Low cost macro photography
Posted by Phytopath on Nov 28, 2010
Today I have a guest blogger, Rob Fairweather of wilddogphotographics.com, who is quite a dab hand at taking close up photographs of flowers and bugs.
In this post, Rob is talking about a cheap torch he purchased from the hardware store and ended up using it with his camera to take macro shots, instead of using an expensive flash.
Over the past year or so, digital cameras have begun to “come of age”.
Many “Compacts” are beginning to challenge the more expensive DSLRs (Digital Single Lens Reflex) cameras – where specialist functions are involved.
Of course, there’s always the size, weight and convenience aspect of the Compact, but in certain areas, the optics used in the Compacts has unexpected advantages. As the size of the image detector is reduced, the optics can also be made smaller and cheaper – but at the same time, the depth of field of the recorded image increases. (The depth of field is defined as the distance around the focus point where at the intended viewing size, the image is acceptably focussed.) This means that if we want to enlarge an image excessively, then the effective depth of field decreases, because any focussing errors become very noticeable.
One of the biggest problems in macro photography is that as we move closer to the subject, the depth of field decreases dramatically. To increase the depth of field again, we have to reduce the lens aperture (use a higher f stop). This of course reduces the amount of light that the camera sees, and so we have to use a lower shutter speed to compensate. Light levels can drop so far that special electronic flash gear is required! That is – up until now!
A few weeks ago when shopping in our local hardware shop, I noticed some LED torches for sale at around $20. I picked one up, and turned it on – to discover that it had a zoom feature (wide angle to spot), and generated a very intense white light. I bought one there and then.
I’ve been waiting for such a light source for some time. Yesterday I decided to check out it’s suitability for a close-up light source for macro shooting.
I used 3 cameras for my test – a Canon IXUS 860IS (8 Mp slim line), a Canon Powershot G10 (15Mp compact), and a Canon 5D MkII (21Mp DSLR).
The two compacts could focus down to 1 or 2 cm in macro mode, and the SLR to 30 cm with a macro lens fitted. My subject was a bract of flowers measuring about 5cm high on a little succulent. The individual flowers were about 5mm across, and I focussed on one particular flower during each test.
The IXUS lens aperture was fixed at f/2.8, whereas the G10 was shot with the aperture at f/2.8 and also f/8. The 5D was shot at f/2.8 and f/16. Colour rendition with the IXUS needed a little adjustment in Photoshop to match the other two cameras.
Except for the IXUS, I used a tripod to hold the cameras, however the IXUS and G10 would have been quite happy without the tripod, because they were both fitted with image stabilisers.
Settings for each image are as below.
5D_31 f/16, 0.3 seconds - 5D_32 f/2.8, 100th second
G10_33 f/8, 20th second – G10_34 f/2.8, 160th second
IXUS860_21 f/2.8, 500th second.
5D_36 shows the torch and the camera setup while the G10 was photographing the flowers. The depth of field using the 5D for this shot is rather wanting (f.6.3 60th) hand held. I focussed on the camera and figured that the rest was acceptably rendered for this task.
As you can see, the compacts do a much better job with their lensed wide open than the DSLR, and the G10 produces a very acceptable image when stopped down to it’s minimum aperture. It’s lens would have only been about 2cm from the flowers during the shoot. For very small subjects in the garden (bugs etc,) the torch light can be zoomed in to produce a very intense light spot.
Total cost of the lighting setup – about $20 – and you get to find your way home in the dark!
Rob Fairweather www.wilddogphotographics.com
Soil Amelioration
Posted by Phytopath on Nov 23, 2010
Ameliorate: – to improve or make better.
I believe that virgin soil needs no amelioration. It is fine just as it is.
The problem we face is, the soil we farm or garden in, is not as we want it, for the plants that we would like to grow in it and has probably been altered through previous farming or gardening practices.
So we add fertilizers, lime and gypsum etc. in the hope that we can improve the existing soil conditions.
My question is “What’s to improve on Mother Nature?”
I think a better term or word (other than ameliorate) would be ‘change’ or ‘manipulate’ – to our advantage.
So, here are some suggestions to change your current soil conditions and why you would consider such changes.
Most of the soil amendments or additives used in the garden alter the soil structure (gypsum) or the soil pH (lime).
Good soil structure is important because it allows the free movement of water through the soil profile as well as allowing harmful gases to escape from the soil around the root zone of plants.
A soil with a good structure also allows easy movement of oxygen into the pore spaces between the soil particles.
Why is this important?
If your soil has a poor structure due to compaction (stop parking the car on the front lawn), the air and water cannot move freely through the soil profile and there is a good chance that newly planted trees and shrubs would find it difficult for their roots to penetrate the soil.
For existing trees and shrubs, it would mean that any water added to the soil, through irrigation or rain, would travel extremely slowly through the profile and possibly linger like a bad smell. The plant roots would start to die from lack of oxygen (nothing to do with the bad smell) because the water is being held in all of the pore spaces. Poor drainage, we call it.
Many clay soils are considered to have poor structure and the usual recommendation is to add gypsum.
Be aware that gypsum does not react with all clay soils.
There are two predominate types of clay soil. Slaking clay and dispersing clay.
Gypsum will only react with dispersing clay. It flocculates (look it up in the dictionary) the soil particles, kind of clumps them together, to create larger pores for better drainage.
The best way to treat slaking clay is to add organic matter.
How do you know if you have slaking or dispersing clay?
You could ask an Agronomist or you could attend one of my talks. Or hang in there and I will eventually cover it in a future blog post.
Sandy soils can also have poor structure.
Unlike clay soil, water can move very quickly through sandy soil.
Many sandy soils are referred to as ‘gutless’, meaning they have little ability to sustain good plant growth.
The reason for this is the free movement of water through the profile. The water leaches or takes with it, any nutrients that were previously available for plant growth.
The lack of ability to hold on to moisture for any length of time, also means that plants can suffer from water stress more often than if the same plants were grown in a good loamy soil.
The best way to address these problems is to add organic matter.
The organic matter will help to retain moisture in the soil and it will also help to retain and release nutrients to the plant.
So why do gardeners add lime?
You sometimes hear the terms ‘sweet soil’ and ‘sour soil’. This is a reference to the acidity (sour) or alkalinity (sweet) of a soil.
Many farmers add massive amounts of fertilizers to their crops. Over time this can cause the soil to become acidic. To address this problem, they add lime to the soil.
The reason for doing this, whether on a farm or in a suburban backyard, is the relationship between soil pH and nutrient (fertilizer) uptake by plant roots.
Plants have a preference for the amount and type of nutrients available to them. Just like you and I have a preference in what we like to eat.
If the soil pH is outside of the limit or tolerance of a particular plant, then the plant is unable to extract the particular nutrients that it requires for good growth. The nutrients are often there but the plant cannot access them for various reasons.
Think of yourself looking to go out for a meal but the restaurant is closed. The food is there but you cannot access it unless someone opens the door to the restaurant.
Changing soil pH is sort of like opening the door to the restaurant. All of a sudden the plant has access to the required nutrients.
If your soil is acidic and you are not growing acid loving plants, then the addition of lime will help to reduce the acidity. The amount of lime used will depend on your soil type. Seek professional advice.
If your soil is alkaline and you would like to grow azaleas – forget about it.
Alkaline soil can be encouraged to be less alkaline with the addition of sulphur. This is not however a cheap fix like lime. Again, seek professional advice.
This post is getting quite lengthy and more like a lesson than a blog post. I must stop somewhere, so here it is.
If you have a real interest in soil science, there are many books available on the subject, from beginners to advanced.
The more you understand your soil, the easier gardening becomes.
Grevillea robusta
Posted by Phytopath on Nov 15, 2010
Grevillea robusta is locally known as Silky Oak. It was given this common name by pine cutters who thought the timber resembled English oak and also noticed that the timber was silky when newly split.
The species name robusta, comes from Latin robustus, which refers to the stature of the tree.
It grows naturally in southern Queensland and northern New South Wales, often found along creek and river banks.
Large numbers of trees were planted in Hawaii and South Africa. In Uganda and East Africa the tree is used to shade coffee plants.
The tree can grow quite fast and tall, up to 35 metres, with a straight trunk. Once mature it has a somewhat pyramid shape.
Because of the fast growth and the showy flowers in spring, the tree has been a favourite for avenue planting where space allows it. For most city back yards the tree is considered too large.
The leaves are fern-like in appearance (pinnately lobed with secondary and tertiary lobes, see pic) and light green in colour on the surface with a lighter coloured underside. They can be up to 30 cm (12”) long and the reason for the lighter coloured underside is the fact that they are covered with silky hairs.
If the tree is under stress at any time, either from cold or drought, it has a tendency to drop its leaves.
The flowers, when they appear, are spectacular. Each raceme is up to 12 cm (5”) and each flower is about 10 mm long. The style is about 20 mm long, brightly coloured and remains after the perianth has fallen. In plain English, they are toothbrush-like, shaped flowers, bright gold/orange in colour.
The flowers produce copious amounts of nectar and the tree is an excellent bird attractor. Not only honey eater birds and parrots are attracted to the volumes of nectar, but bees are also lured into the mass of golden flowers.
What a wonderful tree to have in the garden. It has the ability to draw birds and bees from far and wide, and once in the garden they can also visit other plants, to pollinate them.
Gardeners who grow this plant as an indoor specimen, (UK and Europe), sadly, never get to experience the beauty of this tree in flower.
Many Australian publications on ‘Bush Tucker’, note that the Aboriginal people made a drink from the flowers or sucked the nectar straight from the flowers, reported to be high in vitamin C. The University of Queensland Botany Club, also mention a palatable drink can be made from the nectar rich flowers. However, in 1930 a mixture of pistils, capsules and seed were tested by Smith and White and found to have a positive cyanide reaction. I am not aware if this test has been repeated. All I can say is, proceed with caution.
Grevillea robusta is a very hardy tree and because of its hardiness, it has been used extensively as a rootstock for less hardy species of grevillea as well a rootstock for weeping standards. To produce a weeping standard grevillea, allow the rootstock (Grevillea robusta) to grow to about 2 metres (just over 6 feet) or any height you want really and then graft a prostrate species on top.
If you would like to experiment with a weeping standard, find someone in your neighbourhood who has a Silky Oak growing. Knock on their door and ask politely if they have any young seedlings available that you might be able to use. I can almost guarantee that they will welcome you in with open arms, because the darn things seed so prolifically that it is almost a pest plant (in the right climate). Be warned.
Trompe l’oeil
Posted by Phytopath on Nov 10, 2010
What an interesting name for life-like, art-work.
Artists create three dimensional images on a two dimensional canvas (whatever the canvas might be) which forms the optical illusion.
I remember receiving an email a few years ago called ‘chalk art.’ It was mind blowing.
The artist was creating three dimensional images on the pavement. They were so real that people using the footpath would avoid what appeared to be a hole in the ground where tradesmen were working.
Another email I received showed a picture of a Trompe l’oeil mural painted on a bathroom floor. The floor of the bathroom appeared to be non-existent – you could see the ground beneath, as if looking from a plane. There was even a person falling to the ground.
Would you use the bathroom if that is what you saw when you opened the door? I think a few profanities might escape my mouth before I set foot on the floor.
So what does this have to do with gardening?
Murals are often used in courtyard gardens to create the illusion of space.
If done well, they can trick the eye into believing there is ‘something there’, when in fact it is probably a wall. The ‘something’ could be a water feature, a door or gate into another part of the garden or just more garden.
I am fortunate enough to know a lovely lady who paints Trompe l’oeil for sale. She also holds classes on rare occasions. I look forward to participating in her next one.
Here is some of her work.
Murals by Rose Hill.
In My Garden – late October
Posted by Phytopath on Nov 1, 2010
Strolling around my garden between showers of rain, I thought a series of photos showing various stages of flower development on Grevillea ‘Moonlight’, might interest you.
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Grevillea ‘Moonlight’
also known as Grevillea ‘Edna Ellen’
Raised from seed in Proston Queensland, Australia.
A shrub growing 3 or 4 metres high and 2.5 metres wide.
Racemes up to 20 cm long, flowering most of the year.
