APS-C méretű vetített képAz APS-C méretű képet vetítő objektíveket kimondottan a digitális fényképezőgépekhez fejlesztették, ezért nem használhatók filmes gépeken, vagy olyan digitális fényképezőgépeken, amelyekben az APS-C méretűnél nagyobb érzékelő található. Nem ultrahangos AF-esAz ultrahangos automatikus élességállítással szerelt objektívek általában halkabbak és gyorsabbak, mint a tradicionálisan működő objektívek. Egy vagy több alacsony szórású lencsetag is van benneAz alacsony szórású lencsetagok segítenek csökkenteni a kromatikus aberrációt. Nem stabilizáltA képstabilizátor segít csökkenteni a kéz remegéséből adódó elmosódásokat. A stabilizátor hatása elsősorban nagy gyújtótávolságnál és gyenge megvilágításnál érezhető. A képstabilizátor 1-3 fényértéknyi előnyt biztosít a nem stabilizált objektívekhez képest. Fém bajonettAz olcsóbb objektívek általában műanyag, míg a drágábbak fém bajonettel készülnek. Általában a fém bajonettek tartósabbak, így gyakori objektívcserénék ez a szerencsésebb. Ha egy fényképezőgépet főleg egy objektívvel használunk, akkor a bajonett anyaga nem annyira lényeges. Belső élességállításúA belső élességállítású objektívek mérete az élességállítás során nem változik. A front lencse fixA fix frontlencse az élesség és/vagy a gyújtótávolság állításakor nem fordul el. Ez lehetővé teszi, hogy a fotós szirom alakú napellenzőt használjon. A fix frontlencse megjönnyíti a polarizációs szűrők használatát is. Nincs becsúsztatható szűrőA becsúsztatható szűrőket olyan objektíveknél alkalmazzák, amelyek frontlencséje túl nagy, illetve amelyek látószöge túl nagy ahhoz, hogy hagyományos szűrőket lehessen rájuk tenni. Általában a nagy fényerejű tele, illetve az ultra-nagy látószögű objektíveknél fordul elő ez a megoldás. |
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Az objektív felépítésének tervezésekor az elsődleges szempontok a digitális tükörreflexes fényképezőgépek jellemzői voltak. A különleges, alacsony színszórású SLD lencsetag hatékonyan kompenzálja a digitális tükörreflexes fényképezőgépekre jellemző laterális kromatikus aberrációt. A két aszférikus lencsetag számos különféle aberrációt korrigál, és az egész zoom tartományon át kiváló minőségű felvételeket biztosít. A speciális alacsony színszórású (SLD) lencsetag és a két aszférikus lencsetag minden típusú aberrációt hatékonyan kiiktat. A "Super Multi Layer" (SML) többrétegű lencsebevonat utánozhatatlan színegyensúlyt eredményez, és minimálisra csökkenti a digitális fényképezőgépekre jellemző becsillantást és a szellemkép-képződést. Az objektív az egész zoom tartományon át 28 cm közelpontot biztosít, ami kifejezetten kényelmes a makrófotózáshoz. Az objektív belső élességállítási rendszerrel rendelkezik. Ez az objektív nagyszerűen korrigálja a nagy fényerejű objektívekre jellemző peremsötétedést. Új felépítése révén az optika elsőrangú perifériális világosságot eredményez a felvételeken.
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| Elérhető bajonett(ek) | Canon EF, Nikon F, Pentax K, Sony / Minolta A, FourThirds, Sigma |
| Felhasználási terület(ek) | Portré, Tájkép, Épület |
| Kategóriák | Standard zoom |
| Szorzó | 1.5× |
| Stabilizátor | nem |
| Gyújtótávolság | 18 - 50 mm (2,8× zoom) |
| Objektív felépítése | 15 lencsetag 13 csoportban |
| Látószög |
35mm: nincs adat digitális: 69.3-27.9° |
| Lamellák száma | 7 |
| Legnagyobb blende | nagy látószög: f/2,8 tele: f/2,8 |
| Legkisebb blende | nagy látószög: f/22 tele: nincs adat |
| Legkisebb tárgytávolság | 28 cm |
| Nagyítás | 0,2× |
| Szűrőmenet | 67 mm |
| Méret | ∅ 74.1 × 84.1 mm |
| Tömeg | 445 g |
| Megjegyzések |
|
| AF sebesség | nincs adat |
| AF hang | |
| Belső élességállítás | igen |
| Belső zoom | nincs adat |
| Fix frontlencse | igen |
| Bajonett típusa | fém |
| Időjárásálló | nincs adat |
| Becsúsztatható szűrők | nem |
| Ultrahangos AF | nem |
| APS-C méretű vetített kép | igen |
| Alacsony szórású lencsetag | igen |
| Kemény tok | nincs adat |
| Puha tok | tartozék |
| Napellenző |
tartozék nyomtatható napellenző |
| Állvány adapter | nincs adat | Már nem kapható | igen |
2004. november 24.
I have a Canon 20D, and I have had these lenses:
Canon 50mm/1.8 (my reference standard for the best lens performance I can reasonably expect)
Canon 28-135 IS
Canon 28/2.8
Sigma 18-50/2.8
Canon 18-55 EFS
I have found that the Sigma 18-50/2.8 is the lens I keep on my camera most of the time. It has very good color, contrast, sharpness, saturation, and low distortion and aberration. By contrast to the 18-55 kit lens that came with my camera, the Sigma is in a whole different class. I would compare it favorably with my Canon 28/2.8 prime lens. I have never used a prime lens wider than 28mm, so I can't speak as to what the distortion is like at 18mm compared to a prime, but in general I am very pleased with the Sigma.
I find it has better dynamic range than the Canon 28-135 did; I can get better textures and ranges of intensity.
For the highest quality, I always go to my Canon 50/1.8, but in walking around and general shooting, I use the Sigma.
I was interested in the Canon 17-40L, but from what I have seen there is not a lot of difference in the quality from that lens and this one. Perhaps a little less distortion, but nothing you would notice unless you are taking pictures of brick walls.
2004. december 26.
This lens is soooo sharp. I returned a sigma 17-35mm EX DG HSM. The 17-35mm was a good lens with superb build. The 18-50mm f/2.8 is a great lens with good build. HSM would be nice and so would full time manual focus. Having said that. The focus is fast but not silent. However it is not loud either. And the auto focus is sharp, so I haven't had to use manual focus. It is so light that at first you think hey is the build cheap? No it isn't! It works well on my EOS 20D. If Sigma could make this lens 17-85mm they would sell a million of them. There is a lock for zoom creep but I never use it because there is no zoom creep. Oh yes the color and contrast are also great.
2005. szeptember 16.
Image stabilization is the new hotness in lens design, but being an old-fashioned sort, I went on a search for a lens with a wide maximum aperture instead. Sure, IS and VR give you the ability to hand-hold week long exposures, but what if your subject is moving? Amazing what a difference that extra stop can make when you need to capture action in low light. Plus, the AF system works better, and the viewfinder is brighter.
Cost, however, is what drove me to this lens. Due to financial constraints, I could afford no more than $500 for a lens for my 300D, which knocked the Canon L-series glass out of contention. After looking at the Tokina and Sigma 28-70 F2.8 lenses, I discovered this lens was in the pipeline and held out for it.
It's not a replacement for the Canon L-Series lenses. That's the bad news. The good news is that this is possibly the PERFECT advanced amatuer lens. Good optical quality, though a little soft at F2.8. Focuses quickly, and "wanders" less than other EF-mount lenses I own (18-55mm EF-S kit lens; low-end Sigma 28-90). The wide aperture allows for auto focusing in what feel like "no light" situations.
Strengths:
Quick focus, little focus "wander", good build quality, included sunshade and case, relatively light weight and small size
Weaknesses:
Works only with APS-C image sensors, a little soft at F2.8
2006. január 02.
I am very happy with my purchase of this lens. I bought it to replace my Rebel XT's 18-55mm kit lens, and it compliments the camera very well. The greatest strength of this lens is its remarkable sharpness. Even 100% crops retain their quality. Shots are even acceptable at f2.8 (better than or equal to the kit lens at f8+), and past f8 the lens is stunningly sharp. I uploaded some shots and 100% crops to amazon in order to illustrate my point. The sharpness of this lens is easily comparable to Canon's 17-40, which says quite a lot.
The corners are not as sharp as the center, especially in wide angles. Outside of the center, the 18-50 is also prone to chromatic abberations/fringing but not worse than almost any other lense. Barrel distortion is present at 18mm but much better than the competition (ie, the 17-40L and 17-85 IS).
Color saturation is good- not as impressive as the Canon 17-40 but still perfectly adequate and very good with a slight software sharpening boost.
The only true negative I have found is a propensity for light lens flare. Even when the sun is out of frame by 20 degrees, flare can still occur. (note that this flaring is not major, and I have often not even noticed it until the second or third time I come back to a picture) I have also noticed flare from street lamps in 10+ second night shots. The lens comes with a decent hood (as well as a pretty nice soft case) in order to help prevent flares. However, I have noticed flaring in cases where the sun was so indirect I never would have thought to attach the hood. The lens cap also cannot be accessed while the hood is on, which is a frustrating design quirk. While, even in the best lenses, flare is not totally avoidable the 18-50 flares much more frequently than other lenses I have used. I don't know if this is an issue with the internal optics or the coatings used on the lens.
Even considering flare problems, I would buy this lens again without a second thought. Its only direct competitor in quality is the Canon 17-40L, which is more expensive, shorter in range, has a narrower max aperture and worse barrel distortion. I am extremely happy with almost every shot this lens generates, and its moderate price makes the 18-50 f2.8 a great companion for the Rebel XT.
2007. január 27.
I currently own this lens. It's a great all-purpose lens and I think it's very fresh even at 2.8. Razor sharp from f4-f11. Very comparable IQ to Canon L lenses. The only real differences are the Canon L's weather sealing and quieter/faster autofocus. Is the difference worth $700+ to you? This lens comes with me to every wedding I shoot. You tell me!
2006. október 06.
I took a look a this lens almost as a fluke -- I wanted something that gave me quick speed at 2.8 but had more range than than the prime standard 50/1.8...and I was so pleased with the lens I have used it quite a bit more than I thought I would. The quality of the photos is excellent, good colors, good contrast. The lens is relatively light (less than a pound) so it "feels good" on the body. Compare this lens to the Tamron 17-50/2.8 They are virtually identical. This is a supurb replacement for your standard kit lens.
2006. június 08.
I use this lens on my Nikon D70. It's great. Before I bought it, I thought I should get a lens with better range, example, the Nikon 18-200mm lens. My friend had told me about this one, so I decided to buy it for the heckuvit. I was glad I did. The range isn't a big deal now, but the only problem is--umm--uhh--I can't really think of any problems I've had with this lens, besides the fact that I all of my lenses, I use this one the most, and I paid all that money for the other lenses! Trust me, it's great.
2007. április 02.
I bought this lens because my REAL Nikon film lenses did not perform well with my new digital SLR. To make the whole story short, I had invested $1400 in a digital SLR in hopes that I could use my Nikon lenses. But to my surprise...those lenses didn't perform well at all. So I took a chance on this Sigma lens (after reading the reviews of course). It was the least expensive lens in my bag but it gave the best result. The images were very sharp with good colors and detail. Again, thanks to those who took the time to write the earlier reviews. They had helped me tremendously.
2007. január 11.
This is a good lens to have in the bag for an amateur photographer like myself. The lens is relatively fast with a constant 2.8 aperture throughout the zoom. The lens is sharp at f-stops 4 and above and workes quite well even wide open. I use it on a Nikon D50. Focusing is fast. Overall I am quite happy with the purchase. Check out pictures at
[.....]
2006. november 26.
I recently made the jump into my first DSLR, a Pentax K100D. However, like most "kit" lenses, the provided 18-55 seemed to be average at best (based on reviews, etc), so I opted to get the body only, then pick and choose some lenses.
I went with a Pentax 10-17mm fisheye-superwide zoom, and a Sigma 70-300 telephoto zoom. I like the extreme perspectives those lenses can provide.
However, for the bread-and-butter mid-range lens, I decided to pay a bit more (OK, three times the price of the kit lens, and more than either other lens) for the extra f-stops and reputed sharpness of this lens.
The lens is a little larger and heavier than similar-range slower lenses due to the extra glass. It has a zoom-lock at 18mm which prevents the zoom from creeping out if you are the type to let your camera hang on the strap - I'm not. I support the camera under the lens in my left hand.
As with my other Sigma lens, they recommend putting it in manual-focus mode when adding or removing the nice included lens hood to prevent damage to the focusing system. Perhaps that's a good habit to get into, though remember to slide it back into AF (if that's your style) or you'll be fumbling to focus your first shot :-)
For some reason, Sigma is not consistent with their zoom rotation direction - it's counterclockwise wide-to-zoom on the 18-50, but clockwise on the 70-300.
I'm happy with the results. Now (a year later), it is discontinued (replaced by a macro version), and sells for $100 less. As they say, a picture is worth a thousands words, so I'm posting some photos in the Amazon collection.
2007. augusztus 09.
Allow me to start off by stating that I am an "old school film" photographer. When I mean old school I am talking about Nikon F and Nikkormat cameras. I also acquired some Pentax screwmount bodies and lenses back in the late sixties and early seventies. The lenses were made of metal and glass. They were sturdy, uncomplicated and still considered sharp to this day. Today we have too much plastic IMHO. Not to mention motors!
I joined the digital revolution awhile back. I'm still waiting for affordable Nikon bodies that meter with the AI lenses. The D200 is just too much for me to consider.
Recently, I purchased an affordable Pentax K100D with the kit lens. After doing my own testing at various apertures and focal length settings, I came to the conclusion that it was OK for the money but I wanted something sharper.
So I bought this Sigma lens. This Sigma lens is way better and more costly but definitely worth it. Wide open it blows the kit lens away. Its wider (f:2.8) than the kit lens (f:3.5). In darkened interiors that little extra one half F stop will come in handy and be sharper as a bonus! Also, its F:2.8 over the entire focal range. This lens is a worthy investment and you will notice the sharpness.
Pros:
Sharp
Larger minimum F stop
responsive
Cons:
Costs more than the Pentax kit lens
Uses larger filters (62mm as opposed to 52mm)
Weighs more (I don't mind though)
I feel that the Pros outweigh the Cons. Go for it. You won't be sorry.
2007. október 26.
First of all, if you have already bought the kit lens, and use it mostly outdoors, don't bother to buy this one. However, if you are doing a lot of in-house shooting, say, in a museum; or other situations you need this f/2.8 yet no tripod is available, then this is the lens for you.
Comparing to the kit lens, the most impressive property of this lens is its f/2.8. As said before, it gave you a night-&-day difference in low-light conditions. The quality of the Sigma brandname is satisfying.
Budgetwise, if you have more money, go for the SLD/ELD model, which is only $70 more. If you are tight on the green, don't forget this: for the kit lens, the fliters-kit are only $17 at amazon, yet for this 67mm, a single filter will cost you $50+.
2007. augusztus 09.
I purchased this lens for use with a Pentax *ist D on a trip to China involving a lot of architectural and indoor sights, some in dim light. Although some reviews rate the 17-70 more highly, I selected this lens for the aperature. Overall it performed extremely well, providing sharp and reasonably fast focus and minimal distortion as long as it was not used at an extreme wide angle. I am very pleased with the purchase.
2007. május 23.
Product performed as expected. Excellent low light performance and very fast lens. At extreme wide angle (18mm) you may need to rotate lens petal shape lens cover to keep shadow out or just take lens cover off. Built solid (great build quality) with metal mount and excellent finish. The lens is sharpe throughout the zoom range. The EX version is impressive with a good solid feel to the lens. This lens is on my camera 80% of the time. Vendor shipped product in safe and expedited manner. I will do business with them again.
| Nikon Complete Lens Cleaner Kit$8,04 | |
| LensPEN Lens Cleaning System$0,99 | |
| Carl Zeiss Optical Inc Lens Spray Cleaner (3-Ounce Bottle)$2,49 | |