I thought it might be an idea to post a few (
) words on a couple of issues that are coming up regularly when photographing flies. This came out of discussion on mrtrout’s very useful thread on Backgrounds.
It is clear that a lot of folk have problems getting their fly shots sharp. Several factors are at play here, so let’s address them one at a time.
(I should add that I am addressing archive shots of flies, where we want the thing to look as sharp as pos, rather than arty shots, where we are deliberately setting it up so it is part in-focus, part blurred.)
1 FOCUS
The main problem with focusing is that the plane of accurate focus is literally a plane. After that, it is a case of how much more of the scene you can convince the eye is also in focus - nearer the camera and further away from the camera. This apparent range of extra focus is called depth of field. One third of it is in front of the subject, and two thirds behind it – that is often worth keeping in mind when choosing where to focus. Several factors affect how much depth of field you have.
1 The aperture of the lens. The more closed down the lens, the more depth of field. However, closing down the lens to very narrow apertures softens the image, so beware of using f32!
Have a play with the DP Reviews widget…
Here is my macro lens laid bare…
Lens performance
Note that it does its sharpest work around f7.1.
2 The focal length of the lens. If you are doing landscapes with a wide-angle lens at 15 mm, you will naturally get a lot of the scene in focus. If you are using a 100 mm lens, you will get a lot less in focus. Macro lenses good for flies are often around the 100 mm mark, so that is one reason we struggle with our fly shots.
3 Distance between camera and subject. Again, if we are shooting a distant landscape, focusing is not a big issue – it is often set to ‘infinity’ or near it. The closer to the camera, the less depth of field you have. So, where is the fly? About 2 inches away! More problems
4 Sensor size. The larger the sensor on your camera, the less depth of field you have, everything else being equal. So, those with a full frame sensor such as on a Canon 5D will have much less depth of field than those using a compact.
So, taking all the above on board, what we have is a problem to get the fly in sharp focus. The best way I have found follows. You may be able to do similar with your set-up, you may be able to adapt it for your set-up, you may have your own way. What is essential is that you get a part of the fly that the eye will check for focus sitting bang on the focal plane.
Remember that you may have less than 1 mm of play either side of the plane, so you need to be physically able to fine tune your focus. The best way to fine tune is to forget about camera settings like autofocus, and even turning the focus barrel on the lens, but actually move either the camera or the fly. You can’t in practical terms move a camera back and forth less than 1 mm at a time unless you have a macro rail...
macro rail
I prefer to move the fly. That means having it in something that can move easily, so don’t put your fly in a rigid vice
. Stick it in one of Scratch’s fly clips and attach it to a mobile base with a blob of Blu-tack.
The eye looks for something that it can tell is in focus. The dressing is a bit nebulous – fibres sticking this way and that – towards and away from the camera – so I reckon the eye generally checks out the metal of the hook - the point or the eye or both. So, if you can get the hook point and the hook eye looking sharp, the rest will be accepted regardless. So, start by lining up the fly so the hook point and the hook eye are the same distance from the camera’s sensor.
Next, I put my camera in ‘live view’ mode, which displays the image on the LCD. Compacts do this anyway. Then I use the 10x zoom feature so I can zoom-in on the hook point. If you are using a compact it may have a similar feature available. If so, I highly recommend you use it. When I have the magnified view of the hook point on the LCD, I move the fly back and forth until I see it as sharp. As I keep saying, there might be less than 1 mm of travel between sharp and horribly blurry!!!
2 EXPOSURE
Exposure affects sharpness. You want to have the shot correctly exposed, or slightly under-exposed for maximum sharpness. If it is over-exposed, the extra light ‘bleeds’ into your edges and takes the sharpness off them.
3 MOTION BLUR
If you are using tungsten/halogen/LED etc lighting, you will often be running into seconds with your shutter time, so you need to stay stock still when taking the shot. Any movement you make will vibrate desks, tripods, fly mounts, cameras, and that vibration will transfer to the image. If you have an SLR, use mirror lock-up. Always use either a remote shutter release cord or the self-timer to take the shot.
4 PROCESSING
The original image formed by the camera has been softened slightly by a thing called the low pass filter. This sits in front of the sensor and its job is to avoid the formation of moire patterning. You therefore usually need to apply a bit of sharpening to get back that razor’s edge look (if you seek it). If you shoot JPEGs, your camera will have added sharpening when it has been processing your file. If you think your shots could do with a bit more, you should be able to adjust the amount in your menus. If you have it ramped up full and think it could do with more, you can add it in Photoshop, but you need to be careful you do not overcook it. You should not use sharpening to try to cure a shot that was blurry due to poor focusing or movement – it won’t manage it.
For folk who shoot in RAW, you are best to do your RAW processing first with the sharpening sliders set to zero. Then, resize for web presentation and only then add sharpening in Photoshop. I use a plug-in called Power Retouche, but there are myriad tools with myriad ways to add it. Here is a Powerpoint slide-show to let you see how a fly looks with varying degrees of sharpening added.
Sharpening slide show
The numbers just happen to be Power Retouche’s 'Smart Sharpen' values. Your method will have its own measures. If you keep hitting page down you can scroll through all the amounts and see how its appearance changes – eventually jumping back to zero.
You will see that with all sharpening at zero, the basic shot is in focus, but with a slightly soft appearance. Depending on how you like it to look, you could go for any of the zero, 50, 100 or 150 settings. By the time you get to 200, and worse at 300, the ‘aliasing’ is giving the hook point and diagonal deer hair fibres a ‘stair-case’ look. There are also white halos starting to appear outside the dark edges. Too much!
5 PRESENTATION
Lastly we come to what you can do to get your fly to look good when it is posted. The forum display system changes the zoom on images larger than 758 pixels wide. With some browsers, such as Internet Explorer, images displayed at close to but not equal to 100% zoom can look distorted, which may affect sharpness. So, I would suggest you make your files 758 pixels wide and avoid that possibility. (Also, suggest changing to Firefox if you are using Internet Explorer.) We also suspect some auto-resizing systems (Photobucket
) may be causing issues, so recommend you do your own resizing.
Resizing and sharpening are highly destructive/reconstructive processes, so it is no wonder they can mess with your precious images. If you are working with RAW files and going with applying the sharpening last, you should resize the image to 758 pixels first, then add the sharpening. If you shoot JPEGs you should do as little as possible to them after they come out the camera, as the camera has applied sharpening and intended it to be a finished article.
Hope the above helps.
Col
Getting fly shots sharp
SKB tackle supporter. I love Furled Leaders.
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