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07-03-2011, 12:58 PM   #1
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Advice please!

Hi all, new to the site and hoping for some good objective advice!
I have 2 converters, a Sigma 1.4x-s rear converter-a and a Sigma 2x tele-macro converter. The both look oldish. I have a Pentax K20D camera. I need two bit of advice. I am looking at the Sigma 70-200mm f2.8 lens. Will either of them Autofocus on it? Part 2 of the advice is the following. I have a Tamron 70-300mm f4-5.6 lens. I am looking at the Sigma 70-200mm f2.8 lens as I mentioned but it is quite pricey. I need to know if I will notice a difference from my Tamron lens to be able to justify the cost. I do all types of photography, Sports, Portrait, Landscapes, Sunsets etc. Any advice will be much appreciated!

07-03-2011, 01:13 PM   #2
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I doubt the teleconverters will work for AF on the Sigma 70-200. The teleconverters need the SDm/HSM contacts for AF to even have a chance of working. Then even if they do, you might be disappointed to find the lens struggling to lock focus at the long end as it does with the Tamron 1.4x TC.

There is a world of difference between a fast 70-200 compared with a consumer-level 70-300. If you don't have the need for speed at these focal lengths (typically for action and thin depth of field), then sticking with the 70-300 would suffice for your purposes. If you know you need more than what you have to get the shots you want, you'd have to think seriously about investing into a faster lens such as the 70-200, which is actually one of the most cost-effective f/2.8 telephoto lenses available.
07-03-2011, 01:33 PM   #3
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you listed sports and portraits.
For portraits, the 70-200 is awesome. Super sharp, shallow dof thanks to the large 2.8 aperture combined with its longish focal length for nice background-to-subject compression.

for sports, the fast aperture gives you the benefit of being able to use faster shutter speeds, allowing you to cut down on motion blur as well as having the ability to shoot in lower light.

however, it is a bit pricey. If you know you can use the large aperture to benefit your shooting, i say go for it. However, the tamron is also a fairly capable lens in it's own right, so if you can't quite swallow the pricetag just yet, or your not sure about whether you can use it to full effect, stick with the tamron.
07-07-2011, 09:51 AM   #4
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Thanks for the advice... I have taken the plunge and ordered it... now cant wait for it to arrive!

07-07-2011, 10:09 AM   #5
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Congratulations. Don't forget to share your experiences with it once it arrives!

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