Blog Post

Back to Basics

Derek Smith • 10 July 2020
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  

Louth Photographic Society

by Derek Smith 20 February 2025
The Society held the prestigious Print of the Year (POTY) competition last night. Our judge for the evening was the affable, and highly experienced Brian Gromett. The feedback on the prints presented on the evening was exceptional, I am sure that many members, me included, had not considered some of the compositional elements in our photographic prints that Brian pointed out, and many of us gained a lot of insight last night. The “Print of The Year” award was given to Keith Rossington for his portrayal of “Nige” in the Colour section, and to Dave Turner with his stunning “Reading Isaiah 31” in the Monochrome section, congratulations to them both. The Competition page of the website has been updated, however I would be grateful if members could provide me with copies of images with a top three placement, as many of those images are missing.
by Derek Smith 18 February 2025
GAS, (Gear Acquisition Syndrome), is something that afflicts us all at times, I have the Fuji X-T3, and the Fuji X-S20, and 95% of the time I’m very pleased with the images that I create with these cameras and my lenses. As good as the Fuji XF 70-300mm lens is though, sometimes I do need a little more reach, and the Fuji XF 100 – 400mm lens is too big, too heavy, and too expensive. However, whenever a new camera is announced, there’s often a temptation to consider other camera systems. Now, OM Systems have recently announced the micro four thirds sensor camera the OM-3, and I keep looking at that camera, but the pricing of almost £2000 is beyond my budget, and it may not suit my photography style. Several years ago, I sold all my Sony gear, and bought into the Olympus micro four thirds system, creating some wonderful images, but the focusing on the E-M5 wasn’t great for birds in flight, otherwise my photos from Olympus were generally good. When considering a new camera, or choosing another brand of camera, its important to evaluate exactly what you hope to achieve by changing camera brand. Whilst I enjoy my portrait, and glamour photography, I want to take more landscape, nature, and macro images. For my needs any new camera must have dual UHS II card slots, and a focus joystick, the best fit came down to two cameras the Canon EOS R7, and the OM Systems OM 1. The R7 is outside my budget, and I wasn’t sure about the ergonomics, and so I’ve decided on a used micro four thirds sensor OM System OM 1. The purchase will be financed by selling my Fuji X-T3 and buying the OM System OM 1 camera, a 25mm f/1.8 lens, (full frame equivalent 50mm), and a 75 – 300mm (full frame equivalent 150 – 600mm) zoom lens. I have always had a soft spot for the Olympus / OM System cameras, the latest OM 1, and OM 3 cameras have the new 20-megapixel BSI sensor with 1053 cross type contrast, and phase detect focus points, and new faster processor, resulting in improved autofocus, and several computational photographic modes including Live ND filters, “In camera focus stacking”, and a “Live Composite” mode for low light night photography. This photo of barges was taken with an Olympus E-PL7 camera at f/6.3, 1/500, ISO 200, with the Olympus M.Zuiko 17mm f/1.8 prime lens.
by Graham Harrison 16 February 2025
Last week it was my turn to show you some PDI's some new and some the oldest PDI's I had, I hope you all enjoyed the evening. The oldest ones were from 2011 when I first ventured into digital cameras, I was a bit late converting waiting to see if they would catch on, they certainly did and for most of us now film and especially transparency film is a distant memory, but a happy one. This week, Wednesday 19th February, we hold our Print Of The Year (POTY) competition; and the judge for the evening will be Brian Grommett. I did visit Gibraltar point the other week and photographed my first Marsh Harrier, it was a long way off even for my 600mm lens which gives you 900mm on an APS sensor camera, so not the sharpest photograph but good to see. Very little else to photograph but a good lunch at the cafe there. There is a sand racing meeting at Mablethorpe today (Sunday) at about 11.30, which members may be interested in attending to get some good sport photographs. If only this cloud cover would disappear. Regards Graham
by Derek Smith 13 February 2025
It’s always interesting to view other members photographic work, most of the work displayed from other photographers is only shown in our competitions. Our meeting held last night was “Presidents Night”, a chance to view what photographic subjects, and outings that Graham Harrison has taken over last year, and some from proceeding years. Members were treated to an impressive cornucopia of projected images, Graham showed photos from his trips to Conwy, Wales, the Yorkshire, and Northumberland coasts. These are just some of the images from Grahams extensive collection of images. Thank you, Graham, for a very interesting evening, Dave Mann for refreshments; always much appreciated, and a big welcome to our newest member Steve Chapman.
by Graham Harrison 9 February 2025
Good Morning All Last week at the club we held a PDI competition, with the categories of "Local Still Life" and "Open", member Tony Gaskins judged the Open with a lot of thought and advice shortlisting nine and picking Derek Smith's portrait G'day as the overall winner. I then had the task of judging the still life, there were quite a lot of different ideas for still life, but I shortlisted the ones I thought fitted the subject best and picking Derek Smith's coffee break which in my opinion was an excellent example of still life photography. The results with images of the top three are on our website. Entries for print of the year (POTY) need bringing in this Wednesday with an email of your titles and which subject the photograph is in to Dave Turner please. This coming week, Wednesday 12th February, for President's night; I will be showing PDI's including some from Yorkshire and North Wales. Regards Graham
by Derek Smith 7 February 2025
We held our PDI competition last night, with the categories of “Local Still Life”, and “Open”. Tony Gaskins began the evening with his judging of the “Open” category, which I always feel is the more difficult category to judge. Tony performed the task of judging excellently, assessing each image as presented to him, providing thoughtful, and useful critique on the various submitted entries. Tony “held back” nine images for further assessment to award a higher points score, then finally choosing the top three images, keeping members in suspense, I was surprised when Tony selected my portrait of a male model as first place. “G’day” was a portrait of a Hungarian male model over for an inexpensive short break in Skegness, I provided the Australian bush hat, and scarf as props for this photo. After the break, it was Graham Harrison’s turn to perform the judging role, this time for the “Local Still Life” category. I personally found this a particularly difficult category to shoot, the keys to a successful image in this category, are imagination, creativity, and most important the lighting of the subject. I use LED constant lighting for still life, as do other members, because the lighting can be positioned exactly as required. I had several unsuccessful attempts at producing images for this category, before selecting three images for submission into the competition. Graham skillfully selected eight images as “hold backs” before choosing the final top three, again I was surprised to find my “Coffee Time” image in first place. Overall, some stunning images were entered into the competition, making for a successful evening, the website Competition page has been updated with the full results. A big thank you to Tony, and Graham for judging, and Dave Mann for his hard work providing the refreshments.
by Graham Harrison 2 February 2025
Good Morning All Thank you Peter for your presentation on Cuba and Prague. We did have a bit of an iffy start to the night but thanks to Paul Rudd the night was saved and power restored. There is a full report on our blog. This week, Wednesday 5th February, we are holding a local competition, with the categories of "Local Still Life" and "Open" (no restrictions) all entries need to be in by midnight tonight, I will be judging the still life and Tony Gaskins the open. It will soon be our print of the year, POTY, to newer members who might think February is an unusual time for the competition it's because our camera club year runs from the first Wednesday in May to the last Wednesday in April. You need to send your titles to Dave Turner and bring your prints on February 12th. All the information on entering the print of the year is on our website but feel free to email Dave if you are unsure. Don't forget to think about the March PDI competition including the moon, the one I took at Linwood would just about qualify. There is also the "Prime Time" project, of one photo a month taken with a prime lens to think about now we are into February. Regards Graham
by Derek Smith 30 January 2025
Our very own Peter Cory gave an insightful, and interesting talk on his travels to Cuba, and Prague in the Czech Republic. Peter began his illustrated talk with his visit to Havana, Cuba where he had a week’s holiday in 2000 with family. His photos gave a traveller’s viewpoint of Cuba, with some rundown buildings in the poorer areas, the iconic American cars from the 1950s, and the majesty of the Spanish built cathedral. After the break, Peter continued his talk with his visit to Prague in 2009, and compared to Cuba, the historic city centre looked prosperous and clean. The various photos of Prague made me want to visit the city for a short break sometime in the future. Many thanks to Peter for taking the time to compile the talk, and present to members of the club for a fascinating evening.
by Graham Harrison 26 January 2025
Good Morning, All Last week at the club we had our 2024 project night, "Numbers", only four members had completed the project, hopefully it inspired you to do this year's project "Prime Time" otherwise you may have to put up with one of my old presentations again. There is a report on our website covering the evening. This week, Wednesday 29th January, our member Peter Cory will be giving a presentation on Cuba and Prague. Don't forget to send your local PDI's to Harry, the subject is "Still Life" which you can take in your own house if you wanted, so don't have to venture far, the trick I have found is coming up with ideas. There is also an Open competition. Deadline is midnight, Sunday 2nd February. Harry would also like six PDI's from us all for the N&EMPF club PDI competition, the main rule is they should not have already been in the NEMPF PDI competition and be the best you have. The N&EMPF projector has a 4:3 aspect ratio, so images should be resized to a maximum 1600px width, and 1200px height. Regards Graham
by Derek Smith 23 January 2025
At our meeting last night members presented their 2024 “Numbers” Projects, this was one photo each month, where the photo included a number. The Society chooses a different project each year, for this year, 2025, the project will be “Prime Time”, one photo each month using the same prime (fixed focal length) lens. The evening was well attended, the members images displayed were of high quality, and showed individuality, and creativity in the approach to the project. Graham rounded off the evening with a viewing of his images taken over last summer, and at Beamish. All the images can be viewed on the Projects Page, listed under the Competition Page on the navigation bar.
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