Friday, December 13, 2013

Getting Started

 Rapala manea,  1/125 at  f11,  ISO 100

 

How's It Done?

 
As with most things in life, there’s no one method that's going to work in every situation. However, this is some of what I’ve learned over a fair bit of trial and error, (and mostly by not being too shy to ask people who are better than me how they do it. ) 





What are we aiming for? 

 

The picture above illustrates the classic butterfly photograph. All of the insect sharply in focus, contained within the frame and correctly exposed, with the background an out-of-focus mush a stop or two darker than the foreground and tonally different enough to give depth and separation. 

So, how to make that happen?

Well, not with the camera on auto – you need to control at least some of the parameters, and preferably all of them.  

The Importance of Aperture


Let’s assume we’ve got the macro lens on the camera. Mine’s the 100mm Canon – maybe you’re using a 200mm lens, which means you can be further away from your subject, but you’ve got more problems with hand-held camera shake. You win some, you lose some. 

Aporia crataegi,1/180 at f8, ISO 200
Perpendicular to the plane of the insect, so all nicely in focus.

To keep as much of the insect in focus, you need to be perpendicular to the plane of the insect. In this position, the insect's either in focus or it's not. However, it's not always possible to get square on to the insect, and in that case, depth of field becomes an issue. 

With a large aperture, f2 say, or f4, you'll find that part of the insect is in focus, but as you travel further away or closer to the lens, focus is no longer sharp. As you decrease the aperture, the amount of the insect that stays in focus increases.

So, to increase the chances of having the insect sharp in the picture, set the camera to aperture priority, and dictate an f-stop of f11.

 Thymelicus lineolus, 1/200 at f4, ISO 100
With this large aperture (f4), the eye is in focus, but as we move forward or back from that plane, the focus starts to drop off quickly.  Solve it by decreasing the aperture.

Why not go the whole hog and turn the aperture right down to f32? Two reasons – the first is that very little light will enter the camera, and secondly, depth of field becomes too great. Everything is in focus, which is the last thing we want – we are hoping to control what is in focus, and what isn’t. 


Papilio machaon,  1/200 at f22,  ISO 800
   At a small aperture, depth of field becomes too great. Here the background is as sharp as the foreground. We don't usually want this.

At the camera to subject distances that are the usual with macro photography, f11 is a good place to start. You'll see some photos here where I've tried to create something more interesting by using a large aperture, but it does make life much more difficult.


Argynnis adippe, 1/125 at f4, ISO 100
  Really difficult to keep the butterfly in focus at this aperture, especially if there's a bit of a breeze that keeps moving the insect towards and away from you. I should have gone to f8 or f11, and increased the ISO setting.

 

 

Focussing. To auto, or not to auto?


Are you going to use autofocus? Two schools of thought: one says you focus on the insect manually, then follow focus by rolling slightly backwards and forwards on the ball of your feet.  Me, I select the single centre point sensor, then use this to autofocus on the part of the insect that I must have sharp - I find it’s quicker and more accurate than my manual focusing skills. Not everyone agrees. The problem with autofocus is that you often have a stray piece of grass or stem in front of the lens, and it will try to focus on this rather than your subject. You’ll scratch your head wondering what on earth is going on, and why you can’t get a focus on the insect. 

 Cyanaris semiargus, 1/125 at f11, ISO 800
You don't have to get on the plane of the insect - it can often make for a much more interesting shot if you don't. Here I focussed on the eye, and kept refocussing as the butterfly walked towards me. And yes, you do often have to get on your belly to get the shot!


 


Limenitis reducta, 1/1500 at f2,8  ISO 400

A bit ambitious to hold focus at f2.8, but when it comes off, it really separates the insect from the background. Here the background would have been much sharper and more distracting at f11.


Where do you focus? The eyes normally, or just behind the head if the insect's in a position like Plebejus argus below with its wings open.  A picture where the eyes are out of focus is useless – if the eyes are in focus and the rest of the insect isn’t, you have a chance of creating something interesting. But the eyes must always be sharp. 
Parnassius mnemosyne, 1/180 at f8, ISO 400
I like this shot - slowly goes out of focus at the back, but that's OK. Nice splash of purple tufted vetch to give a bit of colour, and a perfect specimen of a rare butterfly.


Euphydryas maturna,1/200 at f4, ISO 100
  I used to try and shoot everything at a large aperture, but I had too many wasted shots. Here, the eye's in focus, but the palpi aren't. Shame - it's another rare species.


 
Coenonympha arcania, 1/200 at f4 ISO 100
Shot at f4. Again - would have been easier and safer at a smaller aperture. 
I got away with it here, with a nice soft focus blur in front and behind the insect. 

Carterocephalus palaemon,1/125 at f5.6, ISO 100
 The head's in focus, so the wings can afford to lose some sharpness, but with a bit of fortuitous back-lighting from the sun it makes a nice picture. 




Watch your Exposure


So, we’re shooting at f11. If we’re on aperture priority, point the camera at something in the light that you expect to be shooting, and see what exposure is suggested by your internal meter. If it’s less than 1/125, you’re going to have difficulty holding the camera steady enough without a tripod (and who chases butterflies with a tripod, in spite of what the magazines suggest?). The rule here is that you don’t try to hand-hold a camera when the exposure is more than the reciprocal of the lens focal length.  So, if you’re using a 200mm macro, don’t try and hand-hold at more than 1/200. If you’re using a 100mm lens, you should be able to get away with 1/100. Any more than that, unless you've got a very steady hand, your pictures will be subject to camera shake and will appear out of focus.(easiest way to tell - if all the picture is similarly out of focus, the problem is camera-shake. If you can detect a plane in the picture that is in focus, albeit not the one you intended, then you focussed incorrectly).

Melitaea phoebe, 1/200 at f9.5, ISO 200


So often a compromise - make the aperture any smaller to increase depth of field, then  I'd have to increase the exposure. But if I go much smaller, the exposure will creep up towards my hand-held limit of 1/100


 
Plebejus argus,  1/180 at f8, ISO 200

Not quite on the plane of the insect, but still pretty sharp from top to bottom. Here I'd focus on the thorax, just behind the head, to keep as much of the wing area sharp.If I'd focussed on the head (which is the part of the insect closest to the camera), I would have started losing focus on the area furthest away (the hind wings).


So, if the exposure is threatening to come in at, say, 1/50, what options are available? First, wait for a sunnier day, or find a sunnier location.  Secondly, increase the ISO reading until the exposure is inside that reciprocal limit. (But be aware that you’re sacrificing quality as you move from ISO 100 to 800 and beyond. The acceptability of this quality loss will depend on the make and model of your camera and what you intend doing with the final pictures. Are you printing A1 posters, for instance?) Thirdly, open up the aperture to f8, or f5.6, but realise that in doing so, you’re sacrificing depth of field. Your focusing will have to be more accurate. 

 

 

 

Background Briefing


So, at this stage, go out and take some photographs of insects. You’re aiming for pictures that are correctly exposed, with foreground (ie the insect) sharply focused, and the background out of focus.  Keep an eye on the background – it's easy to get absorbed in the insect and not realise what's happening behind – and aim for an attractive tonal variation. Often just moving slightly to one side can greatly improve the shot because of a background change. 


Danaus chrysippus,  1/125 at f11, ISO 100

Danaus chrysippus, 1/125 at f11, ISO 100
 It's easy to not notice bits of distraction until after you get home. That second stem in the top pictures ruins the composition.Often just a small change of position (of the photographer!) can improve the shot.




Danaus plexippus,  1/350 at f8, ISO 400

Danaus plexippus,  1/350 at f8 ISO 400

The first shot has distracting grass blades around it. The second is better, but still not getting much tonal separation from the background - that's another issue.








Thymelicus sylvestris,   1/125 at f9.5, ISO 400

 Nasty bit of distracting background that spoils the shot.


What do we want from a background?  A tonal variation from the foreground, darker or lighter, to create a sense of depth in the picture.  By also throwing it out of focus, we make any individual elements in the background much less distracting. Because we’re using depth of field (or lack of it) to mush the background, the further the background is away from the main subject, the easier it is to get that separation.  Of course, this assumes there is some physical separation between the insect and the background, otherwise you’re stuck with the same treatment for both.

Carcharodus lavatherae, 1/250 at f6.7 ISO 800
Background doesn't always have to be darker than the foreground. Here, with a fairly drab and dark subject, the lighter background and the pink of the plant work OK.The sun backlighting from the left hand side helps as well.



Libythea celtis   1/125 at f8, ISO 400
 Sometimes you struggle to make an insect look interesting. Here we have to rely on the "attitude" of the subject. 


Here’s where the depth of field preview button on the camera comes into its own. Find out how to use it. With experience, you’ll find you need it less, but it’s very useful when starting out with macro photography to be able to preview your finished result. (Without the preview button, you’re viewing the depth of field at the largest aperture of your lens, not the aperture that you’ve selected for the picture). 


We can enjoy taking photographs like this for quite a while.  But we can do better. 



Getting Flashy

The next quantum leap in making quality photographs comes with using flash. It enables us to operate in areas where it would otherwise be impossible, means that we can use smaller apertures, puts vibrancy into otherwise flat pictures  and gives  us control over the tonal difference between foreground and background. 


Tanaecia pelea  1/100 at f2.8 ISO 800
 Here in the forest I had no flash, so had to open up to f2.8 with ISO 800. It's all very flat and disappointing.



Zerynthia cerisyi  1/125 at f11, ISO 400
  The problem here was that the background and foreground were tonally too similar. Without a flash, it was hard to separate the two in the soft early morning light.


Melitaea ornata 1/125 at f8, ISO 400

 Same location, same time of day as the shot above, but by choosing a different background there's just enough separation to make the shot work without flash.



If you’ve got a dedicated flash that goes with your camera that uses TTL metering, or some variant thereof, you’re most of the way there. The TTL metering works in such a way that once the subject of the picture has received what the camera calculates to be sufficient light from the flash, the flash is shut off. 

What this means is that you can no longer alter the exposure on the subject by changing the aperture. The flash automatically determines when the subject has received sufficient light - if you reduce the aperture, the flash duration will change to compensate.

So, set the flash to TTL, and the camera to aperture priority. Set your white balance to flash (it's not too different to daylight) or leave it on auto. Start with ISO 100, and set the aperture to f11. Now shoot your insect. 

You should find that the foreground is correctly exposed, because the flash will cut off as soon as your camera’s internal meter believes that the point indicated by your sensor has received sufficient light - a much shorter time than the total exposure allowed. The flash is taking care of the foreground automatically. But what has happened to the background? 

Depending on the level of ambient light (ie the natural daylight falling on your background), you re quite likely to find yourself in a situation like this.



Glaucopsyche alexis, 1/200 at f9.5, ISO 100
Pyrgus sidae, 1/200  at f9.5, ISO 100
It now looks as if you’re shooting butterflies at midnight – which isn’t an attractive look. In this case, increase the aperture, or the ISO setting, to bring the background level back to an acceptable level. 
(Incidentally, these shots have also succumbed to the inherent tendency of the Canon flash to slightly underexpose. This can be fixed in the camera menu by dialling in a flash exposure compensation. Personally I don't bother, as I've always considered underexposure much easier to correct in post-production than overexposure. If your'e one of those who likes to get it all correct in the camera, then by all means compensate.)

There is now an issue that we hadn't anticipated. The insect is receiving an exposure via the flash, but also a (smaller) exposure from the same ambient light that is lighting your background. As long as the insect doesn't move, this isn't going to be a problem, but it becomes an issue when taking shots of certain butterflies and moths. These tropical swallowtails never stop beating their wings, so the ambient exposure now becomes a problem:



Graphium sarpedon, 1/125 at f11, ISO 200
Flash can freeze the motion for us at 1/1000 or even less, but it can't stop the blur from the exposure that we're giving the background.  The insect is receiving both the very short flash exposure (which is sharp), and the longer, non-flash, ambient exposure of 1/125, whcih creates the blur on the wings. A smaller aperture and lower ISO setting would have prevented this, but we'd then have the "midnight" effect discussed above.(Many photographers will set their camera to "second-curtain synch" in these circumstances, so that if there is a blur it is behind, rather than in front of the sharp part of the picture - a more logical look.)



These are very challenging beasts to photograph well. The problem is not so much the speed of their wingbeats - we can freeze this with the flash - but how to handle the consequent background issues and prevent the "midnight" look. (Another strategy on a bright sunny day is to abandon flash altogether, and aim for a very short exposure with a wide aperture, but this poses other problems - these are fast-moving insects, so chasing focus with a wide aperture demands real talent)



Papilio polytes, 1/125 at f11, ISO 200




As long as you're using your flash in  TTL mode, it will continue to correctly expose your foreground while the background exposure changes.

Your aperture and ISO settings may need to change slightly as you move from place to place, and as the sun/cloud cover changes. Usually, what you'll be doing is setting the camera aperture and ISO to slightly underexpose the background, and then using your flash to create the principal exposure on the foreground. 

 1/125 at f11, ISO 800



I fire off a few shots like this when I arrive at a location, just to check that I'm getting the right sort of exposure on the background, and a decent separation from the foreground. If you're not happy with the background exposure, you can change your aperture (which will also change your depth of field), or your ISO setting. Throughout all this, your foreground exposure will remain unchanged as long as your flash is set toTTL.(Not strictly true, but it'll do for now)

So, if you change your aperture setting (remember, we're still on aperture priority), what changes is the exposure for the background. The subject is lit (primarily) by the flash, and this will override, but not totally eliminate, the ambient light exposure.

Over to You


So is that all? Of course not. 

You’ll find that the flash is a bit harsh, creating unwanted highlights  and making the insect look “lit” unnaturally– a soft box will greatly improve the look, giving the impression that the insect was illuminated by natural light.

Cethosia cyane  1/80 at f18, ISO 100
A raw flash gun can be harsh - the soft box makes a huge difference.


Softbox attached to the flash. Don't leave home without it.

Anything that diffuses the light will do - you can improvise with greaseproof paper wrapped around the flash head. Mine looks more sophisticated than it really is, I think I paid about $10 for it. You just put it round the flash gun and pull the elastic tight.


The softbox is not much more than a couple of bits of cardboard, but it makes a huge difference. Get it from here:
http://dx.com/
(and lots of other great gadgets and toys, too.)




Polyommatus icarus,  1/200 at f9.5, ISO 100
Just because it's raining doesn't mean you can't take photographs. With the softbox, the flash gives a natural look.



Ideopsis vulgaris 1/125 at f11, ISO 200
Photographed in the middle of a rain storm. Background darker than I'd usually go for, but it's a difficult insect to separate from the background.Should have increased the aperture a little.


You may find that because of the location of the hot shoe on your camera, the length of the macro lens causes a shadow to fall on the bottom half of your frame. You may then find it desirable, (and take better pictures too), by mounting the flash in a different position –coming in from about ten o clock gives much more texture in the shot than a flat-on flash.

A better arrangement, with the flash held away from the axis of the lens. But a bit more ungainly in the field.


If you’re in a studio setting, or dealing with subjects that are static, then a tripod, or a monopod can be useful, and give you more scope for exposure settings. In my experience, a tripod is useless for photographing butterflies unless the insect has been stunned by freezing (and I don’t do that).  

Softbox, flash cord, articulated arm and bracket, to mount the flash away from the axis of the lens.
 








I use this toy a lot to see the results of experimenting with exposure, aperture and ISO setting. It's about the size of an insect, and it's easy to see whether focus is an issue or not, and how the background exposure is working. (Also stops you getting bored if there's nothing around to shoot. Kastner & Oehler, Graz, 2 Euros)



There's plenty more to talk about. Moving from aperture priority to full manual on the camera gives another level of control over what happens to that background.  To ring-flash or not to ring-flash? Flash exposure compensation? Full manual flash exposure, rear-curtain synch, RAW or not? 


Let me know if you don’t follow any of this. It's not the whole story, but it should at least get you started. The secret, as you know, is practice, practice, practice - and the beauty of digital is that you get instant feedback.






















No comments:

Post a Comment