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Thread: Tips - Lens, Hood, Filter and few more....

  1. #1

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    Tips - Lens, Hood, Filter and few more....

    Using Lens Hoods

    Shade Your Glass

    A lens hood stops light coming into the lens at extreme angles and being reflected inside the lens. This can lower the contrast of the image. Compact camera designs often include some degree of lens protection in the camera design. For cameras with interchangeable lenses, most lenses come either with integral or accessory lens hoods.

    Flare

    When there are strong light sources - such as the sun, you can get the familiar 'flare' spots on images. Different lenses give different patterns of flare; the shapes of the larger spots depend on the shape of the lens iris, and the colours depend on the glass and coatings in use. Normally you want to avoid these effects, but occasionally they can add interest - as they more often to in film or video footage. A lens hood enables you to shoot 'contre-jour' or towards the light source, so long as you keep it outside the image area, without excessive flare. This can produce some exciting results.

    Shapes and sizes

    Lens hoods need to be matched to the angle of view of the lens. They should exclude as much light as possible without being visible in the picture. Since pictures are rectangular, you can exclude the greatest possible amount of non-image forming light using a rectangular hood, but in practical terms the difference between this and a circular hood appears to be minimal. One disadvantage of the rectangular design is that it needs to be precisely aligned - if it is twisted round at all it will cause vignetting. It is most useful for wide-angle lenses with built in lenshoods.
    Telephoto lenses have a narrow angle of view, and a long lens hood is needed to make the most of this, often almost doubling the length of the lens. These often slide back when not in use, or can be removed. Detachable hoods can often be turned round and loosely fitted over the lens to take up less room in your camera bag,

    Zoom lenses

    Unless the lens design were to automatically zoom the lens hood as well as the lens elements, the lens hood has to accommodate the widest angle of view of the lens, This means it will be less effective at longer focal lengths.

    Fittings

    Lens hoods come in different shapes, sizes and material, but are most often provided with lenses. As I've found, it can be difficult (read expensive or impossible) to find a replacement for some if you lose one. If manufacturers always used a filter thread to attach them it would make life simpler, but some have proprietary bayonet fittings. If you lose a lens hood it may be possible to replace it from the manufacturer or by one that screws into the filter thread, but suitable replacements are hard to find.
    When lens hoods do fit in the filter thread, they normally provide a further thread so you can attach filters inside them. If you use a filter on the lens all the time for protection, the lens hood can be attached in front of this.
    Some lenses have built-in hoods, in most cases a sensible provision. Bayonet fittings are really only needed where lens hoods need to be removable and use a rectangular rather than a circular aperture.

    Why you need a lens hood

    Lens hoods are most necessary when you want to take pictures with the camera pointing close to a strong light source, particularly the sun. Few lens hoods are actually as effective as they might be, and it is often necessary to provide some extra shading to stop direct sunlight falling on the lens.

    For studio work and when using cameras on a tripod, it is possible to use accessory bellows-mounted lens hoods for precise control.
    For faster working with an SLR camera, it often helps to hold your left hard resting on the lens hood so as to provide some fuirther shade. You can see the result of this in the viewfinder - and also your fingers if you put them into the picture. Since most viewfinders do not show the very edge of the frame, it may then be necessary to crop your fingers from the extreme edge of the image when printing.

    Lens hoods also have two other very practical uses. They help to protect the lens when stood on a surface or in your camera bag and when changing lense, and also help to keep your fingers away from the front of the lens. For short lenses in particular, it is very easy to put your fingers on the front element, leaving dirty finger marks on the surface that will seriously degrade your images. With very wide angle lenses, the surface of the lens needs to be kept spotless, as dust is less out of focus than with longer lenses.

    Also with short wide-angle lenses, it is easy to take pictures with fingers straying into the corners of the frame. I've got more than enough few taken with my 15 mm and 20mm lenses that prove it.

    Lens Basics

    Cost and Quality

    Camera lenses cost from a few pence to tens of thousands of dollars, but all do basically the same job of making an image on the film or sensor. You can even take pictures without a lens using a pinhole camera. Some high-budget advertising campaigns have been shot this way, using large sheet film, giving results you would never guess came from a pinhole (in some cases the client didn't either.) At least one photographer has won an advertising award with an image literally taken using the bottom from a bottle. If you have the creativity you can work in many different ways. However in general, expensive lenses are likely to produce higher quality results.

    Most of us use lenses made for photographic use, either on cameras with a fixed lens or with those that take interchangeable lenses.

    Many pros will have spent several times as much on lenses as they have on the camera. But even the cheapest lenses on disposable cameras can produce good pictures.

    Prime Lenses and Zooms

    Photographic lenses come in two main types: fixed focal length (prime lenses) and zooms. Zoom lenses let you alter the focal length - and thus the angle of view that the picture takes in - while remaining focussed at the same distance.

    Focal length

    The focal length of a simple lens is the distance from its centre to the sharp image it gives of a distant object. This and the film size determines the angle of view that the lens gives on film (or sensor.) With a SLR camera (Single Lens Reflex) the viewfinder image is also created by the lens and will change according to the focal length of the lens in use. Non-SLR cameras with interchangeable lenses may show different white light frames for the different lenses.

    Wide Angle Lenses

    Short focal lengths compared to the sensor give a wide angle of view and are usually called wide-angle lenses. On 35mm cameras, any lens of 35mm or less is a wide angle lens, with those of around 24mm or less being called ultra-wide.

    Standard Lenses

    Lenses with a focal length around the same size as the sensor diagonal give a moderate angle of view and are called standard lenses. On 35mm cameras these are between 40mm and 55 mm.

    Telephoto Lenses

    Those lenses with a long focal length give a narrow angle of view. In the early days of photography they were known as long focus lenses. Lens designers soon started to use a trick called telephoto design to make these lenses shorter, and we now call all long focus lenses 'telephoto lenses' - most but not all are. Short telephoto lenses - around 70-105mm focal length for 35mm - are sometimes called portrait lenses, as they are great for 'head and shoulders' pictures. 200mm is probably the most common length for a telephoto now, with birders and some sports photographers favouring much longer glass - perhaps 400 to 600mm
    35mm equivalents

    35mm cameras dominated photography from the 1960s to the turn of the century and many photographers still think of focal lengths in terms of their equivalents on the 35mm format. So a 7.6mm focal length lens on a consumer digital camera may be referred to as a '39mm equivalent' - in other words it gives the same angle of view as a 39mm lens would give on the 35mm format.

    Zoom lenses

    A zoom lens can have different focal lengths, usually with a ring (or less commonly a slide) to move to alter the focal length. They are designed to keep in focus when the focal length is changed. When zoom lenses became popular in the 1970s, they were all telephoto lenses, often covering the range 70-210mm; some people still assume that zoom lenses are telephotos. My favourite zoom is a 12-24mm wide-angle, and there are some zooms that go from wide-angle to telephoto.

    With smaller formats it is much easier to design zoom lenses with an extreme range. Zooms for 35mm are normally limited to a ratio of longest to shortest focal length of about 3:1, while for consumer digital cameras, 6:1 is not unusual

    Zoom or Prime Lens?

    Generally affordable zoom lenses have smaller maximum apertures than most fixed focal length lenses.

    Prime lenses are generally lighter than zoom lenses, but a zoom lens will possibly replace two or three prime lenses, and be lighter, cheaper and less bulky than three lenses.

    Prime lenses usually have less distortion than zoom lenses.
    When photographing a rectangular subject, the image almost always will either bulge slightly out in the middle giving a barrel effect, or slightly in, resembling a pincushion. Lenses with 'good drawing' are those that have low distortion. The effects of distortion are usually only noticeable with subjects with straight lines - such as most buildings, seldom with portraits etc.

    More details on Lenses

    Using Wide Angle Lenses
    What are wide angle lenses?
    Wide-angle lenses are those that give a wider angle of view than standard lenses. To do this they need to have a shorter focal length.
    Using Wide Angles

    Wide-angles are the most misunderstood of lenses, at least so far as beginners in photography are concerned. They tend to see a wide-angle as being used 'to get everything in'. There are a few cases where they do enable you, for example, to photograph room interiors which could not be done with a standard lens, but their main use is to allow you to get closer to the subject.

    Working with a wide-angle you tend to engage more with whatever you are photographing, getting closer to it in every way. Wide-angles are 'hot', involving you more closely with whatever you are photographing.

    Technically, wide-angles are easier to use, giving you greater depth of field and cutting down the effect of camera shake, but compositionally their wider viewpoint tends to make images more complex.

    For 35mm cameras, the format diagonal is 43mm and typical standard lenses have focal lengths of 40-55mm. Wide-angle lenses are generally 35mm focal length and less.

    35mm

    35mm is only a slightly wide-angle compared to the format diagonal, and only a little more wider if compared with the typical standard lens of 50mm focal length. Many photographers have used a 35mm lens as their normal lens, either on a rangefinder or an a fixed lens compact camera.
    35mm is a fine lens for candid work with a rangefinder or compact camera. It's relatively wide angle of view means that precise framing is less essential when working close to the subject. It also gives and increased depth of field compared to the standard lens.

    Fast 35mm lenses, such as the 35mm f1.4 for the Leica are great lenses for shooting in low light. Using a Leica you can normally shoot without camera shake with a 35mm lens at 1/30s, and Leitz lenses give good results at full aperture.

    28mm

    The 28mm is the first true wide-angle, and again a fine focal length for photojournalism. Apertures tend to be slightly less wide than for the 35mm, but depth of field is better. Working at f5.6 you can get sharp images of subjects between about 5 to 10 feet.

    21mm, 24mm

    With these ultra-wide lenses, it is hard to avoid some noticeable stretching of objects close to the edges of the frame. This so-called 'wide-angle distortion' is not really a distortion, but the natural consequence of imaging over such a wide angle with a rectilinear perspective. Lenses wider than 21mm begin to get difficult to use well. In crowds you tend to bump into the people you are photographing as you look at them through the viewfinder, and the wide-angle distortion can become extreme. Which can be fun!

    Digital SLRs and Wide Angles

    The smaller sensors of most digital cameras turn the moderate wide-angles to standard lenses, and the extreme wides to normal lenses. To get an extreme wide effect you need to work with something like a

    12mm lens.

    We may one day see truly affordable dSLRs with 35mm 'full-frame' sized sensors, but I doubt it. There is simply no need for them when a sensor half this size can deliver all the quality most of us ever need. It seems more likely that all manufacturers will standardize on the current smaller sensor size, and begin slowly to bring out a full range of lenses and bodies designed for the roughly 24x18mm sensors. The big market for dSLRs is among those who are new to the format, currently using comsumer digital cameras, not the minority with existing 35mm film outfits. Moving to the new sensor size will also give lens sales a boost as photographers need to replace existing lenses.

    Telephotos Magnify

    What are telephoto lenses?

    Lenses that give a narrower angle of view than a standard lens are called telephoto lenses, though strictly speaking this is a particular way of making lenses. Most long focal length lenses in use on cameras today are telephoto lenses.

    Taking pictures through a telephoto lens is like using a telescope or binoculars - it makes everything look larger.

    Narrow Field of View

    These lenses have a narrower field of view than a standard lens. For 35mm format cameras we think of lenses from 70-120mm as short telephotos (often called portrait lenses), of those around 135-210mm as moderate or normal telephotos, and those of 300mm or more as extreme telephoto lenses.

    Details

    The main use of telephoto lenses is enabling you to select a small part of the subject - to pick a detail.

    You also use them when you can't move closer to the subject - perhaps if there is a river or a busy road in the way.

    Portraits

    Short telephoto lenses are especially useful for impressive head and shoulder portraits. The working distance you need with them gives a natural looking perspective and makes it easy to get a sufficient depth of field to make the whole of the person's face sharp.

    Isolating the Subject

    Moderate telephoto lenses are great for picking out details and isolating things from distracting material. Generally they are compact and light to carry, and fairly easy lenses to use, although you need to focus with care. Their limited depth of field can be used to make a subject stand out strongly against a confusing background by shooting at a wide aperture.

    Specialist Uses

    Extreme telephotos are lenses for specialist purposes such as sports and wild-life. With 35mm, a 400mm lens lets you stand on the boundary of a pitch and photograph action in the centre. Extreme telephotos are much easier to use when the action will occur in a predictable place - with rapidly shifting areas of interest it is easier to use a moderate telephoto.

    Flattened Perspective

    Telephoto lenses give a 'flat' perspective, reducing the impression of distance between different objects in the picture. This tends to create a more abstract effect.

    Camera Shake

    Telephotos magnify your camera shake as well as the subject, so you need to use fast shutter speeds. The slowest speed you should use is 1/focal length - use the '35mm equivalent' focal length for other formats. With a 500mm lens, use 1/500 or faster, with a 135mm, 1/125 or faster. Use a tripod if you need slower speeds.

    Limited Depth of Field

    Focus needs to be precise, as the depth of field of these lenses is limited, leaving little or no margin for error.

    Many people using or buying their first telephoto lens find their pictures are unsharp (you can read their comments in so-called 'user reviews' at many web sites.) Usually this is camera shake and incorrect focussing, and no fault of the lens.

    Technology to the rescue

    Two relatively modern developments have greatly improved the ease of use of telephoto lenses. First is autofocus, found in most modern cameras. Normally this will be much faster than manual focussing and more accurate, but you need to make sure you are focussing on the important part of the subject (normally the eyes in a portrait.) Often this will mean locking focus on this point (usually by holding the release half-way down) then reframing slightly to take the picture.

    Better cameras even have autofocus systems that will keep an object moving towards you in focus - so long as you keep it in the focus area in the viewfinder. These are great for following athletes and other similar moving objects - you can 'lock on' to the subject when it is some distance away and then fire the shutter release when the framing is correct.
    The problem of camera shake has been attacked using vibration reduction systems, either built into the lens or the camera body. Mechanical systems use gyroscopically stabilised lens or mirror elements to keep the image still when you shake, while some digital cameras use digital image processing to achieve a similar result. Both enable you to shoot at slower shutter speeds - perhaps 2 speeds slower than with a normal lens of the same focal length - but will not compensate for a moving subject.

    Size and Weight

    Good, wide aperture long focal length lenses are large, heavy and expensive. Vibration reduction systems increase the cost considerably. Wide apertures not only make it possible to work in lower light, they also make the viewfinder image much brighter in SLR cameras, and focussing faster and more accurate - whether manual or auto. However for most purposes you can get great results from relatively small and cheap lenses.

    Zoom or Prime

    Long focal length zoom lenses are relatively easy to design, and a good zoom lens is likely to be of similar quality to a fixed focal length. Zoom lenses give great flexibility and the control they give over framing is especially important in digital cameras, where every pixel counts.

    Filter Types

    The most common use of a filter is to protect delicate and expensive lenses. Most photographers use a UV, 1A or 1B filter permanently on the front of interchangeable lenses for this purpose, replacing it when it becomes damaged. There are a few lenses which are unable to take front-mounted filters.

    Filters can also be used for correction to make the image more accurate or to create various effects. Filters are mainly used on SLR cameras. Many photographers seldom use a filter other than as lens protection.
    Correction filters

    Film response

    Black and white films are generally less sensitive to red light than the human eye. The filter that most accurately corrects this is a light green, although a yellow filter is more often used. Colour filters pass more light of their colour and less of other colours.

    A yellow filter cuts down on the transmission of blue light, making skies appear darker and thus clouds stand out more.

    Modern panchromatic b/w films have better red sensitivity than older emulsions, and yellow filters are less needed than when most textbooks were envisaged (even new books published today are largely copied from older works.) It is seldom now worth using green or yellow correction filters.

    Contrast filters

    These are coloured filters used with black and white films to lighten tones corresponding to the filter colour and darken those of other colours. Most used are orange and red filters, which are used to produce dramatically darkened skies.

    Colour temperature filters

    These are used with colour film and have either a cooling or a warming effect. Cooling filters (80A, B and C) are pale blue and warming a pale straw colour. Warming filters (81A, B or C - C is the strongest) are useful to prevent a cold feel to pictures taken on overcast days or in shady areas on sunny days. With digital cameras, colour temperature is adjusted using the white balance setting on the camera or in the converter software for raw files.

    Fluorescent filters

    These are generally pink and designed to correct the unnatural greenish tinge of fluorescent lights. There are many different types of light, and different manufacturers filters have different colours to cope with these. They will usually improve the colour cast but not entirely correct it.

    Polarising Filter

    These preferentially pass light waves vibrating in a particular plane, enabling them to be used to cut down reflections from polarised light sources such as the sun. By removing surface reflections they can produce an exaggerated colour saturation in images, and need to be used carefully. These filters come in a rotating mount and need to be rotated while observing the image to obtain the required effect.
    There are two types of polarising filter, normal and circular. You need to consult your camera manual to see which you should use. Most autofocus cameras need the more expensive circular polarisers.

    Effects filters

    These produce various special effects such as starbursts around light sources or diffusion. The single filters sold largely for amateur use are generally too predictable in effect to be of much interest. Although the effect may look great for the first few images, it soon becomes tedious. By combining several filters more varied results are possible.
    Infrared filters

    These are generally deep red or black and transmit little if any visible light but are transparent in the UV region of the spectrum. You need to use UV film with them.

    Neutral Density Filters

    These simply cut down the light intensity, useful for when you want long exposures in daylight. Most useful is a .9, which needs a 3 stop exposure increase.

    Screw Mounted or Squares?

    Filters can either be used as screw mounted filters that fit the filter thread of the lens or as plastic filter squares that fit in a special holder, which fits on the filter thread. The best known system is Cokin, who make two sizes, A and the larger P needed for larger lenses. Except for the UV protective filter, it is generally cheaper and more flexible to use filter squares, as by buying further filter holders it is possible to use the same filters on several lenses with different filter thread sizes. There is a larger range of filters available as squares, including various graduated filters.

    Some filters may also be available as thin gelatin filters. These are intended for special uses and a too flimsy and easily damaged for normal camera use. Sheets of thin plastic filter material are also made for use with photographic lights. These may have optical imperfections and are not generally suitable for use in front of the lens.

    Okay guys and galls....hope this will help some of u why sometime our picture not to our expectation kan

    Jie Lea Adra
    "Our lives improve only when we take chances and the first and most difficult risk we can take is to be honest with ourselves." - Walter Anderson



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  2. #2

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    :shock: :shock: :shock: :shock: :shock:

  3. #3
    erkhhhh....panjang gila notes...hurmmm take time nak baca n paham2kan..hehe... :roll:
    ::happiness is... a sad song..::

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  4. #4

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    baca pelan2 tau...sampai faham....

    Actually topic nie ade di discuss semasa perjumpaan di Mid Valley tempoh hari cuma x secara detail.....

    Jie Lea Adra
    "Our lives improve only when we take chances and the first and most difficult risk we can take is to be honest with ourselves." - Walter Anderson



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  5. #5

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    makin manyakk baca makin manyakkk tadak faham oiiiiiii ....makin fenin feninn jadinyaaa :roll: :roll:

  6. #6

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    felan felan baca tau...jgn gelabah..udah....
    "Our lives improve only when we take chances and the first and most difficult risk we can take is to be honest with ourselves." - Walter Anderson



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  7. #7

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    yaa.... ana kena baca felan..felan..nanti ente kasi baca, ana ikut..aa..baa..ta...sa...felen..felan... :lol: itu makhraj tada betul lah..kasi nipis..nipis...lah...
    Tak tahu cara upload foto di Fotomedia Malaysia??http://www.fotomedia.com.my/forum/showthread.php?t=8574

  8. #8

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    buat ler kak zain...yg penting ade feham.....
    "Our lives improve only when we take chances and the first and most difficult risk we can take is to be honest with ourselves." - Walter Anderson



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  9. #9

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    ana mau tanya itu jie lah..apa pasal ana punya mentul warna kuninlah..ana mau hijaulah srupa itu Bubba...banyak cantiklah hijau... :lol:
    Tak tahu cara upload foto di Fotomedia Malaysia??http://www.fotomedia.com.my/forum/showthread.php?t=8574

  10. #10

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    itu kena tanya dgn Admin ler....itu lampu kuning standby....sat lagi merah ler....
    "Our lives improve only when we take chances and the first and most difficult risk we can take is to be honest with ourselves." - Walter Anderson



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  11. #11
    banyaknya nak baca.. tak pe banyak masa lagi
    memerlukan kamera percuma

  12. #12

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    Baca slow2 kalau tak paham boleh tanya kak jie...
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  13. #13
    dah abis slow dah baca ni.. mata pun dah naik kembang . heheh
    memerlukan kamera percuma

  14. #14

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    Susah sgt. print je..then bila ada masa leh baca dimana jua anda berada.
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  15. #15
    tak pe esok lusa sambung baca balik.. baru efektif..

    idea print tuh agak bernas juga
    memerlukan kamera percuma

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