tamron 18-200 opinions?

[xdjoynerx]

http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=363594&is=REG

http://www.bhphotovideo.com/images/largeimages/363594.jpg

any one own this lens and have any thing to say about it?

[tim]

I don't own it, but hyperzooms that cover such a wide range usually get poor reviews. F6.3 at 200mm is very, very slow.

[mr.photoguy]

yeah I don't want to imagine being locked in to f6.3 @ 200mm ... I doubt you could get that real blured background bokeh effect.
you can go on www.pbase.com, and search for the lens. Then just review all the sample images posted.

I don't like compromise(sp) lenses though.

[Jesper]

If it's f/6.3 at 200mm, you cannot use auto focus with this lens on a non-1-series body (300D, 350D, 10D, 20D). The non-1-series bodies need an aperture of at least f/5.6 for auto focus to work. Probably the lens tricks the camera, so that the camera thinks it's f/5.6 while it's really f/6.3. Some Sigma lenses do this to make sure that you can still use auto focus.

[mr.photoguy]

I looked on pbase.com and I didn't see one sample image with this lens...
hmm ... that's strange.
I know if there is a lens out there for the 20D/10D/300/350D then there are sample images on that site of the lens.

[Jesper]

I looked on pbase.com and I didn't see one sample image with this lens...
hmm ... that's strange.
I know if there is a lens out there for the 20D/10D/300/350D then there are sample images on that site of the lens.Not so strange, since this is a very new lens: http://www.dpreview.com/news/0502/05022105tamron_18-200mm.asp
Probably not many people have it yet.

[intechpcx]

If it's f/6.3 at 200mm, you cannot use auto focus with this lens on a non-1-series body (300D, 350D, 10D, 20D). The non-1-series bodies need an aperture of at least f/5.6 for auto focus to work. Probably the lens tricks the camera, so that the camera thinks it's f/5.6 while it's really f/6.3. Some Sigma lenses do this to make sure that you can still use auto focus.

Jesper, can you please clarify this post? The way it reads (at least to me) is that it appears you're saying that the D-Rebs and 10&20D's can't focus if the lens has a max aperture smaller than 5.6. I question that only because I don't understand what aperture has to do with the auto focus. I was under the impression that the focus is based on the contrast of the subject in the focus area. Is it a light thing? I'd like to understand better if you're able to explain it further.

[Jesper]

Jesper, can you please clarify this post? The way it reads (at least to me) is that it appears you're saying that the D-Rebs and 10&20D's can't focus if the lens has a max aperture smaller than 5.6. I question that only because I don't understand what aperture has to do with the auto focus. I was under the impression that the focus is based on the contrast of the subject in the focus area. Is it a light thing? I'd like to understand better if you're able to explain it further.
That's right - the 10D, 20D etc. automatically switch off autofocus when the max. aperture of the lens is greater than f/5.6.

The aperture determines how much light gets through the lens. A lens with a larger max. aperture (smaller f-stop number) lets in more light than a lens with a smaller max. aperture (larger f-stop number). The amount of light halves with each f-stop: an f/5.6 lens lets through half the amount of light as an f/4 lens, which lets through half the light of an f/2.8 lens etc. If you look through the viewfinder with an f/2.8 lens on the camera, you'll see this - it's much brighter than with an f/5.6 lens.

For autofocus to work reliably, the camera needs a minimum amount of light. For non-1-series cameras, there's not enough light if the max. aperture is larger than f/5.6. The professional 1-series cameras have a better autofocus system that needs less light, so they can still focus up to f/8.

Some lenses tell the camera that the aperture is f/5.6 instead of the real value f/6.3, so that the camera doesn't automatically switch off its AF system. Ofcourse at f/6.3 less light enters the camera, but the difference with f/5.6 is not so large, so AF will most likely still work, even though it's really outside the camera's specs.

[intechpcx]

That's right - the 10D, 20D etc. automatically switch off autofocus when the max. aperture of the lens is greater than f/5.6.

....

For autofocus to work reliably, the camera needs a minimum amount of light. For non-1-series cameras, there's not enough light if the max. aperture is larger than f/5.6. The professional 1-series cameras have a better autofocus system that needs less light, so they can still focus up to f/8.



That's the explanation I was looking for. I was not aware of that. Of course both of my lenses have max apertures of 5.6 or better so I guess I wouldn't have run into it. Good to know though, I wonder if the D-Reb and others would take a hit on AF performance with that lens (assuming the lens reports the min. ap. the way you described).

[MrChad]

That's a lot of lens for not much price.

I have a Sigma 18-125mm hyper zoom and I love the lens.

I can't comment on the Tamron but it may be your cup of tea.
It may be a tad slow indoors on the long end but if you're on vacation or outside in the sun the benefits of that lens might come in handy.

[ron chappel]

My experience with such lenses is that they are not QUITE good enough for most people.
They tend to be slightly lower in image quality than say,a kit zoom like the EF-s 18-55.
But then the sigma 18-125 is said to be slightly better than the kit lens and gets some very positive comments so who knows? Tamron might have a good one :)

[RodneyCyr]

A Google search found this site with sample photographs, including comparison shots with the 17-40L and 17-85 Canon lenses.

http://imageevent.com/publicgallery/photography/tamron000?z=2&c=3&n=1&m=-1&w=4&x=0&p=10

[nwoods]

I own this lens, or did for less than a week. I was looking for the perfect "walkabout" lens, and I really thought this was it, until I shot a few hundred images. Not a single one turned out the way I'd like. I shot in every mode, setting, aperature, shutter speed, wb, and ISO, and got nothing but flat, dull, slightly unfocused images. I was very disapointed, so returned it after only a few days.

Still looking for that perfect lightweight walkabout lens :-)

Cheers,

Nathan Woods

[nwoods]

Hmmm...just looked at the test photos linke above:
http://imageevent.com/publicgallery/photography/tamron000?z=2&c=3&n=1&m=-1&w=4&x=0&p=10

My images were not nearly as good, making me wonder if I got a bad one? Still, there is a noticable fall off in the higher aperatures.

NW

[Andy_T]

If it's f/6.3 at 200mm, you cannot use auto focus with this lens on a non-1-series body (300D, 350D, 10D, 20D).

Technically, that should be the case.

The autofocus shutoff is a feature of the camera to ensure consistent autofocus. So rather than have a lens hunt in low light, Canon has decided that you should not have AF at all (or buy the more expensive 1 series :wink: )

However, I suspect that as with the Sigma 50-500, the lens tricks the camera into believing it has f/5.6 (instead of f/6.3) on the long end, so that the autofocus is not disabled.
Whether it focuses very well, remains to be tested. Should not be a problem in good light, but maybe more so if you shoot in badly lit conditions.

Otherwise, the lens would not make much sense for the intended buyers.

Best regards,
Andy