Showing posts with label 18mm. Show all posts
Showing posts with label 18mm. Show all posts

Tamron A19-100 Adaptall SP 70-210mm F/3.5 Manual Focus Lens with Hood and Case Review

Tamron A19-100 Adaptall SP 70-210mm F/3.5 Manual Focus Lens with Hood and Case
Average Reviews:

(More customer reviews)
In my opinion, and for several reasons, this is the best 70-210 zoom lens ever designed and manufactured. Overall somewhat above average performance within its class, plus several notable design features. This later one-touch constant F3.5 aperture zoom features a unique "reverse" zooming cam in which the zoom collar moves forward to become a lens shade when zooming to the longer focal lengths. This, in conjunction with the bayonet lens hood, assures that the optics are always optimally shaded against stray light. The model 19AH has approximately 50% better overall resolution and contrast compared to the earlier two-touch model 52A. Macro optical performance is exceptional (for a zoom), reaching 1:2.66 life size at the 210mm position. Macro performance towards the corners of the field is superior to the earlier model. Achieving this high level of optical performance throughout the entire zooming and focusing ranges was no easy task.
Compare the optical design of this lens with the optical design for the earlier 70-210 model 52A. You will note that Tamron still uses a four element focus group to greatly control aberrations and to provide extremely good macro performance. The primary aberration which needs to be controlled within any continuous focusing telephoto macro zoom lens is spherical aberration. Several of Tamron's SP telephoto prime lenses use a special spherical aberration compensator group to virtually eliminate focus induced spherical aberration. Unfortunately, a spherical aberration compensator group is impossible to incorporate within a telephoto zoom lens since the zoom's variator and compensator groups occupy the space within the optical design where the spherical aberration compensator group would be placed. Tamron's optical engineers had to seek out other solutions. The only practical solution was to further refine the design of the four element focus group to not merely minimize focus induced spherical aberration, but to actually compensate for it to a fair degree. This is the purpose of the focus group's cemented doublet which looks like a meniscus lens. It allowed Tamron to optimize this lens for focus distances which are much closer to infinity rather than macro, yet also allows focus induced spherical aberration to be compensated for fairly well when close focusing. But there is a limit to this design approach, and this is why this lens is limited to a 1:2.66 macro magnification ratio compared to the earlier model's 1:2 macro magnification ratio. The result, however, is a 3:1 zoom lens which not only is sharp when photographing distant subjects but also is fairly sharp when used for macro photography.
In terms of overall optical performance, solid construction, ease of handling, zero zoom creep, and optimized variable shading when the lens is used with its lens hood, you can see why I think that this is the best 70-210 zoom lens ever produced by any manufacturer. In short, Tamron achieved the optimal balance of the overall optical and mechanical design features which Tamron wished to incorporate into this lens.

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Another in highest quality SP series, This 70-210mm lens with the constant F/3.5 maximum aperture and a 3x zooming ratio. Tele-macro is also available with a maximum magnification ratio of 1:2.6. The true color reproduction quality combined with the macro feature make this lens an excellent choice for flower photography or any detailed nature study. Utilizing Tamron's Adaptall system, this lens will fit most manual focus cameras with the proper adapter (purchased separately).

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Tamron AF 18-200mm f/3.5-6.3 XR Di II LD Aspherical (IF) Macro Zoom Lens for Canon Digital SLR Cameras Review

Tamron AF 18-200mm f/3.5-6.3 XR Di II LD Aspherical (IF) Macro Zoom Lens for Canon Digital SLR Cameras
Average Reviews:

(More customer reviews)
Like a baseball player with a decent batting average, some power, a little bit of speed and fairly good fielding ability, the Tamron 18-200 lens won't be an All-Star any time soon because it does not excel at any one thing. But, like that $500k/year utility infielder, this lens DOES provide a very good all-around value for what it is. Does it compare to a prime lens at either end? Heck, no. Is it a good lens to use when you can't carry a wide choice of lenses with you? Absolutely.
I've been using this lens on my 20D quite a bit and have only a few minor gripes: it tends to hunt for AF (especially as you get closer to 200mm), and it's not the quietest lens I've used.
An earlier reviewer mentioned that it maxed out at about 160mm. My own analysis shows that it is short of 200mm, but not by that large an extent; I found it much closer to 190. Still, there's no doubt that these zoom lenses with extreme ranges like this have a built-in fudge factor.
Another reviewer described the problems he encountered when using two screw-on filters. There aren't too many primes that I've used that will avoid vignetting when using two filters. Heck, my 10-22 can barely handle one extra-slim. As for darkening the image - well, you're adding two more pieces of glass to a highly-complex lens assembly... just asking for trouble.
As for the concern regarding blur at longer focal lengths, I highly recommend the use of a tripod. I noticed the exact same thing - blur and lack of sharpness - at lengths over 100mm. Keep the old rule of thumb in mind - if you're shooting handheld, your shutter speed should be no slower than the inverse of your focal length. A 200mm lens on a 20D (or Rebel XT for that matter), is an effective 320mm - I wouldn't recommend shooting any slower than 1/500 at max zoom with this lens - UNLESS you're using a tripod. When I mounted it firmly, I got great shots with no blur.
Keep in mind that you get what you pay for here: the convenience of a wide-angle, normal, and moderate telephoto lens in one piece. If you're shooting professionally, or need absolutely perfect images, then carry the three or four lenses that this would otherwise replace in your bag. But if you want one easy-to-use, satisfactory lens, go for this one. It's a jack-of-all-trades, ace-of-none kinda deal.


Click Here to see more reviews about: Tamron AF 18-200mm f/3.5-6.3 XR Di II LD Aspherical (IF) Macro Zoom Lens for Canon Digital SLR Cameras

Tamron AF 18-200mm f/3.5-6.3 XR Di II LD Aspherical (IF) Macro Zoom Lens for Canon Digital SLR Cameras

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Click here for more information about Tamron AF 18-200mm f/3.5-6.3 XR Di II LD Aspherical (IF) Macro Zoom Lens for Canon Digital SLR Cameras