Annual General Meeting last session and the picture is broadly good, most importantly the average attendance is up and the finances are sound. Two committee members stood down, Steve Hallam from the Treasurer post (and thirty years on the committee covering just about everything) and Julie Kaye as Competition Secretary and who has conducted and introduced and overhaul of the competition rules as well as run the competition rounds for this season. Club thanks to them both for their service and for making a difference. We are still looking for a replacement for Julie so club members this is your chance to step up. Welcome to Dave Hughes who takes over as Club Secretary.
Next two sessions are about building a panel and will be a pair of group focused practical sessions and an introduction to the Kingswood Salver, a subject to which we will return later in the year. There will be a shoot this next session and an edit and present session the following week. The subject will be shadows, so lets take this opportunity to talk about photographing umbra.
A shadow is a dark figure or image cast on a surface by a body intercepting light. Interpretation of this opens up a huge range of possibilities. The first is do we include all three of the elements involved, the light source, the intervening body, the resulting shadow. The result is a product of contrast, captured by the sensor. Compositionally it is, or can be, quite challenging. Like any other photography it has to be deliberate to be successful.
Perhaps the most effective way of creating a shadow effect is from a single light source, but there are ways of modifying that light before it reaches the intervening body so as to create interest. Gobos are stencils put in between the light source and the background. They are widely used in film and television, and are an easy DIY project for us still photographers and can be very effective.
From portrait session variation to a whole genre, we are talking here of film noir, there are a myriad of possibilities, some very straightforward. However the scale does not have to be large for this little venture to the left side of the histogram.
It is, as ever, about keeping things simple, and the usual suspects: Have one thing that bears the visual weight of the image; Police the boarders of your frame for unwanted intrusions and remove them; Check exposure for the effect you are looking for – high key, low key or on the button; Fill the frame and check the relationship of the foreground to the background; Are the objects in the frame balanced for the maximum impact? What is going to have to be done in post? Colour balanced and depth of field sufficient?
Do silhouettes count? Well yes and no. Yes in that it fits with our definition we started with no in that the silhouette is a dark shape and outline of a subject against a lighter background (i.e. it is back lit) whereas a shadow is a dark area or shape produced by something coming in between the light source and the and a surface. The less picky way of looking at it is that they both produce high contrast areas for effect and the cause of that effect isn’t really important to the outcome.
Silhouettes, by the very nature of their production, are harder where shadows can wrap themselves over the and around the subject, can be soft or hard, can be modified, coloured and generally manipulated for a range of effects. The shadow is also a way of modelling the 2D environment that is a photographic image to give the appearance of something that is 3D. There are plenty of options.
So club, this Thursday, bring your camera, tripod, torches and or flash guns, bring some props to practice on.
Our speaker this week was Richard Price talking on the very small and the infinite (at least the bit of it we can see) – Macro to Astro. As ever a hugely informative and accessible evening given to a packed hall.
When talking Macro (on a ratio of reproduction to actual size of the subject of 1:1 or greater) we will be including what is close up photography too as there is a technical difference but not, as far as next meetings practical is concerned, no difference worth the time.
These are both areas of photography that appear complicated but, whilst demanding, they can be easily accessed. And they are both absorbing aspects of photography and being both accessible and demanding they teach us a lot about our equipment and how light works with it. It also tells us a lot about our kit and can involve finding work arounds. For instance my manufacturers own 50mm lens will not work on anything but manual and with the depth of field preview button held down with my extension rings. My third party lenses work just fine. Took a while to work out how to get the nifty to work, but it was worth the effort. With a mirrorless camera like mine the DOF preview button is usually redundant -what you see in the view finder is exactly what you get as an image. Only it isn’t redundant at all and I am rather glad it’s there.
Of course, how near/far you want to go is a matter of budget but only really at the extremes. You can get some perfectly acceptable macro shots with a kit lens and a reversing ring (about £7 for a 52mm filter – size it’s written on the front of your lens, in the case of our 52mm example as Ø52). You can also use a coupling ring to reverse one and add another lens to it to make a longer focal length and a greater degree of magnification. In both case it might be advisable to take any UV filters you have off the end of the lens.
The next option Rich gave us was using screw in filters (lenses) of varying dioptres. These are available for around £15 (and upwards depending on filter size), but as with everything else you get what you pay for. Essentially these are like reading glasses for your lens, they are lenses that fit on the end of lenses. If you buy them for the largest filter size you have in your range of lenses you can buy a set of step down rings to fit them to your smaller filter sizes (usually for around £5).
Extension tubes, moving the lens away from the focal plane foreshortening its focusing capacity, use no intermediary glass at all, so there is no risk of flare or softening enhanced by putting more barriers between subject and sensor. By shortening that distance a degree of magnification results by getting closer to the subject. This is generally a more expensive route than the two previously discussed. this is because a certain amount of electronic communication has to be allowed for in the design of the tubes and this complicates the manufacturing process making it more expensive. It isn’t always effective either (see example given above) and work rounds result. However, the more you pay, generally, the more you get in terms of functionality and performance, though this is not an absolute guide.
Finally there is the most expensive option, the dedicated macro lens. Without a doubt this is the higher performer when it comes to producing quality of images in terms of sharpness and contrast, and without a doubt. But all that comes at a cost and even the cheapest all manual lenses cost several hundred pounds. Whichever route we go, macro/close up photography can be done anywhere and relatively easily and cheaply. One extra technique that might help is Focus Stacking. It can be done in Photoshop, as per the link, but failing that you might want to try CombineZP which is free and simple to use.
Now focus stacking as a technique makes a good link to the second half of our evening, Astro-photography. The reason being that photo stacking is an often used technique when taking photographs of the stars. It’s not an absolute requirement, though, and the basics are relatively straightforward. Rich recommended using StarStax, which is freeware, as you were wondering and developed with astro-photography in mind. But we get a little ahead of ourselves.
Dark areas in the UK are few and far between. Light pollution is a serious problem, not just for photographers but for wild life too, in our rather crowded island. Even in designated Dark Areas there are problems at the extremities where towns and villages emit a glow low on the horizon. So it takes some work.
The pollution part is best thought of as the light you would eliminate if you could. The night sky isn’t black, the horizon is always discernible. The sky itself is also quite bright. If we are trying to record as much detail as possible (known as Deep Sky astrophotography) we are going to be fighting the noise generated by the sensor of the camera, especially at higher ISO’s but even at the lowest setting because where there is a signal there will be noise. If we treat the sky as black either by exposing or reducing it to black in post production then the fainter details are going to get lost. The point is the sky isn’t really black, it’s closer to a dirty orange colour. Because of the light pollution and the reflective nature of Earth’s atmosphere.
We can get round this in post by adjusting levels, picking the darkest part of our image as a start point with the eye dropper and adjusting the levels. It’s a matter of trial and error really. As is white balance. Regardless, this will all be a matter of trial and mostly error at the beginning and that is actually part of the fun. Learning new techniques like this means we learn more about the competencies and capabilities of our equipment and allows us to do more things with it.
Our thanks again to Richard and good luck as he takes this and his other presentations on the road.
N E X T M E E T I NG
Macro and close up practical evening. Bring cameras tripods and that reversing ring you just ordered off Amazon.
Club Social with photo-booth and a bokeh table this week, the last of 2016. So we will talk a little bit about Bokeh before completing our examination of light modifiers, in particular the “hard” modifiers (that’s about the quality of the light not the difficulty of use), and wish you all the best till next year.
Bokeh is, I have a lingering suspicion, the best of , if not exactly a bad, then at least, an unavoidable, thing. It is points of light rendered by a lens in the area beyond the zone of acceptable focus. It has, by association, a certain dream like quality. Whether that association with bleary eyes is as the result of a blow to the head, strong liquor, watching too many ’60’s films, recently arising from a deep sleep or a biological need for spectacles I leave to the individual imagination and circumstances. That’s not the sort of explanation I am trying to provide. That’s between you, your conscience and the likelihood of your significant other cracking your alibi.
The shallower the depth of field the greater the area of view that will be out of focus. Bokeh occurs at the point where single light sources lose their shape and become mini suns or circular (sort of) shapes of light. The term is Japanese, meaning blurred or something that approximates to that. It is the product of lens design which in itself is limited by the laws of physics.
That blurred area, behind the subject in focus, is formed by circular pools of light where the light has spread out rather than been brought to focus. The patterns formed are diffraction patterns whose edges assume the shape of the lens aperture in the diaphragm through which they pass.
The shape (and number) of the diaphragm blades will impact in the shape of the blobs in the background. The size and smoothness are regulated by light source, focal length, aperture and the diaphragm and what constitutes “good” bokeh is purely a matter of personal taste.
We started last post to talk about light modifiers, specifically “soft” modifiers. So that leaves the “hard” modifiers. Probably the thing to note first is that hard light is the default with flash/strobes (I am going to use the terms interchangeably). Flash is probably the first port of call for additional and controllable light for most photographers progressing through the hobby. There are a number of pro’s and cons in using it. On camera and off camera flash provide some of the same problems but generally off camera flash, that which uses a separate flash gun, is by far the more flexible option and the one we will be talking about here.
More specifically on camera flash is more likely to deliver red-eye, demonising your subjects, the light is harsh and direct and can only come from the direction of the camera. Built in flash is less powerful than off camera, separate units and you can’t always control the intensity of light you do have manually. That isn’t to say that built in flash doesn’t have its uses, just that those uses are relatively limited compared to the more modifiable off camera varieties.
All flash lighting needs modifying most of the time, and there are four basic types of hard modifiers:
- Reflectors – your common or garden light modifying accessory, bowl shaped, they have a single but important purpose, to cut down light spill – light that spills to the sides of (a bare) bulb in a strobe (not exclusively) and when using umbrellas or grids. Also below.
- Grids – Does what it says on the tin. Black tubes formed in a lattice work they are very effective in stopping scattered light rays coming from the (strobe) bulb, creating a thin, relatively soft beam of light, which arguably puts it into the soft category I know, but I think sits better in this list. The quality of light is determined by the density of the grid (the number of tubes in the grid), while the size of the beam (expressed in degrees) is determined by the thickness of the grid. The grid is regulated by gates acting as barn doors, movable flaps on each side which allow for finer, narrower, beam control.
- Snoot – is a cone which focuses light to create a very harsh, small beam of light. Can be rigid or flexible, allowing for some control.
- Beauty dish – A small reflector, (usually gold, silver, or white) is placed in front of the strobe / flash, while a bowl-shaped reflector is placed around the light source. This creates a very even, hard light with an extremely sharp drop-off. Used almost exclusively in portraiture, it is very useful as a key light.
These are not mutually exclusive pieces of equipment. They can be and should be mixed and matched according to the creative need. They don’t all have to be shop bought, DIY is always an option, but for the bought stuff the guiding principle, generally, is, you get what you pay for, especially when talking about longevity. This in itself can be a function of the frequency and conditions of use, however when starting out, certainly a look round e-bay or other on line shops will throw up some “bargains”. The bargain is what you feel the value of what you have is.
There are three other essential elements, not, I would put forward, necessarily directly under the heading of light modifiers as they don’t work directly on the source. These are: flags, scrims and bounces (reflectors).
- Flags block light. Bought flags tend to be black material, some are paper, stretched over a frame with a small handle to make it easier to place on a stand accurately. Black paper and tape will get you a similar effect to stop a white or light coloured wall from reflecting or for shading specularity in shiny objects. Their primary use is to control light spill and keep down highlights.
- Scrims are panels covered in diffusing cloth, placed where light needs softened locally. You have probably seen them on film and TV sets, spreading tent like over the actors, in order to provide a soft and even light.
- Reflectors, other than the ones that wrap around your light source, a.k.a bounces, or bounce cards, can be anything that will reflect enough light to be useful, but are usually white, silver or gold material stretched out on a frame. You are probably aware of the five sided reflectors that also have a black surface and an opaque white that can be used as a scrim. Mirrors are frequently used, especially small ones on product shots. They are usually a way of lightening shadows created by the key and other lights. The type of material determines the light’s quality and, and intensity is a product of the distance from the subject and the reflectivity of the surface used. The black on a five sided reflector, for instance, is used to reduce the amount of light going into the subject.
And that, as they say in the World of Onions, is Shallot for 2016. Happy New Year.
N E X T M E E T I N G
5th Jan 2017 19:30 – Editing Images: Bring your laptops and challenge your editing skills.
It must be Autumn because last meeting we did a light painting session courtesy of Myk Garton and guest light painter Tony Cullen – many thanks guys. Every time we do this there is something new and I will admit that it is one of my favourite things to do photographically. Attendance was high which proves its popularity with other club members too. This was the introductory evening and we will be doing some more advanced techniques on December 1st. Of course light painting isn’t necessarily seasonal, but the ever shortening days this side of the Winter Solstice means that available light is at a premium. The “Season of mists and mellow fruitfulness” (that man Keats again) means a lot more than landscapers getting a lie in. The light, generally, has a quality of its own because of the relatively low angle of the sun to the horizon. Problem is there isn’t a lot of it.
So, provide our own. This is as close outdoors as we get to the degree of control of light in a studio. The big difference is we make benefit of the dark. The contrast levels are extreme, but that is a virtue not a vice. The canvas is light on dark but in a more high contrast way than we see in daylight, where we could argue that the opposite is true (wrong as everything we see is via reflected light, but since when did wrong prevent an argument?). Strobists use flash guns to recreate the flood of light which they can control the direction and beam, with a white balance of its own. When drawing on the black canvas, with torches, coloured lights or even fire, the colour balance doesn’t tend to be a big consideration, at least in the sense of it being something that needs correcting. Painting a scene in light as opposed to drawing a scene with light presents different technical challenges, but can be done with the same kit and a bit of patience. I say a bit, oftentimes a lot of patience.
In fact there are a number of different ways to think of light painting, and where we start, the way in which we are thinking of the images we want to capture, determines the outcome more than anything else. Yes this may come under the heading of “Well, duh” but any technique has strengths and weaknesses according to the situation. Selection is the key. The first decision is are we lighting the subject or creating an effect? Our desired look will determine the way we use the lights and the sort of lights we use. Again, we may say “Duh”, but it’s surprising how hard we can make the job by not prepping for a final outcome in the first place. We might be combining both, after all. What about spontaneity and experimentation, we say? Much better to have an idea to execute and vary than to just turn up having watched several hours of YouTube videos with a load of kit and a vague idea. We may be technically proficient but that is no good if we are subject deficient – the difference between a body with a camera and a photographer.
The point to start, where when who and how because that is going to dictate what we can and cannot do. Use a familiar or scout a location in the day light. Decide what the subjects are likely to be and what kit we are going to take with us. If unfamiliar with orbs, zoom bursts, camera rotations, double exposures and the like the answer is “Should have been at club”. That aside, the first thing is, if not in total darkness or very near, determine what the level of ambient light is. This determines the time we have to paint in. If it isn’t a factor then fine, open the shutter for as long as it will go or as long as needed, then set the camera pre-focused and to manual – this meeting was about familiarising people with their equipment in those modes in order to capture those sort of effects.
If we want a basic explanation of light painting it is that it is long exposure photography. In the dark. The meter is useless without some level of ambient light and the length of exposure is dependent upon what we want to paint in and what we are painting with, that is to say, in the practical sense, it is going to be the product of experimentation. The light gathering capabilities of the sensor are going to be tested, select the lowest ISO to help keep the noise to a minimum (remember boost the signal, boost the noise and that is what you do when we up the ISO). We are going to need a tripod and, a personal preference, a remote shutter release.
Light trails, using moving lights – the most popular seems to be vehicle trails which, let’s face it, aren’t too difficult to come by in a city of 400,000 people – are also simple to set up and to execute. 8 to 10 seconds, ISO 100, F8 on a well lit street, as a starting point towards getting a reasonably exposed photograph overall and, as long as the vehicles are moving even relatively slowly, then some interesting effects can be captured. Vary the angles, either by setting the camera up more obliquely to the traffic than at a right angle, or find a bend or a roundabout to get some swoosh into the picture. Zooming whilst the shutter is open also does interesting things to the trails often setting them off at angles we wouldn’t expect and rotating the camera through 90 degrees during the exposure, as long as we keep the axis constant, can do interesting things to lights in the background (as alluded to above).
I know that is a cliché but nonetheless I am going to repeat it. There are so many variations that we truly are only limited by the imagination and for once, it doesn’t have to be at any great expense. Yes we can spend an inordinate amount of money on these techniques but actually experimenting with the basics will yield some fine and interesting results. I, for one, am really looking forward to part two of our light painting sessions.
Last evening the event was about making photography fun. Thank you to our speaker Margaret Collis. Fun, who could be against that? Well debates on Puritan Philosophy and outlook aside, fun is, generally, in the words of Sellar and Yateman “A good thing” (1066 and All That: A Memorable History of England, comprising all the parts you can remember, including 103 Good Things, 5 Bad Kings and 2 Genuine Dates). Fun with a camera, well what else?
Sometimes, some people make me wonder if the fascination with the craft squeezes the fun element out of it. Margaret pointed out that some people do seem to let competitions dictate their style and habits, which is a shame because that is also limiting of the ability to develop and learn in new directions. For the amateur fun forms a big part, there are plenty of other, less expensive hobbies out there after all. But even the best hobbies have their ups and downs, few though have the capacity for variation that photography offers. So, this week the blog is going to be dedicated to making pictures work. Basically we are limited by our own imagination, one of those useless truisms because if we can’t imagine it in the first place we are unlikely to do it ….
So let’s assume we are feeling lazy or for some other, less fortunate reason, we are housebound, where to start? There are plenty of things around the house. A favourite is to use toys or miniature figures to play with scale around common household goods, even foods. Then there are water droplets, frozen flowers, oil on and in water, the list goes on. You don’t need to sail the world to get your photographs, though that does sound like a great idea. Peering over the duvet or over the crater of a volcano the successful picture has variations around a common technical theme, the exposure triangle, but however well the technicalities are executed, all successful pictures prompt an emotional response. Avoid the technically proficient, artistically deficient. The key to that emotional response is to make a story out of the elements: a simple, bold, cleanly framed, single element which in the balance of everything in it, we call a narrative.
Narrative, is about events linked by common elements, a thread, a story. We are familiar with the idea of spoken or written narrative, of those told in films and on TV. Making the one frame narrative is actually more familiar to ourselves than we may think. In thinking it we can think it too difficult, but actually it is quite natural to us. We contrive these all the time because, it seems we are hard wired to make stories of things in order to make sense of them. We become photographers when we stop taking image of things and start making images about things.
There are two situations this covers, the individual photograph always and photographs in series, from a collage (which can be very difficult to get right) to a sequence around a common theme, which we will label a project. I stress the point about the individual photograph because even if it is being part of a wider story (the Kingswood Salver is an excellent case in point), it has to stand in relation to the others on its own technical and aesthetic merits. The technical we have talked about and talk about all the time, not least because it is generally easy to agree about. The aesthetic, what we consider beauty in relation to a person or object, is both what we are talking about and a subject all of its own. A philosophical one, a scientific one, a personal one, too big for this little blog, beauty is a context of a combination of qualities, including shape, colour, or form, that pleases the imaginative senses of an individual, especially the sight. Look at these photographs culled from Friday’s Guardian (14 October 2016) newspaper website, pick your favourite and decide what you like about its shapes, colours and forms.
So can we use a bit of logic from what we have said about the connectivity at the centre of our photographic narrative? Well a couple of points I think. Firstly it is made, on purpose by framing and lighting and positioning. It is a product of selection. It is made by context. Secondly, and derived from this, it is deliberate.
Now it is beginning to sound very complex and a little off-putting. It is actually a question of looking, actively looking, pictorially, at what is around you. Now we make images for more than one reason. It can be a quick note, a documentary record, a statement, a creative impulse, a memory, and so on and so forth. Our guides to looking are the rules of composition, they help us find those connections that we alluded to above. This is as much about learning to see in the picture format as anything else. That is the key to starting, being deliberate, we referred to this last week and before when we talked about opportunities falling to the prepared. Serendipity. That can be aided by putting in another step before we press the shutter and that is to ask ourselves why this picture appeals.
Essentially, then we are going to end up with a mixture of pictures (point, click and chimp) and images (see, compose and capture) and that is OK. In fact we can see the differences between them and that can help with our own development. But it should not be a trial, it is about moving and direction and seeing and taking those pictures for the same reasons as always. Because it is fun.
Well apologies for late posting but having terrible trouble with rural broadband. We were back to table top photography, always a favourite and a good one to hone your photographic skills on. We will also look at the last of week 2’s Q and A about DSLR v CSC/Mirror-less systems.
Table Top. Does what it says on the tin. Take something you can place on a table, make it interesting, light it photograph it. What is difficult in that? In truth it is one of those thing that is both straight forward but not necessarily that easy to get just right. But it is fun and it is relatively easy to set up and it can be as cheap as you want to make it. It is also an exercise in the basics of photography and as such is something well worth spending a rainy day, or part thereof.
Of course it is as involved and difficult as you want to make it, and some people do, but as with everything else with this craft, if you don’t get the basics right the rest is of little consequence. Or maybe you can pass it off as abstract art, depends upon your contacts. In the professional arena it is known as product photography, for all the reasons you would expect. It’s photography. Taken of clients products. Glad we got that out of the way early. The thing with that is that, whereas your product might be metallic, shiny, glass, matt, brightly coloured, black etc etc the clients expectations are going to be unique. Even when they want something like ….. they want something different. Otherwise it might fall to a competitors advantage. Energizer Bunny anyone? Yes you have seen him/her/it somewhere before ….
The basic set up into which you place your object is a flat surface, a light, a backdrop, usually plain, usually white, and a camera. The first addition to this is a reflector. Arguably you could swap light source for reflector and using existing light in this. Indeed I would put a reflector in the essentials. A useable five in one To get the ISO down to around the 100/200 mark I would suggest the next thing you acquire is a tripod. Then maybe a second light source. Some flags for putting more control into shadows, a light tent etc etc. Possibly more than any other area of photography this one opens itself up to DIY alternatives, or, if you are being hip as opposed to waiting for a replacement for one, hacks.
This is the area of photography where you have most control of the light, that is total control of the light, but as I have said before any videographer will tell you that the easiest thing about light is the theory of it. However, the control of the light is a good start when learning about how to put the light together with a subject to make a photograph. In the wild, as it were, we are more and more dependent upon what others or nature provide us with. This does not mean that it cannot be manipulated but it certainly gets more involved. Playing with reflections, bokeh and perspective is just basic fun. Certainly you will very soon come up against minimum focus, depth of field and other macro problems, all of which can be solved, all of which teach us something. Coming from the novice perspective we certainly learn to fill the frame.
OK the last of week 2’s Q&A, this time about CSC (Mirror-less) V DSLR. Undoubtedly a lot of nonsense has been talked about this. The alleged quality differences these days are pretty much that, alleged otherwise not proven in terms of general use, though certainly there are differences and certainly both have there advocates, but the reality is they are growing closer together for the everyday amateur and professional alike. Thing may be different at the nano-level but whether they are mission critical is another story entirely. Size, weight, battery life and access to lens ranges, are all “issues” largely of fan boys and people with other brands to sell, though each brand certainly has its own story.
The question is more nuanced than the badge on the front though. Perhaps the biggest selling point of a CSC/SLT Mirror-less camera is the fact that when you look through the viewfinder what you see is exactly what you get. This point alone (though it doesn’t stop people chimping I have noticed) I think is a, maybe the, major advantage for the amateur over the DSLR. It should, however, be noted that I am speaking here from the point of view of a stills photographer. The videographer has a different set of demands of a camera and may come to the same conclusion on either side of the argument, but for different reasons. Another part of this dynamic is the age of the camera you are comparing. In 2016 the differences seem to have shrunk, somewhat. In 2014, and into 2015, the dynamic range and the point at which noise intrudes definitely fell to the DSLR’s advantage. Then came the Sony A7 series and the big advances of the MK 2 versions of them the Alpha 6000 and 6300, and this week 6500; the Nikon D500; Fuji XT Mk2, even Hasselblad, they are coming thick and fast now. Some people seem to think that mirror-less is the future. They might be right but there is certainly life in the DSLR yet.
Ultimately it’s down to what you feel most comfortable with, of course.
Quiz Nights. You can’t beat them so we joined ‘em. Thanks to Myk Garton for putting the evening together, I know from first hand experience just how much effort goes into making it look effortless. And of course all participants showed themselves masters of their hobby. This week on the blog we will wrap up two of the three remaining questions from the Week 2 Q by looking at: What is front curtain, rear curtain and slow flash? And what is Back button focus? This week has also been the big European photographic trade show, Photokina, held in Germany, one year I will have sufficient time and money to go …..
Still, daydreaming aside, what is front curtain, rear curtain and slow synch flash? Flash, aka strobes, aka those lighty things, is an area that is both technical and often ignored by the amateur. Yet it is one of the most effective accessories we can purchase. After all most of us have one built into our cameras, even if it does get overlooked most of the time. There is more to this than we will look at here, indeed we will visit this in a future blog, but for now we will explore the question that was put concerning these three often found menu options.
For this specific question we do not have to differentiate between off camera flash (or strobes if you prefer) and on camera (that is pop-up or otherwise built in). The reason behind this is that this is a specific question of the firing order of the flash in relation to the curtain or shutter. Mostly this is done off the position of what is known as the front curtain. The majority of cameras have a two curtain (shutter) set up. This enables faster shutter speeds, the flash synch speed of your camera is actually around about the fastest speed that the whole of the sensor is exposed. Otherwise it is exposed through a slit formed by the front and the rear shutter curtains moving across the sensor plane at a fixed distance apart. The faster the shutter speed the closer the gap.
If you expose using a strobe/flash unit above the flash synchronisation speed you get a dark band of varying width according to the shutter speed as the duration of a flash is extremely short. Because the lens projects things upside down onto the sensor and the shutters move from top to bottom this band will appear from the bottom upwards. Not so much of a problem if you only need light at the top of the frame, but not actually something that is easy to fine control both because of the position of the shutter at any given time and how much darker the rest of the frame is.
So why have a front curtain flash and a rear curtain flash? It’s to do with the motion blur in the frame and where the pulse of light freezes that in time. The least subtle explanation, nonetheless one that actually holds true, is that you use front shutter curtain to freeze the action. You might use your maximum shutter synch speed (often automatically set but that depends upon make and model of your camera body) to give yourself the maximum chance of freezing the action. You use the rear shutter curtain and, usually, a lower shutter speed to freeze the foreground and retain some motion blur in the scene. And slow synch flash? Well that is an automatic camera mode that forces a slower shutter speed and synchronises the flash. You can get some very different looking results from the same scene using these variations. As ever, try it out for yourself.
Back button focusing, once you’ve tried it you will never go back. At least that is what its fans say and there is no denying that it is a very useful tool. We looked at this on the blog last August viz “Back Button Focusing (refer to your manual for the native translation in your Camera’s Brand-Speak) does exactly what it says on the incredibly expensive magnesium alloy tin, or plastic camera body as befits your pockets/needs/delusions of grandeur. It is a button on the back of your camera body that activates the camera’s focusing system in isolation from the shutter release. When you operate via the shutter release a half pressure triggers the autofocusing system (assuming you are not mounting a manual lens) and a full depress activates the shutter release. Usually the shutter will not fire until the camera processor detects all the algorithms are in place to produce a point of focus and an acceptable circle of confusion (i.e. something is in focus …). The button itself is usually marked AF or a version thereof and is normally accessible with the right thumb (I’ve never seen one on the left but then I haven’t conducted a survey in any depth). And it’s on the back of the camera.”
Yeah, that is what it is but what use is it? Well first off there is the fact that, whilst depressed, the AF button means that you hold whatever it is you have focused on. In the automatic modes focus shifts when you shift what you are looking at, which can be time consuming. In order to keep the focusing, for instance if you want to shift the main point of focus to the edge of the frame and blur the background. You might want to add to that you can use the continuous mode (AF-C or AF-Servo depending on your camera body manufacturer) of focusing on your camera when following action and use the AF button to freeze the most advantageous point (takes some practice but worth the effort with a high degree of movement in the frame). Or basically no more having to focus every time you let go of the shutter which takes time and can mean that you loose your shot. Annoying when it was already in focus the last time you half depressed the shutter.
So now you know. Next meeting is Table Top photography, a practical so bring your cameras and tripods. Maybe your flashes too!