Vivitar 19 - 35 zoom

I have a Vivitar 19 - 35 zoom len used on a 7XI. This lens has a 77mm

filter thread and my filter of this size seems almost as heavy as the

lens itself!

The question is - can the extra weight slow down the AF

significantly, or even damage the AF mechanism? Especially with the

hood fitted as well.

Another point is do people tend to focus manually with this type of

lens due to the depth of field available?

Hi.

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I don't own this lens but still, dare to answer. As far as i know, this lens has a focussing which does not make the front element rotate. I don't see how the *weight* of an attached(heavy)filter would slow down af. And even if it would have to move(rotate) while autofocussing, i don't think you would see a difference in af speed. Same valid for the hood.<br>

Are you sure it's not an issue of the filter cutting off lots of light so the af sensor is getting blinded?<br>

As to damage, the only thing i can imagine is that the lens has a wide manual-focus ring which is easy to block with your finger, while in af mode. That might hurt the af mechanism of the camera, but you would notice the struggle of the af motor under your hands...

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Second point: with my ultrawide(tokina 17mm at-x) i autofocus almost always; it is just so extremely quick and accurate, i don't even think about mf. Only when i want a special close object very off-center in the viewfinder to bring into focus.

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cheers.

Thanks for the responses.

I should have made it clear that the front element on the Vivitar does rotate. With the filter fitted the AF seems slower and perhaps overshoots due to the inertia of the filter. It's purely a mechanical issue - there is no question of the sensor being obcscured although there may be some vignetting. Perhaps I will take a chance and leave it off. Its rather an old filter and does seem unusually heavy.

If you're really considering this, it has to be a helluva heavy filter! what filter is it, anyway?

So, you found yourself the solution - manual focussing.

By the way - how good is the 7xi's focussation? is it closer to the lower end(3,5xi) mechanism, or to the 9xi?

It's an old Kowa UV filter weighing around 70g - around three times as heavy as another 77mm 1A filter I have. I had not appreciated that it was unusually heavy, the glass must be very thick...

I will of course use the lighter one in future.

Thanks again for the responses.