Approve the Cookies
This website uses cookies to improve your user experience. By using this site, you agree to our use of cookies. Read More.
OK
Index  •   • New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear  •   • Reviews
New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear  •   • Reviews
Register to forums    Log in

 
FORUMS Canon Cameras, Lenses & Accessories Canon EOS Digital Cameras
Thread started 07 Mar 2010 (Sunday) 08:48
Prev/next
sponsored links
(this ad will go away when you log in as registered member)

Questions re. Highlight Alert

 
Scott_online
Senior Member
Joined Aug 2009
Mar 07, 2010 08:48 |  #1

Aka the 'blinkies'.

I frequently use these to judge how much exposure compensation I need to dial-in in order to minimise blown highlights on a subject (i.e. I dial-in negative compensation until I can get rid of the blinkies, at least in the section of the image that I'm bothered about).

However, I've noticed that when I actually get the RAW into DPP, I can usually undo whatever compensation I've applied without triggering DPP's highlight alert.

I'm shooting RAW only, but I think the camera still generates a JPEG for display purposes and to embed in the RAW. Is this correct? If so, is the camera's histogram based on the JPEG or the RAW? That might explain why the camera thinks the highlights are clipped when in fact they're not.

:confused:


flickr (external link)

LOG IN TO REPLY
sponsored links
(this ad will go away when you log in as registered member)
pingflood
Member
247 posts
Joined Dec 2008
Mar 07, 2010 08:58 |  #2

Yes, you are absolutely correct; the JPEG is embedded and based on the camera settings; histogram is generated from that. If you lower the contrast on the camera settings you can usually get it closer to the "real" limits of the RAW though you'll still be able to recover some of the "blinkie" areas.


1DsII, 7D, EF 85/1.8, EF 50/1.4, EF 24-105L, EF 100-400L, EF 400/5.6L, EF 500/4L, Samyang 14/2.8, Zeiss ZE 50/1.4 Planar

LOG IN TO REPLY
bohdank
Cream of the Crop
bohdank's Avatar
14,060 posts
Joined Jan 2008
Montreal, Canada
Mar 07, 2010 09:13 |  #3

It's based on the JPG, hence the Picture Style. Other than Faithful/Nuetral, the other ones are all jacked in one way or another. If you are using the blinkies (I do) then set the camera to either of the 2 PS's I mentioned. I use Faithfull.

It's best to get it right, in camera, since there is only so much you can do in post. If any one channel is truly blown out, beyond recovery, you can still eliminate the Highlight Alert in post but if the color information is truly lost (255), all you will be doing is removing the alert but not recovering the color information since none is there.


Bohdan - I may be, and probably am, completely wrong.
Gear List

Montreal Concert, Event and Portrait Photographerexternal link
Flickrexternal link

LOG IN TO REPLY
pingflood
Member
247 posts
Joined Dec 2008
Mar 07, 2010 09:14 |  #4

bohdank wrote in post #9745421external link
It's based on the JPG, hence the Picture Style. Other than Faithful/Nuetral, the other ones are all jacked in one way or another. If you are using the blinkies (I do) then set the camera to either of the 2 PS's I mentioned. I use Faithfull.

It's best to get it right, in camera, since there is only so much you can do in post. If any one channel is truly blown out, beyond recovery, you can still eliminate the Highlight Alert in post but if the color information is truly lost (255), all you will be doing is removing the alert but not recovering the color information since none is there.

If you're looking to get the best possible raw image to work with, getting it "right, in camera" means pushing the boundaries a bit and having highlight alerts regardless of your jpeg settings. You're right that once it's blown it's blown, but there's a fair bit of headroom that you're missing out on if you shooting strictly within the jpeg parameters.


1DsII, 7D, EF 85/1.8, EF 50/1.4, EF 24-105L, EF 100-400L, EF 400/5.6L, EF 500/4L, Samyang 14/2.8, Zeiss ZE 50/1.4 Planar

LOG IN TO REPLY
Scott_online
THREAD ­ STARTER
Senior Member
Joined Aug 2009
Mar 07, 2010 09:21 |  #5

Thank you both.

I guess the trick is knowing just how much you can push it...


flickr (external link)

LOG IN TO REPLY
bohdank
Cream of the Crop
bohdank's Avatar
14,060 posts
Joined Jan 2008
Montreal, Canada
Mar 07, 2010 10:14 |  #6

pingflood wrote in post #9745426external link
If you're looking to get the best possible raw image to work with, getting it "right, in camera" means pushing the boundaries a bit and having highlight alerts regardless of your jpeg settings. You're right that once it's blown it's blown, but there's a fair bit of headroom that you're missing out on if you shooting strictly within the jpeg parameters.

Very true. I did not say that one must eliminate all blinkies incamera nor is it necessarily something you would want to do, depending on the shot and lighting but, with experience, one gets better at judging what is more important.

The more accurate your starting point (Faithful/Nuetral) , the better position one is in making an informed decision.


Bohdan - I may be, and probably am, completely wrong.
Gear List

Montreal Concert, Event and Portrait Photographerexternal link
Flickrexternal link

LOG IN TO REPLY
RDKirk
Adorama says I'm "packed."
RDKirk's Avatar
12,552 posts
Joined May 2004
USA
Mar 07, 2010 10:27 |  #7

Scott_online wrote in post #9745451external link
Thank you both.

I guess the trick is knowing just how much you can push it...

A bit of testing will tell you that.

Compare this in your testing as well with your camera set for the RBG histogram, rather than just the luminance histogram (the blinkies work with luminance, BTW). The RGB histogram will show you how and where some highlights blow out the predominant channel before blowing then all out--the luminance histogram (and the blinkies) only show you when all three channels are blown.

This is why skin highlights frequently go out of control. The red channel in skin tones blows out first before the blinkies make note of it, and you wind up with bald highlights when you know you should have had more headroom in raw than you saw on the luminance histogram or the blinkies. But if you close tight to, say, the forehead of the subject, the RGB histogram would show you that the red channel was clipping.

Now, you don't always (and can't always) zoom in on the subject's forehead to do an RGB histogram reading, but if you do some careful testing, you can determine how much "Kentucky windage" to give exposure in the common situations that you run in to.

One good thing about the old Zone System...at least you learned how to really test the capabilities of your tools, processes, and materials in a systematic manner.




LOG IN TO REPLY
tzalman
Fatal attraction.
tzalman's Avatar
13,377 posts
Joined Apr 2005
Gesher Haziv, Israel
Mar 07, 2010 10:43 |  #8

If I see blinkies I look at the green histogram. The sensor is more sensitive to green so in most lighting the green channel receives more exposure. (The exceptions are filtered light sources, like in a rock concert or a close-up of a rose where all the light entering the lens is reflected from the flower.) During the white balancing done to the embedded jpg the red and blue values are multiplied to bring them up to and beyond the green and this can trip the blinkies, but the green channel remains very close to its RAW level and in most situations if the green is not clipped the other two channels are not either.


Elie / אלי

LOG IN TO REPLY
MGH
Senior Member
MGH's Avatar
266 posts
Joined Jan 2010
Malaga,Spain
Mar 07, 2010 11:05 |  #9

Hi...If you always shoot RAW and you can live with a green cast to the camara display then use UniWB and a Nuetrel picture style.I have a Canon 500D and it works perfect.If you do not know what UniWB is There´s lots of info in this forum,do a search....


flickrexternal link

LOG IN TO REPLY
Erik_L
Goldmember
3,160 posts
Joined Oct 2009
Minnesota
Mar 07, 2010 11:32 |  #10

some good info in here. I just turned my blinkies on and switched to RGB histogram - was never sure of the benefit before reading this. This is especially useful when trying to get shots of my friend welding -

IMAGE NOT FOUND IMAGE IS A REDIRECT OR MISSING!
HTTP response: NOT FOUND | MIME changed to 'image/gif' | Redirected to error image by FLICKR


I over-exposed because most of the arc is "blown"

then again, it would look pretty stupid if you could see the wire hitting the metal - the illusion of "IMMENSE FLAME" would sortof be destroyed.

Canon EOS 1D III
Manfrotto 190X Pro B w/324RC2 "Action Head" | Canon 580EX II
Sigma 20 f/1.8 | Canon 35 f/1.4 L | Sigma 50 f/1.4 | Sigma 85 f/1.4 | Canon 135 f/2 L
Flickexternal linkr

LOG IN TO REPLY
sponsored links
(this ad will go away when you log in as registered member)

1,810 views & 0 likes for this thread
Questions re. Highlight Alert
FORUMS Canon Cameras, Lenses & Accessories Canon EOS Digital Cameras


Not a member yet? Click here to register to the forums.
Registered members get all the features: search, following threads, own gear list and ratings, likes, more forums, private messaging, thread follow, notifications, own gallery, settings, view hosted photos, own reviews and more...


AAA

Send feedback to staff    •   Jump to forum...    •   Rules    •   Index    •   New posts    •   RTAT    •   'Best of'    •   Gallery    •   Gear    •   Reviews    •   Polls

COOKIES DISCLAIMER: This website uses cookies to improve your user experience. By using this site, you agree to our use of cookies. Privacy policy and cookie usage info.

POWERED BY AMASS 1.4version 1.4
made in Finland
by Pekka Saarinen
for photography-on-the.net
Spent 0.00205 for 4 database queries.
PAGE COMPLETED IN 0.02s
Latest registered member is xeunskate
880 guests, 433 members online
Simultaneous users record so far is 6430, that happened on Dec 03, 2017