide variety of camera brands.  This month I'll make a small exception -- I'm going to start with something Sony-specific and kind of technical, then at the end I'll get to something non-technical that every shooter from every type of camera needs to know.

Focusing Differences between Sony's A-Mount and E-Mount

Grafting video onto a traditional DSLR architecture can be fraught with problems.  Sure, Sony cleverly integrated the fixed semi-transparent mirror into it's A-mount platform to keep phase-detect autofocus in movie mode, but there's still the problem of autofocusing with anything but a wide-open f/stop (it can't), or changing f/stops mid shot (which it can't for historic reasons).  

So when Sony went to design the E-mount (originally called the "NEX") platform, they were designed from the ground up to support video seamlessly.  BUT there's an inherent theoretical focusing problem that no camera manufacturer has been able to address, and so it's important to understand the focus-tracking strengths of both the A-mount and E-mount cameras so you'll understand the limits of your equipment.  

I could write about it, but some things are just more intuitive with video.  Watch this; it has already caused quite a stir online in just 24 hours after it was posted to youtube:

Things I neglected to mention in the video:
  1. Remember, the A7 has phase-detect AF points baked into the sensor to help under these very conditions.  Despite this, the E-mount STILL has a theoretical disadvantage.
  2. I was not trying to bash any particular platform.  My purpose with the video is to let people better understand how the camera evolved, and to touch on the strengths and weaknesses of each platform.  It's always useful to know under which circumstances your equipment will hit its limits, even if you never push it that far.  There are a lot of people for whom this situation may never come up.
  3. If you've ever wondered why I've never been asked by Sony to be one of their "Artisans of Imagery", this video (and, let's face it, all my other videos too) should give you a pretty good idea. :-)  
  4. Different E-mount cameras behave slightly differently.  For example, my NEX-7 keeps the f/stop closed ALL THE TIME except for when it's trying to acquire focus for the first time. 
  5. More about the firsts with Polaroid – they were the first (correct me if I'm wrong) to use asymmetric optical elements (different shape on the front and back of lens).  Polaroid was (were?) also the first to do autofocusing by bouncing ultrasonic sound bursts off the subject and timing how long it took for them to return.  
  6. The pentaprism only reverses left and right, leaving up and down alone.  (In the video I said it corrected for both.)
  7. See that wristband I'm wearing?  Grandchild #1 made that for me.  I'll never take it off.
Quick Announcements

  1. The Spanish version of the Olympus O-MD E-M1 ebook is now out!  (La versión en español de la galardonada Olympus E-M1 ebook Disponible ahora!)
  2. The Boston Seminar is coming up -- May 2-3.  Still some room!
  3. A new ebook for the Olympus E-M5 II ebook is in the pipeline!  Send me an email (Gary at Friedman Archives dot com) if you'd like to be put on the notification list.
  4. There's also a Nashville Seminar coming up at the end of May.  Many are traveling from several states away to attend.  Be one of them! :-) 
  5. Next Time in Cameracraft – Patrick Ward's amazing career during the golden age of photojournalism (interestingly, nobody recognized it as a golden age at the time.  The age had to end first before it could be labeled.)  You can see more of his work on his blog.  Subscribe to Cameracraft, an old-school labor of love which emphasizes the art of photography and not just the technical stuff!  
Patrick Ward's latest book is called "Being English" - he excels at capturing ordinary people at play.  His book encompassing the best of his life's work can be purchased at

Back-Button Focus ebook is out!

Probably one of the most misunderstood aspects of these modern cameras are the ways you can combine customization elements to benefit a particular photographer's shooting style.  For example, this is my favorite customization for shooting portraits in the studio (I'm not including menu items because they're all different in different cameras):

  • Focus Mode --> Manual Focus
  • Assign the AF/MF button to AF/MF Control Hold
  • Focus Area --> Flexible Spot

With this configuration, when I'm shooting in the studio, I really only need to press the AF/MF button once to focus, then let it go and then shoot away, refocusing ONLY should the distance between the camera and the subject change.  This is better than using the camera's default configuration, necessitating a focus-lock / recompose / shoot cycle for EACH PICTURE TAKEN.  

With the above configuration, the camera remains in manual focus mode all the time until I press the AF/MF button, in which case it quickly does an AF lock.  Once the camera locks focus, I remove my thumb from the button and the camera goes back to manual focus mode.  I only focus when I need to, and it is a very seamless operation!

This is just one example of a Back-Button Focus (BBF) configuration.  And combining custom functions for particular usage scenarios can really help you work quickly in the field.  And so, Ross Warner has created a very detailed and nuanced guide on how to configure the most popular Sony mirrorless cameras (A6000, and the A7 permutations) to use BBF in a variety of shooting situations, including landscape, portrait, movies, tracking moving subjects, and more.  

The e-booklet sells for a paltry $6.95 and is available here.  Customize further!

Something Really Big

In my writing, I'm often pulled in two different directions.  Yes, these cameras are complex and everyone wants to understand what all these technical features do.  And I'm told I explain these things well, so that's certainly gratifying.

But I constantly get emails from people from all walks of life, asking, "I'm going on vacation soon.  What [expensive piece of glass] should I get?"  And the thinking behind these innocent-sounding questions is, "If only I had better gear, then I'll be much happier with my pictures!"  Too bad that's a myth.  The truth is more harsh: if you're not happy with your pictures now, better / more expensive equipment won't fix it.

The false paradigm bothered me so much that I went and created the Friedman Archives Seminars, designed to combat this misinformation and teach people what was REALLY important in photography, using whatever camera they had.  And for the last decade I've literally been around the world spreading this message, which seemed to resonate quite strongly with attendees.  Interestingly, although the two-day course was aimed at beginners, there have been no end of experienced photographers who have been shooting for 30 years in attendance, saying how inspiring it was, and how wonderful to get a refresher course on the basics - basics that nobody seems to talk about anymore.  Well worth the time and money.

I love conducting these seminars, but a couple of years ago my wife and I made the decision to limit them to about 4 a year to bring a little more balance to our lives.  Of course this was a frustrating decision because there are many people in many cities I will simply never get to.

And so for them, in October 2014 I had a seminar professionally videotaped, with an eye toward making it available as a video course you could view in the comfort of your home, wherever in the world you lived.

Sounds easy, but anyone who's ever videotaped their child's dance recital or school play can tell you that watching the videotape is not nearly as enjoyable or engaging as being there.  And nobody wants to sit on their couch and watch 16 hours of video straight.  (Unless you're binge watching a Netflix series, of course.)

And so in an effort to make the video enjoyable and engaging, I've been editing Day 1 of the seminar by hand non-stop since October.  Once I got it down to its essence (about 3 hours of video), I then broke it up into chapters, with each chapter followed by reinforcements, exercises, and additional reading to make the lessons stick.  The response from the beta testers has been reassuringly positive - "engaging and enlightening" they said.  Even the experienced photographers remarked what a breath of fresh air my approach is.  Just like the feedback from the live event!

Having said all that, I'm here to announce that Day 1 of the seminar is now, at long last, available for purchase!  It has been renamed as "The Forgotten Secrets of the Kodachrome Shooters", referring to how professional photographers got "Wow!" images in the days before Photoshop, RAW, or even autofocus.  It is being hosted by a company called, and you should be able to stream the video lessons to any device you own.  And at USD $69.95, it actually costs less than attending the seminar in person!

I put a lot of work into this.  I hope you get just as much out of it.   It's been a decade in the making.

Parting Shot

The last time we visited Boston was during a record-breaking snowstorm, which my wife enjoyed immensely (but not so much by the rest of the town.)  Many of you who reside in places that receive considerably more snow might laugh at this, but remember Boston is a coastal town and for them this was pretty considerable.

They weren't on the ground... they were leaning back and practically vertical. :-)

We'll be back May 2-3 to conduct a seminar - I believe the snow will be mostly gone by that point!

Until next time
Yours Truly, Gary Friedman


  1. Does the Back Button Focus eBook apply to the A77M2 as well?

    1. Yes and no. The basic customizations can be applied, but camera-specific menu commands for the A77 II won't be there.

  2. Great video, Gary. I own the Sony A77ii (having upgraded from the A77 which I bought in 2011) and have been migrating to the Olympus E-M1 during the past year. One thing I've noticed when comparing the two is that the E-M1 CDAF focus seems more precise. I've been holding on to the Sony primarily for C-AF when shooting my son's sports activities, but with the latest firmware update to the E-M1, combined with the fantastic 40-150/2.8, I'm finding the E-M1 to be more consistent and accurate with its focussing.

    I've done AF calibration for all of my Sony lenses, but find I get a better percentage of keepers with the E-M1. Curious to know your thoughts.

    1. Glad another has found the E-M1.
      I had my "rush of brains to the head" last year when I changed equipment over a year ago.
      Had been with Nikon since the late 50s, but now a retired photographer, and 72years old,I find the quality of photos to be great and the weight difference is making quite a difference to my fallen arches!!

    2. CDAF will always be accurate; whereas phase-detect's accuracy (whether in a DSLR or SLT) is always at the mercy of the alignment of the mirror. Glad you're liking your E-m1; you really can't buy a bad camera today.

  3. Que gran cámara la A 77, solo echaba de menos el full-frame, por fín apareció y ya tengo la A99. con la que he acondicionado mi cerebro para ella, y ya la uso como algo incorporado en mí. Casi todos lo requisitos que yo necesitaba están en ella. Acompañada de una buena óptica es inmejorable para mí.

    1. ¡Enhorabuena! Espero que su nuevo equipo te sirve bien. Gary

  4. Great video Gary. Well researched as always. Does the focusing problem apply to the A99 as well, or just E-mount

    1. I prefer to call it a"characteristic" rather than a "problem", and anyway it's E-mount only. GF

  5. Above you mention streaming your new video seminar, but the web site states "You'll get 22 files". Hoping I can download to my tablet to enjoy in non-WiFi environments. -Mark

    1. Yes, between the streaming videos and the downloadable .pdf files which reinforce each chapter, there are a total of 22 files. The video files are streaming-only because I don't want them to end up on torrent sites like so many of my ebooks do. Besides, each video file is between 2-5 GB in size; making them cumbersome for most people to handle.

  6. hi, do I understand correctly that the theoretical disadvantage of the mirrorless goes away if you shoot with the aperture either wide open or nearly so? as in Aperture priority mode.

    1. Thank you, sorry for lateness of reading your answer. I keep watching your video. It has helped me increase my understanding of what is important. I also really like your style.
      I read on some other forum that mirrorless can only track when the shutter is open. (if true and 180degree shutter then that's 50% of the time)
      I wonder, it seems logical?

      If so, then maybe SLT should have an advantage at same shutter/wide-aperature/iso? What do you think?

      I'm into video frame grabs of young children. (Grandkids) I'm starting to think that Nikon 1 size of sensor will allow open aperture while increasing dof. Sony RX10 ii should also be a good choice, while full frame may sometimes require stopping down to get sufficient dof in some circumstances. IF Tracking Moving faces is the priority??

      As you can guess, it's time for my next camera purchase while I keep my eos-m for recording video of events at school.

      Your thoughts will be of huge interest to me...

      Best Regards,Tim

  7. Hi Gary,
    I know this is a very old posting but is there a book available for BBF using the A99ii and A77ii?
    You wrote "Ross Warner has created a very detailed and nuanced guide on how to configure the most popular Sony mirrorless cameras (A6000, and the A7 permutations) to use BBF in a variety of shooting situations, including landscape, portrait, movies, tracking moving subjects, and more."

    1. No book needed; use the center button of both cameras to implement "Focus Standard" - it instantly switches from whatever focus area and focus mode you have set to Center and AF-S. Simple!

  8. So set Center Button to "standard" along with decoupling focus with shutter? But that doesn't actually activate focus, it just moves focus to center focus point, right? What I'm wrestling with is how all that works with Center Lock On AF. Do I have to have a separate button set for Af-On if I've got the shutter decoupled from focus and the Center button on standard? I apologize but it's just all confusing.