EOS 350D - JPG over-exposed, RAW fine

[spotty69]

I bought my EOS 350D second hand around 18 months ago. Recently, I've been noticing that when I shoot in program mode (as I do 90% of the time) them the JPGs are very over-exposed, whereas the RAW files are fine. Any ideas?!


Many thanks....

[neuroanatomist]

Welcome to the TDP Forums!

whereas the RAW files are fine

How are you viewing the RAW files? Different RAW converters produce different results. How to RAW images converted to JPGs in Canon's DPP compare to the in-camera JPGs?


Also, what Picture Style are you using?

[spotty69]

I'm looking at the RAW files in Picasa. Not very advanced I know, but suits me for basic stuff.


Comparing the unprocessed RAW files and the JPG side by side, the JPGs are generally over exposed.


Here's an example - albeit both JPG files, and resized here for size reasons, the difference is obvious. Shot with program AE, 18-55 kit lens, f8.0, 1/250s, 79mm, ISO 200. Note that NO processing has taken place - one is converted from RAW and resized, the other is jsut resized from the camera-produced JPG.


[img]/cfs-file.ashx/__key/CommunityServer.Components.UserFiles/00.00.00.45.84/eos350_5F00_jpg_5F00_512x768.jpg[/img]


[img]/cfs-file.ashx/__key/CommunityServer.Components.UserFiles/00.00.00.45.84/eos350_5F00_raw_5F00_511x768.jpg[/img]

[neuroanatomist]

First, sorry about the Picture Style question - not a feature on the 350D.


First question is how you got a shot at 79mm from your 18-55mm kit lens. Must be some lens... [:P] (Kidding, sorry!)


Well, the in-camera JPG (top) is certainly brighter than the converted RAW (bottom). But, is the top one overexposed, or is the bottom one underexposed? I don't mean how they look to our eyes, I mean compared to how the camera's exposure meter intended them to look.


When you say 'no processing' you mean that you didn't do any. Processing was done, though, as part of the RAW conversion.

I'm looking at the RAW files in Picasa.

Not exactly. You can't really look at RAW image files - from the 350D they are 12-bit images (14-bit from newer cameras), and computer monitors are 8-bit or 6-bit (most laptop displays are 6-bits). So you're never looking at the full data in the RAW file. What you're seeing is Picasa's conversion of the 350D RAW files. Different RAW converters process RAW images differently, depending on how the converter is written. Given Picasa's main purpose and user base (who, for the most part, are looking for 'basic stuff'), it may be that Picasa's RAW converter is somehow optimizing the exposure.


Slight digression for another example - when you take your JPGs to be printed at a chain store (Target, Walmart, whatever), the processor 'optimizes' your images - often changing the exposure, so if your intent is a dark, moody print to show emotion, the computer there will unhelpfully brighten that shot up for you, unless you specifically tell the operator to turn off the automatic adjustments, assuming s/he knows how).


So, if Picasa is doing something 'helpful' like that, your result may be very well different from the in-camera JPG. I use a Mac, and the Mac OS natively reads and works with RAW image files (and converts them to JPGs, of course). I can see clear differences in the JPG files produced by iPhoto vs. DPP, from the same RAW file.


So, as a troubleshooting step, I suggest trying DPP - since Canon wrote the code for both DPP and the in-camera RAW conversions, they are going to be pretty close.