>Has anyone heard of problems with the 24-290 Ang zoom’s internal works?
>Not the optics but the mechanical workings for moving the optic group are apparently wearing out too quickly with startling jolts while zooming. This was brought to my attention by a 1st AC I trust who had troubles with a DP's package he was prepping. He consulted a rental house here in Los Angeles. The rental tech reported the problem was general and major overhaul was required to address.
>I have worked with a 24-290 that had no such problem and found it to be exceptional. As with all zoom lenses care should be taken to properly pack the lens for shipping (or even travelling in the camera truck). Oppenheimer cameras used to have a data sheet for various zooms that instructed the best place to leave the zoom (fully wide or fully zoomed in).
>I believe the idea was that there is a spring to assist moving the optical group and you stored the zoom depending on which end of the zoom range the spring was at rest ( not stretched out). Also if damaged at least the problem would be at full wide or full tight and not in the middle of the zoom.
>I always packed lenses with focus at infinity and iris wide open when they came off the camera. The 24-290 uses such large (heavy) optics (and opens to 2.8, focus down to 4') that this care would be very important.
operator / steadicam, LA
>I always thought the zoom should be somewhere in the middle based on the theory that this allows some gentle movement in the mechanism as opposed to hitting a hard stop. Akin to packing a tripod head with the locks disengaged and drags set to zero.
>I always heard that it had to do with how the mechanics of the lens were designed, and that at one end or the other was the Strongest resting place, and least subject to damage.
>I've always packed zooms at their longest focal length, on the theory that if it suffers some kind of bump or bruise that's where the greatest depth of focus is (see Color IR thread).
>I don't know how rational this is....(considering that if rear focus goes out then there will typically be only one place in the zoom range where it will appear "right")
>Zooms should travel as follows :
>1/. Iris wide open so the leaves rest on one another rather than being extended out towards the centre of the lens.
>2/. Focus ring at infinity so the focusing helix is fully engaged (for close focus it is typically partially disengaged-extended as far as possible towards the front)
>3/. Zoom ring at the long end so the zooming groups are fully engaged towards the back of the lens so they don’t cause as much bending/twisting torque in case of a shock(the Cookes occasionally will brake the plastic "tire" on the roller when dropped form high enough) Also sometimes the ring.
>These are only general guidelines. When in doubt you should try to contact respective manufacturers-they usually have their recommendations.
>Every AC should know and do this when putting away a zoom.
>Like Mr. Campell stated, zooms should be put in their case at one end or the other of the zoom range, focused at infinity and the iris fully open (or closed).
>Any good rental house should have a list with which end of the zoom range each lens should be stored at. Springs not stretched is one criteria but also you don't want the internal lens groups close to each other during shipment. A rough bump could cause them to hit each other and cause damage. The 24-290 is large and any rough handling during travelling would only be worse because of its size and weight. I have heard of similar problems with the 18-100 Cooke.
First Assistant Camera
Detroit, MI USA
>Jacek Zakowicz wrote :
class="style9">>3/. Zoom ring at the long end so the zooming groups are fully engaged >towards the back of the lens so they don’t cause as much >bending/twisting torque in case of a shock
>When my 3yr old decided to try his hand at operating he tipped over my Aaton complete with Canon 7-56. I thought the lens was a goner. Fortunately it hit rods first but still impacted the lens hard. Now that I think about it the lens was fully zoomed in. Other than a depth reset all was okay.
>I was very lucky.
>Oh, and I told my 3yr old no more operating until he has a union card!
New Orleans, La
>There are reasons why rental companies spend a great deal of money buying top of the line cases for their equipment. If you're going to spend tens of thousands of dollars on a lens, buy a DI delicate instrument) case from somebody like A&J.
>Making your own case, may save you a few bucks, but this is a situation where "almost as good as" can turn out to be a very expensive savings.
>As a friend of mine who races motorcycles says: "Got a hundred dollar head? Buy a hundred dollar helmet."