Monday, July 22, 2013

A99 & A77: Same Settings, Different Exposures


Also in this issue:
  • A Death in the Family
  • How I Shot This Really Annoying Sculpture
  • Rescheduled Seminars 

A99 & A77: Same Settings, Different Exposures 


It started out innocently enough.  Here I was, photographing a science experiment we found in the pantry one night (a potato that decided to start sprouting) and so I thought I'd document it in the studio and go for some dramatic light.  I used just one flash on the right, set to manual output.  An early shot can be seen above.  (As always, click on any image to see a larger version.)

"The depth-of-field is too shallow" I said to myself.  "The front leaves are very sharp; but the back ones 4 inches back are too fuzzy".  And so I switched from an A99 to an A77, knowing that the smaller sensor will give about 1.5 stops' worth of increased depth-of-field for the same composition.  I carefully set up the camera so all the settings were identical, and took a similarly-composed shot:



Whoa!  The A77 shot was brighter.  I was expecting an identical exposure.  Oh, well, time for bed.

The next day I was shooting some publicity shots for a real estate mogul, and while he was preparing for his video I took some additional test shots of a member of his entourage:

Same lens, same light, same settings.  But the A77 shot (left) still came out brighter than the A99 (right).
Yeah, I wrote books on both cameras, but it never occurred to me to do side-by-side exposure testing.  Time to do that now.

Here are two shots taken of a bland, neutral subject with the A99 and A77 set to "Auto".

Program mode - A77 (left), A99 (right).  Pretty close.

A quick check of the EXIF information shows that the exposure value for the two cameras was actually different.  At ISO 400 and f/2.8, the A77 shot at 1/30th of a second, whereas the A99 shot at 1/13th.  The A99 let in more light, to make it look as light as the A77.

And here is the same shot with the same two cameras set to manual exposure mode (ISO 400, f/2.8, 1/30th):
Manual exposure mode using identical conditions - A77 (left), A99 (right).
So clearly, the cameras themselves know that they respond to the same light differently, and when set to an automatic exposure mode they take this into account when calculating an exposure.  It's only when the controls are all set manually and compared that the difference in sensitivity becomes visible.

Am I the first to notice this?  Apparently not.  DxOMark tested both the A77 (link here) and A99 (link here) and sure enough, starting at ISO 100, the A99 was almost 1 stop less sensitive than the 77 at all ISO settings.  (Click on the "Measurements" tab on each page in the above links to see the ISO test.  I don't have permission to post the results here.)

So, if you're like me and shoot with multiple cameras in controlled situations, be aware that switching bodies will yield slightly different results, even though the cameras' settings and lighting and composition are identical.

A Death in the Family

My Mother-in-law passed away at the end of June, leaving behind 3 daughters, 7 grandchildren, and 5.5 great-grandchildren.  She was much loved by the community, but she left her daughters with a huge estate that needed to be liquidated.  Not a fun time for anyone.  I cancelled all seminars for the rest of the year (Seattle, Vancouver, Australia, New Zealand) so I could help my wife with what can best be described as a very stressful period.

My mother-in-law.  We had to move the studio down to the garage since she couldn't get the wheelchair upstairs.
Going through someone else's estate gives one pause; it makes you wonder just how many "things" a person really needs in order to be happy.  And how much do we want to burden our children with our possessions upon our death?  I think I'm at the point where I'm no longer interested in acquiring more stuff (camera gear aside, only because it's kind of my business).

True story: Before my mother-in-law died, our daughter asked her, 'Gram, what thing do you especially like in this house?", thinking she would get a good story and keep the chachkie in remembrance.  "That piece!", she replied, pointing to the ugliest thing in the house.


"Why? What's the story behind it?". "No story. I just like it, that's all." So I thought "Why keep a scary-looking ivory carving around the kids when you can just take a good picture of it and hide the object?" Which is what I did.

No studio needed for this one.  I took this shot on-site, with two wireless flashes.  The first one (the main light) was diffused using a Lumodi beauty dish, and it produced the image below:


Nice, but I didn't like the dark background.  So placed a 2nd wireless flash on the floor behind her, taking advantage of the large red wall in the kitchen and producing a subtle gradient in the process (brighter on bottom, gradually getting darker toward the top).  A telephoto lens brought it all together.  A behind-the-scenes shot of the simple setup appears below:


Seminars Rescheduled 

The worst of the funeral and estate liquidation process will be over by the end of August, and Carol and I will be very much in need of a break.  So we are re-scheduling just the seminar for Seattle which will happen on Sept. 28-29.  The signup page is here; but if you've already signed up just send me and email and say "ink me in!".

You can learn more about the seminars here.

Until next time...
Yours Truly, Gary Friedman

She really enjoyed the great grandchildren, but it wasn't always the other way around...

40 comments:

  1. condolences.
    I just went through the same thing with my 99 year old father and know understand what you mean about burdening your children with possessions.
    The best thing I got was a series of journals he kept on and off throughout his life.

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  2. Dear Gary

    Please accept our condolences to you and your wife at this sad time
    From Paul and Maureen from Devon England

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    1. I appreciate your condolences, Paul and Peter!

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  3. Best wishes, Gary, through the emotions and challenges your family is facing.

    If I may ask a question please. Wouldn't one expect the A99 to provide a brighter view with the larger sensor and pixels at the same settings? Or is the A77 ISO actually higher than stated by comparison to compensate for its higher pixel density? ....and thus the noise.

    I'm somewhat confused after having shot a lot with both cameras. I sold the A77 to buy my A99.

    thanks kindly if you have a moment to share your thoughts.......... Paul

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    1. I would expect the A99 to have a sensitivity equivalent to ISO 100 when set to ISO 100, irrespective of pixel density, semi-transparent mirror light loss, or any other factors.

      Thanks for your condolences. GF

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  4. Dear Gary,

    Please know that our thoughts and prayers are with you during this tragic time. May you and your family take comfort in your precious memories.

    Seattle is the perfect place for you to take a break and to regain your strength. The beauty will overwhelm your senses, anywhere from the sea, to the islands & lakes, to the mountains and the rain forest & even The Palouse.

    best,
    Ann & Dileep Bhandarkar

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    1. Wow, thanks, Ann! Now your description makes us want to get there faster! :-)

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  5. Buried both my parents relatively recently,Mum in 2011 and Dad in 2012 and your blog struck a chord re possessions. I still have a double garage full to sort out still. It's a tough time for all concerned and you have my sympathies but life goes on.

    And with that in mind photography is a great distraction. Has been for me anyway.

    Some very interesting observations on the A77 & A99. Does that mean the full frame high ISO advantage isn't as great as first thought or have I missed something?

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    1. The advantage is still there, and the A99's autoexposure takes everything into account so unless you're doing some technical work you'd probably never notice it (as I never did until recently).

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  6. Oh dear, here I sit with a world of 'stuff' around me. No, I don't count my photography equipment as 'stuff', it brings me so much joy.

    Sorry for your wife, you and of course all the family's loss.

    Betty in TN

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  7. Dear Gary and Family,
    Words aren't much consolation. Your lovely photo of your mother in law will be a treasure for the rest of the family.
    Sincerely,
    Bob & Dorothy Maher

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  8. Dear Gary,
    Deep condolences to you, your wife and family.She looks like a Grand Lady.

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  9. Dear Gary and Family

    I’m sorry to read about the passing away of your Mother in Law.
    Please pass on our condolences to your family.

    Regards
    The Vellema’s in Dubai

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  10. Hi Gary, condolences to you and your family, when my grandad passed away 5 years ago we spent days going through his old documents and it was full of highs and lows. Finding diarys and letters that he'd written to my nan during WW2 and pictures of us with him as children. His love of photography was the reason I got into it and even when he was in hospital during his last week he still wanted me to bring in my latest photos. Once again condolences to you and your wife.

    Ant

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    1. Many thanks, Ant! Going through the old stuff can be a healing process in itself.

      GF

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  11. Is n't the exposure scale based on the appearance of shadow-detail ? And then in second term on the not washing out of the highlights ? I noticed a slight underexposure by a Nikon D300 as compared to a Sony A700. May be the actual chip in use, as well as the registration software, both help decide on ISO ?

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    1. I think it's the center value between when the shadow noise gets unbearable and when the highlights begin to clip. I think DxOMark has something about their test methodology on their website.

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  12. Sorry to learn of the death of your dear Mother-in-law. Our condolences to you, your wife and all the family.

    Sam & Lucy Morris
    Fall River, Nova Scotia
    Canada.

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  13. Curious to read about the A99 v A77. The obvious next question is whether there are similar differences within the range? My interest is how the A55 compares.

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    1. The first place I would check would be the DxOMark website. On the other hand, had you noticed anything until now?

      -Gary

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  14. Hiya Gary

    Yea its me, the annoying 'which lens do I buy' guy from recent emailing sessions! Thanks to your help I decided one the one I could afford :-)

    That being said, I was about to email you with my results and ask how your mother in law was doing when I found your blog email actually in the 'junk' folder in hotmail! If it wasn't for me checking whats in there daily Id have missed it, it apparently came from 'no sender' and 'no subject' no idea why.

    Please accept my condolences for your sad loss, a bereavement is a trying time for one and all. My father is a hoarder of massive proportions, by that I mean two 60x40ft 12 ft high 'garages' full to the roof and doors, and approximately half an acre of stuff outside. And he's just treated himself to three new 10x8 sheds for more! Oh and a caravan that nobody can get in too not to mention the house :-) Dread isnt the word!

    Just a quick question (Gary runs for the car with family in tow) no it really is quick :-) how do both the A77 and A99 compare with a true 100ISO base line, in short, which is the truer value? Do we need to drop the exposure on the A77 or up it on the A99? Does it really matter? ETTR comes to mind which I find helps a lot with the A77.

    Enjoy your break, and Im sure your seminars will look after themselves. That sculpture is something else! Love the photo and explanation of how it was achieved.

    Kind regards
    Daz

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    1. Hi, Daz. There are estate liquidation companies that specialize in attacking properties like your father's and dealing with everything for you, typically taking about 35% of whatever they can get (which when your time and emotional charge are taken into account is quite a bargain!)

      According to the DxOMark measurements the a77 is spot on and the A99 is low. My understanding is that ETTR (Expose-to-the-right) doesn't work quite as well on the new Sony models since they tweaked how the light distribution is represented in the RAW files.

      GF

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  15. Hi Gary:

    Sincerest condolences on the passing of your Mother-in-Law. With both my parents gone, I know how difficult it is to lose a part of your family. However, time is a healer and change keeps us pursuing how to cope with the next moment. The emotional reaction will make us better and stronger in some way.

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    1. We'll see about THAT! :-) Thanks, Arthur!

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  16. My condolences to you and your family, Gary. I lost my father in June 2012, and my mother has been diagnosed with leukemia and not given very much longer to live. I pray that God be with you and your family during a stressful and difficult time.

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  17. Dear Gary

    My heart-felt condolences to you and your family. Be strong during the period of difficult time. Take care.

    Regards.
    NL Soh

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  18. To everyone who expressed their condolences, a heartfelt "Thank you!". It's never an easy time and just knowing we have your emotional support is in itself assuring.

    GF

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  19. Hi Gary - three brief thoughts on the exposure thing. When they review cameras in dpreview, they give the actual ISOs against the nominal ones, because apparently they aren't the same. Also, in the film biz, we had what we called "t-stops," which were the real f-stops when calibrated against a good meter. Finally, the two cameras are different frame sizes, so the zoom setting would be different for the same composition. Could that affect exposure differences?

    Enjoying my new a77, posting on dpreview.

    Gary Eickmeier (other Gary)

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    1. Hi, Gary. Regarding zoom setting differences, etc., both tests were done with constant-aperture lenses. And the "bland, neutral-subject test" was done with separate lenses - an APS-C lens for the A77, and full-frame for the A99, eliminating the theory that the A77's sensor was only absorbing a fraction of the full-frame lens' light (even though that would have resulted in the A77's images being darker - the opposite of what was observed.) GF

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  20. Gary, please accept my condolences for your family's loss - a tough time for all, no doubt. My thoughts are with you in the coming months as you sort everything out.

    Regarding the A99/77 differences, it sounds like the A99 iso is overstated by about 1 stop, i.e, an iso of 100 is actually 50. Whether intentional or not, it would make the camera's high iso performance appear better than it actually is by about 1 stop. Does that make sense?

    Take care,
    Mike Hendren

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    1. It does make sense, but only if the folks doing the testing are shooting in anything but Manual Exposure mode. (In that case the noise would be lower but the image would be darker, too. :-) ).

      Intentional? It's impossible for me to say.

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  21. Seems to me the loss is in fast shutter speed action shots where you can't just leave the exposure longer.

    Cheers,

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  22. My condolences for your loss. I have 2 in-laws and my mother who are all about same age. That makes me shutter.
    As for the A77/A99 exposure, this might be a dumb question but would be the results if you used off camera flash and used a handheld meter for exposure? Would the shots look identical? Would slide film show even more difference?

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    1. I appreciate your (and everyone else's!) condolences - thanks for sharing them.

      The very first example in this blog post showed an off-camera flash set to manual output (same setup you would get if you were using a handheld meter), and so yes, the results are the same: For identical light and exposure settings, the A99 is less sensitive.

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  23. Hi Gary, so sad news! Please accept my condolences. After my Grandma died, I had to liquidate her house and her estate, so I know about all the work to be done by you now.
    Each of your blog entries I read with a high interest, so I already took part in some of your family matters.

    Some time ago I bought your a900 book, now I'm dealing with the idea of buying a a99...

    All the best to you and Carol and all of your family,

    Alby

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  24. my condolences to you and your family thank you for the wonderful book on my sony rx100, great w0rk, will say a prayer for her

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  25. Te acompaño en el sentimiento Gary

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  26. Gary - my empathy goes to you for your loss - lost my mum over 2 years ago & having to deal with a farm & all over 2000 miles away - seeing all my past get sold at auction as we tried to liquidate the assets. Not fun. Healing will take time.

    Thank you for taking your (emotional) time to share both this loss as well as your technical insight on the two Sony cameras.

    Paul K.

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  27. My condolences to you and your family.

    I've been reading your blog and books for some time. Recently, I purchased the A99 and I find the difference between the A77 and A99 startling in almost every way. The A99 capture/image quality is completely beyond the reach of the A77. I really didn't expect that.

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