“Soft” and “sharp” photos

Christmas decorations, photo taken with f/1.2, 50mm lens.

As holidays are traditionally time to be lazy and just rest, I have not undertaken any major photography projects either. One thing that I have been wondering though, has been the distinction between “soft” and “sharp” photos. There are actually many things intermingling here. In old times, the lenses I used were not capable of delivering optically sharp images, and due to long exposure times, unsensitive film (later: sensors), the images were also often blurry: I had not got the subject in focus and/or there was blur caused by movement (of target and/or the camera shaking). Sometimes the blurry outcomes were visually or artistically interesting, but this was mostly due to pure luck, rather than any skill and planning.

Later, it became feasible to get images that were technically controlled and good-looking according to the standard measurements of image quality. Particularly the smartphone photos have changed the situation in major ways. It should be noted that the small sensor and small lenses in early mobile phone cameras did not even need to have any sort of focus mechanisms – they were called ‘hyperfocal lenses’, meaning that everything from very close distance to infinity would always be “in focus” (at least theoretically). As long as you’d have enough light and not too much movement in the image, you would get “sharp” photos.

Non-optimal “soft” photo: a mobile phone (iPhone) photo, taken with 10x “digital zoom”, which is actually just a cropped detail from the image optically created in the small sensor.

However, sharpness in this sense is not always what a photographer wants. Yes, you might want to have your main subject to be sharp (have a lot of details, and be in perfect focus), but if everything in the image background shows such detail and focus as well, that might be distracting, and aesthetically displeasing.

Thus, the expensive professional cameras and lenses (full frame bodies, and “fast”, wide-aperture lenses) are actually particularly good in producing “soft” rather than “sharp” images. Or, to put it slightly better, they will provide the photographer larger creative space: those systems can be used to produce both sharp and soft looking effects, and the photographer has better control on where both will appear in the image. The smartphone manufacturers have also added algorithmic techniques that are used to make the uniformly-sharp mobile photos softer, or blurry, in selected areas (typically e.g. in the background areas of portrait photos).

Sharpness in photos is both a question of information, and how it is visually expressed. For example, a camera with very low resolution sensor cannot be used to produce large, sharp images, as there is not enough information to start with. A small-size version of the same photo might look acceptably sharp, though. On the other hand, a camera with massively high-resolution sensor does not automatically procude sharp looking images. There are multiple other factors in play, and the visual acuity and contrast are perhaps the most crucial ones. The ray of light that comes through the lens and falls on the sensor produces what is called a “circle of confusion”, and a single spot of the subject should ideally be focused on so small spot in the sensor that it would look like a nice, sharp spot also in the finished image (note that this is also dependent on the visual acuity, the eyes of the person looking at it – meaning that discussions of “sharpness” are also in certain ways always subjective). Good quality optics have little diffraction effects that would optically produce visual blur to the photo.

Daytime photo of naakka (jackdaw) in winter, taken with a 600mm telephoto lens (SIGMA), f/7.1, exposure 1/400 seconds, ISO value at 6400 – with some EOS 550D body/sensor’s visual noise removed in postproduction at Lightroom. Note how the sharp subject is isolated with the blurry bacground even with the f/7+ aperture value, courtesy of long focal-range optics.

Similarly, the sharp and soft images may be affected by “visual noise”, which generally is created in the image sensor. In film days, the “grain” of photography was due to the actual small grains of the photosensitive particles that were used to capture the light and dark areas in the image. There were “low ISO” (less light-sensitive) film materials that had very fine-grained particles, and “high ISO” (highly light-sensitive) films that had larger and coarser particles. Thus, it was possible to take photos in low-light conditions (or e.g. with fast shutter speeds) with the sensitive film, but the downside was that there was more grain (i.e. less sharp details, and more visual noise) in the final developed and enlarged photographs. The same physical principles apply also today, in the case of photosensitive, semiconductive camera sensors: when the amplification of light signal is boosted, the ISO values go up, faster shots or images in darker conditions can be captured, but there will be more visual noise in the finished photos. Thus, the perfectly sharp, noise-free image cannot always be achieved.

But like many photographers seek for the soft “bokeh” effect into the backgrounds (or foregrounds) of their carefully composed photos, some photographers do not shy away from the grainy effects of visual noise, or high ISO values. Similar to the control of sharpness and softness in focus, the use of grain is also a question of control and planning: if all and everything one can produce has noise and grain, there is no real creative choice. Understanding the limitations of photographic equipment (with a lot of training and experimentation) will eventually allow one to utilize also visual “imperfections” to achieve desired atmospheres and artistic effects.

Chocolates were shot with f/1.4 value (50mm lens) – the ‘dreamy’ look was desired here, but note how even the second piece of chocolate is already blurred, as the “zone of acceptable sharpness” (also known as the “depth of field”) is very narrow here.

There is no perfect camera

One of the frustrating parts of upgrading one’s photography tools is the realisation that there indeed is no such thing as “perfect camera”. Truly, there are many good, very good and excellent cameras, lenses and other tools for photography (some also very expensive, some more moderately priced). But none of them is perfect for everything, and will found lacking, if evaluated with criteria that they were not designed to fulfil.

This is particularly important realisation at a point when one is both considering of changing one’s style or approach to photography, at the same time while upgrading one’s equipment. While a certain combination of camera and lens does not force you to photograph certain subject matter, or only in a certain style, there are important limitations in all alternatives, which make them less suitable for some approaches and uses, than others.

For example, if the light weight and ease of combining photo taking with a hurried everyday professional and busy family life is the primary criteria, then investing heavily into serious, professional or semi-professional/enthusiast level photography gear is perhaps not so smart move. The “full frame” (i.e. classic film frame sensor size: 36 x 24 mm) cameras that most professionals use are indeed excellent in capturing a lot of light and details – but these high-resolution camera bodies need to be combined with larger lenses that tend to be much more heavy (and expensive) than some alternatives.

On the other hand, a good smartphone camera might be the optimal solution for many people whose life context only allows taking photos in the middle of everything else – multitasking, or while moving from point A to point B. (E.g. the excellent Huawei P30 Pro is built around a small but high definition 1/1.7″ sized “SuperSensing”, 40 Mp main sensor.)

Another “generalist option” used to be so-called compact cameras, or point-and-shoot cameras, which are in pocket camera category by size. However, these cameras have pretty much lost the competition to smartphones, and there are rather minor advances that can be gained by upgrading from a really good modern smartphone camera to a upscale, 1-inch sensor compact camera, for example. While the lens and sensor of the best of such cameras are indeed better than those in smartphones, the led screens of pocket cameras cannot compete with the 6-inch OLED multitouch displays and UIs of top-of-the-line smartphones. It is much easier to compose interesting photos with these smartphones, and they also come with endless supply of interesting editing tools (apps) that can be installed and used for any need. The capabilities of pocket cameras are much more limited in such areas.

There is an interesting exception among the fixed lens cameras, however, that are still alive and kicking, and that is the “bridge camera” category. These are typically larger cameras that look and behave much like an interchangeable-lens system cameras, but have their single lens permanently attached into the camera. The sensor size in these cameras has traditionally been small, 1/1.7″ or even 1/2.3″ size. The small sensor size, however, allows manufacturers to build exceptionally versatile zoom lenses, that still translate into manageable sized cameras. A good example is the Nikon Coolpix P1000, which has 1/2.3″ sensor coupled with 125x optical zoom – that is, it provides similar field of view as a 24–3000 mm zoom lens would have in a full frame camera (physically P1000’s lenses have a 4.3–539 mm focal length). As a 300 mm is already considered a solid telephoto range, a 3000 mm field of view is insane – it is a telescope, rather than a regular camera lens. You need a tripod for shooting with that lens, and even with image stabilisation it must be difficult to keep any object that far in the shaking frame and compose decent shots. A small sensor and extreme lens system means that the image quality is not very high: according to reviews, particularly in low light conditions the small sensor size and “slow” (small aperture) lens of P1000 translates into noisy images that lack detail. But, to be fair, it is impossible to find a full frame equivalent system that would have a similar focal range (unless one combines a full frame camera body with a real telescope, I guess). This is something that you can use to shoot the craters in the Moon.

A compromise that many hobbyists are using, is getting a system camera body with an “APS-C” (in Canon: 22.2 x 14.8 mm) or “Four-Thirds” (17.3 × 13 mm) sized sensors. These also cannot gather as much light as a full frame cameras do, and thus also will have more noise at low-light conditions, plus their lenses cannot operate as well in large apertures, which translate to relative inability to achieve shallow “depth of field” – which is something that is desirable e.g. in some portrait photography situations. Also, sports and animal photographers need camera-lens combinations that are “fast”, meaning that even in low-light conditions one can take photos that show the fast-moving subject matter in focus and as sharp. The APS-C and Four-Thirds cameras are “good enough” compromises for many hobbyists, since particularly with the impressive progress that has been made in e.g. noise reduction and in automatic focus technologies, it is possible to produce photos with these camera-lens systems that are “good enough” for most purposes. And this can be achieved by equipment that is still relatively compact in size, light-weight, and (importantly), the price of lenses in APS-C and Four-Thirds camera systems is much lower than top-of-the-line professional lenses manufactured and sold to demanding professionals.

A point of comparison: a full-frame compatible 300 mm telephoto Canon lens that is meant for professionals (meaning that is has very solid construction, on top of glass elements that are designed to produce very sharp and bright images with large aperture values) is priced close to 7000 euros (check out “Canon EF 300mm f/2.8 L IS II USM”). In comparison, and from completely other end of options, one can find a much more versatile telephoto zoom lens for APS-C camera, with 70-300 mm focal range, which has price under 200 euros (check our e.g. “Sigma EOS 70-300mm f/4-5.6 DG”). But the f-values here already tell that this lens is much “slower” (that is, it cannot achieve large aperture/small f-values, and therefore will not operate as nicely in low-light conditions – translating also to longer exposure times and/or necessity to use higher ISO settings, which add noise to the image).

But: what is important to notice is that the f-value is not the whole story about the optical and quality characteristics of lenses. And even if one is after that “professional looking” shallow depth of field (and wants to have a nice blurry background “boukeh” effect), it can be achieved with multiple techniques, including shooting with a longer focal range lens (telephoto focal ranges come with more shallow depth of fields) – or even using a smartphone that can apply the subject separation and blur effects with the help of algorithms (your mileage may vary).

And all this discussion has not yet touched the aesthetics. The “commercial / professional” photo aesthetics often dominate the discussion, but there are actually interesting artistic goals that might be achieved by using small-sensor cameras better, than with a full-frame. Some like to create images that are sharp from near to long distance, and smaller sensors suit perfectly for that. Also, there might be artistic reasons for hunting particular “grainy” qualities rather than the common, overly smooth aesthetics. A small sensor camera, or a smartphone might be a good tool for those situations.

One must also think that what is the use situation one is aiming at. In many cases it is no help owning a heavy system camera: if it is always left home, it will not be taking pictures. If the sheer size of the camera attracts attention, or confuses the people you were hoping to feature in the photos, it is no good for you.

Thus, there is no perfect camera that would suit all needs and all opportunities. The hard fact is that if one is planning to shoot “all kinds of images, in all kinds of situations”, then it is very difficult to say what kind of camera and lens are needed – for curious, experimental and exploring photographers it might be pretty impossible to make the “right choice” regarding the tools that would truly be useful for them. Every system will certainly facilitate many options, but every choice inevitably also removes some options from one’s repertoire.

One concrete way forward is of course budget. It is relatively easier with small budget to make advances in photographing mostly landscapes and still-life objects, as a smartphone or e.g. an entry-level APS-C system camera with a rather cheap lens can provide good enough tools for that. However, getting into photography of fast-moving subjects, children, animals – or fast-moving insects (butterflies) or birds, then some dedicated telephoto or macro capabilities are needed, and particularly if these topics are combined with low-light situations, or desire to have really sharp images that have minimal noise, then things can easily get expensive and/or the system becomes really cumbersome to operate and carry around. Professionals use this kinds of heavy and expensive equipment – and are paid to do so. Is it one’s idea of fun and good time as a hobbyist photographer to do similar things? It might be – or not, for some.

Personally, I still need to make up my mind where to go next in my decades-long photography journey. The more pro-style, full-frame world certainly has its certain interesting options, and new generation of mirrorless full-frame cameras are also bit more compact than the older generations of DSLR cameras. However, it is impossible to get away from the laws of physics and optics, and really “capable” full frame lenses tend to be large, heavy and expensive. The style of photography that is based on a selection of high-quality “prime” lenses (as contrasted to zooms) also means that almost every time one changes from taking photos of the landscape to some detail, or close-up/macro subject, one must also physically remove and change those lenses. For a systematic and goal oriented photographer that is not a problem, but I know my own style already, and I tend to be much more opportunistic: looking around, and jumping from subject and style to another all the time.

One needs to make some kinds of compromises. One option that I have been considering recently is that rather than stepping “up” from my current entry level Canon APS-C system, I could also go the other way. There is the interesting Sony bridge camera, Sony RX10 IV, which has a modern 1″ sensor and image processor that enables very fast, 315-point phase-detection autofocus system. The lens in this camera is the most interesting part, though: it is sharp, 24-600mm equivalent F2.4-4 zoom lens designed by Zeiss. This is a rather big camera, though, so like a system cameras, this is nothing you can put into your pocket and carry around daily. In use, if chosen, it would complement the wide-angle and street photography that I would be still doing with my smartphone cameras. This would be a camera that would be dedicated to those telephoto situations in particular. The UI is not perfect, and the touch screen implementation in particular is a bit clumsy. But the autofocus behaviour, and quality of images it creates in bright to medium light conditions is simply excellent. The 1″ sensor cannot compete with full frame systems in low-light conditions, though. There might be some interesting new generation mirrorless camera bodies and lenses coming out this year, which might change the camera landscape in somewhat interesting ways. So: the jury is still out!

Some links for further reading: