DPP doesn't have a genuine Exposure control?

I have been using DPP to adjust images until they looked good.

I can see now that may have been a mistake because I didn't understand why they were looking good.

Perhaps I need to stop processing images until I understand what is going on underneath the hood.

Is the source code available?

Once upon a time, in the distant past in hi-tech terms, in other words 6 years ago, there were no Picture Styles. Canon xxxD and xxD cameras and DPP had one profile that was used. It produced a fairly bland image because at Canon they assumed that anybody who is enough into photography to have a DSLR will want an image that is a good platform for post-processing. Then, while the folks at Canon were having a little snooze, the market changed. Soccer-moms and Joe-the-plumbers bought DSLRs and they didn't want bland; they wanted zip and zap and knock-your-eyes-out. Nikon produced its own line of budget DSLRs with circus colors and Canon woke up because of a sharp pain in its corporate wallet and invented PICTURE STYLES. And what do PSs do? They are more than mere profiles that characterize how the camera sees colors, they also contain curves that jazz up contrast and saturation, more in the midtones while retaining the white and black points. Separate curves for each channel so the PSs can have different colorations. Poor little Brightness does its linear exposure adjustment, but then the PS gets slapped onto the data.

But I still say that although it may be helpful (and definitely fun) to understand the what and why, the bottom line is the image. Is the fact that DPP imposes curves enough reason for seeking another converter? Try the free trials. See if you can do better with LR/ACR, Cap 1, Aperture, etc (where you still apply curves but have more control over them). Or accept DPP for what it is (which is a lot) and dig it.

tonylong wrote in post #12936887
I don't have the technical expertise either.

In general, I'd say a Linear adjustment moves all tonal values "forward" (or backwards) evenly, until either highlights clip at the RGB values of 255, 255, 255 or blacks clip at 0, 0, 0. In DPP, you get good RGB values only if you use the Linear option, although the Linear option does away with the pre-processing that the software does (which applies a non-linear curve the best I can understand) which makes most of the image, well, very dark.

In the non-linear mode, the curve has already been applied, so the Brightness slider goes along with the non-linear mode. It will be strongest when not dealing with the brightest areas (although you can still get clipping if you push it). I haven't really done any serious testing with shadow areas.

Know, though, that the Raw Brightness control only goes to a +/-2 EV adjustment, so you are limited there to how far you can "push" things -- a highlight would have to already be at +1 EV to clip if pushed by two stops. However, if your image really needs it, then you can go the two stops in Raw and then go to the RGB tab and push things even more. So there you can go to what, at least a four stop upping in exposure. Interestingly enough in the non-linear option, the boost in the RGB histogram does show, but it does not in the Raw histogram. But, for many scenes if you've set Brightness to the max in both tabs, much if not most of your images will likely have blown highlights. And, if you slide your pointers over the bright areas, the RGB reading at the bottom of the window will show the bright readings of the preview from the non-linear setting. But, if you turn on the Linear option. you will likely get a whole different picture -- you will see the linear Raw data after the linear brightness adjustment of four stops or so. Some highlights will likely be clipped, but much of what "lost" in the non-linear conversion is still visible!

And so, what practical value is all this? Hmm, don't know...although it is a good exercise in understanding some of the underlying "stuff", especially with Raw processing. But, I'll tell you, I am still very much in the "whatever works for you camp". There are undoubtedly some understandings that will help me work more efficiently -- for example, the DPP Brightness slider seems to act a lot like the Lightroom/Camera Raw Brightness, in that it (acting in a non-linear way) will "try" to slow down highlight clipping -- well that's fine for me -- Brighten does a pretty good job for what it advertises, brightening a scene, and if it can do that but not push too hard on highlights, I'm happy for that (and I'm happy with my Lightroom Brightness slider for the same reason)!

I assume when you talk about linear and non linear you are referring to the the preferences - tool palette - tone curve interpolation methods - curve & strait ?

Could anyone please post a pre/post series of images obtained in the Linear mode? activate the 'Linear' checkbox (which should cancel all tonal arrangements done to the image), and develop a RAW file 3 times: one with 0.0 in Brightness in the RAW tab, another one with -1EV, and finally with +1EV.
If the profile chosen is Adobe RGB will be best.

Thanks!

The only checkbox I could find was the curve and strait in the preferences. I checked the strait box.


http://i33.photobucket​.com/albums/d74/Zenon1​/0-EV.jpg

+1
http://i33.photobucket​.com/albums/d74/Zenon1​/1-EV.jpg

-1
http://i33.photobucket​.com/albums/d74/Zenon1​/_1-EV.jpg

It's in the RAW tab, right below Contrast-Highlight-Shadow. See here:

Ah. I'll do it again. Thanks for responding.

Well I'm not sure these will be of any use to you. This is what happened when activated linear. I am going to have to the Canon DPP tutorials for the explanation.


http://i33.photobucket​.com …s/d74/Zenon1/0d​e5bf5e.jpg

+1
http://i33.photobucket​.com/albums/d74/Zenon1​/1-7.jpg

-1
http://i33.photobucket​.com/albums/d74/Zenon1​/_1.jpg

That was interesting. It is sort of a graduated ND filter/HDR feature.

digital paradise wrote in post #12938736
That was interesting. It is sort of a graduated ND filter/HDR feature.

According to DPP help(F1) Linear is only useful if you are going to be doing advanced editing in other software, i.e. PS.

At last we got it. Those images are linear, i.e. they have gamma=1, that is whay they display dark if you don't assign them properly (I opened them in PS assigning linear sRGB and they displayed perfectly).

But the gamma question is irrelevant to us, the important thing is that the Linear mode in DPP additionally ensures that no processing at all has been applied to the images. This is a mandatory condition so that the curves I calculate make sense.

I have then calculated the curves from 0 to +1 and from 0 to -1, and they correspond to a genuine Exposure adjustment:

HTTP response: NOT FOUND | MIME changed to 'image/jpeg'

HTTP response: NOT FOUND | MIME changed to 'image/jpeg'

tkerr wrote in post #12938867
According to DPP help(F1) Linear is only useful if you are going to be doing advanced editing in other software, i.e. PS.

I was wondering when someone was going to mention this!

tkerr wrote in post #12938867
According to DPP help(F1) Linear is only useful if you are going to be doing advanced editing in other software, i.e. PS.

-Douglas- wrote in post #12938967
I was wondering when someone was going to mention this!

Irrelevant. I just needed the Linear mode to ensure no processing had been applied in order to have a correct calculation of the curves, not meaning Linear mode has to be used to have a genuine Exposure control.

_GUI_ wrote in post #12938965
At last we got it. Those images are linear, i.e. they have gamma=1, that is whay they display dark if you don't assign them properly (I opened them in PS assigning linear sRGB and they displayed perfectly).

But the gamma question is irrelevant to us, the important thing is that the Linear mode in DPP additionally ensures that no processing at all has been applied to the images. This is a mandatory condition so that the curves I calculate make sense.

I have then calculated the curves from 0 to +1 and from 0 to -1, and they correspond to a genuine Exposure adjustment:

HTTP response: NOT FOUND | MIME changed to 'image/jpeg'

.

HTTP response: NOT FOUND | MIME changed to 'image/jpeg'

(ignore the end part of the -1 curve, your images simply didn't have data to calculate the curves there)

So the conclusion is that the Bright control in the RAW tab, is a genuine Exposure adjustment (producing the same effect on RAW levels you would get by modifying exposure in the camera with aperture and shutter, and not any strange 'invention' from Canon).

What's this useful for? in my case just for fun since I don't use DPP. For a DPP user, to know that the effect in image levels with that setting is the same as a camera exposure change.

I asked two questions along the thread no one answered:

'If you shoot for instance ISO100 1/500 f/4, and then shoot again ISO100 1/1000 f/4, and develop both RAW files with the same settings in DPP but pushing the second by +1EV, don't you get exactly the same image?'

'imagine you are shooting a bracketing with different exposures, and want to use DPP to match their exposures and fuse them in layers for HDR. Can you confirm if the resulting images will share exactly the same exposure (as expected from a genuine exposure control), or I'll find some other 'differences' among them?'

Now I know the answer is yes to both.

Thank you

Thanks for doing the work. I never had any issues using it before and I doubt if I would have stopped using it if your tests discovered it was not a true exposure adjustment. It is good to know though. Besides I Iearned something today.

digital paradise wrote in post #12939012
I never had any issues using it before and I doubt if I would have stopped using it if your tests discovered it was not a true exposure adjustment.

I found very strange that DPP didn't have a proper exposure adjustment, it's a basic tool (and besides the easiest to implement in the code, just need to multiply levels by a constant factor: 2.0 for the +1EV, and 0.5 for the -1EV). If using a linear profile, the same is achieved in PS with: