What should I expect for focusing time on a superzoom lens (a57)?

Started Jan 15, 2013 | Discussions thread
vw671 Contributing Member • Posts: 539
Re: What should I expect for focusing time on a superzoom lens (a57)?

hooraysimpsons wrote:


I recently purchased a used sigma 18-250 (not the new macro one) for use on my slt-a57. However, it focuses extremely slow (on the order of seconds) and sometimes not at all. One of the reasons my wife wanted the a57 was for the high framerate especially when using the lcd screen. So we want to maintain that functionality. I found some reports online reporting problems with sigma lens and the autofocus system on the SLT cameras. So we are returning the lens and trying to find another copy or different lens (including possibly the new macro version to reduce weight since it will primarily be a travel lens).

So my questions is how fast should I expect the superzoom lenses to focus? Would it be significantly different from the 18-55 kit lens?

When I say superzoom lenses I mean ones like the Sony 18-250, sigma 18-250 and tamron 18-270.


Superzooms aren't really known for their fast AF speed. I once had the same Sigma 18-250 HSM you current have and it's as about good as your going to get in terms of AF speed on any Superzoom. If it's taking "seconds" to focus your either trying to use it in conditions where there isn't enough light (*it's not a fast lens) or there is some thing wrong with it.

 vw671's gear list:vw671's gear list
Sony RX100 Sony SLT-A57 Sony a77 II Tamron SP 70-300mm F/4-5.6 Di USD Sony DT 16-50mm F2.8 SSM +2 more
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