Sharpening
Paul Malley • 18 April 2022
SHARPENING
A few Blog entries back, I submitted a short piece of work regarding my use of 'Auto-ISO' which, I'm pleased to say, generated some interest and subsequent discussion at the Clubhouse. In a bid to keep alternative thoughts and views going, this time I'm including a section on my preferred method of Sharpening images (lights blue touch-paper and steps back...), - please note I said "my preferred method" as, not only are there a number of ways of sharpening an image, but it is one of the most 'Subjective' issues when concluding a workflow process.
Many DSLR units are fitted with an anti-aliasing filter in the sensor path, which counter affects the moiré patterning, or coloured cross parallax of some light wavelengths. Anything placed in front of the sensor, can optically reduce the efficiency of the light path so, to overcome this, a degree of sharpening of an image is required, to reinstate any corrective action. Newer DSLR and Mirrorless units do not all have this anti-aliasing filter, but sharpening is still applied within the workflow.
Sharpening works by producing a better defined line (NOT the same as contrast) at boundary edges, (in the good old wet darkroom, this was termed Acutance). The degree and method of sharpening as stated, is hugely subjective as, applied to the wrong style of image, or at the wrong focal viewpoint, or in too greater strength can be detrimental. I have seen the evolving of sharpening within 'Photoshop Elements' since about 2008, where it was issued as a simple one-click function under the 'Enhance' Tab as 'auto-sharpen'. This was a quick one-stop pass that applied sharpening via an algorithm which, although hit and miss at times, gave a somewhat credible change. In subsequent versions, it became more refined, and sliders were introduced, offering control into variable levels of overall sharpness. About 10yrs ago, a huge step-change came in whereby the edge radius and strength could be altered to suit, offering 0.1 pixel units. Nowadays, sharpening can be done on separate layers, combined with clarity, contrast and split down within different layers, even identifying selective target areas to sharpen, before they are all merged down like layers in a sandwich.
For me, in my current Affinity Photo Software, I use a 3-stage sharpening process (Please note there are differences at the final stage for presentation in Print format, or display as a PDI). I conduct each stage in isolation, and it is done as the final part of my jpeg workflow process before I save the image.
Stage 1. This is a PRE-SHARPEN action, where the minimal radius and strength factor are applied to the overall image via the strangely termed 'Unsharp Mask' (each part of the image gets the same sharpening factor in one operation).
Stage 2. This is CREATIVE or SELECTIVE Sharpening, where I can select/identify what part of the image I wish to enhance beyond Stage 1. It may be the model's eyes, a tree in a landscape, or a head-on motorcycle fairing. In this stage, using a New Layer, selecting a brush, I work round the item and check it is bounded by the infamous 'marching ants'. Once identified a second pass is given using the same as in Stage 1. Once completed, a simple deselect of the marching ants shows the added 'pop' of the detail within the selected area. I then Merge/Flatten the Layers into one.
Stage 3. The final action is termed OUTPUT Sharpening. For me, working in PDI, I resize the document to the longest 1920 x 1200 format and apply a final overall sharpen in Unsharp Mask at a low output. This third and final stage can be dramatic as it is at the output for a good projected resolution.
If all has worked well, the image should have a nice, overall sharpness courtesy of stages 1 and 3 and the main point which the viewer may concentrate or gravitate to should have that extra pop, courtesy of Stage 2.
As a small aside, I remove my Noise during RAW conversion, as you don't want to be working on a noise image, either by creating Layers and putting Noise on top of Noise, or sharpening Noise at three separate stages. Noise can also have the effect of apparent sharpness reduction, - so get rid of it early.
Be wary of over sharpening, it can lead to artefacts, jagged edges or fringing, in worse cases it can also promote haloing or banding separation. Sometimes, less is more and I usually 'back-off a bit' on my final sharpening, rather than push a sharpening boundary.
Have a try with small amounts of sharpening, on different Layers (always on a working copy file, not the original primary jpeg) and pick something out that you want the viewer to look at. I have done my 3-Stage approach on this image of the Kingfisher, with selective sharpening applied to the head and leading edge of the wing.
Louth Photographic Society
We had a really good turn out for the visit to Rimac last night and the weather was fantastic for taking wildlife photographs. There was plenty to photograph from moths and butterflies to many different birds, there were also plenty of wildflowers as well. I think we all took plenty of photographs so the competitions should have plenty of entries this year. We spent just over two hours photographing and walking round then some of us visited the Prussian Queen in Saltfleetby, where we were made to feel welcome and quenched our thirsts.
Paul Malley, a gentle, genial, giant of a man sadly passed away recently after a long illness. Paul had been a longtime member of the Louth Photographic Society, and had served in several roles, Treasurer at one time, and latterly as a stalwart active member on the Committee. Always ready with helpful knowledge, and advice, Paul was calm in a crisis, and insightful, able to understand both sides of a discussion, and suggest a compromise. An outstanding photographer, dedicated to his craft, he produced some excellent images, some of which are shared here. Rest in peace my friend, you will be much missed by Pam, family, friends, and members of the Louth Photographic Society.
Good Morning All Last week at the club we held our monthly print competition, there was a good entry of just over 40 prints and of a very good standard. Tony Gaskins won the subject, Britain's Coastline with an excellent photograph of Whitby and Dave Tuner was 1st in the Open with an excellent misty morning photograph at Buttermere. Thank you to all that entered, and all the results are on our website. This week, Wednesday 25th June, we are going to Rimac near Saltfleet, I have heard there is quite a bit of wildlife there at the moment, let's hope we are lucky. If we meet in the car park at 6.30pm and set of as a group though we usually get stretched out as we go. I have attached a map, but if you are on a corner and there is a track going towards the sea at the area shown on the map you should be ok. Regards Graham
Our print competition with the categories of “Britain's Coastline”, and “Open” was held last night. Gail Wrigg, the LPA President, was the judge for the evening, and there were some stunning prints submitted into the competition to review. The images were judged fairly, majoring on the technical imperfections of the images, depth of focus, composition, elements within an image that could have been removed, and improved cropping of an image. Gail always connects with the audience with her critique of the submitted competition entries. It's surprising how the print medium looks, and feels so different from an image viewed on a screen, just very alive, and tactile. The competition results have been updated on the Competition page of our website.
Good Morning All, I visited Welton-Le-Wold nature reserve the other evening, a bit like a small Red Hill, there were a lot more wildflowers there than Red Hill but again not many insects, it may be better in the daytime? It is only about two miles from Louth as well. Last week was the LPA battle at Scunthorpe, only Dave Turner went taking our prints with him, not a good result for Louth, 1st Grimsby 258, 2nd Scunthorpe 245 and 3rd Louth 236, quite a difference from the first round but that's LPA battles. The next round is at Cleethorpes, it would be good if a few more members could attend. It will soon be our annual dinner at the Splash, any more deposits this week please and menu choices by midnight Wednesday please, otherwise you may go hungry. This week, Wednesday 18th June, we hold our monthly print competition, with the categories of “Britain's Coastline” and “Open” there has been a good entry so should be a good night. Regards Graham
Good Morning All Last week we visited Red Hill nature reserve, a very good turnout, but the wildlife didn't seem to know we were going, it's quite worrying though the lack of any butterflies or any other insects of any sorts. Hopefully we all got some photographs before we visited the Three horseshoes at Goulceby. I did photograph an unusual caterpillar but couldn't manage to identify it? This week we are away in the LPA Battles at Scunthorpe, for anyone planning to attend it is at the Pavilion, Bramley Crescent, Bottesford DN16 35N this Wednesday 11th at 7.30pm. I don't think I will make it due to work but hopefully some members will attend. There will be no meeting at Louth this week as members will be a way at Scunthorpe. The following week, Wednesday 18th June, we are holding the monthly print competition, if you can email your titles to Dave Turner by midnight Wednesday 11th if you have not already and bring your prints in on the night by 7 pm as no one is there to collect them this week. There are still a few deposits for the meal to come in yet, but in two week's time will be ok. If you can send your menu choices to me if you are attending by midnight 0n the 18th June please, as they need typing out and sending to the Splash two weeks in advance. Well, I think that's all, Regards Graham
When you use a digital camera for the first time it’s tempting to shoot in fully “Auto” mode, however if you continue using this mode you will be missing out on the full functionality, and capability of your camera. What I would suggest is to use one of the other modes, most photographers use the semi-automatic “Aperture Priority”, denoted by the A or Av on the mode dial, this is not as daunting as it may at first sound. There are 3 variables to obtain a properly exposed photograph, aperture, the lens opening letting the light onto the camera sensor, shutter speed, a slow 1/60 sec shutter speed allows a greater amount of light to reach the sensor than 1/250 second, and ISO, which adjusts the sensitivity of the sensor to light. Using “Aperture Priority” mode (A or Av) allows the photographer to take control over the camera settings for improved photos, and greater creative control. Switch to "Aperture Priority" mode and use the dial, or touchscreen to vary the lens opening size, displayed as an "F" number in the viewfinder or rear screen. A lower F number allows a greater amount of light to reach the sensor, reducing depth of field. A higher F number increases depth of field. To put this into perspective, I like to think of the aperture values in terms of bands: – f/1.2 – f/4 for portraits, or subject isolation, with a narrow “depth of field” f/4 – f/7.1 for wildlife, and architecture photos f/7.1 – f/16 produces great landscape images with a large “depth of field” ensuring the photo is sharp from the foreground to the distant background. These aperture values are not meant to be arbitrary, but rather to provide some guidance, the “depth of field” will vary depending on the focal length of the lens, the size of the sensor, and the distance of the photographer to the subject. The ISO value can be set to Auto ISO, or fixed at a set value, if the shutter speed drops below 1/60, the image may become “soft” the ISO can be increased to raise the shutter speed, thus ensuring a sharper image. The two images of Filey crazy golf course demonstrate the advantage of choosing an “Aperture Priority” over “Auto” mode. With the camera in “Auto” mode an aperture of f/4.5 was chosen by the camera, and the foreground rock becomes soft. Selecting “Aperture Priority”, and choosing f/8, the image is now sharp from the foreground to the background.
At Red Hill nature reserve last night members had the opportunity to practice their macro skills. The evening was bright, but with a chilly wind, both of which made macro photography fairly challenging. Macro photography needs patience and a wealth of subjects, we didn’t see any butterflies, only a couple of grasshoppers, and a ladybird. In the wildflower meadow the orchids hadn’t grown fully yet, there was plenty of Birds Foot Trefoil around, I managed to get a reasonable shot of a grasshopper, and a grass seed head, which are posted on here. It was good to see so many members attending; it was a chance to get down to ground level and see the beauty of macro / close up photography.
Good Morning All Bank Holiday Monday I went to Chambers wood in search of the Marsh Fritillary, a butterfly I had never seen before, it must have been a good year for them as there were quite a lot of them about in the meadows. Last week at the club we concentrated on macro and close up photography, showing a DVD the first half which should have given us all the technical knowledge we will need for this weeks outing to Red Hill. The second half Derek demonstrated with the help of his carved owl some of the things that had been shown in the DVD. You can go to Red Hill earlier if you like but if we say meet for 6.30pm at the reserve and I have checked the website for The Three Horseshoes at Goulceby and it says it is open until 10pm, so that's refreshments sorted. Red Hill is just over 8 miles from Louth, on the Wolds near Stenigot, the nearest postcode is LN11 9UE and a map is on the Lincolnshire wildlife trust's website. I will have my phone in case you get lost, but I can't guarantee a signal out there ( 07884316994 ). To find Red Hill if you head for Goulceby from Louth by going past the top end of Hubbards Hills you should find it ok. The following week we are away at Scunthorpe for round two of the LPA battles, more info next week for members who are planning to attend. Regards Graham
At our meeting last night an instructional DVD on “Macro Photography” was shown. The DVD material was quite detailed, very interesting, with lots of facts, and figures to consider. After the break, I attempted to unpack some of that detail with a practical demonstration using my own camera, (the OM Systems OM-1) a set of extension tubes, an LED light, and an on-camera flash. There’s lots to consider when beginning with macro photography, first of which I would say is get to know your camera, being able to adjust aperture, ISO, and watching the shutter speed if shooting in Aperture Priority mode to optimise exposure, and detail. Next, lens choice, select a lens with the closest focusing distance, if you have a dedicated macro lens then use that, otherwise a set of extension tubes may bring your camera closer to your subject. Choosing a subject, and lighting the subject with a LED light, or a camera flash speedlight will yield improved results. Don’t be afraid to experiment with settings, only by continual practice will the best images in this incredible genre, that is macro photography be realised, above all have fun. We meet at Red Hill Nature Reserve, Goulceby next week, Wednesday 4th June, to hopefully capture some amazing macro photography.
