Macro lenses are some of the sharpest optical lenses you will find because a good macro needs excellent spherical and chromatic compensation. The downside to macros (vs non-macro primes of the same focal length) is that they are slower in autofocus, and generally poor in low light autofocus.
My previous macro photography kit (50mm prime lens with a x10 diopeter attachment) has got me pretty far with mimimal outlay. The trouble is that I’ve outgrown that setup.
Firstly, the lens I was using gives a very small focusing distance. That was not a problem until I started thinking about using a flash. The distance between the camera and subject is too small for me to add artificial lighting.
The second issue is that although I was getting pretty sharp images, they were only that – pretty sharp. I wanted to get my hands on a true macro lens so I could go really sharp.
Here’s the updated kit that solves my problems;
How did I arrive at that combination? Well, with macros, there’s actually not much thinking involved…
Macro lenses: the technical basics, quickly
- A true macro lens is one that can focus close enough such that the image seen by the sensor is the same size as the original object. Your images are invariably bigger than the sensor, hence the final subject will always be magnified. Manufacturers generally call a true macro a ‘1:1 macro’. We will call them ‘macros’.
- Macro lenses are some of the sharpest optical lenses you will find because a good macro needs excellent spherical and chromatic compensation. Nobody makes a bad 1:1 macro lens. Read that last part again, its important, as it will stop you poring over loads of reviews (and I should know; its the conclusion I reached after reading practically every Tamron 90mm/f2.8 vs Sigma AF 105mm f/2.8 EX macro DG review there is and poring over online sample shots).
- The downside to macros (vs non-macro primes of the same focal length) is that they are slower in autofocus, and generally poor in low light autofocus. The reason for this is that macros tend to have more turns on their focusing screw thread. This is neccessary for fine adjustment when focusing at short macro ranges, but is clearly a disadvantage when focusing on mid-distance fast moving action. Although macros tend to be fast glass (e.g. f2.8), don’t assume they can be used just like a fast prime.
- Normal lenses sometimes also have a macro mode. Such modes are not true macro as they (a) do not achieve 1:1 (they usually get to 1:2 or 1:4) and (b) they are not at their sharpest at macro distances. We will call such lenses ‘standard lenses’. You should only consider a standard lens with macro capability if you only see yourself dabbling occasionally in macro photography.
Buying a macro: the basics, quickly
- Although macro lenses can be expensive, they have a smaller market than standard lenses and you will usually be able to find one brand of macro lens on sale if you are able to wait a couple of months. As nobody makes a bad true macro, you will save a lot of head-scratching and poring over online reviews if you simply pick the first one that you see reduced to a reasonable price. All you need to be sure is that it is a 1:1 macro. This advice is an approximation but it works pretty well for APS-C cameras and third party lenses (Sigma/Tamron, etc). For the best possible full frame macro lens, you probably need to buy the (much) more expensive ‘camera manufacturer’s own lens’ (Sony/Nikkor, etc).
- Once you have selected a lens brand, the next choice is focal length. The longer the focal length, the further away the front of the lens will be from the subject. A 50mm macro lens is fine as long as you do not expect to photograph insects (the end of the lens will be almost touching the subject, so they will take fright and crawl/fly away… or get squished!) and nor do you expect to add artificial lighting (because at 50mm there is not sufficient distance between the front of the lens and subject to introduce lighting). If you want the ability to photograph insects and add lighting, you need at least 90mm or 110mm. The downside at 90/110mm is that you have to be some distance away from a subject if you want to use the same lens for portrait photography (you have to be about 3m away with a 90mm to get a good head and shoulders portrait and several metres away to get a full body shot).
I chose Tamron simply because they were on sale and therefore 40% cheaper than the same Sigma lens, and over 100% cheaper than the same Sony lens. I chose 90mm as I wanted sufficient focusing distance to be able to photograph bugs without scaring/squishing them, and so that I could add artificial lighting.
I should note that there is one big downside to the Tamron 90mm against the Sigma/Sony lenses; the Tamron is quite possibly the ugliest camera lens I have ever seen!
There’s a lot of good things about the Tamron optically though, including its sharpness and its general ease of use in macro (discounting perhaps the slow auto-focus and tendancy to ‘hunt’, something that is common to all macro lenses). The most striking good thing about the Tamron for me was its colour reproduction. The lens produces noticeably deeper colour than any other alpha mount lens I have tried.
I’m sure the image above won’t do justice to the vibrancy that this lens produces (as it’s a jpeg created from the original .ARW raw file), but take it from me, this lens produces very sharp and vibrant images that need little post correction.
The lens has a nice limiter switch which has the effect of limiting the focal length from either min focusing distance – 45mm (which you would typically do for macro shooting) or 45mm – infinity (which you would typically do if you were using the lens as a portrait or prime). The effect of limiting is to at least double the focusing speed.
Like other macro lenses in the same price range, the Tamron uses external focusing, meaning that the lens gets physically bigger the closer the focusing target is. Internal focusing (where the lens groups move relative to each other inside the lens) is only available in more expensive lenses. My personal opinion is that internal focusing macros are only useful if you have a full frame camera that can make use of the additional optical quality that tends to come with the better overall build quality. The differences are either slight or non existent for non full frame cameras. Paying double just for a lens that doesn’t change size on my APS-C camera doesn’t add up for me!
One thing to note about the Tamron (and probably, other macro lenses) is that although it is a constant minimum aperture lens, you will often see the aperture change as you zoom in. This is not due to the lens, but is instead the camera compensating for low light; as you zoom in on a macro shot, you cut out more and more light, and it is this (rather than the optics of the lens itself) that cause the aperture change. The issue will occur even on a bright sunny day. The only way to fix this issue is to compensate with a flash, which takes us smoothly onto our next section…
The easiest way to light a macro shot via a single source is by using a ringflash. As you can see from the first image in this article, a ringflash is circular, with the lens looking through the middle. Ring shaped lights are useful in macro photography because they provide even, shadowless lighting when viewed from the camera. They also avoid the camera casting a shadow over the scene, as would happen with a standard camera flash.
A ringflash is also very good for portrait photography – the ‘even shadowless’ bit works well when photographing faces.
The problem with ringflashes is that they are expensive. They are so expensive in fact that the web is full of homebrew versions. See http://strobist.blogspot.com/2006/09/super-cheap-diy-ring-flash.html for a typical example.
You can also avoid paying out for a true ringflash by using a converter such as http://www.ray-flash.com/. Finally, you can use a cheaper LED ring light rather than a ringflash. These use a circle of LEDs rather than a true flashgun – think Christmas lights arranged around the front of the lens… I’m told these are actually ok for macro, although they are useless for portrait photography because they are simply not that bright.
After lots of searching I found a very cheap true ringflash for alpha mount; the Dörr (sometimes spelt ‘Doer’) DAF-14. The Dörr website (http://www.dorrfoto.co.uk, or http://www.doerrfoto.de/ if your German is good) no longer lists it for alpha mount, but it is still available on Amazon UK) but you may have to be quick!
Physically, the DAF-14 has no controls other than an on/of button and the standard manual ‘testflash’ red pushbutton. All configuration occurs through the camera menus. On my Alpha500, the Flash works pretty much flawlessly, with few misfires (and what few misfires I have seen are usually due to my bad camera settings).
Re-charge times are pretty fast for a flash that is priced in only double figures; the ringflash typically charges within a couple of seconds.
Update 2012: As noted in the comments section of this post, the Dorr ringflash does not work with the latest Sony SLT cameras. See comments for more information.
Tamron 90mm 1:1 macro and DAF-14; sample shots
When photographing in macro, you do not usually use a ringflash for shooting under low light. You use a ringflash to get the shutter speed up and/or to enable you to stop down the lens to increase depth of view. Doing either will give you a sharper image.
To illustrate this, let’s first look at a shot taken in perfect lighting conditions. This image was taken under a bright, high sun, immediately preceded by rain (i.e. typical British August weather!).
The image looks ok, but if you look at actual size (1:1 pixel), you see the problem;
Macro photography requires lots of light and still subjects. In this shot I actually have both, but its still not enough to avoid blurring. Although I am shooting hand held, using a tripod would only fix half the problem; a still camera is some use, but the leaf is still moving slightly.
A better way forward is to use the ringflash. Yes, even in high sun! Take a look;
As is normal for macro, I am shooting in Aperture Priority mode. The use of the ringflash has not significantly changed the composition tone or colour, but it has increased our shutter speed to 1/160s. This has a significant effect on image sharpness;
There, much sharper! Unfortunately, as the god of photography gives, she also takes. We now have a second problem; we can see the ringflash! Note – you will rarely see the ringflash in this way, I am just using examples with very reflective surfaces purposely to give us a good, difficult macro example. The fix is actually easy though; just use the healing clone tool in Lightroom.
Here’s another example;
Although the second image above has the ringflash healed out, I have made no changes to colour and tone. The colours are as-shot; another example of the nice colour reproduction the Tamron produces. Also worth noting here is the lack of any shadows that suggest that I am actually using a flash at all.
Here’s a final macro shot. In this one, all I’ve changed the as-shot is exposure by +0.5 in Lightroom;
Again, the ringflash is working with an optically accurate lens to give us a very sharp, focused image, even though I am hand held (and stopped down to f18!).
You might think that this shot could be done with a standard flash, but note that the lens front is about 5cm from the subject. A standard flash would not work at this distance as it would cast a shadow from the lens onto the subject.
I’ll also post some of my recent portrait ringflash shots as soon as I get the appropriate web-publish permission.
Macro lenses are some of the best optical lenses you will find, although they tend to suffer from poorer (slower) autofocusing when compared against standard lenses. The biggest deciding factors when looking for a macro lens is camera sensor size. If you are using APS-C, then the cheapest mainstream third party camera lens (Sigma, Tamron, etc) will almost certainly suffice. If you are looking at full frame, I suspect that you will have to go for a more expensive manufacturer (Sony/Nikon/Canon, etc) lens.
Ringflashes are very useful in macro photography. The major advantage of a ringflash in macro is not typically that it illumiates the scene, but that it allows you to use a much faster shutter speed. Ringflashes can be very expensive, but decent cheap true ringflashes are available if you are prepared to search a little. As cheap ringflashes are available, I would not recommend some of the home brew alternatives (although they can be fun to try!). LED ringlights are another cheap alternative for macro lighting, but they suffer from much lower maximum brightness and are useless for portrait photography, whereas a true ringFlash is useful for both macro and portraits.