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 |
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| 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 27.
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.
2007. január 12.
This is a terrific lens, but Sigma has now re-released it as an 18-50mm F/2.8 EX DC Lens with MACRO capability (can focus down to 8", and 1:3 magnification), for very little additional cost, making this version of the lens essentially obsolete.
Furthermore, the other reviewer is correct that Cameta's (or Amazon's) description is quite misleading. This is NOT the Macro version of this lens. It will NOT give you 1:1 magnification (nor will the Macro version, for that matter, so I'm at a loss as to how such an unrealistic claim found its way into the ad copy!)
To locate the NEW, improved version of this lens, search on:
Sigma 18-50mm 2.8 MACRO CANON (one is also made for Nikons)
2006. szeptember 19.
I bought this lens with my Canon Rebel XTi. The default lens that came with the camera was very bad (EF-S 18-55mm f3.5-5.6). I don't recommend it to anyone, it is really a waste of the camera's capabilities, and the pictures you get may not be as good as that from a point and shoot camera.
I am very happy with the Sigma lens. I love the f2.8 feature as it makes indoor pictures (w/o flash) much better. The pictures are pretty sharp in general (especially around the focus point). Beware that taking pictures at f2.8 can be tricky, i.e. while the image center is in focus, the edges and other more distant points may be not be (try increasing the f number if there is sufficient light).
There are three lenses in the market with comparable price & performance: Sigma 18-50mm f/2.8 EX DC, Tamron SP AF17-50mm F/2.8 Di II LD and Canon EF-S 17-85mm f/4-5.6 IS USM. Sigma is the cheapest and the other two are a bit more expensive.
I've just compared my Sigma with a friend's Canon today. The picture qualities were almost identical. Canon was a bit sharper due to Image Stabilization, but f2.8 in Sigma compansates for that. Overall, the picture qualities were very very similar. Canon has a slightly wider range of zoom, but I don't know if it worthy of $150 price delta. The barrel distortion at 18mm is noticeable with both cameras.
The reviews I read online indicate that Tamron and Sigma lenses are pretty similar, although the reviews for Tamron are a bit better. I haven't tested the Tamron yet.
I haven't had any focusing issues with the Sigma. It takes a while to get used to auto-focus function in Rebel cameras and perfect focusing is not 100% guaranteed. But that's true for any lens. You just need to learn how to do it.
I am aware of only one lens which is considerably better than the Sigma: Canon EF-S 17-55mm f/2.8 IS USM. That lens really rocks. Its colors are more saturated and it is sharper due to IS. However, it is _very_ expensive. If you cannot afford it, one of the three lenses above can be your choice. Sigma offers the best value among three, and it has pretty good performance.
2005. szeptember 17.
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
2007. január 12.
This is indeed a very good lens with strong reviews. It provides an affordable alternative to the unaffordable over-one-grand Nikkor 17-55 f/2.8.
Why would you want to get an f/2.8 constant aperture lens like this when you could get a "superzoom" lense that goes from 18-200mm?
Because a constant minimum aperture 2.8 lens like this one allows you to shoot nonblurry photos in low light conditions, AND because it allows you to create the most artistically blurred-out backgrounds in closeup photos. Zooms with variable minimum apertures higher than 2.8 cannot do either of those well. That's what you'll miss out on if you buy the Nikon 18-200mm VR lens, for exampe. VR (Vibration Reduction) can eliminate the effect of a wobbly hand on the camera, but it CAN'T help you "freeze the action" of the scene right in front of you. Only a higher ISO (noisy, grainy, poor resolution) or a wider aperture (confusingly, the low numbers like 2.8, 2.0, 1.8, 1.4 are the wider apertures) can solve the blurry action problem.
BUT DON'T BUY IT. Why not? Because this autumn (Fall '06) Sigma introduced a version of this same lens that is slightly updated, and, importantly, allows you to get closer to a flower or other object (8"!) and magnify such objects up to 1:3 resolution, which begins to approach the Macro range (people define Macro differently, of course, but for many flower lovers 1:3 magnification is sufficient).
The 1:3 magnification option adds a world of beauty to your walk-around picture-taking.
To have a wide-angle lens, a portrait lens, AND a macro lens all on one lens? Terrific. And the price for the MACRO version is only a few dollars more.
HOW TO TELL THE DIFFERENCE: The names of the lenses are basically identical except the newer version includes the word MACRO somewhere in its title. If the product name doesn't say MACRO, it's the older 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.
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.
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
[.....]
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.
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. március 28.
This is a great lens for the money. It works perfect on the K10. The sevice was fast and I look forward to buying more products.
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.
2007. április 04.
Had this lens 2 weeks now, major and huge difference from the kit lens. No vignetting and very fast at 2.8 throughout. I'll update if i find problems later.
And by the way! CHEEEEEEEEEEEEEEEP and affordable :)