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
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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.
Good Morning All We spent last week on the Isle of Wight visiting many of the attractions. This week, Wednesday 9th September, we are back at the club with 15-minute PDI shows of what you did during the summer break, I have Derek Smith, Tony Gaskins, Harry Kerman, Chris Birchmore and Richard Hildred on the list, if I have missed you off, please let me know. I should be there but could be late as away playing golf. Harry is taking entries for the September PDI competition, with the categories of "Objects in the Air" and "Open". Harry will miss the October local competition but will sort the entries out for us, The competition categories will be "Local-Not Edited" and "Open". We judge this competition in house so could do with two volunteers to judge. The local competition is a .jpeg photograph taken and straight from the camera, no cropping, or post processing etc, like the old days taken no more than 25 miles from St James church. Regards Graham
