Tagged: flash

4th January 2018 – Thinking small practising for big.

Happy New Year and we celebrated our return with a well attended evening of table top photography – next week we show the results. This is a good entry point to the year, it’s practical so we get to see and do with others and exchange ideas, but also it is something that we can exercise (more or less) total control over. Yes it might not be our “thing”, yes in the hall we are at the mercy of the overhead lighting and others waiting their turn (on occasion) but the opportunity is the thing.

 

The fact is we can, with very little resource, replicate these moments and use them to our advantage. Find an object – betting the house is full of them. It doesn’t matter what particularly, but, to start with, one that isn’t too shiny, so as we avoid bright spots (specularity) where light sources are reflected in the objects surfaces and not too big – it’s called table top for a reason. This can be controlled but we will come back to that presently.

 

For lights we have torches, they don’t have to be big and powerful (actually something of a disadvantage at close quarters). Some wire twists and something that will be stable when we attach the torch(es) to it as a light stand (or co-opt a friend or relative). Some plain paper to use as a diffuser and Christmas having just passed some coloured sweet wrappers for gels. If we want we can construct yourself a makeshift light box out of an old cardboard box and some grease proof paper, though there are even more minimalist options we can take. We can use tin foil and black card for reflectors and flags.   Ladies and gentlemen I give you your complete photographic studio in miniature!

 

So it’s an entertaining way to pass an evening, useful if we are selling small things on line and we can learn quite a bit about product shots in the process. But it also has other, practical, training uses. It doesn’t make a difference how experienced we are there is always a value to practicing, especially if it is on a subject we don’t usually do. Photography, as David Bailey once pointed out, involves dealing with what is there, photographers don’t enjoy the luxury fine artists have in that anything inconvenient in the scene just doesn’t make it onto the canvas.

 

We have to deal with what is in front of us. The studio is the closest we will ever get to that situation, in miniature or otherwise, being places we put things in rather than take things out. Being a photographer is about having an idea of an image and working with tools we have or can find to work towards what we visualised. Yes I know, that doesn’t really apply to street (actually is does but that is for another time) or at least some forms of street photography. Oh, OK, spray and pray, but like I said, that is for another time.

 

Perhaps the greatest part of this is that we can go through the whole process from visualisation to capturing an image effectively and quickly. And then we can go through the variations of the set up in order to experiment and learn.  Starting with a blank canvas, the light tent is exactly that, we can populate, arrange and light our little stories from scratch. It is a great way to practice basic lighting skills, pretty much for free. In fact thinking of the exercise of placing shapes in relation to each other in a way that gets the attention and lighting it is pretty much the basic definition of photography. Everything we do in these little vignettes can be scaled up. They are good fun and good practise.

 

There is more good practice to be had in controlling light angles too. We mentioned specularity above, basically unwanted reflections. The solutions are straight forward enough and apply to other photographic situations too. Basic rule of reflections is that the angle of incidence equals the angle of reflection. What that means for us is that to avoid glare from a shiny object we don’t need the light source and the camera to be facing the same way. Frame with the camera and then move the light around till the glare disappears. Start at 45 degrees to the camera, you should be plumb in what is known as the family of angles.

 

Constant lights are more convenient here but if we use flash and have triggers so we can use them off camera and using test frames and, of course, knowing the rule of reflection, we know where not to place the lighting in relation to the camera, so that is a start. You don’t necessarily have to have triggers though. The  rest of the solution isn’t complicated and if we use a “big” light source, say from a large soft box then the problem goes away. Don’t have a soft box? A light tent is one answer (basically a multidirectional diffuser). No? A piece of white card to use as a reflector, shoot with the camera facing the card, that will effectively diffuse the light.

 

Finally shadows are just as interesting, if not more so on occasion, and balancing out light and shadow is the root of generating mood in a shot. This is done with what are known as flags. They are used a lot in cinematography and videography. They are also used in product photography. Using them in a table top situation means that DIY options are easily available.

 

So, on these cold and dark evenings there is something to try out.

19th October 2017 – Mike Martin, Making Art Your Own Way

Mike Martin, a member of Kingswood Photographic Society, and a fine photographer, was our speaker. Happy to be a photographer who shoots with post production in mind and only himself to please, Mike showed us a strong, varied and interesting set of mainly art images, with some interesting detours into other genres.

 

He never accepts images as they come out of the camera, viewing this as a stop on the way to what he imagined in the first instance. This can mean a long time in post production, but as an unashamed amateur – i.e. he’s not shooting to a deadline and other people’s  tastes – this is a luxury he can afford. This is part of a long art photography tradition and now that we have the tools to do things in seconds what it would have taken hours and much coin to achieve – if it could be done at all – for an absolute fraction of the cost.

 

Although there is much to be said for getting as much right in camera, that is an awful lot easier when starting with the end in mind, in having a strong idea of what the finished product will look like. This may change as you go along but having a defined end usually leads to less time wasting. Not always, but usually.

 

This is not to say that we shouldn’t experiment or take on new ways of doing adjustments. There is a balance and if we want to learn then making ourselves a little bit uncomfortable by trying new things is going to be an essential part.  Looking, emulating, developing, employing is as good a learning cycle as any.

 

Mike also quoted Henri Cartier Bresson, which we have discussed before: “Sharpness is a bourgeois concept” – that is one that makes the holder appear self important and materialistic, shallow, pretending to be deep, unsophisticated and generally lacking in true class. Certainly it has its place – sharpness is one thing that sells new and ever increasingly expensive lenses. Yes you could back a modern lens against the ones that HCB used pretty much every time in the sharpness stakes, but it’s the brain behind the camera that makes a difference. Mind you context is everything:

“He had his little Leica,” Newton remembers, “and he simply would point and shoot.” Since Cartier-Bresson’s hand isn’t as steady as it used to be, some of the pictures were a bit fuzzy. “Sharpness,” he told Newton, “is a bourgeois concept.” Newton sits back and laughs: “I thought that was just divine.”

Dana Thomas interviewing Helmut Newton, Newsweek, 1 June 2003.

 

Movement certainly formed part of HBC’s photography, two of his most famous images in particular (“Man jumping over a ladder” and “A man rides his bicycle through the Var department”) and blur is certainly going to feature in that – as opposed to the shaky hand of the nonagenarian, as Newton observed.

 

So shaky hand blur and motion blur might be two different things. One will happen at some point in an otherwise unsupported situation as shutter speed, that is the length of time the shutter is open, comes down. Lens/sensor stabilisation certainly lowers the point to where such shake becomes evident and it can even be used as a creative effect by giving us time to move the camera around a fixed point or through a plane.

 

The motion blur we are probably most aware of is the one created by panning with a slow(ish) shutter speed. This keeps our main subject in focus and acceptably sharp  but blurs the background. We often see this used in motorsport photography  and it is also known as a tracking shot. The flip, of course can also be used, where we use a slow shutter speed with a fixed camera and our subject moves across the frame. So we can freeze or blur our subject to get a different feel of motion. The key to both is shutter speed. It can be achieved with a single strobe, or with mixed lighting, the key to both is synchronising the flash with the second curtain also known as the rear curtain. Essentially this means firing the flash at the beginning or the end of the exposure. The effects are very different

 

There is another way of using motion blur that you can use with a zoom lens. It’s called, wait for it, zoom blur. Again it really requires a tripod or at least a monopod because we are working with slow shutter speeds, but the mode, shutter, aperture, manual is less relevant. All these effects are relatively easy to use, but, as with everything else, need a little practice to get right. Even then, especially with unpredictable subjects, it is best to plan a series of shots to give you one or two to work with in post – assuming you need to. That said, motion blur is rewarding to play around with the effects and can also be used in the dark!

 

So an interesting evening that showed many possibilities, the value of forward planning and an artistic vision and not just by adding things in post, but in taking distractions out too. An interesting, varied and singular evening. Our thanks to you, Mike Martin.

12th October 2017 – Steve Dyer My Photography & Building An Off Camera Flash Set Up

This week we had our first of the season’s My Photography sessions, Steve Dyer taking us through his studio work including lights, modifiers and some of his post-production work flow. Some fine images, and a sound outline of the equipment he uses to get his preferred evening was an illustration of some of the talent we have in the club. And Steve was happy to state that the club has played, and continues to do so, a strong part in his development as a photographer.

 

We have looked at light modifiers in the last two posts of 2016, dividing them into soft light modifiers and hard light modifiers. We also referenced the excellent The Strobist website and it remains well worth the effort. These three will form the underpinning of the rest of this post, which will mainly, but not exclusively, be about building an off camera flash on a budget.

 

Steve has spent the last few years and not a little income in collecting his equipment he uses in his set up. The modifiers can be gained quite cheaply, but the build quality is what you really pay for when you buy the more established branded modifiers. One of the keys here is how core these pieces of equipment are to our particular form of photography. Another is our available budget, of course. It can be done relatively cheaply and here we will be looking at the options from a restricted budget perspective.

 

So, our mission is to put together a useable off camera flash with modifiers. Keeping within the basic theme we will start with the flash unit.  Canon Speedlites start at around £160 and, obviously, are designed to work with Canon cameras (though will work with other makes but might have limited use of extended features) and we can pay over £500 for the top of the range and into four figures for the specialist designs. Nikon is not so very different. But how low can we go? The main thing that we give up on a restricted budget is power, as expressed by the Guide Number.

 

The Guide Number (GN) is far more than this though. Usually expressed in meters (feet in the USA) the GN is a tool for calculating the light falling on the subject from that unit at a given distance or F-Stop. How does that work? Actually quite simple. I have a flash gun with a GN of 33. I am 2 meters away from my model. The GN = f Number x Distance. The industry standard is 100 ISO but check the flash-gun’s handbook.

So, back to school maths, GN 33 = f number x 2meters.

Therefore 33 / 2 = f number or 16.5. Set the aperture at f16 to f18 according to the capacity of the lens diaphragm.

 

In an ideal world going to 200 ISO effectively doubles the guide number. Well it would if it weren’t for the laws of physics. There is a thing known as the inverse square law. Double the distance means

four times the light to get the same degree of illumination on a subject. So ISO 400 to get twice the light on the subject from a 100 ISO base.

 

Now TTL metering will sort all this out if the flash unit and the camera are capable of dealing with it, but that basically doubles the cost of the manual flash.  Or we could buy a flash meter (make sure it is a flash meter not just a light meter, and better it is calibrated for photography. as we may waste our money) to do accurate calculations for us. However, dedicated off camera flash meters start at around £175.00. Not within our remit here. This is one area where chimping comes in and getting to know your equipment will really pay off. We can, with practice, get pretty close to right first time but, with the cost per frame and immediacy of digital, test frames consume not a lot other than a little time.

 

As we are talking off camera flash we will need some way of triggering the flash off body. Basically there are three ways to do this: Fixed cable (if the flash unit will take that, but most modern ones will); light trigger; wireless trigger.

 

Wired isn’t much, if indeed any, cheaper at the budget end of the spectrum than wireless. Light triggers (Optical) are built into the front of flash units so enabled and are usually encased in a red plastic cover. These can be triggered by other flashed including on camera flash if you have one built in. Wireless triggers are very popular and even the cheaper ones function pretty well, though it is necessary to maintain a line of site to ensure the flash triggers. The cheaper ones will be more prone to misfire, and will have a limited number of channels they can operate over (usually 4). The more sophisticated units cost more money, are better with weaker signals, can be programmed to fire in zones or sequences, even so there are some good units out there for not a huge amount of money.

 

As an extra and when you have one, essential, piece of kit to complete this summary, a light stand is a good investment.  A light stand will take your flash to a higher angle, usually up to about 9 feet, or just under three meters. This gives us a lot more lighting options.

 

So how much can we do this for? * At 16th October 2017:

 

Flash Unit, Amazon Basics (made by Godox) £26.

Neewer Light Modifiers for Flash £46

This is a pretty complete set and a good start. Refer to the Soft and Hard Light modifier links above and note that some of these quality of light is determined by their size. This is a good place to start, but by no means the only place.

Wireless Triggers  £11

Light Stand £13.60 (two for £22 also available)

All in around £95.

Thanks Steve, for the entry point. The rest of us, enjoy.

 

*There are lights, stands and back drops that members can borrow from the club. See Eddie House.

2nd March 2017 – On lighting angles

It’s all about the light. Not sure how many times I have written that here but it is but a small fraction of the times that I have read it everywhere else.  It is also right and not quite all. It does assume that the thing you have taken the time and effort to point your camera at has a semblance of interest to someone else and that the tools of composition have been suitably employed or ignored-to-particular-effect to create something for the light to fall on, isolate, enhance and otherwise make your efforts worthy.

 

Our next session is light painting, which is always very well attended and makes the light more obvious by reducing the size, direction, angle, distance, shape and colour. These are the six things that we need to control in order to be in command of the result of the single most important element in making an image. Please making, because there is a point to be made that the camera takes the image we make. Viewed from there you can see why a little deeper understanding of light might be useful as we have identified it as the most important element.

 

OK so light without shadow is nothing and we could equally be talking about controlling shadow, in fact that is a useful starting point in itself. It is probably this fact that makes the number one accessory to buy when launching out on this path of painting with light to go with your bright and shiny new camera and lens combination is a five-in-one reflector, though there are pros and cons in using it which need to be mastered.

 

So there are a number of general rules that apply that are useful to carry around in your head, or written down in a note book – what do you mean you don’t carry a notebook? How are you going to keep a record of what works and what doesn’t; or things to try at a later date; or quick calculations of the effects of filters on shutter/aperture? – more importantly to use. So let’s use this blog to investigate the position of the light relative to the camera – just to give that notebook a nudge.

 

Think of a clock face with our camera at 6 and our subject in the centre where the hands (yes it’s analogue) meet.  The light positioned anywhere between 10 and 2 o’clock is going to produce a silhouette and a light coming from behind the subject we would normally treat as a secondary light. We always have to add a source of  light, called a fill light because it fills the shadow in,  and that can be either a reflector or a flash or a continuous light source. This fill light usually comes from anywhere between 4 and 8 on our imaginary Rolex. Creatively a light coming from behind can help create a halo that separates our subject from a dark background but we always have to be careful to light the subject sufficiently. Spot metering can help give you an accurate reading (a separate light meter also has its uses and if we intend to do a lot of studio work  or outdoor portraiture, then definitely worth putting on the equipment list, especially if working with flash).

 

When we position the light source(s) directly from the sides, 3 or 9 o’clock, we get a very dramatic effect characterised by extreme contrast. Unless there is a fill light/reflector on the other side of the subject, the camera will record the subject as being lit on one side with a dark shadow on the opposite. This can be good if you want to create a headshot with a hint of secrecy or ambiguity, less so if you want to convey glamour or a full engagement with the subject.

 

When shooting with light between 4 and 8 o’clock, I’ll come back to 6 o’clock – the camera position – in a moment, this means that the light is coming straight over your shoulders . This has a tendency to produce a flat light lacking significant shadow. Images with flat light often feel like they lack depth and never quite seem to be as we remember the scene being or intended. Basically light and shadow often require further manipulation using diffusers, scrims or in-fills.

 

The six o’clock position is where the camera is and light is at its flattest. That’s why so many on camera/inbuilt flash photographs look so unflattering. Either side of the camera, shadows are created, and shape/texture become more obvious. The width of the shadows increases as the direction of the light moves from the camera towards the side, which is why we see so many lighting set ups set between 4 and 5 o’clock or 7 and 8 – basically 45° to the camera. As a start or a go to you can’t really do better, especially if working out what is going to work best or working a number of angles.

 

And talking of angles, there are three basic ones between camera and subject, two of which are frequently ignored: that is low, eye level and high angles. By far the most photographs are taken from the eye level, which is fine but there are opportunities to mix things up a bit and which will alter the balance of light and shadow too. Easy opportunities not always taken.

 

N E X T  M E E T I N G

Bring your cameras and tripods – 3D light painting

8th December 2016 – ROC Round 2 2016/17 and Light Modifiers

Round 2 of the club competition last meeting and I shall link to the club website here where the winning entries will be posted in due course. Club thanks to our returning judge Roger Mallinson who got though 21 prints and 58 Digital entries in a prompt and informative fashion.

 

This week we are going to return to the studio as it were, and start to investigate light modifiers as previously promised. So, starting with the obvious, just what is a light modifier? Yeah, ok, it’s something that modifies light, a true but otherwise unenlightening answer which we need to look at in a little more detail. If we take the word modify we can use it in two senses:

  1. To change in form or character; alter.
  2. To make less extreme, severe, or strong.

With light the second meaning is a consequence of the first, it is also an inescapable  consequence and though a tad obvious to some the conclusion is the same as the one that Mark and Rob gave us a couple of weeks back, that if you are going to do a lot of this then it is best to buy yourself a light meter. The reasoning is thus, every time you make an adjustment in intensity or distance (one and the same thing often times) then you are going to effect the elements of the exposure triangle and using the old saying: two measures to one cut as a guide, okay two measures to one slick in this case, means a lot of time effort and battery can be spared. For the occasional user then it is a case of trial and error. Eventually you will get to know your kit well enough to be reasonably accurate in your estimations.

 

There are basically two kinds of light modifiers which we can divide into soft light and hard light. Flash is the most likely entry point for a hobbyist into controlled off camera lighting. With flash we tend to use more of the hard modifiers, that is we use them more of the time, but both categories need considering.

 

The thing to remember, that is the thing not to get carried away with, is we modify light to enhance the subject. It is always about the subject, he, she or it, not about the modifier. Unless you are writing about modifiers I suppose. Still, that false conundrum aside we choose the modifier to light the subject, not the subject to show off the mod as a general rule. The subject is the thing. Always.

 

Soft Modifiers

So this week we will start with soft modifiers. Another term for light diffuser, because diffused light gives soft shadows, that is the differences between light and dark look more a gentle grey than a stark black. Make no mistake we are using the light to create shadow. Shadow is the form of the statement we are making and without light there is no shadow.

.

So a soft modifier spreads the available light over a larger surface, that is, larger than the source itself . Smoothing the transition from light to dark on your subject the main use of soft modifiers is for key lighting in portraiture. The key light is usually the primary light source, the brightest and most important.

 

The two most frequently used soft modifiers are softboxes and umbrellas. Softboxes are normally vaguely pyramidal and lined with a silver, highly reflective material. They come in a variety of sizes and those sizes relate to how soft the light is, not how wide spread the light is. Yes, you are right, those two things are directly related. Most softboxes and umbrellas are used at a distance of two meters or less from the subject. Though there will be differences in the areas lit between any two given sizes, at these sort of distances they are minimal and really, really not the point. The point is how diffuse the light is, how soft the shadows are.

 

Softboxes are a studio staple but they can be very bulky, heavy, require more than one stand and generally take up a lot of space even when not being used and can take quite a time to set up. They are good for using with other modifiers though and also good at controlling light spill (basically light coming through at unintended angles which may or may not intrude on your desired effect).

 

A subdivision of the softbox is known as an Octa, octabox, octadome or octa softbox/dome . Octas, as we will call them,  come either as an octagonal shaped softbox or as a hybrid softbox and umbrella. The angle and amount of light fall off is different to a softbox, but they do tend to be a lot more expensive and as bulky as softboxes.

 

There are further modifiers than can be fitted to a softbox or and octa. You can add grids (to give direction), flags (put shadows in), filters (control colour and intensity) to give you a greater control.

 

In case you are thinking, “Hey, I can make my own softbox” then I have to say, yes you can. The difference is in the quality control and the length of time that it is likely to last, but there is no reason why you can’t use tin foil and a cardboard box to put over your light source (flash gun rather than bare bulb, depending on the quality and exclusions of your house insurance and fire damage claims) and a plain shower curtain works wonders (make sure it doesn’t have  blue tinge if made of plastic and yes it will melt over a hot bulb). Go ask YouTube, there are many different videos covering this.

 

Umbrellas

Essentially umbrellas for modifying light as, opposed to keeping the rain off, come in two varieties: Shoot through and reflective. They are a little more untidy in the way that they deal with light, it will spill round the open edges. They are also prone to having a hot spot which may or may not prove a small problem. They are usually a lot cheaper than softboxes or Octas.

 

A shoot through acts like a lampshade, softening the light simply by putting a semi transparent material between light source and subject. A reflective umbrella is opaque, black on the outside with a highly reflective, usually silver, sometimes gold or maybe white interior. These are pointed at the subject so that the open side of the brolly is facing the subject and the flash unit faces the inside, away from the subject, to bounce light from all round the internal reflective surface from every attainable angle.

 

Umbrellas come in a range of sizes from small to huge (10 feet or more) and they are a low price, effective, portable light modifier. This makes them very popular. As already mentioned their biggest disadvantage is their tendency to spill light around the sides. Not a huge problem, normally, but one which does need to be attended to. Unlike softboxes there really aren’t any effective DIY options, but they can be bought pretty cheaply and so even if there was a DIY alternative the cost advantage would probably be very low.

 

Next week we will be looking at hard light modifiers and it is the club social, see website and or Facebook for details and Rob is doing a Bokeh session to boot.

24th November 2016 – Studio Portraiture

Two propositions to start with this week. Firstly, light travels in straight lines in a single direction until it hits a surface that changes its direction or other properties. Secondly, there are, in nature, three basic shapes: the sphere; the cube and the cylinder. Simple as that. Everything, I am reliably informed, is made up of those three shapes, and light travels in straight lines.

 

So to become a studio photographer: (A) Point your light at one or all of the above shapes and (B) press the shutter. And off we go. Shortest blog post ever ….

 

Er, no. These are three dimensional shapes and we, nearly exclusively in photography, work in a two dimensional world we spend a lot of time and more or less conscious effort to make the third dimension appear. Also this is, as was pointed out at the beginning of the evening, as much about shadow as it is light.

 

Surely that doesn’t apply to people, though?

 

Yes it does. When learning lighting it is normal to start by learning to light these three basic shapes. Cones you can make out of a sheet of paper. For cubes a box will do (doesn’t need to be particularly cuboid just represent a square in three dimensions, so a cereal box will do). A ball or even an egg will do for the sphere.

 

When you understand those and how light and shadow work on them thoroughly (many, many, many hours later) the rest is a mixture of experience, knowledge and imagination. And lighting, of course.

 

Starting as ever, with the rule of KISS (polite version: Keep It Short and Simple), members Rob Heslop and Mark O’Grady took us through a basic use of lights and reflector  in the pursuit of some classic look portraits, not forgetting our model for the evening, Summer. Summer, her working name, was rescued from redundancy from a closing Ann Summer’s shop late one Sunday evening, some seven or eight years ago and who has since been kept in a trunk by Mark. Summer, I should point out, is a mannequin. We don’t say shop window dummy any more, that would just be rude. However, it is still legal to keep her in a trunk. In two parts. If Burke and Hare, sorry, Mark and Rob, are to be believed.

 

Yes, well, we shall move on.

 

This is one of those areas of photography, and there are a few, where the general mantra of practice, practice, practice, is especially pertinent. It is also one of a very few where control is total (in a studio) and thus results easily replicated. So are mistakes. It is something worth taking a little time over (and recording, see below) because there is even less excuse than usual for saying “I’ll fix it in post”. If you have ever tried it and wondered why it never came out right it could be that you haven’t had enough practice yet. Or you’re not thinking in such a way as to develop your practice. Enter the sketchbook, a pre-photography art idea that really helps individual progression. The basics are fairly straight forward and this can be a process of getting to know your kit as much as it is getting to know the techniques. I really cannot overstate how useful a sketchbook is in purposeful development.

 

Mark and Rob produced a set of low key portraits (members see the club Facebook Page) using first one then two lights and a reflector. The key element to remember is that an image is a balance of light and dark. Light is what we control as an input, but dark is where the story is told, rather the interplay of light and dark is where the story gets told. There is nothing in the light without shadow. No depth and without depth a flat, unflattering, uninteresting picture.

 

One important thing that came across was that you have to remain aware that there are two elements in the setup that are or can be mobile. The model and the equipment. Most of a shoot can be taken up just changing the lighting positions, or adding light modifiers or changing the angle the photograph is taken from and it is quite surprising how relatively minor changes can make for quite large differences. Similarly slight changes in posture can radically alter the mood of a photograph – I refer you to Gerry Painter’s session last year on posing.

 

 

Ambient light is also an important factor, especially with flash. The first thing to note is that the shutter speed you are employing isn’t anywhere near as important in producing the look of your final shot up to the synch speed of your camera. Flash is of very short duration, thousandths of a second, the shutter has to be fully open so that the curtains do not make shadows across the frame. This is the synchronisation speed and is mechanically limited to around 1/250th of a second. Most cameras have a synch speed of either 1/160th or 1/250th. Some top end models have electronic synch where the shutter itself is part of the sensor and electronic. The problem with this can be that it affects the image by being too quick and hence the subject hasn’t been sufficiently bathed in light. The same end as with the mechanical shutter but a completely different reason – the shutter being too quick rather than too slow. Synch speed is about controlling the amount of ambient light the image contains. This is true for film or digital.

 

 

It is different with constant light, of course, where the shutter speed can be whatever is compatible with the constant provided by the exposure triangle and your processor. There are other considerations with constant light v flash, especially in a studio environment, which we don’t really have space for here. Most considerations evolve around compactness, other uses and intensity of light. Layout in terms of initial cost can also be a consideration, especially for the occasional user.

 

 

All in all a very informative evening and our thanks go out to Mark and Rob.

 

 

N E X T  M E E T I N G

 

Light painting practical.

 

 

22nd September 2016 – Quiz Night and More Answers

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!