Shooting inside museums ... well, one isn't generally allowed to photograph the museum's art collection or installations, and it's only the rare museum that provides grist for long lens work, like the Tate Modern and its vast Turbine Hall. So my usual notion is to concentrate on people and deal with the usual horrid lighting situations ... A wide-normal and/or normal to short portrait tele, both fast, are the ideal lenses to have. An ultrawide is sometimes very handy too, but I need to be in the right mood for it.
EG: at MOMA in SF, I carried just the Rollei 35S which has a 40mm f/2.8 lens (wide-normal). I liked the set of photos it made for me ... architectural: http://farm4.static.flickr.com/3422/3844190734_2da6a80f8c_o.jpg people: http://farm3.static.flickr.com/2527/3843402077_96fbb062d9_o.jpg set: http://www.flickr.com/photos/gdgphoto/sets/72157622105937452/ Given the lenses you mention above, I'd leave the 50-135 home, carry the 16-45 and 12-24. Or I'd find a fast lens ... the 35, 43 or 50mm ... and carry that along with the 12-24. -- Godfrey godfreydigiorgi.posterous.com -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.

