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
The LPA Battles competition was held last night at Axholme Camera Club, in Haxey Church Hall. I attended as the Louth Photographic Society representative, bringing the Battles prints with me. It was a closely fought contest with some excellent prints from Axholme, Barton, and ourselves. The judge for the evening was Steve Dormer, from Doncaster, and he was very relaxed in his judging of the prints, providing excellent critique on each print. At break time, Steve had held back a total of 13 prints for further assessment and award of higher points, Axholme, and Louth had 5 each prints held back, with Barton 3 prints. The attached photo shows all the held back prints on the print stand. At the end of the evening Axholme took 1 st place with, 266 points, Louth came 2 nd with 258 points, and Barton 3 rd with 251 points. As the prints were taken off the stand, one print remained, it was a Louth print titled “Sleeping” by David Whitehouse, this print was awarded 20 points, and the judge Steve was very taken with the image, well done David.
Good Morning All Last week members walked along the Swaby valley, we have done the walk before, but it is now very grown up with nettles, grass and brambles. Not put off Chris led us through the valley to Swaby, there were six of us plus three more who caught us up in Swaby. The butterflies we saw as I am finding out this year just don't want to settle but we did manage some photographs before returning and going for a drink in the Massingberd Arms. This week there is an LPA Battle at Axholme on Wednesday starting at 7.30, if anyone would like to attend, please email me for details or look on Axholme's website. We are not having a meeting in Louth this week, probably as well the way the football went last night and with the next match on Wednesday evening. Regards Graham
Last night our members enjoyed a visit to the Swaby valley nature reserve. We crossed over two fields from South Thoresby, then followed the course of the Swaby Beck chalk stream through the valley, the public footpath was bounded by dense vegetation that hindered our progress at times. There was plenty to see around the reserve, myriad butterflies flitted around in a very lively manner, making for difficult photography, I spotted several small grasshoppers, and soldier beetles in the long grass, I tried to photograph a ladybird, but it was gone by the time I focussed on the creature. It was a very enjoyable evening, with good friendly company, and our camera skills were needed for the macro photography, these are a few of my photos from the evening.
Good Morning All Last week's outing was re-scheduled due to a clash with a certain world cup match, the good news was a victory for England, however we intend to still hold the outing on Wednesday 22 nd July. I did go to the Festival of Flight at the Shuttleworth collection, Old Warden last weekend. It was too windy for some of the old Biplanes, but we were treated to a four-and-a-half-hour display featuring many planes that I had never seen fly before. The De Havilland Comet was built to compete in the 1934 race from Britain to Australia, only three were built and it's good to see it flying, the aircraft design was quite advanced for 1934. This week, Wednesday 8th July, we have another camera club outing to the Swaby Valley, meeting at 6pm. Swaby is just off the A16 heading from Louth to Skegness. Regards Graham
Last night’s Louth Photographic Societies outing to Kirkby gravel pits nature reserve was cancelled as some members preferred to watch some sporting gentleman by the name of Harry Kane. (Congratulations to the England team) The reserve is small, and simply laid out, a public footpath leads along a tree lined avenue to the river Bain at the back of the reserve. Historic sand and gravel extraction has left a large lake in the centre of the reserve, several ducks and waterfowl inhabit the lake and there is a bird hide on the shoreline. Returning to the road, there is a path running parallel to the road bounded by a hedge, insects of various types can be found in this area, damselflies, butterflies, and hover-flies are often prolific. Our outing to Kirkby Gravel pits is now scheduled for Wednesday 22nd July. Parking is on the verge by the roadside. Kirkby Gravel pits are fairly close to where I live, and it’s reserve that I often visit, these are some photos from a visit in July last year.
Good morning, All, Last week at the club we had our monthly print competition, Trees and Open. There was a very good entry with a high standard of photography on show. Tony Gaskins was first in the Open and I managed a first in the trees, all the results are on our website and there is also a blog on the evening. This week, Wednesday 1st July, we are having an outing to Kirkby Gravel Pits, if we meet at 6.30 at the reserve, though you can arrive earlier as there are usually dragonflies etc around the entrance. If we walk straight ahead first, then anyone who arrives late can find us. I have struggled to find a map, but you can see the location on the Lincolnshire wildlife Trust website. Kirkby Grave Pits is also a good reserve for birds. Tattershall Road 1 mile south of Kirkby-on-Bain Woodhall Spa Nearest postcode LN10 6YN. Please note - postcodes are for the nearest registered address as we are unable to get postcodes for nature reserves.
A print competition was held last night with the categories of "Trees" as the subject, and "Open". Our judge for the evening was Gail Wrigg from Barton who did an expert job. The first category to be judged was the "Open" with the high standard of prints making the choice of top placement difficult, and Gail held back 9 prints for further evaluation. There were some chuckles from members around one of Richard Hildred's prints of wooden electricity poles titled "In my previous life I used to be one of them" an "in" joke from Richard, which totally baffled Gail. After the break Gail judged the "Trees" category, with 7 prints held back this time for awarding of higher marks, the beautiful colours of some trees, especially the autumnal images contrasting with the stunning monochrome infrared prints from Richard Hildred. It was a great evening, with excellent prints on display, and the website Competition page has been updated with the full results.
Good Morning All Last week we visited the nature reserves at Fir Hill quarry and Muckton wood. I have written a blog report on the evening which is on our website. You can always try something a little different like I did using camera movement. This week, Wednesday 24th June, a print competition will be held, with the categories of "Trees" and "Open" and is to be judged by Gail Wrigg. The following week we have an outing to Kirkby Gravel pits. If you want advice on camera settings etc the outings are the perfect opportunity to ask other members while we all have our cameras. Regards Graham
Each year Louth Photographic Society begins a new project, one photo taken each month on a specific subject, that's 12 photos presented on "Project Night" in January. Last year the subject was "Prime Time" one photo each month taken with the same fixed focal length lens. This year the subject is water, the subject sounds easy enough, and I've completed 5 photos already, but I'm struggling a little with a photo for June. I'm currently on holiday in Corfu, an island surrounded by water which should be easy, but I'm yet to find the "definitive" photo for the project. These are my photos so far this month: Best regards Derek
Good Evening All
