Macro lenses are very special purposes lenses, often in the 100mm and 200mm focal length and are pretty much all prime lenses! Wait you say, I have a macro zoom lens! Well, yes, we will discuss that in a bit.
Essentially in a nutshell any macro lens is a lens which is designed for photographing tiny objects at often very close distances, although the 200mm focal length lets you get back a fair distance – at least for a macro lens it is fairly far. Any macro can focus very much closer than any other lens, often measured in just inches, allowing something the size of a twenty-five cent piece to fill the entire viewfinder and generally have a very high level of sharpness and detail.
The use of macro lenses is wide and varied, and courses exist in local community colleges teaching how to use and some ideas, however typically they focus on things like water droplets, coins, insects, plants or whatever peaks your interest.
Having said that although a macro lens is designed and optimized for very close work, you can use for pretty much anything including photographs of the moon! (for the longer focal length ones)
One important aspect of any macro lens is the magnification ration, or reproduction ratio, which I did elude to briefly above. This essentially is how large the original subject will appear on the sensor or film at closest focus distance. If you have a reproduction ration of 1:1, that means the image on the sensor will be the same size as the original subject. Historically a lens was never considered a true macro lens unless it could achieve a reproduction ratio of at least 1:1 (life size) and some we went well beyond that! Yes it is true in any real definition a lens is not a “true macro” unless it can achieve at least 1:1 and some can go as high as 5:1 – that I five times as large on sensor a life size! Tell that to the marketing teams, as they now brand lenses as macro which are a little closer focus but have no where near a 1:1 reproduction ratio, many can not do any better than 1:3 and one side note almost all true macros ever made are prime lenses and NOT zooms!! These lenses branded as “macro” not only do not provide a high reproduction ratio but typically produce relatively low quality photos when compared to a true macro lens.
On shorter prime getting the 1:1 is often difficult and they may still be true macro at a ratio of 1:2 if 35mm or 50mm lenses, however when used with an extension tube a ratio of 1:1 can easily be obtained.
As mentioned virtually all real macro lenses made are prime lenses and for a reason, engineering a zoom macro is a real challenge! Having said that there are several focal lengths available in macro lenses, with the most common being 50mm, 100mm, 105mm, 180mm and 200mm focal lengths. Smaller and shorter focal lengths like 50mm are smaller, lighter and lower cost. However you do need to get closer to the subject, which can be a challenge with insects which have a relative danger zone around them, which if entered will cause them to flee in haste! Also with close work lighting and shadows can be challenging for macro photography.
The most common focal lengths are around 50mm, 100mm, and 180mm, although the exact values depend on the manufacturer.
Macro lenses with short focal lengths (50mm to 60mm) are cheaper, smaller, and lighter. However, you have to get much closer to the subject, which can be a problem when photographing things like butterflies, as they are easily scared away. You might also find that your shadow gets in the way of the shot. On the flip side the longer focal length lenses of 100mm, 105mm, 180mm and 200mm will allow a much further separation between you and subject, often easier lighting control and easier to create images – but this comes at the cost of larger and heavier lenses and are generally much more expensive to purchase. What you choose is going to depend on what you do and your budget, however personally I would never consider a macro less than 100mm in focal length (my first true macro in the 1980s was a 100mm Minolta f/2.8).
Optically macro lenses are among the sharpest lenses made, and they have unique internal focusing mechanics to achieve this level of sharpness. Most lenses focus by moving virtually all the internal lens elements together as a unit, which is less costly to design but can impact sharpness noticeably at very close distances. This design works well in lenses which are used for longer focus distances, but is one of the major downfalls of lenses which are regular zoom lenses and markets as macro lenses. Macro lenses solve this problem by using an optical element which constantly adjusts the lens’s internal geometry as you focus to provide higher contrast, superb focusing and absolute sharpness across every focus distance. Added to this is that fact that many macros have wider apertures than other lenses (other than exotic lenses – which one might consider macros actually – remember the 100m f/2.8 I mentioned above). Now not all are f/2.8, there are some super macros which are f/4. One other point, most macro lenses I have used do all the focusing internally without altering actual physical length, hence making no difference in actual distance to subject, which can be of huge importance in very close photography.
But there is one catch to macro photography as pretty much any of them have paper thin depth of field, and the longer focal length ones make this even worse. This makes focus stacking almost necessary in many situations. What is focus stacking? Another blog, that’s what!
What it does mean, especially if you want to play with focus stacking is that a tripod is essential!
While we are talking about depth of field and focus stacking, lets discuss focus itself. How does the macro focus! Well some auto-focus macro lenses do exist, but generally are at ridiculous price points! Yes truly ridiculous. The Nikon 200mm f/4 AF lens, which by the way is one of the sharpest in the world, runs at over $2,000 Cdn!! But having a auto-focus may help get that pin sharp image, especially with the paper thin depth of field.
Personally I prefer manual focus on all my macro lenses and use a focusing rail to achieve the focus stacking movement. What is a focusing rail? A small device the lens mounts on, which then attaches to the tripod. This allows precise movement in millimeters of the lens/camera, taking one photo at each small movement. However for some a manual focus lens may be more of a challenge to work with, but once learned I think you will enjoy.
So what if you want to do macro photography with a limited budget, are there any alternatives? Yes there are, extension tubes (which I have), bellow (which I have) or reversing rings (I have never tried). While these all work they also all have disadvantages:
- extension tubes reduce light, quality and may be manual
- bellows reduce light, quality and are always manual
- reversing rings reduce light, will reduce quality (sometimes significantly) and will always be manual
Having said that it can be inexpensive and many have obtained satisfactory results using these methods, so try if you are on limited budget and enjoy.
One final one is close up lenses which attach on the filter threads of lens. These are the worst of any of the options and frankly I would not recommend to anybody ever.
If you are in the macro market, the best on the market have always been Nikon or Canon in macro photography. This is one area where third party lenses often do not quite measure up, although they are quite good they just are not quite there in any I have seen.