LCD screen or viewfinder

[winged_fear]

im kinda new to the whole digital SLR cameras and i have been shopping but i can find one where you can ust the viewfinder and/or the LCD screen to take pictures with. could somebody please help me out and point me to some cameras that do this. i would like it if i could do both at the same time. but is i have to push a button or something to switch it then thats fine too.

[coldrain]

There are currently no DSLR's that have LCD "pre-view" as it is called.
There are two reasons for it, both technical.

The 1st one is that SLR stands for single lens reflex. It means, only one lens is used to look through and to make photos through. The way this is done is with a mirror, the mirror deflects the light up when not taking a photo, allowing you to look through the lens using the view finder. The mirror will snap up when the actual photo is taken. So, you can not show anything on the LCD because there is nothing to see except the back of the mirror.

The 2nd reason is that DSLR's have big sensors. This is what makes them so attractive, they are more dymanic, have less noise, and you can be more creative with depth of field. It also means that the big sensor generates a lot of heat. If you would have live preview, the sensor would continuously be working, and get much too warm. So, that is the 2nd reason DSLR's have no live preview, the sensor would generate too much heat while producing images for the LCD.

The 2nd reason is also the reason why you do not have movie modes on any DSLR, it is simply impossible. So is a panorama mode all Canon cameras except their DSLR's have, you can not use the LCD for framing.

There are two exceptions to this "no LCD pre-view" though.
The Canon 20Da has live preview for 20 seconds especially for astrologocal use. You may only use it at night, and 20 seconds is the limit due to heat reasons.
The Sony R1 is not a DSLR, yet it has a large DSLR-like sensor and allows live preview. The CMOS it uses produces a lot less heat than CCD you mostly find in Sony using DSLR's, and this makes that possible. It also does not use a mirror (it is not a DSLR) so they did not have to solve the problem of designing a mirror that can either be used and down, or parked and up while using the LCD for framing.

As the Sony R1 shows, advancements in CMOS technology will bring DSLR's with live preview options closer. But we will have to wait a bit still, before both the mirror design and sensor problems can be tackled.

[winged_fear]

ok well that helps me some but i have seen an old olympus that does both. my wife wants something that she can change out the lenses in and still use the viewfinder and/or the lcd screen

[coldrain]

ok well that helps me some but i have seen an old olympus that does both. my wife wants something that she can change out the lenses in and still use the viewfinder and/or the lcd screen
Which old Olympus was that?
She is probably not the only one who wants that, but she will have to wait till they are actually available... and that may take years.
Maybe Sony is developing one with Konica Minolta... maybe Canon is working on one... maybe someone else, but since there have been no announcements you may well be waiting years.

[Norm in Fujino]

ok well that helps me some but i have seen an old olympus that does both. my wife wants something that she can change out the lenses in and still use the viewfinder and/or the lcd screen

I don't know what camera you're speaking of, but there have been rumors/hints that Olympus may be about to announce an SLR with dual ovf/LCD; see:

this (http://www.letsgodigital.org/en/news/articles/story_5652.html) and this (http://www.letsgodigital.org/en/news/articles/story_5652.html).

No one knows what's really involved, but at the time of the Olympus+Panasonic 4/3 agreement a year ago, they said they were aiming for the release of a new camera based on jointly developed technology at PMA 2006, which opens February 26 in Orlando. Lost of speculation, not much more.

[scalia]

E-10/E-20 are DSLR with OVF and LCD preview, but no interchangeable lens.
cheers

[George Riehm]

Yup. I can see it now. dSLR with 70-200 f/2.8, hand held, using the LCD for framing. It will certainly be interesting.