Thursday, 28 January 2010
Macro Lens 1.1
What Lens do I need? - Technique Research
In Photography, your lens is often your most important purchase. This photography tutorial outlines some important qualities of different lenses, and how each performs in identical situations.
Choosing a lens is often more difficult then choosing a camera when it comes to purchasing. One thing to remember is that a lens will last several times longer than digital cameras. A D-SLR has a limited lifespan of a couple of years, the prices on cameras just keeps on dropping and purchasing a new camera every 3-5 years is quite reasonable if you want good quality photographs & equipment. A lens on the other hand will (if handled correctly) last much longer then that, so a good lens will be an investment that you can use for a longer period of time.
Another thing to think about is the fact that all the light that reaches the sensor needs to pass through the lens. A low quality lens on a high quality camera will result in bad image quality, but a good lens on a low quality camera can still produce good results (and with low quality camera I mean the companies “entry level” D-SLR cameras).
It’s important to realize that different lenses distort and compress the view. A wide angle lens willdistort the view and distances can seem greater than they really are, while in contrast, a telephoto lens will compress the view and make far away object seem closer than they are. To show this effect I have taken three photos with different lenses, the front object (a street sign) is kept at the same size but the background is drastically different.
Above: 18mm, Wide Angle
Above: 50mm, Normal
Above: 300mm, Telephoto
Normal lens
Normal lenses have a focal length of around 50mm; it resembles the view of the human eye and creates a natural view — unlike wide-angle that distort and telephoto that compresses the view. These lenses usually have a very low f-number, which makes them perfect for photographing in low light conditions.
Back in the days this was the standard lens everybody had, often a 50mm prime lens (more about prime lenses later in this article) with an aperture of f/1.2–f/1.8. The fact that they were so widely used might be one of the reasons why they have now been left behind for most beginners and amateurs — they are just seen as too boring.
Wide-angle lens
Lenses with a wide angle of view have become standard as kit-lenses on most low-end D-SLR cameras on the market, always as zoom lenses. These lenses are great for landscapes, architecture and indoor photography — but be aware of the distortion they create. The closer you are to your object the more distorted it will become, and the distortion is most predominant in the corners.
With such short focal length they can be useful in low-light situations, both because they take in light from a wider angle and because a little camera shake is not as visible as it is on longer focal lengths.
Telephoto lens
These lenses have a narrow view field and a long focal length. Telephoto lenses are great for wildlife and sport photography, and can be good to use for portrait when you want to isolate the model from the background. Telephoto lenses compresses the view which can be both positive and negative depending on the situation.
Telephoto lenses with their longer focal length require better light conditions or the use of a tripod. There are fast telephoto lenses, like a 400mm f/2.8, but these are often very expensive and out of reach when it comes to most amateurs — and most of these lenses are too heavy to be handheld.
The last decade most companies have started to produce these high end telephoto lenses with Image Stabilizer (different companies have different names for it, but the effect is the same) to make them more usable without tripods. Lately this feature has been implanted in more and more low-end lenses as well.
Macro lens
Macro photography is close-up photography. Macro is a word that has been severely abused lately, every photograph of an insect or flower is not macro, and many people seems to have missed the point of what macro is supposed to be. True macro photography is at the scale of 1:1 or greater — this means that the object you’re photographing should be the same size or larger on the sensor.
Most macro lenses have a focal length between 50mm and 200mm, and they usually have a large maximum aperture (low f-number) that gives them both the ability to be fast as well as totally isolate the subject. The background and shallow depth-of-field is a very important part of macro photography and can take quite a lot of time to master.
There are several ways to achieve macro or a macro-effect without a true macro lens; I will go into detail about this in a later part of this series.
Special lenses
FISHEYE LENS
Fisheye lenses are extreme wide-angle lenses, having a 180° horizontal angle of view. There are both Circular and Full-frame fisheye lenses, the circular will create a round image in the center with unexposed (black) edges and the full-frame lens will fill the entire sensor but will only have 180° horizontal and not vertical.
Fisheye lenses are widely used photographing and filming skateboarding, since the entire scene is always in focus and you can easily capture the entire trick without too much movement.
TILT-SHIFT LENS
Tilt-shift lenses are common in architectural photography to avoid the distortion a regular wide-angle lens creates while keeping the entire building in focus. Tilt-shift lenses have more features than just correcting the distortion, they also gives the photographer total control over the focus and depth of field. The lens can create rather odd looking photographs where the field of depth looks “unnatural” and the entire scene looks like it’s a photograph of a miniature.
Prime lenses vs. Zoom lenses
There are two types of lenses, prime and zoom. A prime lens is a lens that has a fixed focal length, these lenses comes in all shapes and price classes. Zoom lenses have taken over the market almost completely on the lower-end; this is mostly because zooms are more versatile. A zoom lens can be a wide-angle lens, a normal lens and a telephoto lens — all in one — where as a prime can only be what it is. High-end telephoto lenses as well as macro lenses are almost always primes.
So why choose a prime instead of a zoom lens then?
Most prime lenses are considerably sharper than the zooms in the same price class, even when you go to the very high-end lenses the primes are sharper but the difference is not as distinct. Not only are primes sharper but they often have a larger maximum aperture which makes them faster and ideal in low-light situations. However, the technology is moving forward at a great speed right now and the noise levels at high ISO isn’t as visible as it was before which makes zoom lenses able to be faster as well.
All in all I would recommend that people have at least one prime in their camera bag, preferably a normal lens, which is the perfect lens for many situations — sharp, fast and light-weight.
The aperture will also affect the sharpness, and most lenses are softer when they are wide open (largest aperture). To prevent this you can always step down one or two f-stops, if the situation allows for it.
Some quick advice on buying a new lens
When it comes to purchasing a new lens there are a few things to consider.
- Who much are you willing to spend
- What do you need it for (sport, landscape, portraits etc)
- What lenses do you already own
- Prime or Zoom
- Image Stabilizer or not
- Filter size
The budget question is rather obvious, don’t buy lenses you can’t afford, period. What you need your lens for is another very important factor, both when it comes to focal length and speed. Previously in this article I explained what the different focal lengths were used for, but I didn’t go into the different lenses in each of the focal length categories. For instance, there are many telephoto zoom lenses on the market but many of them are not suitable for sport due to the fact that they are too slow — and with slow I mean that their largest aperture isn’t letting enough light through to freeze action. Many sport situations require a lens that has an aperture of f/2.8 or larger (consumer telephoto lenses are oftenf/5.6). For situations with low light, especially weddings and such, requires even faster lenses, often between f/1.2 and f/1.8.
It’s also important to consider what lenses you already have in your collection and what a new lens will add. Sometimes you purchase a new lens as an upgrade from your previous lens, sometimes it’s for a focal length that you do not already have. Don’t worry to much about small gaps in the focal length in your collection. For example it’s no problem to have a 16-35mm wide angle, a 50mm prime and a 70-200mm telephoto lens — sure you don’t have lenses that covers 36-49mm or 51-69mm, but those are not big gaps and buying extra lenses to fill such gaps is not something I advice you do.
My personal opinion is that upgrading should add more than just better image quality, for a worth upgrade you should get a faster lens, or a feature such as image stabilizing (article on Image stabilizing coming later). The choice between prime and zoom lenses was described earlier in this article and there’s no right or wrong here, just personal preferences and also depending on the situation.
Last but not least, an aspect that is overlooked most of the time, the filter size. If you don’t use filters you can skip this part. If you’re like me and use several different filters it’s more economical to have the same filter size on all your lenses as well as more convenient. Let’s say you have several lenses with a filter size of 77mm and your looking for a new lens, you can either buy a cheaper 67mm or a more expensive 77mm lens (remember, I’m talking about filter size here). It might actually be more expensive to buy the cheaper lens since you need to buy an extra set of filters. Using step-up rings are an alternative, but they often prevent you from using a lens hood.
So after decided on your next lens purchase, where to buy? The only non-Swedish photo store I can personally recommend is B&H Photo. Great service, good prices and a useful website, I recommend B&H to everyone that ask, it’s a great store. There are other stores, but be careful, there are a lot of fake/bad photography stores online.
Filters and Photography - Technique Research
I have been reading about the different types of filters and their effects - although I do not have any - I think it would be useful for me to invest in a UV filter to protect my lenses particularly on my macro and telephoto lens - as it would protect the, from dust particles and if I dropped it hopefully the UV filter would take the impact and not my lens. The polarizing lens may also be of use to stop glare when shooting outdoors and through glass. Below is information regarding filters taken from photography.net. I have also read more information in several books on exposure.
Filters can add special effects or abilities to your camera lens. Understanding how filters work will give you an extra arsenal of equipment to create that magical shot you’ve been looking for.
Most lenses have the ability to add filters, primarily by screwing them on in front of the lens while some lenses require the filters to be attached at the rear end of the lens. Filters are used for several different reasons: increasing contrast, changing the exposure, capturing invisible light or minimizing reflectionsare just a few to name.
The use of filters has gone downhill in this age of digital photography. These days it’s simply easier to make these changes in post-production instead of using a filter during the photo shoot.
While that might be true, there are still some things we can’t change in post-production, and filters can become a necessity.
UV Filters
UV stands for Ultraviolet, which is light that is invisible to the human eye. UV filters were used to cut down on haziness, such as in mountains and around coastal areas, but the digital sensor isn’t as sensitive to this as 35mm film was. However the UV filters are still around, mainly because these filters are used for lens protection.
Having a UV filter attached to the lens at all times makes the lens more protected from scratches, dust, weather and accidentally dropping the lens. There are debates among photographers about the use of UV filters; some argue that they visually affect the outcome of the photograph while others argue that they don’t affect it and that the filter is a great insurance.
I personally always have a UV filter screwed onto every single one of my lenses, and I’ve had one of my lenses saved thanks to the attached filter. However, if you are going to use a UV filter, don’t buy the cheapest one you can find. If you have a good lens, buy something like a high-end B+W filter.
ND Filters
ND filters, or Neutral Density filters, are a great way to take control over exposure time. These filters are used to reduce the amount of light that reaches the sensor, which makes it possible for the photographer to use a larger aperture for a longer period of time then what would be normal under given circumstances.
An example of this would be the ability to photograph a waterfall with a slow shutter speed during a bright day. Without a ND filter most lenses would not be able to use an aperture small enough for long exposures but with an ND filter attached the photographer can mix and match just how he wants it.
Graduated ND Filters
These filters have the same principle as the regular ND filters but with one important distinction, they do not have the ND effect on the whole glass. The ND effect is gradual and is perfect if you want to have the sky darkened but not the foreground for example. These filters have their limits, such as the gradual transition is a straight line, which might not always be the case with nature… oh, and they are also rather expensive. Most of these filters are rectangular and uses a special holder to place them in.
Polarizing Filters
These polarizing filters have many uses, and are one of my favorite filters to use. Most of them are circular, often called Pol-Cir or CPL filters, and you change the level of polarization by rotating the outer layer of the filter. The polarizer filter affects the photographs in such a way that cannot be reproduced in post-production, which makes it a very useful tool even today.
What it does is reduces reflections on non-metallic surfaces, such as water and glass. Removing reflections can be very useful in both urban and wild life situations and have the ability to totally alter the outcome of the photograph.
Another effect the polarizing filter has is that it increases contrast and color saturation while at the same time reducing haze. This effect can clearly be seen in skies, in which the sky can be darkened and more colorful but keeping the clouds white.
A quick word of advice though is that a polarizing filter will, depending on brand and quality, not let 100% light through — which will affect the exposure. With most brands you will loose one full-stop.
Macro Filters
Macro filters, close-up filters or diopters, are not ordinary filters — they are more like an extra lens you place in front of another lens. This makes close-ups possible even with normal or telephoto lenses, although the result is often not true 1:1 macro. Several filters can be stacked on top of each other to intensify the effect.
I personally would recommend people look into getting an extension tube instead. Extension tubes change the closest possible focus length, without affecting the image quality as badly as macro filters do. The best option is obviously a true macro lens, but an extension tube is much cheaper and might be a good first step into the world of macro photography, and the extension tube can be used together with a macro lens to enhance the magnification.
Macro filters have many drawbacks such as softening up the image considerably, and these filters often produce lacking quality. Use with caution.
Color Filters
Color filters are rarely used anymore; they were primarily used for black & white photography to manipulate thecontrast. An example is using a yellow, orange or red filter, which will increase the contrast between skies and clouds, making the clouds really stand out. These days the effects can quite easily be reproduced digitally with the help of levels and channels.
IR Filters
IR stands for Infrared, and these wavelengths are on the opposite side of the light spectrum from UV. To photograph in IR you need a filter that only lets through IR light, however there are some problems with modern cameras. The sensor is constructed to not record IR light, and unless you want to permanently modify your camera (or purchase specially designed cameras such as Canon’s 20Da) there are some restrictions. This technique is so unique and odd that I will dedicate an entire article about IR photography later on instead of writing how it all works in this one.
Got a stuck filter?
Filters can get stuck fairly easy sometimes, and a stuck filter can render a lens completely useless in some situations. Circular polarizing filters tend to get stuck more often due to the fact that half the filter rotates on its own which can make it difficult to take it off. I’ve found that the best solution to remove stuck filters is to use a filter wrench, which applies the pressure evenly around the filter and thus can make even the most stuck filter come off in a few seconds.
Filter wrenches come in two sizes, one for filter sizes up to 58mm and another for larger sizes. If you use filters this is definitely a piece of equipment that should be in your camera bag, they take no space and can really save your day!
Thursday, 21 January 2010
Photography Interest - Element 1.1
My Equipment Element
My Equipment
Canon EOS Rebel 300D Digital SLR
Canon EFS 18-55mm
Shoulder strap
6.3 MP CMOS sensor, DIGIC Image Processor, and compatibility with dozens of EF lenses and EOS system accessories
7-point wide area AF with superimposed focusing points, 3 AF modes, 12 shooting modes, automatic and enhanced exposure
Controls, highly adaptive white balance controls and intelligent pop-up flash with automatic red-eye reduction.
• Canon EF-S 60mm f2.8 Macro USM
• Canon EF 75-300mm f/4.0-5.6 III
I've experimented with this lens, taking shots of my dog from a distance, swans and other wildlife by the river trent.I played around with various depths of field - the shots show texture - the frog in a local pond, reflections particularly of the Canadian Geese swimming on the river. I've also taken a few landscape shots. Some of the images of the swans are slightly blurred due to me focusing on other areas as opposed to the bird. I was also getting used to a different type of lens.
My camera is quite basic but I feel it is fine to initially learn about photography. I bought my camera second hand from Chris Goodhead’s camera shop in Burton.
I find the download software quite slow but its quite handy to see an overview of all my shots on the camera.
I find the view finder quite small so for distance shots its quite difficult to view faces and product detail unless you zoom in quite close.