The Tube Option
Using a macro tube and kit lens is useless for true flat field macro work, like slide/neg duplication but for most macro dabblers that is something they will never do. Sure the edges and corners will not be critically sharp with a kitty plus extension tube, but sharp all over its not really that useful for most macro work.
You can get pretty close, in fact right down to 1:1 with the right combo of tube and focal length. One little oddity is that kit lenses designed for mirrorless cameras typically need far less extension tube length to get really close, hence most tube kits for mirrorless rigs only include two shorter rings instead of the standard three.
Just in case your wondering “would a fast standard lens work better on the tubes” the answer is maybe, but probably not. Fast lenses are really designed to distance work, when was the last time you heard of a f 1.4 macro lens? Generally when mounted to a tube setup, fast glass suffers from all sort of field curvature issues so your kitty could easily outperform the fast fixed focal length lens because at least it is designed to go reasonably close to start with.
Forget about those really cheap manual tube sets on eBay, they have no way of controlling the aperture, everything ends up being shot wide open. Likewise the cheapies won’t work with your cameras metering or auto focus options. You can pick a full auto set up for between $80-150.00, (these will allow auto focusing) the dearer ones are aluminium and the cheaper ones plastic. For occasional kit lens use plastic is fine and will save a little weight in the bag and ultimately if you get all “macro excited” you will progress to a full bore macro lens anyway.
This branch of kit lens tom-foolery will require a solid tripod, unless you want your shots to look like you took them after downing a couple of bottles of red. You will also need to think about supplementary lighting, the on-camera flash will be worse than useless. I use natural light and small reflectors, but you can use artificial light sources as well, anyhow its all about the light when the going gets tight!
Close Focus Filters
Oh I love these innocent looking little mites, they can open a world of creative options for next to no cost, little weight penalty and an ease of use that can’t be beat.
Though you can purchase filters ranging from 1 to 10 dioptre you'll find a one or two dioptre filter will see you through most of your practical requirements, handily extending the close focusing range of your kit lens. Generally the higher the dioptre rating the poorer the clarity, and frankly most 10s I have tried are next to useless.
Using a number one dioptre macro filter in combination with the wide angle end your lens can produces some rather interesting macro affects that I refer to this as “contextual macro”. With this approach you see the surrounding environment combined with a close-up view of the subject, the image at the top of the page is a good example and the following two continue the theme.
|Here is an example of a contextual macro shot taken at 18 mm on my Sony 18-55 OSS kit lens, the trick is using the macro filter to allow closer focus but still get the wide angle view and I find the look to be very satisfying.|
|And another contextual macro for good measure.|
The close-up filter can also sometimes have an effect on the bokeh in a nice way, giving smoother out of focus areas.
When used in conjunction with the telephoto end of your lens you can slightly increase the apparent focal length, say making your 55mm look like 65mm. This increase can give a more natural perspective for close-up portraits, note however you won't be able focus anything beyond just a metre and a bit, but for these portraits that’s perfect.
|Here I go breaking my own rules and showing my dog pics, |
but Holly the Collie just looks so sweet when shot with the 18-55 OSS and a no 1 close up filter,
roughly equals a 65mm lens at f5.6.
Adding a close up filter can also provide a vehicle for shooting creative “Out of Focus” shots, which can be great fun.
Close up filters don't provide perfect clarity across the entire frame into the comers but the centre and out towards the edges of the image will be more than adequately sharp which for most macro work is fine, but even better when you actually want stuff out of focus like the example below.
|Not just out of focus, now we have "painterly out of focus", again it is the macro filter that makes this possible.|
Somewhere along the way you have probably heard that you should not stop your aperture down too much otherwise your pics get soft due to diffraction. True enough! But don’t let that deter you, if you need more depth of field you can always go small on the hole and big on the sharpening, either “in camera” or in post capture editing.
I have found from experience with thousands of images shot at small apertures, they can easily be sharpened up if needed, but the opposite of adding sharpness when it wasn’t even recorded due to too wide an aperture is near impossible.
Of course there are benefits also to using small apertures other than just getting more DOF. You can use slower shutter speeds and tripod to increase motion effects, you can kill stone dead “moire” (weird colour and false detail ) on patterned objects, get around many of the common lens aberrations and probably even control high contrast scenes a bit better.
Anyways, learn to sharpen files properly and you can happily work away with those small apertures, like f16, 18 or even 22, but just to be on the safe side probably best to leave f28 and smaller alone, they are just a “hole to far” for even the best sharpening tools.
|Original Raw File Shot at f22 on Sony 18-55 OSS set at 18mm, note the distortion, chromatic aberration, vignetting and overall softness of the image.|
|Same image, this is the OCC version (out of camera jpeg), it has less distortion and chromatic aberration and vignetting but still looks a bit soft as a result of diffraction from using such a small aperture.|