Dynamic range

[Andybazyoung]

Hello all,
I have undertaken an on line photography course with the hope of improving my skills and have just completed a 'grey scale' test. My camera, a canon 600d has a dynamic range of 11 rather than 10 as was expected & have been informed although a little high it is still fine. My next assignment is to take images using the cameras, 'dynamic range', 2 stop below & above & with the correct exposure, all in RAW. Then using photoshop correct the worst image & send off the results. The images must be a landscape.
Question x 2! What do I look for & how do I get all the light & dark areas into the same image?
Comments will be gratefully received.
Andy

[Colin Southern]

Hi Andy,

Not sure where you got the "expected 10" from, but DxO mark have it listed as 11.5 - http://www.dxomark.com/index.php/Cam...Canon/EOS-600D.

With regards to your assignment, I suspect that they're trying to show how much overhead there is in a RAW capture - usually a couple of extra stops of safety margin over a JPEG if you don't nail the exposure correctly. If you under-expose your landscape by a couple of stops then it'll look dark initially, but you'll be able to adjust the exposure up a couple of stops in post processing and still have a relatively normal looking image (albeit with higher levels of shadow noise). For the shot that you over-expose, it'll probably look pretty over-exposed initially, but again, you can lower the exposure in post-processing by a couple of stops and - again - you should end up with a pretty normal looking image, although if your shot has any backlighting (light that comes from incident light as opposed to light reflected off an object) then that could well be unrecoverable in the over-exposed shot) (normal metering gives about a 2 & 1/3 stop safety margin with a RAW image at base ISO, thus a 2 stop over-exposure is still recoverable, but all of that is based on REFLECTED light, not incident light. Incident light eats into the safety margin significantly (unless the metering darkens the whole shot to compensate) so a 2 stop over-exposure plus incident light in a scene that meters just the reflected light) usually results in some loss of data).

Normal practice for landscape is to avoid over-exposure and then reveal shadow detail in post processing with the fill light slider.

Hope this helps.

[pnodrog]

Try shooting from a cave or dense grove of trees and use the shadowed area to frame a bright landscape. It is a problem I have struck a number of times and generally resort to combining a couple of exposures. (HDR but avoid the effect like the plague.)

[xpatUSA]

Hello all,
. . . and have just completed a 'grey scale' test. My camera, a canon 600d has a dynamic range of 11 rather than 10 as was expected & have been informed although a little high it is still fine.
Andy

For what it's worth, with a similar test, dpReview gets a bit less than 11:

http://www.dpreview.com/reviews/canoneos600d/12

Dartmoor, huh?