There is a technical difference between Close-Up and Macro Photography but for practical purposes the techniques are similar. Close-Up very commonly involves a single exposure usually (but not always) employing a stopped down lens to accommodate the required depth of field. Indeed it is sometimes desirable to limit the depth of field for emphasis. True Macro, on the other hand, limits the available depth of field considerably. Stopping down and the use of a small sensor camera go some way to alleviate the problem but full control of depth of field requires a number of differentially focused images which are then combined to produce a single image. This technique allows a much enhanced depth of field which is totally under the control of the photographer. While this note contains points relevant to single exposure photography the emphasis is upon stacking.
Do s and Don’t s
Use a Tripod – The stacking software has a job to do aligning all the images before it can stack them. Don’t make its job harder.
Set Camera and Lens to manual focus
Arrange background – although you will be using a limited depth of field it is still best to use either a plain background or a pre-planned out-of-focus background. I have an A3 print of some foliage that I photographed deliberately out of focus.
Plan your light – Even if you have plentiful daylight, small details may well be difficult to resolve either because they are shaded or they are exposed to direct light where relief is lost. A light source from the side will help to detail relief. But beware of reflections from your background, again a light source from the side works best. If you are using natural light, beware days with a strong wind and cumulus cloud – your light will vary to an amazing degree.
White balance – You may well be using multiple light sources. If you have a white background it will turn grey if your white balance is wrong.
Use RAW and batch process your images in the RAW converter of your choice. Make the stacking software’s job as easy as possible.
Focusing – Opinions are divided on the subject of focusing rails. Adrian Davies recommends them but Zerene has an opposite opinion. It might be significant that Adrian had not heard of focus peaking. I have tried both a rail and manual focus adjustments using focus peaking. I find the latter very much easier and effective. If your camera will focus peak – use it.
Focusing again – It might not be significant but if your end results are disappointing remember that the optical viewfinder and the live view screen use technically different methods. The optical viewfinder uses ‘Phase Detection’ the live view ‘Contrast Detection’. They can, and sometimes do, have different focus points. My best results have been with the live view and focus peaking.
Aperture – Your depth of field will be minimal anyway so use the aperture at which your lens performs best.
ISO – Modern cameras are increasingly tolerant of high ISO. Don’t be tempted. Use the lowest ISO that your camera has available. Stacking software will stack digital noise as well! I have processed a stack that produced a horribly grainy resulting image. I blamed the stacking software and then Lightroom before discovering that I had inadvertently left the camera set to ISO 1600. Ordinarily my camera will produce an image at ISO 1600 which exhibits neither visible luminance nor chrominance. But a sequence of such images ruined the stack.
Take your time – You won’t be taking snaps. I recon on an hour per stack.
Range of focus – Start at either the front or back ensuring that your first and last exposure bracket the full range of desired sharp focus. Ensure that the images that you present to the stacking software are all in focusing order. If there is an image out of order the software will produce a composite image that you won’t want to use! The easiest mistake to make (I still do it regularly) is to forget that, whether you use a rail or manually re-focus, the actual area covered will vary slightly from frame to frame. Make sure that everything that you want in the final image is covered in each frame; the stacking software will produce a stacked image that is a common sub-set of the sequence of frames. In other words, you will only get that which is in each and every frame.
Be prepared to take a lot of exposures – I take at least 9 exposures per stack, usually a lot more and I have used up to sixty. If you are photographing true Macro and not just close-up you may need hundreds of exposures.
Shutter release – Don’t use manual shutter release; you will spoil the shot with camera shake. If you have a remote shutter release; use it. If you haven’t a remote then use the self timer although this will add to the session time. Before I bought my remote shutter release I was using the self timer; at the end of the photoshoot I calculated that I had spent three quarters of an hour waiting for the camera!
Stacking software – If you are braver than me you can use Photoshop to stack; I haven’t tried it. If you are serious about this genre of photography you will end up using either Helicon or Zerene Stacker. There is, still available on the internet, free software produced by David Hadley. I used to use this but had problems with later versions and as far as I know, Hadley stopped updating his program in about 2010. I use Zerene, I have not tried Helicon and I have heard (though cannot verify) that Zerene are enjoying an increasing market share. I won’t go into detailed use of the software here but am happy to help anyone who is interested in following this subject further.
Finally – Although stacking pre-supposes a static subject. Make sure that it is static. I have photographed sequences of flowers where my subjects slowly wilted. The sequence was more suitable for time lapse than stacking. Make sure that your subjects stay still; secure them in position if necessary. Try to maintain privacy; people moving, opening doors or currents of air can ruin your set. BANISH THE CAT!
David Bird 14/07/2016