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The Canon EF-S 18-135/3.5-5.6 IS is a wide to telephoto zoom and gives the same angle of view range as a 28-216mm lens would on a full frame 35mm camera. This range covers a lot of applications from landscapes at the 18mm wide end, through portrait shots in the 50-80mm range and on to sports and wildlife when zoomed out to 135mm. With a maximum magnification of about 1/5 life size it’s not a macro lens, but zoomed out and at closest focus it will cover an area as small as about 3 × 4.5″ (75 × 112mm). The Canon EF-S 18-135/3.5-5.6 IS USM, (compare prices), was introduced by Canon in October 2009 at a price of $499.99. It uses a DC motor rather than a USM motor and so it fits in with the line of lenses, which are probably mostly intended for use on the EOS Rebel series bodies—though of course they can be used on any compatible Canon EOS crop sensor DSLR. Being an EF-S series lens, the 18-135/3.5-5.6 is only intended for use on (and indeed will only physically mount on) Canon Crop sensor EOS DSLRs (except for D30, D60 and 10D). It will not mount on any full frame or APS-H (1D series) body. The EF-S 18-135/3.5-5.6 IS uses a conventional focusing motor rather than a USM ring motor. This makes focus somewhat noisier and means that the lens does not have full time manual focus adjustment and for manual focus the AF/M switch must first be set to manual. Manual focus is adjusted by a ring at the front of the lens. The action is pretty much undamped and the throw is about 45 degrees from infinity to close focus, so while manual focus is possible, autofocus will normally be the preferred mode of operation. There are no distance or DOF scales. No case or lens hood are supplied with the lens, but a Lens Hood EW-73B and a Lens Case LP1116 are available from Canon and there are 3rd party lens hoods available at about 1/2 the price of the Canon originals. Bob Atkins The image stabilization system has one mode which stabilizes on both axes. Canon claims up to 4 stops of stabilization (more on that later). During zooming and focusing the front element does not rotate, making the use of a polarizer easier since it can be adjusted once for the required degree of polarization and will not need any readjustment after zooming or refocusing, When zooming from 18mm to 135mm the length extends from 101mm to 140mm, but the length is not affected by focusing. There is no zoom lock, but on the sample I tested there was no zoom creep when the lens was held vertically, so no zoom lock was required. The maximum aperture at each marked focal length is given below: Canon EF-S 18-135/3.5-5.6 IS Specifications Lens specifications: Image Quality Bob Atkins At 18mm there is vignetting wide open, barrel distortion and noticeable chromatic aberration—though if you shoot in RAW and use Canon’s DPP converter, vignetting, distortion and CA can be well corrected. Unless you are shooting brick walls or filling the frame with rectangular subjects, the distortion may not be noticeable (see whole frame image on right). Vignetting is significantly reduced by stopping down a stop and eliminated by f/8. Center sharpness is quite good but also improves by stopping down from f/3.5 to f/5.6. Further stopping down doesn’t increase sharpness. Bob Atkins Corner image quality improves on stopping to to f/5.6 and there is a further slight improvement on stopping down to f/8, f/11 sharpness is similar to f/8. Chromatic aberration (purple/green) is quite strong in the corners of the image with high contrast (black/white) features. Thankfully it is pretty easy to correct post-exposure in DPP if you shoot in RAW (see image on right). Overall performance at the widest setting isn’t bad, but you might want to stop down to f/8 when you can. I did note that the barrel distortion seemed to be quite a bit worse when close focused then when focused at longer distances. “Best” performance may be around 35mm where both center and corner sharpness is good, distortion is low and chromatic aberration is well controlled. Even wide open (f/4.5) performance is good, though it gets very slightly better when stopped down a stop. At 50mm, corner and center sharpness aren’t bad wide open at f/5, but do improve when the lens is stopped down to f/8. Astigmatism is low and chromatic aberration is well controlled. There is slight pincushion distortion and slight vignetting which is essentially gone by f/8. Bob Atkins At 135mm center sharpness wide open (f/5.6) is good and there’s little improvement on stopping down. Corners are a little soft wide open but sharpness there does improve on stopping down to f/8. Chromatic aberration is again visible in the corners of the image, but again can be pretty well eliminated using DPP on RAW files. Vignetting wide open is quite noticeable but is greatly diminished by stopping down a stop to f/8. Stopping down to f/11 brings up the corner sharpness slightly, but center sharpness drops a little, so f/8 is probably the “sweetest” spot at 135mm. Hannah Thiem Image Stabilization When I did handheld IS tests at 135mm I was quite surprised by the results (in a good way). Even at 1/4s I was getting fairly sharp images maybe 25% of the time. In fact I had better luck at 1/4s with IS on than at 1/60s with IS off! That gives a stabilization factor of about 4 stops (Canon claim “up to 4 stops”). That’s pretty impressive. As always with IS, it improves your odds of getting a sharp image at long shutter speeds, it doesn’t guarantee it. As shutter speeds get slower it’s always a good idea to fire off several shots to increase the chances of getting at least one of them acceptably sharp. At 1/25s with IS on, most of the shots were sharp which indicates about 3 stops of stabilization. Whether you get 3 stops or 4 stops, it’s still pretty impressive. Ultimately, the choice comes down to price and zoom range. If price isn’t an issue, you don’t need a wide zoom range and image quality is your primary concern, then you can’t go wrong with the EF-S 17-55/2.8 IS USM. However, if you want to do everything at lower cost and with with one lens you have to compromise somewhat on image quality and lens speed. If convenience is more important than speed and the highest possible image quality, then a lens like the Tamron 18-270 VC is worth considering (VC is Tamron’s version of image stabilization), or the Canon EF-S 18-200 IS. The expanded zoom range can be very useful, although it often leads to greater optical compromises. The EF-S 18-135 IS falls in the middle. The price is less than the zooms with greater range and the image quality is probably slightly better. The USM lenses are more expensive and/or have a smaller zoom range, but have a fast, silent USM motor with full time manual focus. Which lens is the best choice depends on the user’s needs. Hannah Thiem Conclusion The EF-S 18-135 is a pretty decent lens with the “middle of the road” performance you’d expect from a lens of this class. The zoom range of the 18-135 (equivalent to 28-216mm full frame) covers most of the requirements of the average photographer, from wideangle to telephoto, and does it in a single lens with a very effective IS system. For some users this might be the only lens they need and there’s no denying that not having to switch lenses can be a convenience. Those looking for the highest image quality will have to pay more and/or be content with a smaller zoom range Where to Buy Photo.net’s partners have the Canon 18-135/3.5-5.6 lens available. Their prices are fair and you help to support photo.net.
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Canon EF-S 18-200mm f/3.5-5.6 IS [napisao Gand. 6 Rujna 2008.] Canon je obogatio svoju seriju objektiva EF-S svestranim novim modelom: objektivom EF-S 18-200mm f/3.5-5.6 IS. Taj objektiv nudi ekvivalentnu žarišnu duljinu od 29 do 320 mm i zum od 11x, što znači da je sada moguće koristiti samo taj snažan i lagan objektiv, bez potrebe za nošenjem više objektiva na snimanje. Objektiv EF-S 18-200mm f/3.5-5.6 IS namijenjen je korištenju isključivo s fotoaparatima EOS s postoljem za objektiv EF-S, što obuhvaća nove fotoaparate EOS 50D, EOS 1000D i EOS 450D te starije modele. Visokokvalitetna optika EF-S 18-200mm f/3.5-5.6 IS odlikuje se konstrukcijom koja se sastoji od šesnaest elemenata i dvanaest grupa. Njima su obuhvaćene i UD i asferične leće koje minimiziraju kromatske aberacije te jamče oštre detalje na čitavoj slici i pri svakom stupnju uvećanja. Podrška za žarišnu udaljenost od svega 45 cm fotografima pruža neograničenu fleksibilnost pri kadriranju. Optički stabilizator slike s četiri položaja brzine zatvarač Canonov optički stabilizator slike s četiri položaja brzine zatvarača, osmišljen posebno za specifični raspon žarišnih udaljenosti ovog objektiva, pridonosi smanjenju zamućenja slike koje se ponekad pojavljuje kada se snima bez stalka ili pri manjim brzinama zatvarača. Automatsko prepoznavanje panoramskih snimki jamči učinkovite performanse pri praćenju objekata u pokretu. Osim toga, budući da se IS sustav nalazi u objektivu, rezultati su vidljivi u tražilu tijekom kadriranja. Bez popratnih slika i odbljesaka Zbog odbijanja svjetlosti sa senzora za sliku na digitalnim fotoaparatima mogu se pojaviti popratne slike i odbljesci. Da bi se to spriječilo, na objektivu EF-S 18-200mm f/3.5-5.6 IS koriste se optički elementi premazani Canonovim patentiranim premazima Super Spectra te se tako dobivaju oštre, nedeformirane slike s prirodnom ravnotežom boja. plaćeni oglasi: cheap phone card m.personalcashadvance.com