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DPChallenge Forums >> Out and About >> DPC Mentorship - Exposure Part II
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08/12/2005 05:53:24 PM · #1
Group: Exposure Part II
Mentor: Digital Quixote
Students: Britannica, sheapod, papagei, tolovemoon, jtf6agent, Zed Pobre, Tallbloke, buzzrock, armelle, pidge & warddp

This is a continuation of the Exposure Part I mentor group. See the month-long Part I mentoring journey here. Britannica and Zed Pobre have volunteered to help me mentor Part II.

NON-MEMBERS PLEASE READ, TOO:

0. Mentoring a group is a bit of work. I have the capacity and time to handle up to about 10 folks. If you want to join, just PM me and if we have room, you’re in. If not, I’ll keep a waiting list and let you know if someone drops out.

1. If you are not an active member of this mentorship group, please feel free to follow this thread. It is not intended to be exclusionary - we hope everyone can learn from it.

2. If you are not an active member of this group but have a question or comment, please send it directly to me by Private Message. I will either answer you directly or post your comment and its response to the thread. Thank you for understanding that we are trying to keep these groups small and on-topic.

3. Mentors are volunteers with jobs and/or families. They're human too, and may make mistakes on occasion. If you feel the burning need to criticize, point out a mistake, or point out your own infinitely greater knowledge in the subject, please do so in a PM to me, not in this thread.

4. Have fun learning!

Homage to David Simpson

The original idea for these mentor groups came from David Simpson (aboutimage). And he’s the one that got them going. Thanks David!

Message edited by author 2005-09-30 19:31:35.
08/14/2005 07:33:20 PM · #2
Okay, it's time to get started. First, please welcome Zeb Pobre, Tallbloke, buzzrock & armelle to our merry band. and thanks to those carrying over from Part I. Hopefully we'll all learn a lot (including me) and have some fun.

With a couple of exceptions, you all have cameras that shoot RAW and are using an advanced version of Photoshop (7 or above). I know that's not true for a couple of you. My intention is to cover RAW a bit later (so don't worry about it at this point), and I'll try to stick with photo-editing concepts that apply to most photo-editing software. However, I may use specific examples from Photoshop to illustrate (as I did in Part I).

Exercise 1a: I want you to take a photo of the subject of your choice. Do NOT shoot RAW. Now, using the software of your choice, prepare this photo for the web. Upload the original SOOTC and your edited version to your portfolio and show us the thumbnails here. In the Photographer's Comments of your edited photo, detail EVERY post processing step you took that modified any aspect of exposure. In this thread, along with your thumbnails, analyze your own edited photo's exposure ... likes, dislikes, thoughts about how you'd do it differently next time.
Exercise 1b: Examine the photos of each participant and add a comment to their edited photo. In your comment, critique the exposure as you see it and make one suggestion for a post processing improvement. I want you to get used to analyzing and commenting on exposure (from the perspective of post processing) and I want to loosen you up to the idea of articulating constructive suggestions for improvement. Remember to critique the photo's exposure, not the subject, composition or the photographer; and keep it respectful and constructive.
Deadline: End-of-Day (EOD) Thursday 18th August for both 1a and 1b.

Message edited by author 2005-08-15 12:04:40.
08/15/2005 03:08:06 PM · #3
Here are my 2 shots. Now mind you, I had to enter the Rain challenge with faked rain because we had none in over a month. Today it is raining! So here are some crabapples in the rain LOL

First is STOOC ---- then EDITED in PS


The exposure seems good from the getgo - the changes did not alter the overall appearance that much. Mainly, sharpening was an issue. The only thing I would do differently, is perhaps use a tripod. I did use auto WB, as I noticed the scene and just grabbed the camera. Thinking back now, I probably would have set the WB to cloudy.



Message edited by author 2005-08-16 02:11:00.
08/15/2005 04:39:46 PM · #4
Right here's mine

Original................................Edited



Looking forward to comments

I think the original photo looks abit flat even though the histogram is pretty good. I love the clouds and the bit of burning really helped them stand out. I would like to change the sea, it looks a bit sharp, would have been nice to have had a silkier appearance. I'd like to try again with a slower shutter since the boat wasn't moving too fast I think It would have worked.

Steve

Message edited by author 2005-08-16 17:04:01.
08/16/2005 09:18:37 AM · #5
Here's mine from the great sand dunes in Colorado (before and after PS)



I think the exposure was mostly OK with the original photo but it needed some extra lighting. The sand was too dark and the contrast not great enough... I desaturated a lot to enhance the contrast. In the end, after playing with PS, I had a hard time fixing the top left blown out sky corner and the bottom right dark sky blob :)

Armelle
08/16/2005 09:45:10 AM · #6
What a great "workshop." Congratulations! These are all very exciting photos!
08/18/2005 06:47:15 AM · #7

I think the exposure on the 2 is just about right, as far as enough light.I did not use flash wich may have helped to use fill flash in the dark shadows from my back drop..I like the second better but now that I look at again it could use a little brightness to it.
08/18/2005 02:18:10 PM · #8


For the most part, I'm happy with the exposure of the edited shot. I don't like the blown out highlights on his nose though. I used the flash because the paddock was pretty dark. Looking back on it, I should have used flash exposure compensation or simply dropped the power down a point or two.
-Laura
08/18/2005 08:44:35 PM · #9


Ok, so here's my re-edit based on the comments I've received so far from Steve and Zed. I tried to do a bit less tweaking as suggested. I really don't like the blocks of light on the right so I cropped even closer. How funny! My first crop was supposed to get rid of the lights on both sides but somehow I managed to leave a little bit. Pretty observant of me huh? Anyway, I completely avoided the curves adjustment this time. I'm really gonna have to learn to use it properly I guess. lol I don't have a shadow/highlight adjustment in PS 7, or if I do, I don't know where to find it so all I did was up the contrast +5.
Please let me know if you think this is any better. Thanks
- Laura
08/18/2005 09:02:39 PM · #10


Original on the left.
08/19/2005 01:12:56 AM · #11

original/edit
I am heading out of town tomorrow and will be back on Sunday. I may be able to get internet access, but I doubt it. I will pick up as soon as I get back.

Oh yes, and hi everyone!
Thanks in advance

Message edited by author 2005-08-19 01:16:51.
08/19/2005 08:22:57 PM · #12
Exercise 1 Recap
Well, we’re off to a good start. I wanted to get you into the mode of critique and comment and I wanted to see what you were comfortable doing in post processing. At the risk of writing down what you already know, we can begin to draw some lessons:
Lesson 1: Analyze your own photos and critique them as though someone else took them. Then respond to the negatives with post processing edits that minimize the negatives and accentuate the positives.
Lesson 2: Photoshop has powerful “auto” adjustments. I always try them because they are huge time savers, but I rarely keep them because I can get better results with manual adjustments. Don’t be embarrassed if they give you good results, but don’t be shy about undoing them and working manually.
Lesson 3: We have very powerful tools in Photoshop. A light touch with them is almost always better than a heavy hand. Remember each time you use them, something will be gained, but something else will be lost. Usually a light touch balances gains and losses best. If you feel a heavy hand is necessary, consider reshooting to get better exposure IN THE CAMERA.
Lesson 4: We’ll go into this more shortly but remember you can apply edits to a partial frame. Don’t think that only full frame adjustments are the best approach. Selective edits are legal at DPC in advanced editing; only full frame edits are legal in basic editing.
Lesson 5: It’s always best to start with a well exposed image SOOTC and edit from there. Don’t be reluctant to go back and reshoot … or if you won’t be able to, buy yourself exposure insurance using bracketing.
Lesson 6: Editing is a cumulative thing. Often the total is different from the sum of the parts. If you don’t like the results you’re getting, don’t be afraid to go back and start over.

By the way, I was impressed with all the edited photos you all submitted. Good job by all. I'm going to have to work hard to stay ahead of you!

Moving On
In the last exercise, I am wondering if you can tell me where post processing occurred. Your workflow went something like this: 1) Shoot the photo; 2) Upload to your PC; 3) Edit in Photoshop; 4) Save and upload to DPC portfolio; and 5) View on DPC site using your web browser.

Pop Quiz: Where in this work flow did post processing take place? Between the time you pressed the shutter and the time my eyes saw your photo, where were your image's exposure characteristics changed?

PM me with your answers … do not post them here.

Deadline: Sunday Evening, then we'll move along to exercise 2 early next week.

Message edited by author 2005-08-19 20:40:15.
08/22/2005 04:21:23 PM · #13
Pop Quiz Scores
I have most of your quiz results in and I have to admit, it was a bit of a trick question … but with a point. Remember I had asked you not to shoot RAW. And I posed the following workflow: 1) Shoot the photo; 2) Upload to your PC; 3) Edit in Photoshop; 4) Save and upload to DPC portfolio; and 5) View on DPC site using your web browser. Then I asked where post processing occurred. Only one of you really answered correctly saying, “Essentially in almost every step.

1) When I click the shutter, my camera’s sensor captures the light. Since we were not shooting RAW, two forms of post processing occur in the camera. Using my camera as an example … Firstly I had it set to adjust White Balance, do exposure compensation, optimize the image (Vivid), and do long-exposure noise reduction. Secondly, it does jpeg compression. And finally it writes the data to my film card. While this is post processing your camera does, it is still post processing you can control, it alters the light data your camera “saw,” and has the potential to impact your exposure.
2) When I upload to my PC, I am simply copying the photos to my PC’s hard disk. No changes should be occurring here.
3) When I edit in Photoshop, I may do a lot of exposure related post processing. This was the obvious right answer you all got correct.
4) If I use Save for Web to save a jpeg challenge entry, for example, Photoshop further compresses the data. With even minor compression, it is likely that colors will be altered, sometimes subtly, sometimes not so subtly.
5) When I upload to DPC, I am simply copying the photo to the DPC server. No changes should occur here.
6) When I view the photo on the web, my browser (Internet Explorer, Netscape, Firefox, Opera et al) assumes an sRGB color space was used. If you saved your photo using a different color space, the browser will do a color conversion which will impact the colors you see.
7) And finally, it is your monitor that displays your photo. The colors (and brightness and contrast) of your monitor depend on its calibration. If it isn’t calibrated correctly (including calibration for room light), the colors it displays will be altered by the monitor itself.

There are lots of forum threads along the lines of "Why does my picture look different (in my browser, on my PC at work, in Firefox, ...) than it did when I edited it in Photoshop?" 4, 6 and 7 are why!

I won’t belabor all these. We’ll spend some time on RAW conversion a little later. We’ll spend most of our time on Photoshop. And our next stop will be monitor calibration. Stay tuned.

Homework Assignment: But for now, while we are waiting for the next exercise, I’d like you to drag out your camera’s manual and identify all the menu settings which can change exposure in-the-camera between the time the light is captured and the time it is written to your film card. Take some pictures as you play with the various settings. And comment in this thread about what you’ve learned about your camera and its post processing. We must bond with our cameras. Be one with your camera!

Deadline: EOD Wednesday.

Message edited by author 2005-08-22 16:24:00.
08/22/2005 07:23:50 PM · #14
Well, I don't know if I will forgive you for pulling that trick on us LOL

1. Image recording quality - I can set it to 3504x2336 (8.2 million pixels), to 2544x1696 (4.3 mill), 1728x1152 (2 mill), or 3504x2336 RAW (8.2 mill).

2. Red-eye on/off
3. Auto Exposure Bracketing
4. WB Bracketing
5. Custom WB
6. Color temp
7. Color space
8. Custom parameters where I can set saturation, sharpening, contrast, & color tone.

9. Black & White - filter effects, contrast, toning, sharpness

The closer the image comes out of the camera to what you want, the better. I set up my parameters and settings as soon as I got the camera. So it is a good idea to explore the settings to see what you want.


08/24/2005 11:52:19 PM · #15
When shooting RAW, there are exactly five things that affect the exposure of the image data written to the card: aperture, shutter speed, flash power and timing (though flash technique is a complex enough subject to almost warrant its own mentorship program), ISO level, and whether or not long exposure compensation has been turned on. That's it. Control those values precisely, and you control the exposure completely. Describing all of the functions that change these things is a little problematic, however, since there are so many of them. Each of the manual ("creative zone") dial settings have different ways of setting them, locking down either the aperture, the shutter speed, the distance between them, setting everything automatically except for the exposure compensation, or forcing you to set every parameter manually. There are adjustments for metering, adjustments for the controls that control metering (custom function 4 tinkers with the way AE lock works, for instance, while custom function 6 changes whether EC shifts in one half or one third stop increments), adjustments for control of the flash sync speed or to set second curtain sync.

Shooting to jpg, the problem gets much, much worse, since there are a large number of post-processing options, from color filters to contrast/saturation shifts, to white balance options, to color space, and again, these get compounded by custom functions that actually change the way the interface works.

For all that, control of the output is remarkably poor compared to RAW passed through Photoshop, and the judgement of the Canon software often... sucks... so I use jpg only as a sort of improved preview mode (faster viewing on a computer, and if you shoot highest quality, better detail in the previewer in the camera, as the embedded jpg in the RAW data used for previewing is always taken at the lowest setting).

If you really want me to go through and document every 20D setting that could affect exposure and how and why, you'll need to give me at least through the weekend, and be prepared to read something longer than the manual itself. That's kind of an evil question you asked, if you don't mind my saying so, and I just don't have time to answer it by tonight, I'm afraid.

One hidden gotcha that *isn't* covered in the manual that I should note here is that ISO3200 (enabled by C.Fn8) isn't actually a real mode: all it does is set the gain for ISO1600, meter for ISO3200, and then double the values off the sensor mathematically, interleaving odd and even values. It is useful exactly for two things: shooting straight to jpg, and when you want to expose for a precise value between -2 and -3 EC against the internal meter (since one way to look at it is that it's ISO1600 shot at -1 EC with clipped highlights). It isn't documented anywhere, but you can confirm it by looking at your own RAW data by hand or with IRIS.

Incidentally, the Nikon DSLRs have the same behaviour for ISO1600 *and* ISO3200, IIRC... except that one of them (I forget the model) has an ISO3200 that's actually a 1600 gain x2, as opposed to an 800 gain x4, so there's some value in using it for the extra gain, as long as you realize that it's basically forcing you to underexpose by a stop.
08/26/2005 08:56:07 PM · #16
Well, lame answer, but I've learned the white balance settings for my PnS are much different than my dslr.

Lots of other things have already been mentioned as well.

Am finally starting to shoot raw. Shooting jpeg because I was 'comfortable' with it, but I know I need to learn to shoot raw

Cheers
Edit: Gone for the weekend again. Have a good one everyone

Message edited by author 2005-08-26 20:56:32.
08/31/2005 02:35:58 PM · #17
edit: sorry double post

Message edited by author 2005-08-31 14:39:34.
08/31/2005 02:38:55 PM · #18
Well there are loads of different parameters availble to fiddle about with on the 350D

THe parameters contrast, sharpness, saturation and colour tone are all variable on a five point slider (3 being middle) and savable as your own settings.

I must admit I havent fiddled about with this much at all prefering to shoot mostly in RAW and do the fiddling later. Just downloaded "RAWshooter Essentials" which is way better that the supplied "Digial Photo Professional" RAW conversion programmethat that came with the camera.

The one thing I'm looking for advice about though is colour space..should I be shooting in AdobeRGB or sRGB? or which for the web and which for prints?

White balance is still a bit of a mystery too and I havent tried custom balance effectively either, again all this is normally sorted out in the RAW software

One new thing I did discover is that colours are recored more accurately in the lower ISO range....but again all that can be sorted out later with RAW.

In short, I love RAW and use it 99% of the time.

Steve
08/31/2005 02:43:49 PM · #19
Next Exercise
It is a fact of photo-editing life … you can only edit what you see. How can you tell if what you are seeing on your monitor when you edit is “real?” How can you tell if a photo you are voting on is just as the photographer intended? One way to be sure is to calibrate the monitor you use to edit your photos and view/vote on DPC photos.

Thought Experiment: Imagine you turn down the brightness of your monitor So the dark half of the histogram all looks black to you. Every photo you edit will appear too dark. As an editor, you will brighten up the photos until you get good levels and contrast on your now-too-dark-monitor. Post them to DPC and what I will see with my normal monitor settings is a blown out photo. Whose fault is it? Your monitor’s fault. Remember to re-adjust your monitor!

The only way to get predictably good editing results with Photoshop (or any editing software for that matter)is to calibrate your monitor. Here are a few DPC threads on the topic:
Monitor Calibration
New Monitor
Calibrate Your Monitors
I Still Can't Calibrate My Monitor
Standard For Calibration

There are two fundamental calibration processes: Software only; and Hardware/software.

Using software only, it is possible to calibrate your monitor so that brightness and contrast show distinct levels of white and distinct levels of black. It is also possible to calibrate your monitor’s color temperature so colors are right. Adobe Gamma comes with Photoshop and is a good solution. And here are a few links related to software calibration.
epp Monitor Calibration
Photoscientia
Dry Creek Photo
In each of these cases, the software makes certain assumptions about your monitor, about its age, and the fidelity of colors it is capable of. The sad truth is that these assumptions are all approximately right but precisely wrong. In order to calibrate you monitor precisely, you also need a hardware device (colorimeter) to measure the light your monitor produces plus software to then adjust your monitor’s settings. Here are some links to hardware solutions.
ColorVision & DPReview
Colourvision
Computer Darkroom
Color Gear - Monaco Optix XR & Pro
Color Gear - Eye-One Display 2
MDIUSA

I know this seems like a pain in the neck, but now is the time to calibrate your monitor! And remember, your view of your monitor changes with the ambient light in the room where your computer is. I have monitor settings for Dark; Morning sun; Morning clouds; Afternoon sun; and afternoon clouds.

Exercises:
1. Actually carry out the thought experiment above and share your results here in this thread. (Optional)
2. Edit a photo at night with all the lights out in the room. Edit the same photo separately during the day in a bright room (lights plus bright ambient light). Now look at both edited photos side by side and note the differences. Record your photos and observations here.
3. Calibrate your monitor using at a minimum a software-based approach. Okay to use a hardware based approach but optional.
Deadline: Wednesday 7th September.

Message edited by author 2005-08-31 15:00:39.
08/31/2005 04:09:47 PM · #20
One other link that I like for monitor calibration, since it provides color bars:

//pages.prodigy.net/ecmorris/tips/monitor.htm

I went ahead and did a quick try of (1), and immediately drove myself nuts squinting at the menus. I'll go back and try again later when I'm a little calmer. (2) isn't really possible for me, as the room is a dark one, with the windows blocked, but I can try playing with local lighting to see what it does to me. (3) was done a long time ago.
08/31/2005 04:29:36 PM · #21
Originally posted by Tallbloke:

The one thing I'm looking for advice about though is colour space..should I be shooting in AdobeRGB or sRGB? or which for the web and which for prints?

Really short (and slightly wrong) answer: AdobeRGB for prints, and sRGB for monitors. Shoot AdobeRGB in the camera by default, but convert any images that will be displayed only on the web to sRGB for editing.

The longer answer to this gets very, very complex. If you're shooting for raw and always post-processing, it doesn't matter greatly what you shoot in the camera. You lose more information going from sRGB to Adobe than vice versa (and actually, once you have converted to sRGB, there is almost no point in switching back, as you have just permanently discarded most of the extra color information you would want to use)... but you don't lose anything extra in that first import stage in RAW, no matter what you shot in, because it's less a conversion than it is an assignment of initial values. You want to do most of your color editing in whatever your final color space will be... unless you are expecting that you might get print requests based on images displayed on monitors, and don't want to go back and retouch, in which case you want to just leave everything in AdobeRGB, since other people's monitors are mostly hopeless, but print quality is the ultimate measure. Editing an image so that it looks normal in AdobeRGB may cause it to look slightly unsaturated on a monitor not calibrated specifically for it. Photoshop CS2 also has a preview colorspace translation function you can play with, IIRC.

If this sounds confusing, it's because it is. Colorspace management is something that even a lot of professional photographers seem to have only a passing understanding of.

Originally posted by Tallbloke:

White balance is still a bit of a mystery too and I havent tried custom balance effectively either, again all this is normally sorted out in the RAW software

Pre-setting white balance take a lot of experience in recognizing types of light, or time spent with calibration cards before shooting in each light type. As you noted, it doesn't really matter for RAW shooting. There are really two common techniques for dealing with it in RAW: letting the camera decide on its own (AWB), so your previews look mostly correct and you only have to tweak a little during import, or locking the white balance at a single value, and using the resulting jpg as a permanent record of exactly what light was there for your own reference. I know of one person who forcibly sets white balance to something ridiculously low (2600K+0?) so *all* of his preview images look downright weird... but they look uniquely downright weird for every color temperature there was, so he can tell immediately upon review exactly what the lighting situation was to help him tweak his RAW.

Originally posted by Tallbloke:

One new thing I did discover is that colours are recored more accurately in the lower ISO range....but again all that can be sorted out later with RAW.

Now that is weird, and something I haven't observed on my 20D, though I have noticed that the AWB is biased towards green, so I have as a default step on all of my images a -2 hue shift of the red channel. What's the bias you're seeing, and at what ISO does it become visible?

Message edited by author 2005-08-31 16:33:05.
08/31/2005 04:30:29 PM · #22
I went to //www.epaperpress.com/monitorcal/index.html and thankfully saw all the distinguishing shades.

Tried the Adobe Gamma, but have no clue how to adjust contrast, etc on my laptop (that's what I use). Nevermind the part of doing all this with NO ambient light??

Cannot afford the hardware, so I'll just make do :)
08/31/2005 04:34:32 PM · #23
Originally posted by papagei:

I went to //www.epaperpress.com/monitorcal/index.html and thankfully saw all the distinguishing shades.

Tried the Adobe Gamma, but have no clue how to adjust contrast, etc on my laptop (that's what I use). Nevermind the part of doing all this with NO ambient light??

Cannot afford the hardware, so I'll just make do :)

If it's a laptop, take it into the bathroom and close the door. Double-check your power-saving settings, though, because laptops have *three* settings, where monitors have two: brightness, contrast, and power intensity. A lot of systems will dim the display to half power for standard power saving unless you override this behaviour somewhere.
09/01/2005 10:12:11 AM · #24
Thanks for all the advice on monitor calibration. I wish I could add useful information as well. The linked sites are great.

I most often use a laptop and I have only recently paid attention to the monitor after a few of my photos were deemed too dark for voters...

Can't wait to try the with/without light edit!
09/04/2005 02:35:56 PM · #25
I use a dual monitor set-up with my home PC

I calibrated each monitor with Adobe Gamma as best as possible in the same lighting condition but there is still a slight difference of "look" with each monitor.

I check my PP on each monitor and use this slight diffence to double check my edits.

Steve
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