Flash with RAW and JPEG

I accidentally discovered something quite surprising tonight. I was instructed (by she who must be obeyed) to photograph our dining room. I took a picture using JPEG (large, fine) and RAW using the built in flash in P mode.. The RAW image was processed in C1 with very little adjustment.

The JPEG came out very dark but the RAW image looked very good. I took a second JPEG just to sure with the same result. The camera was set on Parameter 1 which is supposed to yield bright, sharp images. According to EXIF both had exactly the same exposure.

Can anyone explain why this would be so.
--
**** Campbell

There should not have been any differences simply because of capture mode. You mentioned that the settings on the two were the same, but that is not necessarily so. Since the camera adjusts the output of the flash automatically, there indeed could have been a very signficant difference in the amount of flash output, resulting in the different exposures, despite the images having the same apertue and shutter speeds.

The only explanation I could offer is that there might have been a slight variation in how the images were shot. This is very reasonable, especially if the images were made hand held. If you want to really test the theory that the theory that the two capture modes have different exposure/flash output values, then every other variable must be carefully controlled (tripod mount, etc). Even a very slight amount of focus/recompose could result in a very different exposure.

Best of luck

M

http://www.michaelphoto.net

**** Campbell19 said:

I accidentally discovered something quite surprising tonight. I was
instructed (by she who must be obeyed) to photograph our dining
room. I took a picture using JPEG (large, fine) and RAW using the
built in flash in P mode.. The RAW image was processed in C1 with
very little adjustment.

The JPEG came out very dark but the RAW image looked very good. I
took a second JPEG just to sure with the same result. The camera
was set on Parameter 1 which is supposed to yield bright, sharp
images. According to EXIF both had exactly the same exposure.

Can anyone explain why this would be so.
--
**** Campbell

Click to expand...

It would be interesting to compare the jpeg embedded in the raw file (you can extract it, e.g. with Canon FVU) to the C1-raw and the camera-jpeg. Or compare FVU converted raws with C1 converted raws.

My guess is that the embedded-jpeg looks the same as the camera-jpeg and the FVU-jpeg, because all use the same in-camera algorithms. The C1-raw might use automatic normalization, while Canon FVU or the camera itself doesnt. Thus, with C1, underexposed images seem correctly exposed and only show more noise.

You also could normalize the camera-jpeg with gimp (image-colors-levels-auto) or photoshop, and it should look similar to the C1-jpeg.

Greetings
Achim

**** Campbell19 said:

I accidentally discovered something quite surprising tonight. I was
instructed (by she who must be obeyed) to photograph our dining
room. I took a picture using JPEG (large, fine) and RAW using the
built in flash in P mode.. The RAW image was processed in C1 with
very little adjustment.

The JPEG came out very dark but the RAW image looked very good. I
took a second JPEG just to sure with the same result. The camera
was set on Parameter 1 which is supposed to yield bright, sharp
images. According to EXIF both had exactly the same exposure.

Can anyone explain why this would be so.
--
**** Campbell

Click to expand...

Thanks,

The composition of the photos was very close to the same altough I was not using a tripod. Also I should have taken more than one RAW to see whether it was a "one off".

I need to re-take the picture tonight (it's early morning here at the moment) so I will use a tripod and take a few shots in each mode.

Even the preview was much brighter in C1 by the way. I find it hard to believe that the capture mode would make that much difference.

Michael Thomas Mitchell said:

The only explanation I could offer is that there might have been a
slight variation in how the images were shot. This is very
reasonable, especially if the images were made hand held. If you
want to really test the theory that the theory that the two capture
modes have different exposure/flash output values, then every other
variable must be carefully controlled (tripod mount, etc). Even a
very slight amount of focus/recompose could result in a very
different exposure.

Best of luck

M

http://www.michaelphoto.net

**** Campbell19 said:

I accidentally discovered something quite surprising tonight. I was
instructed (by she who must be obeyed) to photograph our dining
room. I took a picture using JPEG (large, fine) and RAW using the
built in flash in P mode.. The RAW image was processed in C1 with
very little adjustment.

The JPEG came out very dark but the RAW image looked very good. I
took a second JPEG just to sure with the same result. The camera
was set on Parameter 1 which is supposed to yield bright, sharp
images. According to EXIF both had exactly the same exposure.

Can anyone explain why this would be so.
--
**** Campbell

Click to expand...

Click to expand...

--
**** Campbell

I intend to experiment more later today. I can say that even the pre-view in C1 was much brighter. See my other reply.

AchimS said:

My guess is that the embedded-jpeg looks the same as the
camera-jpeg and the FVU-jpeg, because all use the same in-camera
algorithms. The C1-raw might use automatic normalization, while
Canon FVU or the camera itself doesnt. Thus, with C1, underexposed
images seem correctly exposed and only show more noise.

You also could normalize the camera-jpeg with gimp
(image-colors-levels-auto) or photoshop, and it should look similar
to the C1-jpeg.

Greetings
Achim

**** Campbell19 said:

I accidentally discovered something quite surprising tonight. I was
instructed (by she who must be obeyed) to photograph our dining
room. I took a picture using JPEG (large, fine) and RAW using the
built in flash in P mode.. The RAW image was processed in C1 with
very little adjustment.

The JPEG came out very dark but the RAW image looked very good. I
took a second JPEG just to sure with the same result. The camera
was set on Parameter 1 which is supposed to yield bright, sharp
images. According to EXIF both had exactly the same exposure.

Can anyone explain why this would be so.
--
**** Campbell

Click to expand...

Click to expand...

--
**** Campbell

Marked

**** Campbell19 said:

AchimS said:

My guess is that the embedded-jpeg looks the same as the
camera-jpeg and the FVU-jpeg, because all use the same in-camera
algorithms. The C1-raw might use automatic normalization, while
Canon FVU or the camera itself doesnt. Thus, with C1, underexposed
images seem correctly exposed and only show more noise.

You also could normalize the camera-jpeg with gimp
(image-colors-levels-auto) or photoshop, and it should look similar
to the C1-jpeg.

Greetings
Achim

**** Campbell19 said:

I accidentally discovered something quite surprising tonight. I was
instructed (by she who must be obeyed) to photograph our dining
room. I took a picture using JPEG (large, fine) and RAW using the
built in flash in P mode.. The RAW image was processed in C1 with
very little adjustment.

The JPEG came out very dark but the RAW image looked very good. I
took a second JPEG just to sure with the same result. The camera
was set on Parameter 1 which is supposed to yield bright, sharp
images. According to EXIF both had exactly the same exposure.

Can anyone explain why this would be so.
--
**** Campbell

Click to expand...

Click to expand...

--
**** Campbell

Click to expand...

--
Jim F

I finally got around to it. I set the camera up on a tripod and took three shots in JPEG amd three in RAW.

With slight variations all six were about the same so my previous result must have been a "one off".

**** Campbell19 said:

AchimS said:

My guess is that the embedded-jpeg looks the same as the
camera-jpeg and the FVU-jpeg, because all use the same in-camera
algorithms. The C1-raw might use automatic normalization, while
Canon FVU or the camera itself doesnt. Thus, with C1, underexposed
images seem correctly exposed and only show more noise.

You also could normalize the camera-jpeg with gimp
(image-colors-levels-auto) or photoshop, and it should look similar
to the C1-jpeg.

Greetings
Achim

**** Campbell19 said:

I accidentally discovered something quite surprising tonight. I was
instructed (by she who must be obeyed) to photograph our dining
room. I took a picture using JPEG (large, fine) and RAW using the
built in flash in P mode.. The RAW image was processed in C1 with
very little adjustment.

The JPEG came out very dark but the RAW image looked very good. I
took a second JPEG just to sure with the same result. The camera
was set on Parameter 1 which is supposed to yield bright, sharp
images. According to EXIF both had exactly the same exposure.

Can anyone explain why this would be so.
--
**** Campbell

Click to expand...

Click to expand...

--
**** Campbell

Click to expand...

--
**** Campbell