EOS RT focosing limit

[siow gongzi]

seems the RT don't auto focus well with sigma and tamron lens in the dark. someone told me it only works on certain f-stop and wider.
any RT user care to comment?

Sorry, but what is a RT?

[denizenx]

Real Time lor... the mirror is translucent and does not move for shutter... allowing RealTime preview of the shot, but eats up one stop. not sure about the stop...

anyway how come u buy RT huh? hehe fun huh?

[siow gongzi]

ya it's fun sometimes.
u don't see blank view finder when pressing shutter release.
u r sure of the flash is fired as u can see thru view finder.
u can c the subject while doing long exposure.
u can take fireworks and multi exposure with proper framing.
u can freeze moving object more accurately as the time lag between depressing shutter release and shutter movement is very short.
U will have less camera vibration as the mirror doesn't move.
All the advantages of a range finder without the parallax error.

But, a tad heavy. dim view finder in darker environment. plus this unknown (or known?) f-stop vs focusing issue.

[denizenx]

yeah sounds cool...
but hehe the only current model is the EOS1N rs right?
the viewfinder is dimmer than other SLRs?

was thinking hor.. a new RT model can use those LCD that polarise on electric current....

[siow gongzi]

ya, the 1n RS is my dream cam too, but having had the unpleasant experient with RT on the dim vf, i've scrapped this thought and gone for getting a magnificent Minolta Dynax 7!