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
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
Summer is here at last, maybe?
Last night a few of our members had an outing to Old Bolingbroke village. Initially visiting the Lincolnshire Wildlife Reserve of Sow Dale, off Spilsby Hill at the village entrance, I was a little hesitant at first at entering the reserve because of the grazing cattle. When the cattle herd moved up the hill we climbed over the stile and entered the reserve, as we began to take some photos around the reserve though, the herd returned, but seemed quite docile. Later in the evening we moved on to Bolingbroke castle, and took several photos of the castle, fauna, and flora. It was a lovely evening, good to get out with cameras, and socialise with others.
Good Morning All Last week I went to the Lincoln cathedral to see Queen by candlelight, a great night of music and some different lighting in the cathedral. Last week at the club we held our 1 st round of the LPA Battles against Grimsby and Scunthorpe. Members from the two other clubs attended making it a very full room with some excellent photography on show. Scunthorpe won on 255 points, Louth 2 nd with 250 points and Grimsby 3 rd with 245 points. This week there is a 2 nd round LPA Battle at Grantham on Tuesday evening, if any member wants to attend, please contact me for more details. We did decide to have an outing on Wednesday 10th June, I had thought of Donna Nook, but Derek has come up with another idea, Sow Dale and if time permits Bolingbroke Castle both out Horncastle way. Derek is going to see if it's worth visiting Sow Dale and will let us know. Don't forget to send your print titles to Dave Turner. Regards Graham
It was the LPA Battles last night, with Louth hosting Scunthorpe, and Grimsby. Diane Seddon was the judge for the evening, and gave excellent critique of all the the prints presented to her from the three clubs. Our club room was packed with our members, and representatives from Scunthorpe, and Grimsby clubs. At the break the points scores appeared fairly evenly matched. However, it was the highest scoring prints that swung the competition in favour of Scunthorpe, their still life prints of "Sunflowers", and "Weights and Measures" scored 20 points each, taking their cumulative score to a winning 255 points. None of Louth's prints achieved 20 points, but ended with a respectable 250 points. Grimsby produced some strong prints, "The Road to Talmont", and "What's Your Name?" received 20 points each, their overall score was 245 points. As Diane Seddon said the submitted print entries were of a very good standard, resulting in a closely matched contest. Congratulations to Scunthorpe for securing the lead in this LPA Battle round contest.
