RAW histogram

pawel · Oct 10, 2013

Hi All, is anyone aware of any tethering solution for Canon (and preferably for Mac) that would directly display a RAW histogram?
What I am after is a tool to optimize my shooting workflow, a central point to that being getting exposure right when exposing to the right. In-camera histogram has its flaws and on a couple occasion I have had my share of overexposed images even though the histogram seemed ok (and no overexpo blinking either). It would be great to overcome that by having a straight away RAW based histogram.

Thanks!

Overread · Oct 10, 2013

So long as you've got your in-camera histogram set to have the JPEG editing at neutral values you should get a fairly good representation of the RAW histogram on the back of the camera. You might find that you're blowing a specific colour channel (the red channel often blows very easily) so consider setting your histogram to show the RGB histogram on the back of the camera.

Otherwise you could tether the camera to a laptop using the tethering software supplied in the box with the camera. That would let you get output onto your computer and a fast transfer. I've not looked into it myself so I don't know if the automatically output file will show the RAW or will default to the JPEG for speed, but getting the files off the camera and onto the laptop fast means you can then work with the RAWS themselves direct.

tirediron · Oct 10, 2013

The CamRanger will, since it allows you to transfer raw files. I think Over's solution is the best one, simply middle all your in-camera .jpg settings and use that.

pawel · Oct 10, 2013

Thanks for the replies. Reasonable approach, but not specifically what I am looking for.

I am currently using RGB histogram, adobe RGB color space plus zeroed JPG settings. Now the thing is that the histogram deisplayed is that of the white balanced JPG. I agree that in many cases this is a reasonable representation of the actual saturation of each channel, but just a slight change in white balance may well turn everything around. So what I'd love to see is whether any channel is physically blown out.
Getting the shots from the camera to my laptop is not the complicated part (yes, the otherwise rather basic EOS utility will do that, I do not even need to spend 300 bucks on the Camranger). I just do not necessarily want to look at each image in Lightroom when I am shooting.

By the way, using UniWB (Unitary White Balance) is not a bad idea either, so I may just stick to that eventually. Anyway I hoped that someone has already implemented a RAW based histogram in a not so complicated way. I guess I'll keep googling.

KmH · Oct 10, 2013

What are you shooting, and what metering mode do you use to shoot it?

Specular highlights will pretty much always be over exposed when using ETTR.

pawel · Oct 10, 2013

@tirediron: Btw I looked at Camranger. Are you positive that it supports a RAW histogram? I can't seem to find that feature in their description anywhere.

pawel · Oct 10, 2013

KmH said:
What are you shooting, and what metering mode do you use to shoot it?

Mainly landscape, studio macro and products. I prefer not to rely on camera metering as I have the time to fiddle around with the proper expo.

KmH said:
Specular highlights will pretty much always be over exposed when using ETTR.

Not necessarily. That is exactly what I want to avoid, or at least control.

tirediron · Oct 10, 2013

pawel said:
@tirediron: Btw I looked at Camranger. Are you positive that it supports a RAW histogram? I can't seem to find that feature in their description anywhere.

The CamRanger will stream raw files, so the associated histogram will be a raw histogram.

pawel · Oct 10, 2013

tirediron said:
pawel said:

@tirediron: Btw I looked at Camranger. Are you positive that it supports a RAW histogram? I can't seem to find that feature in their description anywhere.

Click to expand...

The CamRanger will stream raw files, so the associated histogram will be a raw histogram.

As I understand it streams the liveview (streaming RAW would not be possible over WiFi), and after shooting it downloads the RAW and extracts the white balanced JPG. Histogram is based on that. After taking a sacond look at it, I am sure. Atlhough if I am wrong, than it would be just what I am after. I'll take a deeper look. Thanks!

tirediron · Oct 10, 2013

It may be more complex, but based on this from their website, "view full resolution images in JPG or Canon RAW" I assume their streaming the raw file. Why would it not be possible over a wireless connection? It would take a little longer, but at the end of the day, it's nothing more than 'ones' and 'zeroes' and as long as the software on your receiving device can put them back together again... Out of curiosity, why do you need such absolute accuracy?

pawel · Oct 10, 2013

tirediron said:
It may be more complex, but based on this from their website, "view full resolution images in JPG or Canon RAW" I assume their streaming the raw file. Why would it not be possible over a wireless connection? It would take a little longer, but at the end of the day, it's nothing more than 'ones' and 'zeroes' and as long as the software on your receiving device can put them back together again...

By streaming I meant transferring the live view image - that image sequence is not a series of RAWs. And if it was, I believe you would not get a 6 to 18 FPS, but rather one frame every 10 to 15 second. Transferring the post caprute image is a different story - it still takes time, but that's fine. I guess most, if not every tethering software does transfer the RAW files as well. What they display as a post capture image could be the processed RAW or the JPG extracted from the RAW image (or a standalone JPG if you are shooting RAW+JPG). I shoot exclusively RAW as I do not need in-camera JPGs. A full processing of the RAW again takes quite some time - but calculating a histogram from the RAW data could be done relatively quickly.

tirediron said:
Out of curiosity, why do you need such absolute accuracy?

I am not sure that it is about absolute accuracy. I would just call it reasonable accuracy - why not capture better shots if I can. I may be pushing it to a limit that can not be justified for each and every shot, but I am definitely trying to get the best fine art prints out of my images. Considering how much I have invested in equipment, I wouldn't mind putting some extra efforts into achieving even better output.

Ysarex · Oct 10, 2013

Capture One 7 Pro will tether your Canon camera and immediately transfer raw files into the application, but you're going to have to be cabled to a laptop.

Just a note for clarification: even raw conversion software like LR/ACR or C1 doesn't show you a "raw" histogram. You're shown an RGB histogram derived from the converted raw file -- better than the histogram derived from the camera processed JPEG, but still a software interpretation.

Joe

edit: I sympathize with your desire for increased accuracy. I've have never been able to completely shake the uneasy feeling I have since moving from film to digital. When I shot film I had a densitometer that allowed me to get hard data about my exposure and processing. I still long for that hard data. If you're not familiar with it, check out the software app Raw Digger.

TCampbell · Oct 10, 2013

pawel said:
Hi All, is anyone aware of any tethering solution for Canon (and preferably for Mac) that would directly display a RAW histogram?
What I am after is a tool to optimize my shooting workflow, a central point to that being getting exposure right when exposing to the right. In-camera histogram has its flaws and on a couple occasion I have had my share of overexposed images even though the histogram seemed ok (and no overexpo blinking either). It would be great to overcome that by having a straight away RAW based histogram.

Thanks!

Aperture (Mac) tethers to Canon ... and displays histogram info if you are on the info tab.

pawel · Oct 10, 2013

Ysarex said:
Capture One 7 Pro will tether your Canon camera and immediately transfer raw files into the application, but you're going to have to be cabled to a laptop.

Just a note for clarification: even raw conversion software like LR/ACR or C1 doesn't show you a "raw" histogram. You're shown an RGB histogram derived from the converted raw file -- better than the histogram derived from the camera processed JPEG, but still a software interpretation.

Joe

edit: I sympathize with your desire for increased accuracy. I've have never been able to completely shake the uneasy feeling I have since moving from film to digital. When I shot film I had a densitometer that allowed me to get hard data about my exposure and processing. I still long for that hard data. If you're not familiar with it, check out the software app Raw Digger.

Thanks Joe for the advice. Yes, in fact raw converters will all display a calculated (and white balanced) histogram from the converted RAW file. It is exactly the Raw Digger kind of functionality that I am after.
Now it would be great if that could be integrated into a capturing app. I use Lightroom but I am more and more being pushed towards C1.
I have also tried UniWB but I just can't get used to the awful green previews.

Gavjenks · Oct 10, 2013

The raw has more latitude than the jpeg, so if a jpeg derived from the raw shows that it is not blown out, then you should be able to assume that the raw is not blown out either.

The only reason to need raw histograms would be if you were intending to crank it way far away from an actual white balanced image. If you want just a normal photo though, I can't think of any reason this would be necessary.