vvn> In summary, for maximum protection in a fall: vvn> 1. Thick metal, thin metal, or rigid plastic?
vvn> 2. Fully threaded on, or slightly loose? vvn> 3. Filter between lens and hood, or not? vvn> [EMAIL PROTECTED] I don't have any scientific (except common sense) backing of this, but: 1) thick metal would transmit most of the impact energy to filter thread, whic would not be good. Thin metal might bent if thin enough (but most metal hoods are of unbentable rectangular or circular shape, which will hold and not bent, especially in nose-fall), plastic is probably best - it will flex in a fall (returning to original form), and will shatter in fall big enough, saving possibly the lens. Rubber hoods - I had a really great rubber bayonet hood from Tamron, made for 28-135/35-135/35-210 lenses, circular, it's made of really rigid rubber which is nice. I kept it even after selling the dog of lens SP 2.8/35-105... It's like in cars - these have deformation zones. OTOH thin metal hood will surely bent well if falls at right angle, but I don't think they would deform much in nose fall, unlike plastic. 2) I avoid really tightly screwing in hoods or filters, as the rotational force of tightening them too much transmits to the helicoid stops (the two tabs that ride the helicoid inside), and in some not as well made lenses (especially alu-alu helicoid and alu-plastic), this might make the focusing loose or too tight... 3) dunno - but Hoya of the THK (Tokina Hoya Kenko) group says they don't make brass filters because now lenses use plastic or alu filter rings, and it would not be good for the filter to be of harder metal than the lens ring, as the impact might just come tru the filter onto the lens with full force. This makes sense... The best design is IMHO this: lens barrel with bayonet or outer screw hood, directly on OUTER BARREL (focusing ring), with filter thread hidden inside it, on the inner barrel (optics). This would protect the lens and helicoid the most from any damage. Some lenses (Tamron SP 3.5/70-210, Tokina wide zooms, many newer OEM AF ones,...) use this well. 4) dunno... perhaps a plastic deformation zone glassless "filter" between lens and lenshood ;) ? Accidents happen Good light, Frantisek Vlcek - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
