“Not enough contrast, could be sharper!”


Hi Folks,

At the recent Northern Ireland Photographic Association (NIPA) ‘Beginners Competition’ the feedback on images that were not selected for shortlisting were:

“Not enough contrast”

“Not sharp”

When we show members photos up on the big screen and ask for and offer feedback, one of the most often tweaks made in Faststone Image viewer is to increase the contrast. This is simply done with a slider and almost everyone agrees that simply adding some more contrast really improves many an image.

Sharpness, on the other hand, is completely different! It reminds me of the Irishism of a tourist asking the local guy for directions – and is told, “Well if I was going there, I wouldn’t have started from here!”

You may not realise it, but sharpness is actually all about increasing the contrast of edges! I bet that has got you thinking

So where do we start? I can think of a number of starting points: the first being buy a tripod and use it. Learn how to use the self timer or wireless trigger with mirror up. Find out what is the sweet spot of your lens, in many cases it’s f/8 or f/11.

The second starting point; for hand held photography, is the basic knowledge of what I call the ‘holy trinity’ – of speed, aperture and ISO. Every photography must know this!

Briefly; this is the knowledge, gained from practice and experience, of what speed and at what focal length you can hand-hold your camera and still get a sharp image. This will change from lens to lens. Lenses with image stabilisation really do offer two stops leeway. On my 18-200 stabilised lens I know I can get away with, or go as low as 1/15s at 18mm and 1/125 at 200mm for a landscape with nothing moving in my frame. But I have practised this, often braced against something. Clearly; if something is moving in the frame and you want to get it sharp, you will have to up your speed accordingly. This is were the basic understanding of the ‘holy trinity’ comes in; knowing when and how to open up your lens, or increase the ISO, or both, to get the speed you need.

The third starting point, which comes after one and two above being properly applied, is taking the image in raw. If you don’t know how to sharpen a raw image properly for the desired end product, print or screen, then you might be better off taking in raw and jpg. The jpg will be sharpened in camera, the raw isn’t.

In our camera club we often advise new members to take in their photos in raw, as it allows so much more leeway in post production. But I suspect that, while this is true, many new members to photography and especially members new to computers may not have the knowledge, skills or experience to sharpen a raw image. So perhaps we should be advising them to take raw and jpg? Work on the already sharpened jpg and in years to come, when they have more experience and as the software improves and makes things easier, they can always re visit the raw file. I have often revisited my raw files and I know many other camera club members do the same.

Unsharp Mask (USM) is complex and for a novice, easily overdone. The Digital Photo type magazines often offer a step by step guide, saying apply a ‘Unsharp Mask of x.x.x’, but don’t explain why these settings work for one image and a different set of USM works for another. There are books written on this subject! However, products like Lightroom, offer sliders to adjust ‘vibrance’ (USM) and ‘structure’ (High Pass) to make things easier. These adjust the edge contrast, either in mid tones or globally.

For example: the raw image will need what is known as ‘capture sharpening’. ‘Lightroom’ can identify your camera make, sensor and lens and do a really good job of initial ‘capture sharpening’ and lens alignment, globally. ‘Dxo’ and ‘Capture One’ can do the do the same, sort of automatically, but also globally. I use Capture NX and have a batch process, or .set file that allows me to apply ‘capture sharpening’ based on what type of Nikon camera I am using. However, with CNX I can apply the ‘capture sharpening’ selectively

Within an image you may have areas that may require a different approach. Do you want to sharpen fine texture or coarse texture? Different raidi within the USM, that really needs to be applied selectively, rather than globally. Or perhaps using a ‘high pass’ instead, or in support to USM? This were Lightroom, the adjustment brush and ‘vibrance’ and ‘structure’ come in. (I don’t use Lightroom, but I know many of you do, and so I thought I should give it a plug, rather than go on about Capture NX )

Finally; for now, from raw you have to consider where the image is going. There are different approaches to sharpening for glossy paper, compared to matte paper (matte paper absorbs more ink) and a yet another different approach for web or projected image.

Food for thought? The difficulty is, of course, that everyone uses different software! As always, feedback is most welcome!

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