High ISO NR on RAW

Moderated by: guardian

Visit the FM Store · Image Upload · Buy & Sell
FM Forum Rules
Canon SLRs, primes, and zooms lenses reviews

FM Forums | Canon-mount SLRs | Join Image Upload

end

Archive 2008 · High ISO NR on RAW

wilrobking
Offline
Image Upload: On

p.1 #1 · High ISO NR on RAW

I received my new 50D today.

Just wondering if Highlight Tone Priority and High ISO Noise Redcution are applied to RAW images. The manual wasn't very clear to address this.

Page 62, section on RAW
About High ISO speed noise reduction and RAW.
Although High ISO speed noise reduction settings are applied to the recorded images, the images without noise reduction applied are used during image playback (on the LCD monitor and on a TV screen) or direct printing, (Noise my appear in the images.) Confirm the noise reduction effects or print noise-reduced images with Digital Photo Pro (provided software)

Oct 03, 2008 at 06:43 AM

morganb4
Offline
Image Upload: On

p.1 #2 · High ISO NR on RAW

tone priority yes, its alters the way the sensor records
high iso, no thats done by you, in post.

Oct 03, 2008 at 07:01 AM

wilrobking
Offline
Image Upload: On

p.1 #3 · High ISO NR on RAW

morganb4 wrote:
tone priority yes, its alters the way the sensor records
high iso, no thats done by you, in post.

Well why is there a Custom Function for High ISO noise reduction just as there's a Custom Function for Highlight Tone Priority.

Oct 03, 2008 at 07:18 AM

morganb4
Offline
Image Upload: On

p.1 #4 · High ISO NR on RAW

Tone priority relates to the way the image is captured and so is there in RAW. NR is done post capture and is applied after.

The option is there because not all people want either option. I use tone priority sometimes but not other times and I would never consider in camera NR.

Oct 03, 2008 at 07:32 AM

edwardkaraa
Offline
Buy and Sell: On

p.1 #5 · High ISO NR on RAW

Excuse my ignorance, but could anyone explain how tone priority is done at the sensor stage. I was under the impression it was done at the conversion stage.

Oct 03, 2008 at 08:04 AM

morganb4
Offline
Image Upload: On

p.1 #6 · High ISO NR on RAW

shifts the dynamic range of the sensor up in terms of highlights, the trade off is that you gain extra noise in the shadow regions.

Oct 03, 2008 at 08:23 AM

Allan Bruce
Offline
Image Upload: Off

p.1 #7 · High ISO NR on RAW

morganb4 wrote:
shifts the dynamic range of the sensor up in terms of highlights, the trade off is that you gain extra noise in the shadow regions.

Are you 100% sure on this? It was my belief that HTP was done in software...

Oct 03, 2008 at 08:49 AM

edwardkaraa
Offline
Buy and Sell: On

p.1 #8 · High ISO NR on RAW

There is one easy way to find out. Just open a raw file taken with any camera that supports HTP in RIT. If you have the choice to turn on/off HTP, this would mean the raw file is not affected and the HTP is done in software. If there is no such option, it would mean that it is hardware based.

Oct 03, 2008 at 08:57 AM

Desmo
Offline
Image Upload: Off

p.1 #9 · High ISO NR on RAW

That's an interesting question. I have a 40D and sometime use HTP on raw files. According to Canon HTP work by underexposing the picture, then a "special curve" is applied to bring back details in the shadows. It works when it's done in-camera on JPG's.
Now, when converting my raw files, even in DPP,I can see the file is effectively underexposed by approximately one stop.It's not corrected by a "special curve" and I can't find an "automatic" way of correcting it. Is there a HTP command in DPP? I don't see it.

Oct 03, 2008 at 09:30 AM

Dawei Ye
Offline
Image Upload: Off

p.1 #10 · High ISO NR on RAW

I'm not sure about this but based on what's been said the software push of an underexposed pic would explain why the min ISO of HTP is 200 not 100 (since a 200 shot would be captured in 100 and pushed up to 200 whilst holding highlights)

Oct 03, 2008 at 09:50 AM

edwardkaraa
Offline
Buy and Sell: On

p.1 #11 · High ISO NR on RAW

Desmo wrote:
That's an interesting question. I have a 40D and sometime use HTP on raw files. According to Canon HTP work by underexposing the picture, then a "special curve" is applied to bring back details in the shadows. It works when it's done in-camera on JPG's.
Now, when converting my raw files, even in DPP,I can see the file is effectively underexposed by approximately one stop.It's not corrected by a "special curve" and I can't find an "automatic" way of correcting it. Is there a HTP command in DPP? I don't see it.

Can you please try to open the file in raw image task and let us know what you find?

Oct 03, 2008 at 04:33 PM

edwardkaraa
Offline
Buy and Sell: On

p.1 #12 · High ISO NR on RAW

Ok, based on the above, it seems that HTP is indeed done in software. The only analog thing is the reduction of the ISO by 1 stop. Photographers have been doing this for ages. Exposing for highlights and developing for shadows. Digital photographers do the same. Expose as not to burn the highlights and process to bring out shadow details. HTP would then be useful for someone who shoots jpgs and does not have time to PP, like a wedding or event photographer. Anyone shooting raw does not need this mode.

Oct 03, 2008 at 04:44 PM

Desmo
Offline
Image Upload: Off

p.1 #13 · High ISO NR on RAW

Can you please try to open the file in raw image task and let us know what you find?

Interesting suggestion, I never use Raw Image Task.

I tried, nothing special. I can adjust the NR, but nothing about HTP.

I also tried to shoot Raw + Jpg.

Surprisingly I have no visible difference between the two files.... Either this "curve adjustment" is made right at the capture or it's not working on my 40D !!!!! And the Jpg is also underexposed by almost one stop!

I really don't understand how HTP is supposed to work.......

Edited on Oct 03, 2008 at 05:21 PM · View previous versions

Oct 03, 2008 at 05:10 PM

SoundHound
Offline
Buy and Sell: On

p.1 #14 · High ISO NR on RAW

Really no free lunch since the dynamic range is fixed! It benefits those that tend to expose more "to the right"

Oct 03, 2008 at 05:16 PM

kodakeos
Offline
Buy and Sell: On

p.1 #15 · High ISO NR on RAW

I used to use HINR all the time on my 40D with my RAW files and in ACR there is a definite difference between the 2 with the same settings.
I tested this because my g/fs 40D was significantly nosier and we were trying to find out why. We adjusted the HNR with both mine and hers, ON and Off in RAW. There was a small difference in the noise levels between the 2 settings.

Oct 03, 2008 at 05:16 PM

ChrisDM
Offline
Buy and Sell: On

p.1 #16 · High ISO NR on RAW

Well the way I see it the point is moo

. HTP is good for a "quick fix", where you're shooting jpg anyways and there might be just a little highlight out of range. But if you're shooting seriously, and in a scenario where the dynamic range is out of reach of your sensor, you're going to shoot RAW anyways and tune the exposure with a curve in post processing anyways, and perhaps even bracket/blend exposures. You won't rely on a limited in-camera gimmick if it is important enough to shoot RAW in the first place.

Chris M
www.imagineimagery.com

Oct 03, 2008 at 07:58 PM

kidtexas
Online
Image Upload: Off

p.1 #17 · High ISO NR on RAW

edwardkaraa wrote:
Ok, based on the above, it seems that HTP is indeed done in software. The only analog thing is the reduction of the ISO by 1 stop. Photographers have been doing this for ages. Exposing for highlights and developing for shadows. Digital photographers do the same. Expose as not to burn the highlights and process to bring out shadow details. HTP would then be useful for someone who shoots jpgs and does not have time to PP, like a wedding or event photographer. Anyone shooting raw does not need this mode.

Actually the rule is expose for the shadows and develop for the highlights. This is of course for negative film, and usually B&W at that, since the developing cycle is better suited to modification.

Slide film is expose for the highlights, but at that point, you are kind of done. Since the shadows are underexposed there's not much you can do to rescue too much detail there. Which is, as you say, what digital photographers do.

Oct 03, 2008 at 08:56 PM

Daan B
Offline
Image Upload: Off

p.1 #18 · High ISO NR on RAW

So what is the verdict on high ISO NR affecting 50D RAW files?

Another thing... 50D high ISO NR is adjustable in a number of steps. But can it be turned off completely?

Oct 03, 2008 at 09:25 PM

cwphoto
Offline
Image Upload: Off

p.1 #19 · High ISO NR on RAW

Daan B wrote:
So what is the verdict on high ISO NR affecting 50D RAW files?

Another thing... 50D high ISO NR is adjustable in a number of steps. But can it be turned off completely?

No affect.

Oct 04, 2008 at 01:44 AM

edwardkaraa
Offline
Buy and Sell: On

p.1 #20 · High ISO NR on RAW

kidtexas wrote:
edwardkaraa wrote:
Ok, based on the above, it seems that HTP is indeed done in software. The only analog thing is the reduction of the ISO by 1 stop. Photographers have been doing this for ages. Exposing for highlights and developing for shadows. Digital photographers do the same. Expose as not to burn the highlights and process to bring out shadow details. HTP would then be useful for someone who shoots jpgs and does not have time to PP, like a wedding or event photographer. Anyone shooting raw does not need this mode.

Actually the rule is expose for the shadows and develop for the highlights. This is of course for negative film, and usually B&W at that, since the developing cycle is better suited to modification.

Slide film is expose for the highlights, but at that point, you are kind of done. Since the shadows are underexposed there's not much you can do to rescue too much detail there. Which is, as you say, what digital photographers do.

Yes, you are correct.

Oct 04, 2008 at 02:22 AM


FM Forums \| Canon-mount SLRs \| Join Image Upload end