Canon Digital Photography Forums  

Go Back   Canon Digital Photography Forums > 'Sharing Knowhow' section > Talk About Photography > General Photography Talk
Register Rules FAQ Members List Search Today's Posts Mark Forums Read



Reply
 
Thread Tools Display Modes
Old 10th of July 2005 (Sun)   #1
FlyingPete
I am immune
 
FlyingPete's Avatar
 
Join Date: Oct 2003
Location: howick.akl.nz
Posts: 4,091
Default To underexpose or overexpose?

OK, I know the real answer is to get the exposure right, but what if you have a situation with a large variation in light, where there is no correct exposure to get everything in the scene?

Last night I was shooting a concert, the camera's meter predictably can not handle the lighting, and makes a complete screw up of the situation, the situation being a the artist floodlit with a dark background. The typical camera response here is to over expose the artist to try and bring out the background. In this particular instance exposure compensation of around 1-2 stops under worked quite well.

This got me thinking though, when I let the camera do the work I ended up with a white artist with no detail, mainly clipped out to white, no recoverable detail, even in RAW, by correctly exposing the foreground, the background became very dark, however I was surprised how much detail was recoverable still from the background.

Is it better then in difficult lighting to err with caution and under expose, correct later and avoid over exposure at all costs? It seem to me that you will have better luck fixing an under exposed image with a digital than an overexposed one.
FlyingPete is offline   Reply With Quote
This ad block will go away when you log in as member
Old 10th of July 2005 (Sun)   #2
scottbergerphoto
Cream of the Crop
 
scottbergerphoto's Avatar
 
Join Date: Jun 2003
Location: Brooklyn, NY, USA
Posts: 5,430
Default Re: To underexpose or overexpose?

You have really only one option in a fluid situation, when the lighting isn't uniform across the image. Decide what is the most important element in the image and expose for that using a spot or partial spot meter. You will get overexposed areas and underexposed areas, but your main subject will be properly exposed. Shoot Raw and avoid underexposure of the main subject, as this gives you alot of noise when you recover the detail from the underexposed areas. You can use a zoom lens to make your meter function as a spotmeter-just zoom in on the subject to fill the viewfinder, lock in the meter reading and zoom out to recompose.
When dealing with a static situation like a landscape, you can take a series of pictures, usually two, one for the highlights and one for the shadows, taken at precisely the same spot on a tripod and combine them.
__________________
One World, One Voice Against Terror,
Best Regards,
Scott
ScottBergerPhotography

Last edited by scottbergerphoto : 10th of July 2005 (Sun) at 18:06.
scottbergerphoto is offline   Reply With Quote
Old 10th of July 2005 (Sun)   #3
tim
Light Bringer
 
tim's Avatar
 
Join Date: Nov 2004
Location: Wellington, New Zealand
Posts: 49,094
Default Re: To underexpose or overexpose?

Good advice Scott, I especially like the way of using the zoom lens to help a partial meter operate as a spot meter.

I tend to underexpose rather than overexpose, as with RAW it's easier to fix the former than the latter. Of course if you underexpose your main subject at ISO 1600 then increase the exposure the noise will be horrible, and even after noise reduction it won't look great. On the other hand it'll still be better than a white blob.
tim is offline   Reply With Quote
This ad block will go away when you log in as member
Old 10th of July 2005 (Sun)   #4
PhotosGuy
Moderator
 
PhotosGuy's Avatar
 
Join Date: Feb 2004
Location: S. E. Michigan
Posts: 68,206
Default Re: To underexpose or overexpose?

I've usually tried to get the primary subject exposed correctly in RAW & then adjusted the rest in PS.
The opposite of your situation, the 3rd shot here was an exposure for the shadows, & adjusted for the highlights in RAW processing.
As Scott said, "Decide what is the most important element in the image and expose for that."
Learn the rules. Learn when to break them!
__________________
FrankC - 20D, RAW, Manual everything...
Classic Carz, Racing, Air Show, Flowers.
www.FrankCizek.com

Find the light... A few Car Lighting Tips, and MOVE YOUR FEET!
Have you thought about making your own book? // Need an exposure crutch?

New Image Size Limits: Image must not exceed 1280 pixels on any side.
PhotosGuy is offline   Reply With Quote
Old 10th of July 2005 (Sun)   #5
FlyingPete
I am immune
 
FlyingPete's Avatar
 
Join Date: Oct 2003
Location: howick.akl.nz
Posts: 4,091
Default Re: To underexpose or overexpose?

Excellent advice guys, good stuff, now I have an excuse to get a EF1200 and use it for spot metering

It is very much a balancing act, last night I was fortunate that I really only had to worry about the correct exposure of the main subject, pretty serious when you have to compensate for up two stops though. Spent the first 10 minutes or so getting my exposure right.

An other interesting observation of my SLR from the last 10 months or so, I have shot concerts for around 6 years now, but not with a SLR until recently. It is harder to get a good shot with an SLR than a P&S in these lighting condiditons, but when you do get it, it is a really good shot far above the standard of shots I was getting from previous cameras.
FlyingPete is offline   Reply With Quote
Old 10th of July 2005 (Sun)   #6
robertwgross
Cream of the Crop
 
robertwgross's Avatar
 
Join Date: Nov 2002
Location: California
Posts: 9,462
Default Re: To underexpose or overexpose?

I agree with Tim. That is a situation to try partial metering. The camera meter will try to give you a solution based on the center (the artist) and mostly ignore the dark background. Then, if you do a +1/-1 exposure bracketing around that, you ought to get something good.

---Bob Gross---
robertwgross is offline   Reply With Quote
Old 11th of July 2005 (Mon)   #7
blue_max
Goldmember
 
blue_max's Avatar
 
Join Date: Mar 2005
Location: London UK
Posts: 2,622
Default Re: To underexpose or overexpose?

I take it flash was not an option as it can be just the job when there is too much contrast.

Graham
__________________
.
Lamb dressed as mutton.
blue_max is offline   Reply With Quote
Old 11th of July 2005 (Mon)   #8
tim
Light Bringer
 
tim's Avatar
 
Join Date: Nov 2004
Location: Wellington, New Zealand
Posts: 49,094
Default Re: To underexpose or overexpose?

Quote:
Originally Posted by blue_max
I take it flash was not an option as it can be just the job when there is too much contrast.
Flash is generally not allowed at concerts or during theatre.
tim is offline   Reply With Quote
Old 11th of July 2005 (Mon)   #9
FlyingPete
I am immune
 
FlyingPete's Avatar
 
Join Date: Oct 2003
Location: howick.akl.nz
Posts: 4,091
Default Re: To underexpose or overexpose?

Quote:
Originally Posted by tim
Flash is generally not allowed at concerts or during theatre.
That would be right, the usual: Please turn off cellphones, no video or flash photography.

Nothing like a flash going off in your face whilst trying to perform. Also under some circumstances ruins the atmosphere.
FlyingPete is offline   Reply With Quote
Old 11th of July 2005 (Mon)   #10
Andy_T
Compensating for his small ... sensor
 
Join Date: Jan 2003
Location: Kuala Lumpur, Malaysia
Posts: 9,860
Default Re: To underexpose or overexpose?

You can take advantage of the cameras exposure bracketing function (5 fps is very good for this). Better 2 images too much, than completely missing the shot.

Best regards,
Andy
Andy_T is offline   Reply With Quote
Old 11th of July 2005 (Mon)   #11
scottbergerphoto
Cream of the Crop
 
scottbergerphoto's Avatar
 
Join Date: Jun 2003
Location: Brooklyn, NY, USA
Posts: 5,430
Default Re: To underexpose or overexpose?

A word about under/over exposure and Raw. ACR will allow you to recover at least 1 stop overexposure in Raw with no loss of image quality. In addition, 1/2 of all the image data is recorded in the right most segment of the histogram. If your image isn't using that part of the histogram, that data is lost and is not recoverable. That's why when you try to recover data from shadows even at low iso's you get noise. The software is putting back what wasn't there to begin with. To get the most out of your sensor, adjust the exposure so that your histogram almost touches the rightmost end of the graph. Then in ACR reduce the exposure to a normal exposure.
I usually calculate a normal exposure based on a modified zone system (Black, Dark Grey, 18%Grey, Light Grey, White), take the picture and then adjust my exposure to move the histogram to the right. Using this method, I avoid the noise created in shadow recovery.
__________________
One World, One Voice Against Terror,
Best Regards,
Scott
ScottBergerPhotography

Last edited by scottbergerphoto : 11th of July 2005 (Mon) at 06:07.
scottbergerphoto is offline   Reply With Quote
Old 11th of July 2005 (Mon)   #12
CyberDyneSystems
Admin (type T-2000)
 
CyberDyneSystems's Avatar
 
Join Date: Apr 2003
Location: Providence RI
Posts: 39,680
Default Re: To underexpose or overexpose?

I've been trying to get my RAW exposures as hot as possible without blowing highlights...

I am finding that the popular belief that this will help overall image quality is quite true.. that the more to the right I can get an exposure the better the end product will be.

My rule of thumb therefore is as hot as I can get it without blowing out highlights or details in the subject.
CyberDyneSystems is offline   Reply With Quote
Old 11th of July 2005 (Mon)   #13
PhotosGuy
Moderator
 
PhotosGuy's Avatar
 
Join Date: Feb 2004
Location: S. E. Michigan
Posts: 68,206
Default Re: To underexpose or overexpose?

Quote:
To get the most out of your sensor, adjust the exposure so that your histogram almost touches the rightmost end of the graph.
I'd like to point out that you need to have a FLAT white to "almost touches the rightmost end of the graph." If you have a stage light in the frame, or maybe a chrome reflection of the sky, or a bright background that isn't lighting your subject, then your exposure will be off. Like I screwed this shot up.
__________________
FrankC - 20D, RAW, Manual everything...
Classic Carz, Racing, Air Show, Flowers.
www.FrankCizek.com

Find the light... A few Car Lighting Tips, and MOVE YOUR FEET!
Have you thought about making your own book? // Need an exposure crutch?

New Image Size Limits: Image must not exceed 1280 pixels on any side.
PhotosGuy is offline   Reply With Quote
Old 11th of July 2005 (Mon)   #14
scottbergerphoto
Cream of the Crop
 
scottbergerphoto's Avatar
 
Join Date: Jun 2003
Location: Brooklyn, NY, USA
Posts: 5,430
Default Re: To underexpose or overexpose?

Quote:
Originally Posted by PhotosGuy
I'd like to point out that you need to have a FLAT white to "almost touches the rightmost end of the graph." If you have a stage light in the frame, or maybe a chrome reflection of the sky, or a bright background that isn't lighting your subject, then your exposure will be off. Like I screwed this shot up.
Not at all. There doesn't have to be any white in the image. You are intentionally overexposing the subject to move the histogram to the right. As long as you do that in Raw and don't extend past the right end of the histogram, all the data is captured. You just reduce the exposure in ACR. This is completely different than film. As an example, if you were shoot an 18% Grey card with no adjustments for exposing to the right, you would get a single peak right in the middle of the histogram. In exposing to the right, you would overexpose that 18% Grey card by almost 2 stops to move that peak to the near right end of the histogram. Then in ACR, you back off the exposure to the normal exposure. This is to make up for the fact that the sensor does not collect data evenly across the histogram. When you don't use the rightmost part of the histogram, you lose 1/2 the data your sensor is capable of collecting. You basically convert an 8mp camera to a 4mp camera.
__________________
One World, One Voice Against Terror,
Best Regards,
Scott
ScottBergerPhotography

Last edited by scottbergerphoto : 11th of July 2005 (Mon) at 12:48.
scottbergerphoto is offline   Reply With Quote
Old 11th of July 2005 (Mon)   #15
starzphalling
Member
 
Join Date: Jun 2005
Location: illinois
Posts: 109
Default Re: To underexpose or overexpose?

ACR??
starzphalling is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
How do you not overexpose ice hockey? troyer16 Sports 11 7th of January 2007 (Sun) 17:36
Better to overexpose or to use FEC? fi20100 Small Flash and Studio Lighting 3 11th of August 2006 (Fri) 10:14
Overexpose digital and get a better picture?#$%!? TooManyHobbies RAW, Post Processing and Printing 26 15th of June 2006 (Thu) 11:58
how do i not to overexpose a night shot? youyesyou.net General Photography Talk 12 28th of June 2005 (Tue) 15:36
Best quality - Overexpose or underexpose? arumdevil Canon EOS Digital Cameras 26 8th of May 2004 (Sat) 21:34


All times are GMT -5. The time now is 20:19.


Powered by vBulletin® Version 3.6.12
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
This forum is not affiliated with Canon in any way and is run as a free user helpsite by Pekka Saarinen, Helsinki Finland. You will need to register in order to be able to post messages. Cookies are required for registering and posting. HTML in messages is not allowed, plain website addresses are automatically made active by the board.