Confused?
Derek Smith • 15 July 2020
The Circle of Confusion
Confused?
We all “know” that a blurred background behind a subject is hard to obtain with a crop sensor camera, and that macro photography is easier with a micro four third sensor camera because of the “increased” depth of field. Well actually both of these statements are “fake news” often touted on YouTube, or in photographic articles.
Professor Bob Newman wrote on this topic in his Amateur Photography article 11th July 2020 entitled “The Great Leveller”.
In camera optics, a circle of confusion is an optical spot caused by a cone of light rays not coming to a perfect focus (also known as the disk of confusion, circle of indistinctness, blur circle, or blur spot). In other words, Depth of Field.
Professor Newman asserts:
“For macro photography, provided we keep the focus distance, the angle of view and aperture the same, and choose the same disc of confusion, then we’ll get the same results whatever the sensor size”
This appears to be borne out by the Wikipedia article on this subject, with the Circle of Confusion diameter limit based on d/1500 of 0.015mm (micro four thirds) to 0.029mm (full frame), and I challenge anyone to see that difference on an 8x10 print!!
I find macro photography as challenging with my Olympus micro four thirds camera, as I did with my full frame Sony A7. As an example, the Depth of Field for a 120mm lens, at f/5.6 = 0.13m on the Sony A7, and with the Olympus 60mm macro lens (2x crop factor = 120mm) at f/2.8 (2x crop factor = f/5.6) my Depth of Field = 0.14m - not much of an advantage there then!!
In conclusion sensor size should not be the determining factor when choosing a camera. Ergonomics, controls, how the camera “feels” in the hand, size, weight, and lens availability, are perhaps far more important in choosing a camera.
Always remember the image is everything, what camera the image was taken on is immaterial. I recall one of our members producing stunning high-quality images in competitions with his diminutive Sony A5100 APS-C camera.
The above photo was taken on a Nokia Lumia 635 Windows phone and was placed 1st in a recent PDI competition – the image is everything.
Article, and photo: Derek Smith
We all “know” that a blurred background behind a subject is hard to obtain with a crop sensor camera, and that macro photography is easier with a micro four third sensor camera because of the “increased” depth of field. Well actually both of these statements are “fake news” often touted on YouTube, or in photographic articles.
Professor Bob Newman wrote on this topic in his Amateur Photography article 11th July 2020 entitled “The Great Leveller”.
In camera optics, a circle of confusion is an optical spot caused by a cone of light rays not coming to a perfect focus (also known as the disk of confusion, circle of indistinctness, blur circle, or blur spot). In other words, Depth of Field.
Professor Newman asserts:
“For macro photography, provided we keep the focus distance, the angle of view and aperture the same, and choose the same disc of confusion, then we’ll get the same results whatever the sensor size”
This appears to be borne out by the Wikipedia article on this subject, with the Circle of Confusion diameter limit based on d/1500 of 0.015mm (micro four thirds) to 0.029mm (full frame), and I challenge anyone to see that difference on an 8x10 print!!
I find macro photography as challenging with my Olympus micro four thirds camera, as I did with my full frame Sony A7. As an example, the Depth of Field for a 120mm lens, at f/5.6 = 0.13m on the Sony A7, and with the Olympus 60mm macro lens (2x crop factor = 120mm) at f/2.8 (2x crop factor = f/5.6) my Depth of Field = 0.14m - not much of an advantage there then!!
In conclusion sensor size should not be the determining factor when choosing a camera. Ergonomics, controls, how the camera “feels” in the hand, size, weight, and lens availability, are perhaps far more important in choosing a camera.
Always remember the image is everything, what camera the image was taken on is immaterial. I recall one of our members producing stunning high-quality images in competitions with his diminutive Sony A5100 APS-C camera.
The above photo was taken on a Nokia Lumia 635 Windows phone and was placed 1st in a recent PDI competition – the image is everything.
Article, and photo: Derek Smith
Louth Photographic Society
At our meeting last night we held a PDI (printed digital image) competition, with the categories of "Local Unedited", and "Open". As this was a members competition one of our members judged the competition, Tony Gaskins was our first judge for the "Local Unedited" category, these were .jpg images taken straight from the camera, without any editing, apart from the resizing for projection. Presenting an image such as this in a competition is quite a difficult task, the photographer has to ensure that the correct exposure is chosen, the composition, and subject matter has to be precise, everything done in camera. Normally for competition entries, a degree of post processing would be involved, simple edits like toning down highlights, or even removing extraneous objects from a scene, emphasising a moody sky, all not allowed. Tony Gaskins did an excellent job with his judging, providing clear and concise critique of the images presented, he "held back" 8 images for further consideration, awarding higher points, and finally choosing the top three placements. After the break it was Robin Begley's turn to judge the "Open" category, as these were post process edited images the standard was higher than the unedited images, but surprisingly not markedly so. Robin is potentially hoping to become a N&EMPF approved judge, and he had a different style, able to suggest edits that could have improved an image, again his critique was clear and concise communicating well with members. Robin chose 8 images for further consideration, awarding higher points, and finally selecting the top three placements. It was a fabulous, and interesting competition with excellent images, many thanks to both our judges, it's not an easy job, probably nearly as bad as being a referee in a football match!! Many thanks to both our judges, well done.
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Roger Hance Memorial Lecture 16th October
Last night Lee Dixon from Cleethorpes Camera Club gave his first ever presentation to a camera club, which we were privileged to view. His presentation consisted of portraiture, creative, and his genre of choice; wildlife. Lee is an extremely talented photographer, with a highly creative portfolio, his portraits are quite atmospheric, unusual, and capture the essence of the model, and scene. For Lee’s creative work, he buys props from charity shops, often very cheaply, reusing those props in various scenes. For his composite work he will often take one of his photos of a room, and blend it with a subject in Photoshop using “blend” modes. For wildlife he visited Lake Kerkini in Greece to photograph the Pelicans, if the sky is a little on the bland side, Lee will often over expose the image resulting in a striking white background to the subject. On safari in Africa Lee showed us some amazing images of the wildlife, the close-up images of elephants, the wildebeest migration, and this stunning image of a cheetah. Lee was ably assisted by Mike Bennett. More of Lee’s work can be found on his website: https://leedixonphoto.co.uk/ Lee his kindly given permission for his images to be used in this post. Many thanks to Lee, and Mike for an amazing evening.
Good Morning All Last week at the club we held our monthly PDI competition, with the categories of "Objects in the Air" and "Open", there was a very high-quality entry in both competitions and judge Mike Bennett had quite a job on his hands scoring the entries. Well, done to Dave Turner for first place in the Objects in the Air and Tony Gaskins for first place in the Open. All the results are on our website. This week, Wednesday 30th September, our speaker will be Lee Dixon from Cleethorpes Camera Club showing us his natural history, Creative and many other photographs he has taken. It will be the first time Lee has shown his photographs at our club. If anyone else wants to enter PDI's in the 2027 N&EMPF Exhibition, the deadline is this Wednesday at midnight. Harry is still taking entries for the PDI competition, with the categories of "Local Straight from Camera" (unedited .jpg), and "Open", to be held on Wednesday 7th October. Regards Graham
At the meeting last night Mike Bennett judged our competition with the categories of “Objects in the Air”, and “Open”. The standard of entries was excellent, and it gave Mike a tough task of judging the images, Mike gave some very good critique of the images displayed, the feedback helps members to develop compositional skills. Dave Turner was awarded first place for his image of the “Tiger Club Display Team” in the “Objects in the Air” category. Tony Gaskins was awarded first place for his image of the “Spectacular Rustgill” in the “Open” category.
Good Morning All, Last week at the club we watched the N&EMPF PDI Exhibition for 2026, it was a very good evening viewing very high standard images from all over the East Midlands. Dave Turner and I did manage to get images accepted; there is a full report on our website. This week, Wednesday 23rd September, we will hold our monthly PDI competition, with the categories of "Objects in the Air" and "Open", please send entries to Harry by midnight tonight. Harry is also accepting images for the PDI competition, with the categories of "Local Straight out of the Camera (only resizing permitted)" and "Open". Regards Graham
Members were shown the 2026 N&EMPF PDI Exhibition video last night with all of the accepted PDI images in the first part, and after the break the awarded PDI images. There were some stunning images on view, and Louth was successful in having 3 PDI images accepted, Graham Harrison with his image of a Stonechat, and Dave Turner with his portrait of Paul Rudd, and his monochrome image of Kings Cross railway station "Going Down". Overall it was a good inspirational evening.
Good Morning All Last week at the club members had 15 minutes to show what they had done over the summer. It was a very interesting evening with eight members taking part. There were many locations on show and as usual some excellent photography. There is a full report on our blog. This week, Wednesday 16th September, we will be showing the N&EMPF exhibition, this is part one showing all the PDI's that were accepted. This is the highest standard of photography we as individuals take part in as a club. Members sent around 50 entries but only 3 were accepted. If you are inspired to enter the 2027 Exhibition after seeing the show, I send the clubs entries and I can give you more information. Closing date is the end of September. The Maximum size for N&EMPF is 1600 x 1200 3MB sRGB Harry is still taking entries for the monthly PDI competition, with the categories of "Objects in the Air" and "Open". Harry did ask about what can be accepted, and we couldn't really say as long as it's an object in the Air. The best way is to look up the definition of an object first. Harry is also accepting entries for the Local and Open competition in October. Robin is going to judge the Open competition, does anyone fancy judging the "Straight from the camera" category? Regards Graham
The Louth Photographic Society has returned after the summer break. It was an incredible return, with members providing us with some stunning images from over the summer break. A full, and varied smorgasbord of well executed photos, many of us visited Whitby, the North Yorkshire Moors Railway, and further north images from Staithes, and Sandbanks. Tony showed us his long exposure minimalist calming coastal scenes, from the Lincolnshire coast, and Whitby.. Chris brought us some beautiful photos taken of local churches, many of which many of us have never seen. Now I’ve never really seen the attraction of an expensive Leica camera, but when Mark showed his photos from his visit to the German Leica factory in Wetzlar, I now understand, camera bodies, and lenses milled from solid blocks of aluminium, hand polished, hand finished lens glass, and textured leather applied to the camera body, not a robot in sight, just craftsmen, and women making a superb photographic instrument. Sue brought us “pink” ladies driving tractors to raise money for cancer research. Last but definitely not least Richard showed his monochrome, and infrared images of trees, his compositions, and photographic eye bring these tree studies to life, we appreciate them even if some judges don’t understand. Many thanks to all of those members who contributed.
