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Making the most of Depth of Field and Isolating Subjects Using m43 Cameras.

Discussion in 'Micro 4/3 News and Rumors' started by flash, Apr 21, 2011.

  1. flash

    flash Mu-43 Hall of Famer

    Apr 29, 2010
    1 hour from Sydney Australia.
    Gordon
    Thin depth of field (DOF). It’s kind of a holy grail for a lot of serious photographers, especially portrait shooters. Thousands of dollars are spent on lenses that allow it and discussion boards are filled with important and life changing discussions over bokeh, focus shift, and why the Leica Summicron 50mm 0.95 is soooo superior to the Voightlander 50mm 1.1 that you should immediately sell one of your children to get one, knowing full well, that once in your possession you will immediately be hailed as the new Cartier-Bresson. And of course, anyone who doesn’t “get it” is an idiot.

    Meanwhile the members of the medium format forum laugh quietly at your “toy” cameras.......

    With m4/3 many of us are obsessed with trying to get razor thin DOF. I’m definitely in that camp. Sometimes I really need to give myself a swift kick in the butt to remember that m4/3 isn’t going to exactly replicate my 50mm 1.2 canon lens in a small body.

    One of the big marketing and discussion points raised about the benefit of larger sensored cameras is that they allow you to have more control over depth of field. The bigger the sensor the more control you have over depth of field you have. Therefore it is easier to isolate your subject from the background using selective focus. And one of the big statements made for the benefit of micro 4/3 is that the sensor is so much bigger than a compact camera (up to 9 times bigger).

    But the reality is that, while m 4/3 cameras do have bigger sensors than compacts they are also significantly smaller than 35mm sensors, which are significantly smaller than medium format sensors, which......

    And with the exception of the Voightlander Nocton 0.95, 25mm lens, there really isn’t a lot of choice in m4/3 that allows you to have razor thin DOF.

    “But wait! What about the Panasonic 20mm f1.7. There are 5000 pages of incredible samples showing super thin DOF.” No there aren’t. If you look at most of those images the lens has been used more like a macro lens than a standard. It’s not a bad thing (and the 20mm is a fantastic lens), but any lens has a relatively shallow depth of field at 15cm from a subject. At more normal shooting distances and in daily use the aperture of 1.7 on a 20mm lens isn’t actually that thin. It’s about the same as f3.5 on a 35mm sensor. Even the Voightlander is about the same as 1.8 on a 35mm sensor. That’s pretty thin, but a $100.00 Canon 50mm has the same DOF control. Plus, unless you already own one, they’re pretty hard to find. At a thousand dollars (give or take, once taxes are paid and the lens is shipped) and totally manual, it is more than most can or are willing to spend. Until the mythical 50mm f1.4 arrives or the 12-35 f2 zoom. We need to think differently when using m4/3.

    So let’s look at the ways we can make the DOF that normal m4/3 cameras have work for us.

    It’s commonly said that DOF is a function of focal length, aperture and distance to subject. Move further away, more DOF. Stop down the aperture, more DOF. Shoot with a wider lens, more DOF. Now, this is true if the camera and the subject stay in the same positions. But I’m going to suggest that it’s the wrong way to look at DOF. Completely the wrong way.

    Flash’s Rule No1: Depth of field, at any given aperture, is identical regardless of focal length if the sensor and subject size (in the frame) are the same.

    So if you shoot a subject at f2.8 with a 17mm lens or a 45mm lens or a 200mm lens the DOF will be identical in all shots if the subject is the same size (in the frame). That, of course means you have to move your shooting position. As you move it compensates for the change in DOF that changing focal length creates. What actually changes is the angle of view of the lens and the perspective of the image. A wider lens means more background relative to the subject and a more spatial or “3D” look to the image. The longer the lens gets, the less background is included and the ”flatter” the image looks. Both of these things can be used creatively to isolate your subject from the background. But, at the same aperture DOF is the same. If you shoot close with the wide use composition and light to make the subject stand out. If using a telephoto lens use colour and tone to isolate your subject. Neither of these require razor thin DOF.

    Flash’s Rule No2: Focus on the strengths of a system rather than fretting over its weaknesses.

    Let’s face it. If we could all get a 10x8, autofocus, 20x zoom at f.10 for $50.00 we’d all have one. And 99% of all photos taken, would still be aesthetically rubbish. It doesn’t exist. It never will. Move on.

    While a m4/3 camera may not have the ability to limit DOF like 35mm of medium format, they don’t have the ability to maximise DOF like m4/3 does. Sure the Canon 50mm 1.8 has shallower DOF than the Panasonic 20mm, but for taking group shots in low light the Panny wins hands down. It allows you to have more DOF at higher shutter speeds than the Canon. In this case the Canon lens may have too little DOF to get all the members of a group in sharp focus. Or landscapes in low light. The m4/3 system allows more DOF with the same shutter speed. Or the same DOF with a higher shutter speed or lower ISO. Front to back sharp focus? Easy on a m4/3 system. So maybe you should look for subjects and situations where m43 shows its strengths and let the others go by.

    One other thing that m4/3 does better than any other system? Adapted lenses. There are dozens, no hundreds of great manual focus lenses out there that are cheap and work perfectly on m 4/3 with a $20.00 adaptor. Or for a lot more money some of the full sized 4/3 lenses will even AF for you. I have the Pannasonic/Leica 25mm 1.4. That’s a very usable 50mm 2.8 equivalent (35mm). And a wonderful lens in many other ways. I have the Panny 20mm 1.7, but the 4/3 25mm is just better.

    Adapted lenses also include all lenses made for Leica cameras. Want a 50mm 1.1 for under a grand, new? No problems. Check out some of the Voightlander lenses available for Leica bodies as well as the used Leica market. Why not splash out $10,000 on the Leica 50mm f0.95? It will fit perfectly on your EPL2. Stupid? Maybe. But the point is that m4/3 is the most flexible camera system in the world at the moment. And manual focus and exposure is not that hard once you practice a bit.

    Flash’s Rule No3: Good lighting and composition trump shallow depth of field every time.

    I’m not going to mince words here. if you can’t get good subject to background context without having to resort to blurred backgrounds in ever shot, then you have bigger issues than the gear you own or the m4/3 format. Concentrate on what you’re doing and what you’re trying to achieve and then eliminate everything that doesn’t fit into that vision. Photographers are compared to painters, which is wrong. We’re more like sculptors. Painters start with nothing and add what they want. Sculptors start with everything and eliminate what they don’t want. That’s what we do. We start with everything in front of us and then choose the lens (angle of view) subject distance (perspective and subject size) and aperture (DOF) that we want to show. Everything else goes. If your backgrounds are messy or interfering with your subject, change your position or change lenses. Eliminate the distractions. Black and White photographers get this. They eliminate the distraction of colour to concentrate on form and tone.

    Try this. Go out and take 20 portraits at f11. Use clean backgrounds or long lenses. Blue sky, white walls. Have fun. But always look at what you’re putting your subject in front of.

    Flash’s rule No4: Photoshop is not evil.

    Sometimes, no lens is shallow enough. Sometimes you can’t change shooting position, or your long lens is in for repair. Now I know there are lots of purists out there, but come on people. It’s the 21st century. There’s nothing wrong with using the available tools to enhance your vision. If you’re reporting a factual event that’s one thing. If you’re trying to convey an emotion, that’s another. If you think that even 50 years ago photos weren’t manipulated, you’re wrong. The whole zone system is based on manipulating exposure, processing and printing to achieve a specific outcome. Even composition manipulates how an image makes us feel. You can buy a lens that vignettes or do it in photoshop. Shoot it in colour and convert to black and white later. Or you can use Photoshop or plugins like OnOne’s Focal Point to create DOF effects in a computer workflow. I understand that there’s a lot of enjoyment in the challenge in getting it right in camera, but it’s not the only way.

    I hope that this has given you an idea about how to make the most of DOF using the m4/3 system and maybe opened you up to a few new ideas you might want to try.

    Regards

    Gordon
     
    • Like Like x 42
  2. bilzmale

    bilzmale Mu-43 All-Pro

    Nicely put and food for thought.
     
  3. jiroumi

    jiroumi Mu-43 Rookie

    19
    Apr 12, 2011
    Thank you for the insightful post! That helped me understand a lot more about this beast especially in relation to m4/3! :)
     
  4. soundimageplus

    soundimageplus Mu-43 Top Veteran

    782
    Feb 2, 2010
    Worcestershire
    Great stuff. And as someone who likes m4/3 for the fact that it gives me "more DOF" in most situations, I can still appreciate what you are saying. There's a good few people who write about this who I'd love to sit down in detention and make them write out your "rules" for 2 hours until they sink in.
     
    • Like Like x 2
  5. Pan Korop

    Pan Korop Mu-43 Veteran

    479
    Mar 31, 2011
    Phare Ouest
    Mostly agreed, and how well put!

    The DOF issue relative to reproduction ratio, totally right, even if stating it, you're bound to quite an argument with many a "working pro". I usually give up; besides, colleagues are competitors after all, so why bother :rolleyes:

    However, DOF rules don't account for how much the background is blurred. I do agree that good contrast--color, brightness, texture--between subject and back(or fore)ground may bring forward the scene as well or better as shallow DOF.

    Btw, I recently posted something here to show that slow shutter speed while panning (to blur the background) achieves the same on steadily moving subjects, and can be achieved with slow lenses just as well: when you want 1/125s every lens is fast enough.

    However, one thing that many photographers (usually from sports background but not only) know is that ultra-shallow DOF gives the illusion that the shot is sharper than it is. It's the edge contrast between adequately sharp and washed out surrounding which does the trick.

    Hence the shockwave of the 35mm 300/2.8mm appearance in the late 70's. They looked so sharp esp. at wide apertures! And the results SOLD better. Being a pro is making a living, so it mattered. Also, you have to do with whatever surroundings you have, and where some umpires or blue blazers decided the photogs' ghetto should be.

    I'll only ad that one bigger problem with mu43 than large DOF is the VF freeze when you click. Makes panning way more difficult than with a pro-grade SLR. Or to guess if the model winked. I guess the issue will be solved in time...
     
    • Like Like x 1
  6. Narnian

    Narnian Nobody in particular ...

    Aug 6, 2010
    Midlothian, VA
    Richard Elliott
    Maybe it should be Photoshop is EVIL? :wink:
     
  7. ZephyrZ33

    ZephyrZ33 Mu-43 Top Veteran

    685
    Nov 18, 2010
    Southern California
    After being on a long hiatus from these forums, that brief read was a welcomed return.

    Thank you sir.
     
  8. Amin Sabet

    Amin Sabet Administrator

    Apr 10, 2009
    Boston, MA (USA)
    Great post, Gordon. It's all too easy to obsess about the limitations of any gear.
     
  9. Ulfric M Douglas

    Ulfric M Douglas Mu-43 Hall of Famer

    Mar 6, 2010
    Northumberland
    Gordon, this section can me read and misunderstood very easily ;
    If you amend "subject size" to "size of subject in the frame" then you've got a better section.
     
    • Like Like x 2
  10. Pan Korop

    Pan Korop Mu-43 Veteran

    479
    Mar 31, 2011
    Phare Ouest
    Quite.

    Or more precisely : Depth of field, at any given aperture and reproduction ratio, is identical regardless of focal length

    For beginners, reproduction ratio, is "image size" (on the sensor or film) / "subject size".
     
  11. MichaelShea

    MichaelShea Mu-43 Regular

    108
    Jan 27, 2011
    Algarve, Portugal
    FocalPoint has all the subtlety of a sledgehammer. The lens blur filter in CS5 appears far more natural and is easier to control.
     
  12. flash

    flash Mu-43 Hall of Famer

    Apr 29, 2010
    1 hour from Sydney Australia.
    Gordon
    point taken. I've made an amendment.

    Gordon
     
    • Like Like x 1
  13. flash

    flash Mu-43 Hall of Famer

    Apr 29, 2010
    1 hour from Sydney Australia.
    Gordon
    If you have the need to translate terminology for beginners, it kind of defeats the point, as you've made it more difficult for people to get the message. When I'm teaching photographic students, I prefer to stay away from any term that needs too much clarification. There are plenty of technical manuals out there. This was not supposed to be one of them.

    However I do appreciate that precision is important for more advanced shooters.

    Regards

    Gordon
     
    • Like Like x 2
  14. flash

    flash Mu-43 Hall of Famer

    Apr 29, 2010
    1 hour from Sydney Australia.
    Gordon
    I like FocalPoint. YMMV. Sometimes a sledgehammer is exactly the tool required. I can get complex and subtle effects from Focal Point when I need them.

    Anyway, it was only one example that I have first hand knowledge of (unlike say "Bokeh" by Alien Skin which I'm told is great. but I don't have it). I'm sure there are hundreds of tools available.

    Gordon
     
    • Like Like x 1
  15. flash

    flash Mu-43 Hall of Famer

    Apr 29, 2010
    1 hour from Sydney Australia.
    Gordon
    Ha. My camera is Evil.:biggrin: Sometimes I wonder whether Photoshop is out to get me though.:smile:
     
  16. iliakoltsov

    iliakoltsov Mu-43 Regular

    195
    Aug 7, 2010
    Paris
    So if you shoot a subject at f2.8 with a 17mm lens or a 45mm lens or a 200mm lens the DOF will be identical in all shots if the subject is the same size (in the frame)

    may reword it in an understandable way :

    The depth of field is affected by the aperture and the focal length, provided that the image on your frame is the same ( hence you moving out) the DOF should be the same.


    But if you take the picture from the same place you will notice that with a longer lens you end up with a shallower depth of field it is mathematics.

    A longer lense involve a tinier angle , where i do not especially agree, when you say that it flattens the image from my own experience only some lenses do , I believe it is not related to the depth of field or angle of view but rather to the optic itself, one of the best example Tamron SP 70-210 lens that gives you almost 3D rendering if you step it down. Where on the other hand i agree is that to create a longer lens that has such a 3D effect is much harder, hence obviously to some extent i do agree with flash gordon :D

    Also what you forget to mention is that part of the effect of the DOF being doubled is cancelled by the multplication of the focal length.
     
  17. Amin Sabet

    Amin Sabet Administrator

    Apr 10, 2009
    Boston, MA (USA)
    Ilia, Flash and you mean two different things by "flattening". He is talking about perspective, and you are talking about 3D effect.
     
    • Like Like x 1
  18. OPSSam

    OPSSam Mu-43 Regular

    134
    Dec 18, 2010
    NC
    The short version, found on many photo tips and resource pages:

    Depth-of-field is influenced by three things:

    1) Aperture - A small aperture (such as f/16) results in a relatively greater depth-of-field than a large aperture (such as f/4).

    2) Lens focal length - A lens with a short focal length (such as 24mm) has a relatively greater depth-of-field than a lens with a long focal length (such as 200mm) when taking a photograph of a subject from the same location.

    3) Subject distance - When focused on a subject close to the camera, the depth-of-field will be smaller than when focused on a subject further from the camera.

    If you have an average point & shoot and you can't control #1, you can always control the other two depending on the situation and the camera in hand. It's about working around the limitations of your gear.
     
  19. iliakoltsov

    iliakoltsov Mu-43 Regular

    195
    Aug 7, 2010
    Paris
    Photoshop is not an evil , well it is a necessary evil , lets put it this way you like coffee with sugar , but too much sugar will ruin the coffee and if you do not put any sugar the taste will not be right either.

    I follow the policy of the less i use photoshop the better.

    NO electronic processing will make the depth of field as real as if it was made by a lens, especially when sometimes the bokeh on some lenses is very specific. If i cannot take a picture i just say tough it was not my day, In fact the only thing i do generally wb and contrast on most of my pictures.

    Amin concerning the perspective sure the angle of view will reduce it , hence you do have wide angle for landscape and tele for long reach. Different lens behave differently. The lower the angle of view is the closer the arc will be to a line that is mathematics where eventually it becomes a line when you have no angle of view.
     
  20. flash

    flash Mu-43 Hall of Famer

    Apr 29, 2010
    1 hour from Sydney Australia.
    Gordon
    You'll also end up with a different subject size, in the frame. This makes the image fundamentally different. By deciding on subject size aperture and focal length based on how much background you will make more intelligent choices in image composition, rather than standing in a single spot and racking your zoom lens back and forward, wondering why the image doesn't resemble your vision.

    The point was to get people to work out that a telephoto lens doesn't have "real world" shallower depth of field, just because it's a tele. A 1.4 has shallower depth of field than a 2.8 regardless of focal length. You just need may need to move closer toward your subject.

    Gordon