To be honest I had the same concern prior to buying the lens but as it turns out the zoom mechanism is very smooth and is well damped to permit smooth control.. So is the AF .. it has a focus clutch for MF that damps the af ring very nicely. The only down side of the extending zoom is that it shifts the balance slightly although this is not a major concern. I found that the damping on my manfrotto 393 handles this shift in balance well enough that i can let go of the camera/lens combo in any zoom position and the camera will stay put where i leave it. The lens also features a zoom lock that prevents the lens from extending when being carried.
Bottom line ... in real life i don't find that the extending zoom is an issue. My only peeve with the lens (and all sigma ex lenses) is that the lovely sigma EX finish tends to scuff quite easily. regards Patrick On Thu, May 8, 2008 at 9:58 AM, John Whittingham <[EMAIL PROTECTED]> wrote: > Hi Patrick > > Thanks for the reply, very much appreciated. I think the only thing putting > me off is the lens extending when zoomed, it's the main reason why I sold > the 135-400 I had. Having said that it does keep the size down when > transporting the lens in a camera bag. > > One last question, if I may, is the zoom control overly stiff in operation? > (it was on the 135-400 but that isn't/wasn't an EX lens) > > Regards, > > John > > On Thu, 8 May 2008 09:01:25 +0200, Patrick Genovese wrote > > > > I have the bigma and ... > > > > > 1. Does SR work effectively? > > Yes but not as effectively as at the short end.. I estimate the > > effectiveness at the long end (above 300mm) to be around 1 -> 1 1/2 > > stops. > > > > > 2. Is the lens type displayed correctly in the EXIF i.e. Sigma 50-500 > EX? > > No ACR just says sigma > > > > > 3. Aprroximate aperture when zoomed at 300mm f/4, f/4.5, f/5.6? > > IIRC its somewhere around 5.6 > > > > > 4. Does the lens extend when zoomed? > > Yes > > > > > 5. Does the front element rotate when focusing? > > No > > > > One thing to note about the Bigma is that it is have so a good > > tripod/head is almost a must. I use a manfrotto 055pro + a manfrotto > > 393 gimbal head the combo works very well. Hand-held shots are not > > out of the question but your hit rate will take a hit. :-) The > > weight also means that handleld shoots tend to be short in duration. > > In good light the af is reasonably fast and accurate (at least on > > my K10D). > > > > Regards > > > > Patrick > > > > > > -- > > PDML Pentax-Discuss Mail List > > PDML@pdml.net > > http://pdml.net/mailman/listinfo/pdml_pdml.net > > to UNSUBSCRIBE from the PDML, please visit the link directly above > > and follow the directions. > > > > ---------------------------------------------------------------------------------------------------- > > The information transmitted is intended only for the person to whom it is > addressed and may contain > confidential and/or privileged material. If you have received an email in > error please notify Carmel College > on [EMAIL PROTECTED] then delete all copies of it from your systems. > > Although Carmel College scans incoming and outgoing emails and email > attachments for viruses we cannot > guarantee a communication to be free of all viruses nor accept any > responsibility for viruses. > > Although Carmel College monitors incoming and outgoing emails for > inappropriate content, the college cannot > be held responsible for the views or expressions of the author. > The views expressed may not necessarily be those of Carmel College and > Carmel College cannot be held > responsible for any loss or injury resulting from the contents of a message. > > > ---------------------------------------------------------------------------------------------------- > > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and > follow the directions. > -- Regards Patrick Genovese -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
