Tamron af 17

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l>Tamron 17-50mm f/2.8 VC

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Tamron 17-50mm f/2.8 VC XR Di II LD Aspherical IF (2009-)© 2011 pokeht.vn. All rights reserved.

Intro Specifications Performance Usage Compared Recommendations

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Tamron 17-50mm f/2.8 in Nikon mount (72mm filters, 20.1 oz. /569g, about $600), also comes in Canon mount. Enlarge. This miễn phí website"s biggest source of tư vấn is when you use these links, especially these directly to lớn it at Adorama for Nikon, Adorama for Canon, at Amazon for Nikon, or at Amazon for Canon when you get anything, regardless of the country in which you live. Thank you! Ken.

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February 2011 Tamron đánh giá Nikon CanonAll Reviews

Ideal Uses: Perfect for use on amateur digital (Nikon DX & Canon 1.6x) cameras as a general-purpose medium zoom. Unlike many non-Nikon lenses lượt thích Tokina và other Tamrons, this particular Tamron should works great on Nikon"s cheapest D40, D40x, D60, D3000, D3100 và D5000.

Not for: 35mm, full-frame or FX cameras. Not for grab-shots with VC turned on.

Optics:
Mechanics:
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Ergonomics:
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Faulty AF và VC/IS/VR design
Usefulness:
Availability:
Overall:

Introductiontop

Intro Specifications Performance Usage Compared Recommendations

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I personally buy from Adorama, Amazon, Ritz, B&H, Calumet và J&R. I can"t vouch for ads below.

This $600 Tamron has surprisingly good optics, but problems with its VC (VR or IS) and AF systems get in the way of good pictures.

I prefer my $200 Nikon 35mm f/1.8 DX, which is sharper, faster, smaller, lighter, focuses faster, easier and quieter, and is much less expensive. I"m not a fan hâm mộ of midrange zooms, but I must be the only one on earth who isn"t.

If you"re considering this mostly plastic lens, go for it. It works reasonably well — with one big catch:

This Tamron"s VR/IS/VC system works only if you have the time to lớn wait a moment before you snap each & every photo. There is a huge flaw if you make a photo before waiting a second for it khổng lồ settle down. If you snap a photo without waiting for the VC/VR/IS system to settle, it will blur your image worse than if you had no VC, VR or IS! This is because this Tamron"s VC system jumps as it locks and unlocks, so if you don"t wait a moment with your finger half on the shutter for it khổng lồ settle, it will blur your photo in the process of settling! Nikon"s VR and Canon"s IS systems don"t have this problem. This blurred a lot of shots for me before I figured this out. Therefore, this is a horrible lens for news, sport, action and people shots unless you turn off the VR/IS/VC system. If you don"t, and if you shoot at a moment"s notice, the VC system will blur many of your shots!

This Tamron"s other drawback is its primitive (noisy) internal autofocus motor, & that it uses a primitive AF system that requires you move a switch to lớn get from tự động to manual focus. You can"t just grab the focus ring at any time, as you can bởi with the professional Nikon 17-55mm f/2.8 DX & Canon"s 17-55mm f/2.8 IS.

Compatibility intro top

Warning: this lens is made completely without permission from Nikon or Canon. While it probably will work with your camera, there"s no telling that there won"t be some weird incompatibility, & there is always the possibility of incompatibility with future cameras you might buy two years from today. Canon and Nikon lenses don"t have this potential for problems.

When I say "ought to" below, I mean just that. All because this lens ought khổng lồ work, doesn"t mean that it will. I"ve only tried it on a Nikon D7000, on which it works swell.

Nikon

Everything should work perfectly on every DX digital Nikon, even on Nikon"s cheapest digitals like the D40, D40x, D60, D3000, D3100 và D5000.

See Nikon Lens Compatibility for details with your camera. Read down the "AF-S, AF-I," "G" và "VR" columns for this lens. You"ll get the least of all the features displayed in all columns, since "G" (gelding) is a deliberate handicap which removes features.

Canon

Everything ought to work swell with every Canon EOS 1.6x digital camera. That works with EF-S lenses. This lens seems as if it ought khổng lồ work with very old 1.6x cameras that aren"t EF-S compatible, but I didn"t try any myself.

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Tamron 17-50mm. enlarge.

Specificationstop

Intro Specifications Performance Usage Compared Recommendations

Name

Tamron calls this the Tamron 17-50mm f/2.8 XR Di II VC LD Aspherical (IF).

This marketing baloney means:

XR: Extra Refractive-Index glass (allows smaller size)

Di II: Only works on 1.6x & DX cameras, won"t work on 1.3x or 35mm or full-frame cameras.

VC: Vibration Control, same as Nikon VR or Canon IS.

LD: Same as Nikon"s ED or Canon"s UD glass. Probably all comes from Hoya.

Aspherical: Specially curved lens elements.

IF: Internal focusing. Nothing moves, except the focus ring, as focused.

Optics

19 elements và 14 groups!

Internal focusing.

BBAR "Broad-Band Anti-Reflective" multicoating.

Diaphragm

7 conventional blades

Stops down lớn f/32

Aperture Ring

None.

Coverage

Small-format digital, 16 x 24mm maximum.

Will not cover full-frame or 35mm film.

Focal Length

17-50mm.

On a DX camera gives angles of view similar to what a 26-75mm lens gives when used on an FX or 35mm camera.

Used on a Canon 1.6x camera, it covers angles of view similar lớn what a 27-80mm lens would see on a 35mm camera.

Angle of view

78°45" ~ 31°11."

Close Focus

0.29m (11.4 inches) from the image sensor, which means just inches (centimeters) from the front of the lens.

Maximum Reproduction Ratio

1:4.8.

Hard Infinity Focus Stop?

No, you must let the AF system find infinity.

Focus Scale

Yes.

Depth-of-Field Scale

No.

Infra-Red Focus Index

No way, José.

Filter Thread

72mm, plastic.

Does not rotate, but pumps in & out with zooming.

Size

94.5mm (3.7 in) long by 3.13" (79.6mm) diameter, specified.

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Weight

20.070 oz. (569.1g.), measured, in Nikon mount.

Tamron specifies 570g (20.1 oz.).

Hood

AB003 plastic bayonet, included.

Made in

Japan.

Warranty, USA

6 years.

Announced

Nikon Mount: 17 September 2009.

Canon Mount: 23 October 2009.

Tamron model Number

B005.

Nikon: B005NII.

Canon: B005C.

Packaging

Silver-ink single-wall box, folded corrugated insert.

Included

Lens, paperwork, hood, caps.

No case.

Price

$600, USA, February 2011.

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Box, Tamron 17-50mm.

Performancetop

Intro Specifications Performance Usage Compared Recommendations

OverallFocus Bokeh Caps CleanlinessDistortionErgonomics

Falloff Filters Focus Breathing Ghosts Lateral màu sắc Fringes

Mechanics Sharpness SunstarsVibration Control Zooming

Overall performance top

The Tamron 17-50mm works fine, but only it you remember khổng lồ let the VC system stabilize before shooting. This is not a lens for grab shots with the VC system.

Autofocus performance top

AF Noise

This Tamron, at least in Nikon mount, uses a dinky electric motor to move the focus ring. It sounds lượt thích a toy.

This is how Canon did it — back in 1987.

AF Speed

AF tốc độ is fast enough in Nikon mount.

The focus ring moves during autofocus, so keep your fingers off the focus ring during autofocus!

AF Accuracy

AF seems fine at f/2.8 at all focal lengths on my Nikon D7000.

Manual Focus

Manual focus is great; but you vị have to lớn move a switch.

Unlike the Nikon & Canon, you may not touch the focus ring until after you"ve moved the switch on the lens to lớn MF. If you move the ring while in AF, you"ll be working against the motor built into the lens.

What Moves

Focus is internal, so nothing moves externally except the focus ring, which moves even during autofocus.

Bokeh performance top

Bokeh, the character of out of focus backgrounds, not simply how far out of focus they are, is crummy at 50mm. At 50mm, backgrounds are bothersome at all apertures.

I didn"t try at shorter settings; at shorter settings, depth-of-field is much larger so backgrounds are rarely out of focus to worry about bokeh.

Here are crops from the center of 100% DX 16MP (Nikon D7000) images, focused on a reference phase lattice (the đen sides) at 3 meters (10 feet) with synthetic reference vegetation at 15 meters (50 fee). Printed full-image at this size, these would be about 50 x 33" (130 x 85 cm) prints, at least as seen on most 100 DPI computer monitors:

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Caps performance top

The Tamron front cap is merely OK, although I"d leave it in the box và replace it with a good Nikon cap since the newest Nikon caps are much sturdier và easier khổng lồ get on & off than the Tamron caps.

The Tamron rear caps for Nikon stink because you must stop what you"re doing and align them carefully khổng lồ the dot on the lens before you twist them on. Forget it!

I"d use a real Nikon rear cap instead, since you can pop them on without having to stop & look.

Cleanliness performance top

This Tamron arrived sealed from the factory with more than the usual amount of white dirt specks on the exterior.

You"d never notice this, but in my laboratory"s clean-room where I open these and photograph them, I do.

Since I had lớn spend time spotting this out, I mention it here, because I hate wasting my time spotting-out dirt shipped by the manufacturer.

Distortion performance top

The Tamron 17-50mm has less distortion than expected.

It has barrel distortion at 17mm, and not much anywhere else.

This can be corrected for critical use by plugging these figures into Photoshop"s lens distortion filter. These aren"t facts or specifications, they are the results of my research that requires hours of photography and calculations on the resulting data.