Back to Basics
Derek Smith • 10 July 2020
Kaya
Photo By: Derek Smith
Hypericum
Photo By: Derek Smith
Back to Basics
Recently someone I know bought a new camera, and of course they had many questions, I had to research these to find the right answers, and the first question was:
What is Lens Focal Length?
Focal length, usually represented in millimeters (mm), is the basic description of a photographic lens. It is not a measurement of the actual length of a lens, but a calculation of an optical distance from the point where light rays converge to form a sharp image of an object to the digital sensor or 35mm film at the focal plane in the camera. The focal length of a lens is determined when the lens is focused at infinity.
Lens focal length also tells us the angle of view—how much of the scene will be captured—and the magnification—how large individual elements will be. The longer the focal length, the narrower the angle of view and the higher the magnification. The shorter the focal length, the wider the angle of view and the lower the magnification.
As an example use a short focal length 24mm (16mm* or 12mm**) to capture the interior of a room, or a landscape view.
* = APS-C crop sensor camera ** = Micro Four Thirds crop sensor camera
What is Aperture in Photography?
Aperture refers to the opening of a lens's diaphragm through which light passes. It is calibrated in f/stops and is generally written as numbers such as 1.4, 2, 2.8, 4, 5.6, 8, 11 and 16. Lower f/stops give more exposure because they represent the larger apertures, while the higher f/stops give less exposure because they represent smaller apertures. This may seem a little contradictory at first but will become clearer as you take pictures at varying f/stops. Be sure to check your manual first to learn how to set Aperture Priority for your camera, then try experimenting to get comfortable with changing the aperture and recognising the effects different apertures will have on the end-result image.
Selecting a wide aperture of f/2 would ensure that only a small portion of the image would be sharp, whereas a narrower aperture of f/10 would ensure that a greater part of the image would be in focus.
What is ISO in Photography?
In digital cameras ISO measures the sensitivity of the image sensor, the lower the number the less sensitive your camera is to light and the lower the noise in the image.
Higher ISO numbers mean your sensor becomes more sensitive to light which allows you to use your camera in low light situations, the trade-off of doing so is more noise in the final image.
An example of a situation you might want to choose a higher ISO would be photographing an indoor sporting event where the light is low and your subject is moving fast. By choosing a higher ISO you can use a faster shutter speed to freeze the movement.
What is exposure in photography?
The light meter in a digital camera calculates the correct exposure of the image based on 3 parameters: ISO, shutter speed, and aperture. This is known as the "exposure triangle". Creatively the photographer chooses 1 or 2 of these parameters based upon the subject. As an example when photographing a moving subject you may select a shutter speed of 1/500 to "freeze" the action, ensuring the the subject is sharp. In the case of a portrait in the front of a distracting background the photographer might select an aperture of f/2 to isolate the subject from the background. The choice of ISO again is an artistic choice, the photographer may choose to set the ISO to "Auto" if the light is variable, alternatively in the case of the portrait set the ISO to the base level of 100 or 200, to give a noise free image.
In the case of the portrait of Kaya, I used a lens with focal length of 90mm (60*, 45**) our location was in shadow under a railway bridge, I set the aperture to f/1.8, and set the ISO to 400. I was using "Aperture Priority" as the camera mode, with the ISO, and aperture fixed the camera calculated the correct shutter speed of 1/200 to give the correct exposure.
The photo of the Hypericum flower was captured with a 120mm macro lens (80*, 60**) ISO 800, aperture f/4, and a shutter speed of 1/60 calculated by the camera.
For further reading on the exposure triangle I found this website to be useful:
https://photographylife.com/what-is-exposure-triangle
Recently someone I know bought a new camera, and of course they had many questions, I had to research these to find the right answers, and the first question was:
What is Lens Focal Length?
Focal length, usually represented in millimeters (mm), is the basic description of a photographic lens. It is not a measurement of the actual length of a lens, but a calculation of an optical distance from the point where light rays converge to form a sharp image of an object to the digital sensor or 35mm film at the focal plane in the camera. The focal length of a lens is determined when the lens is focused at infinity.
Lens focal length also tells us the angle of view—how much of the scene will be captured—and the magnification—how large individual elements will be. The longer the focal length, the narrower the angle of view and the higher the magnification. The shorter the focal length, the wider the angle of view and the lower the magnification.
As an example use a short focal length 24mm (16mm* or 12mm**) to capture the interior of a room, or a landscape view.
* = APS-C crop sensor camera ** = Micro Four Thirds crop sensor camera
What is Aperture in Photography?
Aperture refers to the opening of a lens's diaphragm through which light passes. It is calibrated in f/stops and is generally written as numbers such as 1.4, 2, 2.8, 4, 5.6, 8, 11 and 16. Lower f/stops give more exposure because they represent the larger apertures, while the higher f/stops give less exposure because they represent smaller apertures. This may seem a little contradictory at first but will become clearer as you take pictures at varying f/stops. Be sure to check your manual first to learn how to set Aperture Priority for your camera, then try experimenting to get comfortable with changing the aperture and recognising the effects different apertures will have on the end-result image.
Selecting a wide aperture of f/2 would ensure that only a small portion of the image would be sharp, whereas a narrower aperture of f/10 would ensure that a greater part of the image would be in focus.
What is ISO in Photography?
In digital cameras ISO measures the sensitivity of the image sensor, the lower the number the less sensitive your camera is to light and the lower the noise in the image.
Higher ISO numbers mean your sensor becomes more sensitive to light which allows you to use your camera in low light situations, the trade-off of doing so is more noise in the final image.
An example of a situation you might want to choose a higher ISO would be photographing an indoor sporting event where the light is low and your subject is moving fast. By choosing a higher ISO you can use a faster shutter speed to freeze the movement.
What is exposure in photography?
The light meter in a digital camera calculates the correct exposure of the image based on 3 parameters: ISO, shutter speed, and aperture. This is known as the "exposure triangle". Creatively the photographer chooses 1 or 2 of these parameters based upon the subject. As an example when photographing a moving subject you may select a shutter speed of 1/500 to "freeze" the action, ensuring the the subject is sharp. In the case of a portrait in the front of a distracting background the photographer might select an aperture of f/2 to isolate the subject from the background. The choice of ISO again is an artistic choice, the photographer may choose to set the ISO to "Auto" if the light is variable, alternatively in the case of the portrait set the ISO to the base level of 100 or 200, to give a noise free image.
In the case of the portrait of Kaya, I used a lens with focal length of 90mm (60*, 45**) our location was in shadow under a railway bridge, I set the aperture to f/1.8, and set the ISO to 400. I was using "Aperture Priority" as the camera mode, with the ISO, and aperture fixed the camera calculated the correct shutter speed of 1/200 to give the correct exposure.
The photo of the Hypericum flower was captured with a 120mm macro lens (80*, 60**) ISO 800, aperture f/4, and a shutter speed of 1/60 calculated by the camera.
For further reading on the exposure triangle I found this website to be useful:
https://photographylife.com/what-is-exposure-triangle
Louth Photographic Society
Good Morning All Last week at the club we held a committee meeting, which was very productive, we made the final arrangements for the exhibition, charity night, and studio evening as well as other items on the agenda. We are holding an Exhibition opening night at Louth Museum on Friday 17th April celebrating 70 years of Louth Photographic Society. There will be a small buffet and cold drinks available, if any member would like to donate a bottle of wine to the occasion please hand it to Harry at one of our club nights. This week, Wednesday 25th March, member Chris Birchmore will be giving us a presentation. The following week is a local competition, with the categoriess of "Local Nature" (up to 25 miles radius from St James church) and "Open" (unlimited mileage) please send your entries to Harry before midnight, Sunday 29th March. Members Steve Chapman will judge the Nature category, and Dave Turner the Open category. Regards Graham
Good Morning All Last week at the club we held our monthly PDI competition judged by Martyn Wrigg, the standard of entries was very high and well done to Tony Gaskins for a first in the Architectural Detail and Derek Smith for his first place in the Open. All the results are on our website under competitions. This week, Wednesday 18th March we will be holding a Committee meeting, just committee members for this one. The following week Chris Birchmore is the speaker for the night. Harry is now accepting entries for the PDI local competition, with the categories of "Local Nature" and "Open". We judge this competition in house so if you would like to judge one of the subjects please let me know. Regards Graham
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A PDI (Projected Digital Image) competition was held last night with the categories of "Architectural Detail", and "Open". Martyn Wrigg was our judge for the evening, and he competently judged the submitted images, although he diid surprise with some of his choices of placing, but that's a judges perogative. Martyn complemented members on the quality of the images presented, which had made some of his decisions difficult. First placed was "It's a Fixer Upper" in the Architectural Detail section, and "Dervish Musician" in the Open section. Congratulations to Robin Begley, who as one of our newest members submitted some impressive images, achieving a 3rd place in "Architectural Details", and 2nd in the "Open" category. All the results are now posted to our website Competition page.
Good Morning All Last week at the club member Steve Chapman gave us an insight into his life and especially his time at Ilam Park in Derbyshire photographing for the National Trust. Steve showed us many photographs he had taken of the people involved with the trust and the Peak District. The second half was dedicated to Steve's own work, some superb aircraft photography as well as many other subjects. There is a report on the evening on our blog page. This week, Wednesday 11th March we are holding a PDI competition, with the categories of "Architectural Detail " and "Open" to be judged by Martyn Wrigg of Barton. The following week is a committee meeting for the committee members only on that evening. For newer members we have two committee meetings a year. Regards Graham
Last night Steve Chapman presented a selection of images from his archives. Steve had previously been a volunteer photographer for the National Trust, and he showed many photos from the Ilam Park Estate, Dovedale, it was interesting to see some of the "behind the scenes" photos. The Jacobite reenactment battle scenes were amazing, the uniforms showed great attention to detail, and there were some real characters among the reenactors. After the break Steve showed some of his general photography, he has a great photographic eye, as some of his photos showed with different colours, shapes, and leading lines. Steve has taken many photos of agricultural machinery, and risked life and limb to create some close up aircraft photos. For atmosphere, just look at these horseriders at the top of the hill on a cool early morning. For heartstopping imagery look at these children on the side of a building, the children are photos on the side of the building, however, Steve wasted no time in capturing this stunning image. Many thanks to Steve for a fascinating evening.
Good Morning All Last week at the club I gave you a PDI (Projected Digital Image) presentation showing photographs I had taken on my travels last year, following up with some past and present photographs of Binbrook. I hope you all enjoyed the evening and maybe saw parts of England you hadn't seen before. This week, Wednesday 4th March, our member Steve Chapman will be showing us photographs he has taken. This is Steve's first time showing the club his work so will be a very good night. Harry is now accepting your PDI's for the next competition, with the categories of "Architectural Detail" and "Open". The closing date is Friday 6th March. Regards Graham
The N&EMPF Exhibition will be on display in Cleethorpes from 3rd March.
It was "President's Night" with Graham Harrison showing some of his images from short breaks, and holidays around the UK. Graham rented a holiday cottage in Newbiggin, Northumberland, and showed many of his photos from that area, including a visit to Lindisfarne, where the castle on the rocky outcrop made for an impressive photo. In Suffolk, Graham visited Pakefield, and photographed the colourful beach huts at the top of the shingle beach, he also showed several photos from the Lake District. One of my favourite photos from last night was St. Mary's Lighthouse, Whitley Bay, with the groins in juxtaposition. Thank you Graham for a very interesting evening.
Good Morning All Last week at the club Harry and Chris gave us an insight into how our exhibition preparation is going, we have a lot of historical photos to go on show and there may be room for some more up to date ones but Harry and Chris will see how much room we have left when they start putting it all together at the museum. I also took the time to find out what you wanted in the new program, filling in the competition subjects and outings. This week, Wednesday 25th February, it is the Presidents night, so that's my night and I will be showing you what I got up to in 2025. The rainbow at Brough castle gives you idea of one area I visited. Harry is now accepting entries for the next PDI competition, with the categories of "Architectural Detail" and "Open". The new program is nearly done and to give you a chance to get ready for the first two competitions in May and June the subjects are May, PDI comp - Landscapes with water and Open and June, Print competition, Trees and Open. Regards Graham
