Self-control with depth-of-field

Too shallow depth of field - Jim Harmer's mistake

I get it.  Depth of field is fun to play with and makes our pictures look amazing, but I'm here to say that more of a good thing is not always better.

Look at the image featured on this page of my beautiful wife, Emily.  The depth-of-field adds to this image to make her stand off the page; however, this image suffers from too shallow depth of field.  The depth of field was only about two inches in this picture because I used an aperture of f/1.8, a 50mm lens, and I was only two or three feet away from the subject.  You can see that part of her face is out of the plane of focus, and that is a bit distracting.  What I really wanted was to make her completely in focus and just blur out the background.  You might not be able to tell this on the small preview of the image, but it's obvious if you click to make it big.  This post is for those of you who always crank the aperture down to the lowest number available.

Controlling depth of field tip #1: Remember that aperture is not the only factor that controls depth of field.  If you are physically close to your subject and are using a long lens, this will drastically decrease the depth of field.  Remembering this will be a reminder that you might have to use a slightly higher aperture in this situation so that the depth of field isn't too shallow.

Controlling depth of field tip #2: Don't let depth of field look like a mistake.  We all know you didn't INTENTIONALLY blur part of the face.  It was an accident.  Show enough care for your photos to watch out for these mistakes.

Controlling depth of field tip #3: Carefully monitor the hairs that often stick up toward the back of someone's head.  This is one of the easiest ways to tell if your depth of field is too shallow.  Look on the LCD at the hairs toward the top of the head to see if they are in sharp focus.

Controlling depth of field tip #4: Zoom in to 100% on your LCD.  If you aren't sure if the depth of field is too shallow on a portrait, zoom all the way in on a photo you've just taken and check problem areas like the nose, hairs on the top of the head, etc.

Controlling depth of field tip #5: If you want the background to be extremely blurry while still getting the entire model in perfectly sharp focus, just have the model take a few steps forward.  Separation between the model and the background will make that background appear much creamier.

Have you noticed this problem in your own photos?  Does this even matter?  Sound off in a comment below.  I'd love to know your thoughts.

8 thoughts on “Self-control with depth-of-field”

  1. Yes I have this problem more than I care to admit. Not so much when shooting portraits, but way to many times when working with my macro lens. I never seem to get it quite right when shooting flowers.

  2. When I first got my 50mm, I shot in f1.8 all the time. It’s a nasty habit. But after I learned to use manual mode, I got it straightened out.

  3. Wanting to purchase an f1.8 lense, but not sure whether to get a 50 mm or 80 mm.
    Mostly taking pictures of my children- no landscapes.

    1. I see your comment is from 4 years ago so you probably chose your lens by now…. but for anyone else who reads this:

      I’m only a beginner, but the field of view a lens gives will be affected by the sensor size of your camera. On a full frame sensor camera (e.g. Nikon’s FX range), the field of view from any lens will be greater (i.e. more zoomed out) than the field of view you get with the same lens on a crop sensor camera.

      If the crop factor is 1.5 (e.g. Nikon’s DX range), then you need a 50mm lens to achieve the same field of view as that given by a 75mm lens on a full frame camera.

      You multiply the focal length by the crop factor if you are using a crop sensor and want to know what the equivalent on full frame would be.

      So 50mm on a full frame will look almost the same as 80mm on a DX.

      1. “So 50mm on a full frame will look almost the same as 80mm on a DX.”


        other way round…. 80mm on a full frame will look almost the same as 50mm on a DX…. confusing subject isn’t it!!

  4. Very helpful, thanks for this.

    I’ve just started out using a DSLR & am attempting to become more familiar with DOF and making choices re distance-to-subject, f-stop and focal length.

    Found your web page post very relevant as I’d just shot a head & shoulders image at f1.8 and seen the same issue – my subject’s face is only partly in focus. I had chosen f1.8 for maximum background blur, without realising just how shallow DOF is at f1.8.

    I realise that the focus point is a plane, and everything in front or behind will be out of focus by increasing amounts the further away you get from the focal plane, but that there is a field within which things are acceptably in focus. But I hadn’t realised just how shallow that field can be at f1.8.

    I downloaded an app to calculate DOF.

    On a DX sized sensor, using a 50mm lens at f1.8, if your subject is 1 metre away then according to this app DOF is only 2.5cm. I didn’t realise just how shallow DOF would be with these lens and aperture choices.

    According to this app, if I want a DOF of around 24cms (potentially enough for the person’s entire face and head to be in focus), and I want to use f1.8, then with a 50mm lens they need to be 3 metres away – in which case, it will no longer be a head and shoulders only shot, even on a DX rather than FX camera.

    Doubling the focal length to 100mm, the subject would then need to be 6 metres away to achieve around 24cms of DOF.

    So it seems there is no way to get approximately 24cms of acceptable depth of field at f1.8 with just a head & shoulders shot? You need to move away from your subject to get that kind of DOF, meaning that far more of them will fill the frame. And if you then zoom in so their head and shoulders fill the frame, then you need to move back even further to still achieve the same 24cms DOF, because of the way DOF reduces as focal length increases.

    But I guess the advantage to moving away from your subject and zooming in on them is that at least the background will get magnified, meaning it will be more blurred.

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