DSLR lens

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Decoding the lens jargon

The almost sentence-long collection of letters and numbers on the side of a lens barrelcan tell you all sorts of things about a lens. But the details which you should probably pay

the most attention to are those which detail the focal length, maximum aperture, lens

mount and format type.

Focal length

Focal length is expressed in mm and a higher number means a bigger zoom, while alower number mean the lens can be used for wider shots. As a rough reference, the

human eye is said to see about the equialent of !"-#" mm on a full frame camera $moreon that later%. A number lower than !"-#" mm will ta&e in a bigger iew than you

naturally see, while higher numbers mean focus will be on a smaller aspect of your iew.
http://www.gizmag.com/camera-lens-buying-guide/29141/pictures#20

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'f the lens has a focal length range with two numbers $say ()-*" mm% this means it+s a

zoom lens and is capable of zooming and being used at any point across that range.oweer, if there is a single focal length number $#" mm for instance% it+s a prime lens,

so ta&ing in more or less of the iew will require you to get closer or further away from

your subect. Traditionally, primes hae been considered to be optically superior tozooms, because trade-offs hae to be made when producing zoom lenses. But that+s not to

say that some zooms are not better than some prime lenses.

To ma&e understanding focal length more difficult, the same focal length lens gies

different iews on cameras with arious sensor sizes, because of the crop factor $thesensor only ta&es up part of the proected image%. As a result, many manufactures gie a

!# mm-format equialent on lenses designed for cameras with smaller sensors and in this

article descriptions are based on on !# mm-format. Therefore, if your camera has asmaller sensor, and there+s a good chance it does, you+ll need to consider this when

deciding which lens you need.

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'f you+re using a full frame camera there+s no calculation needed, a lens will gie you the

field of iew you+d expect from its number. 'f your camera has an A/-0 sensor $1i&on

23 2/45s, /ony 1637% it has a crop factor of 8.# - meaning you multiply the lensfocal length by 8.# to get its equialent !# mm-format focal length. For 0anon A/-0

cameras that number is 8.9, for :icro Four Thirds cameras it+s (." and for the 1i&on 8

series it+s (.;.

That means a !# mm lens would gie a field of iew equialent to #9 mm on an A/-0camera li&e a 0anon ;"2 and equialent to ;" mm on a :icro Four Thirds camera li&e

the

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/ome zoom lenses hae a ariable maximum aperture meaning that it changes depending

on focal length. /o, while a 8*-("" mm F!.#-#.9 lens would hae a maximum aperture ofF!.# at 8* mm, it would be be F#.9 by the time you zoomed to ("" mm.

Lens Mount

't goes without saying that you want to buy a lens that will attach on your camera, and

this is &nown as the lens mount. 0amera manufacturers generally ma&e lenses with

proprietry mounts which will only fit their deices, sometimes haing multiple lensmounts for different camera lines. The maor exception to this is :icro Four Thirds

lenses which can be used on respectie

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these are things li&e the 0anon 6F-:, Fuifilm 3F, 1i&on 8, /ony 6, /amsung 13 and

entax . As mentioned earlier,

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What they are:ltra Cide angle lenses hae a focal length of around less than () mm$in !# mm-format%, this means they can ta&e in a wider scene than is typical, though

they+re not only about getting all of a subect into a shot. 5ectilinear ultra wides help &eep

straight lines, ust that, while fisheyes will reproduce buildings with cured walls.

Image characteristics:Because of the wide field of iew, shots with ultra wide anglelenses typically feature a large depth of field. 'mages tend to pull in subects that are

close, and push away more distant ones ma&ing them appear further apart. erspectiedistortion of ultra wides can gie falling-building-syndrome $where ertical linesconerge% but this can be corrected in post-processing, or minimized with good

technique.

What they are used for:Chile often seen as a specialist lens, ultra wide angles can be

used in a number of ways. Typical uses include landscape, architecture and interiorphotography. 6en the distortion can be used creatiely, especially when using fisheye

lenses.

Wide Angle

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What they are:Typically coering a focal length between () mm and !# mm, CideAngle lenses are aailable as primes or zooms and come with either ariable or fixed

maximum aperture.

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What the are? The &it lens your 2/45 or interchangeable lens mirrorless camera camewith is probably an example of a standard zoom lens, coering a focal range of around

!#-;" mm.

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What they are:Telephoto lenses are those with a focal length in excess of ;" mm,

though many people would argue that EtrueE telephoto lenses are ones which exceed 8!#

mm. They focus on a much narrower field of iew than other lenses, which means theyare good for focusing in on specific details or distant subects. They are generally larger

and heaier than equally specified wider lenses.

Image characteristics:Because they hae a narrower angle of iew, telephoto lensesbring far away subects closer. They can also hae the effect of compressing the sense of

distance in a scene and ma&ing obects appear closer together. A narrow depth of field

means that a subect can be in focus with a blurred bac&ground and foreground.

What they are used for:'n addition to being used to photograph subects you can+t $ordon+t want to% get close to - li&e sports or wildlife - telephoto lenses can be used for

shooting portraits and een landscapes where their normalization of relatie size can be

used to gie a sense of scale.

Super#oom

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What they are? /uperzooms are do-it-all lenses which coer focal lengths from wide to

telephoto. They can be good for uses in situations where you can+t or don+t want to bechanging lenses and they normally change in length as you zoom.

Image characteristics:Because compromises hae had to be made producing a do-it-all

lens, superzooms do not hae the same image quality of more dedicated lenses and oftenhae slower and ariable maximum apertures.

What they are used for:

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What they are?

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Cith changes in focal length and maximum aperture come another set of lens changes,namely size, weight and price. 'deally we+d all be wielding a 89-9"" mm F8.* lens.

nfortunately, not only does physics dictate that such a lens would need to be huge and

ery heay, it would also cost a fortune to produce, if it was een possible.

As such, any lens is going to ma&e compromises to fit into a pac&age of a size and weight

which suits its users. 6xtreme focal lengths and larger apertures mean bigger and heaier

lenses, which along with the bigger price-tags is why they are typically used by

professionals who can ustify purchasing them.

Image sta(ili#ation% (uild )uality and *ideo

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There are a number of other features which you may want thin& about, regarding your

next lens. 'mage stabilization allows for use of slower shutter speeds without suffering

camera sha&e $though some brands incorporate this into camera bodies rather than thelens%. /tabilization is also ery handy if you+re shooting lots of ideo, in which case you

might also want to thin& about lenses with power zooms which can zoom at adustable

speeds.

Ceather-sealing means you can use your lens $assuming your camera is equally weather-sealed% in extreme weather conditions and normally also means a higher leel of build

quality.

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Below are a number of typical situations that &it-lens-toting photographers often find

themseles in. For each example, we+e highlighted some of the factors that should be

considered when trying to find the right lens for the ob. Chile these are factors whichare releant whateer camera and lens system you+re using, in each case we+e also

highlighted a couple of lenses that would be a good choice for specific set-ups without

blowing the budget.

I &ant an all,day tra*el lens

Chen you+re on holiday or traeling, you probably don+t want to be lugging seeral lenses

and cameras around with you G unless you+re the most dedicated of photographers, that is.

't+s often the same if you+re trying to enoy a day with the family and don+t want to spendall day changing lenses and moaning about your bac&.

As such, a good all-day or trael lens would be one that was easy enough to carry around,

but still offered you the freedom to capture shots from landscapes to portraits, and zoom

in on distant obects. For :icro Four Thirds shooters, that could be something li&e theanasonic 4umix H Iario 8)-8)" mm f>!.#-#.9, or the AF-/ 23 1'@@!.#-#.9H 62 I5 '' if a 23 1i&on is your 2/45 or choice.

I &ant to do street photography

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/treet photography can be done with almost any lens, though a !"" mm F(.* might raise

a few eyebrows from your subects. oweer, a focal range of around !#-#" mm is oftenseen as the ideal for capturing the moment in urban areas.

nless you want all of your subects loo&ing directly at the camera, you+d probably be

best sered by something discrete. 't+s also important that street photography lenses

feature a fast maximum aperture for lower-light situations. This means that something

li&e the Fui 3F (! mm f8.) 5 4ens would be a great selection. The /igma !# mm F8.)2H /: has also been ery well receied by many 2/45 street shooters.

I struggle to photograph my -ids running around in the garden

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:any people shell out for a 2/45 or mirrorless interchangeable lens camera when theyhae a child, but by the time that child starts running around, the &it lens struggles to

&eep up, both in terms of aperture and focal range. This is especially true if you+re trying

to photograph the &ids running around in the garden or on the sports field.

This means you need something with a bit more reach, but probably without the bul& andweight that a professional lens would bring. A zoom lens will allow you to &eep your

shots framed as you want while your subect moes around in front of you. /o, if you feelyou ust need some added reach, the 6F-/ ##-(#" mm f>)-#.9 '/ '' could get you closerto the action. But if you want a bit more speed $and to be the best equipped parent at the

game%, there+s the 0anon 6F ;"-("" mm f>)4 /:.

I &ant to ta-e landscape photographs

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Chile the &it lenses which come with most cameras are surprisingly good at the wide

angle end, you could find that they don+t quite go far enough for some of the landscape

images you try to ta&e. /o, unless you+re able to &eep moing bac&wards, you+re going toneed a new lens.

Focal length is &ey here, and you+ll only get some landscapes if you+e got an ultra wide

angle lens. ou could go for either a prime or a zoom, but most people in this situation

are probably going to be best-sered by a zoom. A lens li&e the AF-/ 23 1'@@

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After a while you might find that you+e simply outgrown your &it lens. ou suddenly

find that it+s stifling your creatie ambitions and preenting you from ta&ing the photos

that you want, een if they are within its focal length reach.

This is the ideal time to get yourself a fast prime lens, and the good news is that you don+thae to spend a fortune to do it. Hetting something li&e a 1i&on AF-/ 23 1'@@8.*H or the /ony 6 #" mm f>8.*

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oweer, buying new lenses doesn+t hae to mean spending a fortune. Ce+e seen how

relatiely inexpensie primes li&e the nifty-fifty $#" mm F8.*% can change your

photography foreer. There are also thousands of second-hand lenses which will wor&ust as well as new ones out there G especially for 2/45 shooters, where you can often

use a ("-year-old lens. ou neer &now, your father might een hae some lying around

in the attic.

opefully this article hasn+t made you feel compelled to buy more and more lenses, asthat really wasn+t the aim. 'f you+re not sure if you need a new lens, you probably don+t.

'nstead, we hope this has helped you understand what to loo& for when you feel that your

current lenses are preenting you from being the photographer you want to be.

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Manufacturers like to try to make things easy for you when you're shopping for a digitalcamera, especially by highlighting certain measurements of their models, such as largemegapixel amounts and big LCD screen sizes.

owe!er, such numbers don't always tell the entire story, especially when looking at zoomlenses on a digital camera. Manufacturers measure zoom capabilities of digital cameras in twoconfigurations" #ptical zoom !s. digital zoom. $t's important to understand the zoom lens,because the two types of zooms are !astly different from each other. $n the battle of opticalzoom !s. digital zoom, only one %% optical zoom %% is consistently useful for photographers.

&ith most digital cameras, the zoom lens mo!es outward when in use, extending from thecamera body. ome digital cameras, howe!er, create the zoom while ad(usting the lens onlywithin the camera body. Continue reading to find more information that can help youunderstand camera zoom lenses better and that can help you put an end to the debate ofoptical zoom !s. digital zoom)

Optical Zoom

#ptical zoom measures the actual increase in the focal length of the lens. *ocal length is thedistance between the center of the lens and the image sensor. +y mo!ing the lens fartherfrom the image sensor inside the camera body, the zoom increases because a smaller portionof the scene strikes the image sensor, resulting in magnification.

&hen using optical zoom, some digital cameras will ha!e a smooth zoom, meaning you canstop at any point along the entire length of the zoom for a partial zoom. ome digital cameraswill use distincti!e stops along the length of the zoom, usually limiting you to between fourand se!en partial zoom positions.

Digital Zoomhe digital zoom measurement on a digital camera, to put it bluntly, is worthless under mostshooting circumstances. Digital zoom is a technology where the camera shoots the photo andthen crops and magnifies it to create an artificial close%up photo. his process re-uires

magnifying or remo!ing indi!idual pixels, which can cause image -uality degradation.

Most of the time you can perform functions e-ual to a digital zoom with photo%editing softwareon your computer after you shoot the photo. $f you don't ha!e time for or access to editingsoftware, you can use digital zoom to shoot at a high resolution and then create an artificialclose%up by remo!ing pixels and cropping the photo down to a lower resolution that still meetsyour printing needs. #b!iously, the usefulness of digital zoom is limited to certaincircumstances.

Understanding Zoom Measurement

&hen looking at specifications for a digital camera, both the optical and digital zoommeasurements are listed as a number and an /, such as 0/ or 12/. 3 larger numbersignifies a stronger magnification capability.

4eep in mind that not e!ery camera's 12/ optical zoom measurement is the same.Manufacturers measure the optical zoom from one extreme of the lens' capabilities to the

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other. $n other words, the multiplier is the difference between the smallest and largestmagnification measurements of the lens. *or example, if a 12/ optical zoom lens on a digitalcamera has a minimum magnification e-ui!alent to 05mm, the camera would ha!e a 052mmmaximum zoom. owe!er, if the digital camera offers some additional wide%angle capabilitiesand has a minimum 67mm e-ui!alency, then the 12/ optical zoom would only ha!e amaximum zoom of 672mm.

he zoom range should be listed in the camera's specifications, usually in a format similar to05mm film e-ui!alent" 67mm%672mm.8 $n most cases, a 52mm lens measurement isconsidered as normal, with no magnification and no wide%angle capability.

Interchangeable Lenses

Digital cameras aimed at beginners and intermediate users typically only offer a built%in lens.Most digital L9 cameras, howe!er, can make use of interchangeable lenses. &ith a digitalL9, if your first lens doesn't ha!e the wide%angle or zoom capabilities that you want, you canpurchase additional lenses that pro!ide more zoom or better wide%angle options.

Digital L9 cameras are more expensi!e than the point%and%shoot models, and they're usually

aimed at intermediate or ad!anced photographers.

Some Zoom Lens Drawbacks

3lthough choosing a point%and%shoot camera with a large optical zoom lens is desirable formany photographers, it sometimes presents a few minor drawbacks.

Noise.ome beginner%le!el, inexpensi!e cameras suffer from lower image -uality

because of noise when the lens is extended to the maximum zoom capability. Digitalcamera noise is a set of stray pixels that don't record correctly, usually appearing as

purple edges in a photo.

Pincushioning.Maximum zoom also sometimes causes pincushioning, which is a

distortion where the left and right edges of the photo appear stretched. orizontallines appear slightly cur!ed toward the middle of the frame. 3gain, this problem

usually is limited to beginner%le!el, inexpensi!e cameras with large zoom lenses.

Slower shutter response time.&hen using the maximum zoom magnification, the

shutter response time sometimes slows, which may cause blurry photos. :ou alsocould miss a spontaneous photo because of the slower shutter response. $t simplytakes the digital camera longer to focus on the image at the maximum zoom setting,which explains the slower shutter response time. uch problems are magnified whenshooting at maximum zoom in low light.

e!uires a tripod.;sing a long zoom lens can cause increased camera shake. ome

digital cameras can correct this problem through image stabilization. :ou also can usea tripod to pre!ent blurry photos from camera shake.

Don"t #e $ooled

&hen highlighting the specifications of their products, some manufacturers will combine thedigital zoom and optical zoom measurements, allowing them to showcase a large combinedzoom number on the front of the box.

:ou, howe!er, need to look only at the optical zoom number, which might be listed in a corneron the back of the box, along with a host of other specification numbers. :ou might ha!e to doa little searching to find the optical zoom measurement of a particular model.
http://cameras.about.com/od/technologies/a/image_stabiliza.htmhttp://cameras.about.com/od/technologies/a/image_stabiliza.htm

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$n the case of digital camera zoom lenses, it pays to read the fine print. ;nderstand the zoomlens, and you'll make the most of your digital camera purchase.

DSLR lens

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