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Amin Sabet

Gear Tests Small Format Deep DOF Advantage - Fact or Myth?

Small Format Deep DOF Advantage - Fact or Myth?

  1. Amin Sabet

    Amin Sabet Administrator Staff Member

    Jul 3, 2010
    Amin Sabet submitted a new resource:

    Small Format Deep DOF Advantage - Fact or Myth? - Small Format Deep DOF Advantage - Fact or Myth?

    Read more about this resource...
     
    Last edited: Jan 24, 2016
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  2. ZDP-189

    ZDP-189 Twitter: <a href="http://twitter.com/#!/ZDP189">@Z

    64
    Apr 18, 2011
    I have a 5DII, but I use a GX100 or GX200 for all my 'product' photographs. I need the combination of a 70mm equivalent AoV lens and reasonable DoF. At full zoom and full wide, I get a DoF that covers anything I'd want to photograph. On the 5DII, I'd have to close down to F/22 to get the same DoF and with 4.5 stops less light and diffraction limitation, I may as well not have bothered.
     
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  3. soundimageplus

    soundimageplus Lounge Top Veteran S.C. Charter Member

    578
    Jul 6, 2010
    Good post. Though this topic is known to provoke heated debate!!

    One of the great advantages of m4/3, and to a certain extent APS-C, sensors for me is this DOF advantage. I work outdoors most of the time, usually in good light. I generally walk some distance and have no desire, or the back muscles, to carry a tripod. Since what I shoot is mostly in the landscape/location/travel catergory, I'm usually looking to get the maximum depth-of-field at a low ISO. Since I'm working hand-held almost exclusively I also want a high enough shutter speed to eliminate camera shake.

    Because of the m4/3 2x sensor crop I get quite an advantage. I tend to use a lot of wide-angle lenses. So for a shot where I would use a 28mm lens on full-frame, I can use a 14mm on m4/3 for the same angle of view. If I choose the same aperture, say f/8, I will get more DOF on m4/3 because a 14mm lens at f/8 gives more DOF than a 28mm lens at f/8. If I'm happy with the DOF I get from that 28mm at f/8 on full-frame, then on m4/3 I have a further advantage, in that I can use a wider aperture on the 14mm lens on m4/3 and achieve the same DOF. I can therefore use either a faster shutter speed or a lower ISO or both.

    When I used medium format film cameras, usually with films like Fuji Velvia, this advantage was reversed. I had to use smaller apertures to get the DOF I wanted, and using an ISO 50 film made it essential to either work in very good light, have very steady hands or use a tripod.

    People often complain about the fact that its difficult to get limited DOF on m4/3 but for me its the opposite reaction. One of the reasons I'm so enthusiastic about it and use it so much is because it makes what I do so much easier. By using base ISO I get no problems with noise, and indeed using my GH2, which has ISO 160 as its base means I can shoot high quality images at (mostly) the aperture I want with a decent shutter speed which avoids camera shake and produces crisp sharp pictures. I can also take advantage of using relatively slow, but extemely useful zoom lenses.

    With regard to interior work, I switched from using full-frame (5DMkII) to APS-C (7D) to give me a little more "room for manouvre" with DOF. Working quickly in a rapidly changing situation meant my primary aim was to get my subject sharp and in-focus. I never had a client complain about the fact that too much was in focus, or the bokeh wasn't very nice!! First and foremost its important to "get the shot" and while switching to APS-C didn't give me a huge advantage, it gave me enough to make it worthwhile.

    One of the reasons I am hoping that Sony can produce the rumoured 24MP APS-C sensor is precisely because of the above. I'd personally love a 24MP m4/3 sensor. I wouldn't care if it was unusable above 400 ISO because I'd probably never move it from its lowest ISO setting. But thats just my particular needs.

    I just wish that m4/3 had been around years ago. Then I wouldn't have had to drag myself, cameras, lenses and tripods up mountains, with the current state of my back as a direct result of this. However it does enable me to continue to do what I do in (relative) comfort and I'm extremely grateful for that.
     
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  4. PeterB666

    PeterB666 Lounge Top Veteran S.C. Charter Member

    Looks like there may be a little bit of a front focussing problem with the 5D too.

    One of the biggest things to come to grips with for me when I went from 1/1.7" sensor cameras (Sony DSC-V3) to the Olympus Pen was the loss of depth of field. Particularly with macro. It was less of a jump going from MFT to the 1.5x crop sensor of the Nikon D90.

    Sometimes shallow depth of field is great, but there are other occassions where a lot of depth of field wins.
     
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  5. Amin Sabet

    Amin Sabet Administrator Staff Member

    Jul 3, 2010
    No front focus, Peter. It's just that the 5D is a much taller camera and therefore with the base of the two cameras at the same height, the Ricoh was closer to the immediate proximal floor (therefore throwing it out of focus). Note that maximum sharpness is in the same location for both, and the background elements are similarly OOF in each case.

    --------------

    As you can see, I wrote this post in 2007. A lot has changed in sensor technology, and we now have 35mm sensors with substantially lower read noise than the Canon 5D. Meanwhile, small sensor technology has also improved, and this particular debate has continued.

    What I've come to realize is that the basic assumptions for the arguments are often flawed. In the DPReview forums, for example, there are a lot of math-inclined folks who love to make the following arguments:

    1. For otherwise equal sensor technology, more pixels is always better (contrary to what they hold to be the "megapixel myth")
    2. For equal sensor technology, larger sensor image quality will always match or exceed small sensor image quality (even for matched, deep DOF in handheld, low light conditions.
    Even a cursory glance at these statements raises will cause a thinking person to realize that if argument #1 is true and if smaller sensors tend to have a higher pixel pitch (which is true), then the assumption for #2 (equal sensor technology) is unlikely to be satisfied.

    The reality today is that the camera offerings out there have strikingly different sensor technologies. The Leica M9 is an example - CCD instead of CMOS, and no AA filter. Dramatically different sensor tech than our CMOS DSLRs. Same for medium format. We have Sigma's Foveon tech, and now other companies seem to be preparing to bring out their own 3-layer sensors. Even within the APS-C DSLR camp, we have cameras with higher read noise than certain MFT cameras and other APS-C sensors which have higher dynamic range than certain current 35mm format cameras! Meanwhile, for small (less than 1") sensor cameras, the pixel density is very high, and the research & development dollars are likewise very high. Very different sensor technologies all around.

    Thus, the whole concept of "For equal sensor technology, [argument]" becomes kind of pointless when we are surrounded by mostly unequal sensor technology.
     
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  6. soundimageplus

    soundimageplus Lounge Top Veteran S.C. Charter Member

    578
    Jul 6, 2010
    All very true and completely ignored by many.
    Just two examples from my experience.
    Leica M9 - full frame but very poor dynamic range. The Pentax K-5 APS-C sensor is much better.
    Samsung NX100 - 14MP APS-C sensor but no better high ISO performance than 12MP m4/3 cameras.

    Add in strength of AA filter and lens "correction" software and you have radically different results, which don't follow preconceived dogma.


     
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  7. Herman

    Herman The Image Stimulator S.C. Charter Member

    Jul 11, 2010
    The Netherlands
    Real Name:
    Herman
    Interesting thread! Will the Pentax NC-1 be the start of a "new area", great DOF, small enough to always take with you, interchangable lens system, though no EVF / OVF ?
     
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