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07/24/2005 08:15:17 PM · #76
Originally posted by tolovemoon:

{snip} ...
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Tracy, I waited to comment on yours, even though it was first in (Way to go!!!), beacuse I wanted to make a specific point with your images. It is interesting to me that your 4 images, as the exposure changes, create very different photos with different subjects of interest. You can see this at the thumnail level without even opening the images.
Lesson 1: As EV Comp changes from lighter to darker, my eye is drawn to different parts of the photo. In your lightest photo I am drawn to the golden macaroni in the top plate. In the 3rd photo my eye is drawn to the lovely shadows due to the texture of the plate. In the final photo my eye is drawn to the shape of the plates and how the circles overlap. This is a high contrast photo so EV comp creates a little different effect on different parts of the photo.
Lesson 2: Then to repeat a previous conclusion ... the best exposure includes the idea of preserving light data combined with the idea of your purpose for the photo and what part of the photo you intend to use.

And you all have drawn a couple of important conclusions ... Read the manual; Learn your camera; Develop a personal workflow designed to give you good exposure; Bond with your camera, Grasshopper.

Message edited by author 2005-07-24 20:30:39.
07/25/2005 05:45:21 AM · #77
Originally posted by Digital Quixote:

Wow David, this is terrific! You've gone over and above the call of duty here. You make me proud! I am pleased you included in your post how you did it. Worth reading and learning from. As with the others, let me draw a few lessons from this.

Lesson 1: The greater the bracket interval size, the greater will be the variation in exposure across the bracket. When the EV interval is 1, it goes from pretty white to pretty dark. When it's 1/3 the gradations are more subtle. With many cameras, you can choose the interval size. So choose it to fit how you work and the "spread" you're after.
Lesson 2: Note that the middle row of images are exactly the same. Why? Because they are all exposed at EV +0 ... i.e. no EV Comp adjustment at all. Logical, right?

So, Oh Wise One, what's the best exposure? Beats me.

Lesson 3: One way to think about it is to ask in which exposures has David a) achieved good tonal range; b) created no blown highlights; c) lost no blacks? These are probably good candidates for best exposed.
Lesson 4: Another way to think about it relates to how David would crop the image. If he cropped each of his 15 photos according to his purpose for the photo, one of those crops will be "best" according to a, b, & c above.

There may be other subtle factors in choosing the best. But here's the real lesson for bracketing EV Comp ...

Lesson 5: Using EV Comp in the first place, and bracketing around your best metering method EV 0 will buy you insurance that you'll get at least one good one. Then let the games begin in Photoshop. With that best exposed original, you will have seized the high ground in your battle for a ribbon!

Since I didn't remember to mention what I learned in this exercise, I'll mention what I've learned from playing with the images since posting (and reading this response).

The dynamic range of the scene was very small -- which I believe was the result of the low light on the scene. At just over 2 stops from the darkest to the lightest there are many exposures that capture the entire range. I was curious to see if any of these exposures were significantly better than the others. The first thing I did was to use Levels expand the dynamic range of each image to the full range of tones available by pulling the left and right sliders inward to the base of the 'humps'. This had the result of nearly eliminating the differences in brightness between those that I tried -- with the little difference in brightness that remained easily eliminated by adjusting the middle slider a bit.

From this I learned two things:
One is that the further away the tone of the image I was working on was from the one I was matching it to (EV 0 in this case) the more I had to play with it to get it where I wanted it. The more done the more detail seemed to be lost -- probably not a significant amount, but I did notice it since I was looking for it.

The other think I learned is that as long as there was no clipping on the high or low side it didn't matter tone-wise, how dark or light it was exposed at. That is not a contridiction of the above since the loss of detail I mentioned is not related to the tones of the image, but was likely the result of having to do more to the image to change the tones.

The next thing I wanted to mention has to do with the color balance of the image. The camera I use has 4 preset WB settings; sunlight, overcast, incadescent, florescent -- which seem to have always being off color in common with each other. It also has an auto WB option, but not a custom WB that I can set. The auto WB is set against whatever the meter reads to set the exposure, and neither is changable without loosing the other. The end result is that if I expose against anything other than white, grey or black the image will have a color shift of some form or another.

As always, I forget something while taking the pics -- this time it was this bit about WB. I should have metered against my grey card and adjusted from there to what I wanted to be the middle of the bracket. With hindsight I went ahead and metered the grey card in the same light and compared the result with the notes I made during the shoot. The grey card is -2/3 stop from the middle of the bracket I choose. So, if I'm keeping this all straight, I should have set EV +2/3, metered the grey card and locked the exposure and WB from that -- then manually bracketed from there. I could have saved myself the dingy color cast that is keeping the white plate from looking white.

Keeping notes is already coming in handy for referring back to. :D

The colorcast can be considered minor, since it is fairly easy to fix; but I need to remember to do everything possible during the shoot so I don't have to fix it in PS later. But, I've heard it said an expert is someone who has made all the mistakes, so I'm at least one step closer. :p

David
07/25/2005 11:48:21 AM · #78
Sorry I'm so late... I've actually had these on my computer since Wednesday (I think), just had forgotten to upload them :(.

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07/25/2005 01:14:54 PM · #79
Originally posted by cpickett:

Sorry I'm so late... I've actually had these on my computer since Wednesday (I think), just had forgotten to upload them :(.
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Thanks Chris for posting these. They too do a nice job of illustrating what we are doing here. I am about out of lessons on this exercise but would ask you to look at my prior posts and then think about what you've learned about EV Comp, Bracketing and your camera that you will build into your personal photo workflow.
07/25/2005 02:31:27 PM · #80
Okay, time to move along.
Over the course of our time together, several of you have said you shoot in Auto mode and several have said you shoot in Manual mode. Those shooting in Auto have expressed dissatisfaction with the exposure you get. Those shooting Manual have complained you don’t have enough time to get your shot set up. Let’s do something about both of these issues and get good exposure in the bargain.

On my D70, I have several auto modes (Auto, Portrait, Landscape, Macro, Sports, Night and Backlit). Your camera will have one, and maybe more, of these. They all calculate incoming light using “some” metering mode, and calculate how to set ISO, Aperture, Shutter Speed, Focus and Flash to give you a “good” picture. The various flavors of Auto have various preferences for the settings depending on the subject you choose, but they’re still setting all the options using a program running on the camera’s computer. You may want to review these in your camera's manual, but that strictly optional for now.

In my case, that program was written by an engineer at Nikon. Now why would I let an engineer at Nikon set up my camera for a shot? He’s not even here! Well it’s fine if you want a quick snap, I guess, but we’re photographers. Let’s see if we can do better!

I also have a Manual mode where I have to set everything before I click the shutter. That means I set ISO, Aperture, Shutter, White Balance, Compose the shot, Focus … and finally Click. That is a lot to get done. I simply can’t do it all on any but the most static set shot.

Among us we are shooting Nikon D70, Canon 300D and 20D, Olympus C-720UZ, Fuji Finepix s3100 and Panasonic DMC-FZ20 (and maybe a few more) cameras. They are all a little different in their shooting modes, and ranges of ISO, Aperture, Shutter Speed but the concepts we’ll cover will apply to all and all the cameras will be up to our next exercises.

In our next few exercises, we are going to divorce the Auto modes and the Manual mode and explore the degrees of freedom we have to control exposure. I will start with ISO, then move on to Aperture, Shutter Speed and may get to a special case (White Balance) if you want.

Each degree of freedom has a dark side; an unintended consequence; a side effect that we’ll have to manage. Don’t worry, this will be fun!


Look for Exercise 4 shortly, he said, buying a little time to come up with the exercise.

Message edited by author 2005-07-27 19:09:22.
07/25/2005 05:02:39 PM · #81
Exposure Degrees of Freedom – ISO
One of the things that influence exposure in a film camera is the sensitivity of the film. Very sensitive film needs only a little light to make an image. Less sensitive film needs more light. Depending on how brightly lit your subject is, you would choose more or less sensitive film. The same is true of Digital but our sensor replaces the film and we refer to the sensitivity of the sensor. And unlike film, we can set sensor sensitivity dynamically in the camera shot-by-shot. We do this by adjusting ISO.

In order to record enough light to form a well exposed image … one thing we can do is choose the ISO … higher in a very dark setting. Lower in a very bright setting. I know we can change other stuff and we’ll get to that in future lessons, so go with the flow, okay?

My D70 goes from ISO 200 to 1600. Different cameras will have a different lower bound (100 for Canon, 80 for others) or a different upper bound (3200 for Canon, I think, and 400 or 800 for others.) If I choose a very high ISO for a brightly lit scene, I may over expose the image. A more common problem is choosing a very low ISO for a dark scene, in which case I may not be able to get enough light into the camera and the image will be under exposed. Okay so far? So the trick is to choose just the right ISO … something you will learn to do as you take more and more pictures, read your manual, and bond with your camera.

As I said in my previous post, there is a dark side to this degree of freedom. The higher the ISO, the more grain (noise) is recorded in the image. Too much grain may spoil the image. Look at the (admittedly uninteresting) picture below. I shot this on purpose to emphasize the issue of grain. It is SOOTC.
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Now look closely at a 100% crop at ISO 200, 800, and 1600. You will have to click on the thumbnails. See how the grain increases with the ISO? See how the three are almost identically exposed?
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Clearly my best strategy for good image quality is to choose the lowest ISO I can get away with. And having done that, if I still have unwanted grain, I can try to fix it in Photoshop or with noise reduction tools like Neat Image, Noise Ninja, or others.

Exercise 4 ISO
Part a: Study the 3 100% crops and make sure you understand the relationship between ISO and grain (or noise).
Part b: If necessary, drag out your manual and determine what the ISO limits are for your camera and how to set them.
Part c: Set your camera to Aperture Priority, Auto Focus, Manual ISO and shoot a 3 frame, well exposed, study of the impact of ISO but do NOT use your flash. A tripod will make this easier, but isn't a requirement. Post 100% crops of each of the three here along with what you’ve learned and how this will influence you photo work flow.
Optional Part d: If you have noise reduction software available, take the noisiest of the 3 and try to fix the noise. Post your results here with your personal lessons learned.
Deadline: Let’s try to complete this by end-of-day Wednesday.

Message edited by author 2005-07-25 17:23:52.
07/25/2005 06:52:14 PM · #82
This is kind of extra to recap 1,2 and 3 exercises....
OK for me to understand EV exposure or bracketing, last night I tried some more shots of my son... Wich manually I can bracket. My camera doesnt take the shots of 3 or more for assurance... Unless I have read my manual wrong.. Anyways yall dont have to comment on these unless you want too.. I just thought I share becasue I thought they were rather good with the explanation of how I took them..

Something else though I am wondering....On my 35 mm film slr camera its a digital in a sense it gives me warnings too when something isnt right with the settings.. I get them a lot.. specially in dark situations..Does this mean its sord of bracketing for my assurance.. Maybe a silly question I am just curious...Everyone has a wide range of light colors like in their images and that I am sure to the difference of cameras and light. So what if an area is so poorly lit and we all were shooting there at the same time using the same settings would the images everyone took still be different.. ? I could probably answer this but wanted assurance....:) ' . substr('//images.dpchallenge.com/images_portfolio/9581/thumb/208916.jpg', strrpos('//images.dpchallenge.com/images_portfolio/9581/thumb/208916.jpg', '/') + 1) . '' . substr('//images.dpchallenge.com/images_portfolio/9581/thumb/208887.jpg', strrpos('//images.dpchallenge.com/images_portfolio/9581/thumb/208887.jpg', '/') + 1) . '' . substr('//images.dpchallenge.com/images_portfolio/9581/thumb/208889.jpg', strrpos('//images.dpchallenge.com/images_portfolio/9581/thumb/208889.jpg', '/') + 1) . '' . substr('//images.dpchallenge.com/images_portfolio/9581/thumb/208890.jpg', strrpos('//images.dpchallenge.com/images_portfolio/9581/thumb/208890.jpg', '/') + 1) . '
07/25/2005 10:30:16 PM · #83
Originally posted by sheapod:

bcoble
I also posted this on your evaluative metering shot but I wanted to make sure you received it so I'm copying it here. You may already have this information. If so...disregard. :-)

The FZ20 does allow you to see the histogram. In fact, unlike the dslr's you can see a real time histogram and know before you even press the shutter what the exposure is going to be. The FZ20 is my back up camera and from my experience with it, I always had to have the EV Comp set about 2/3 under to yield good results. Also, if this is a frequent problem you might try the lens hood that came with the camera.(If you can find it that is. It took me hours to locate mine.) It blocks out a lot of light. I still have my manual so if there are any questions you'd like answered feel free to PM me or post in the thread. If I know the answer I'll tell you, if I don't...I'll look it up! :-)
-Laura


Thank you very much.
07/26/2005 02:30:27 PM · #84
Exercise 4:

First, an apology for not completing the assignment as given -- the shutter speed on my camera will only go up to 1/30sec in Aperture priority and I needed much longer with the lighting I had available.

The setup is the same as the previous exercise, same plate (saucer) and counter as well. I didn't have an egg so used a cup and spoon instead -- you didn't specifically say to use an egg, but it sounded interesting. The lighting is still to my right and behind. I didn't place a white paper behind it this time as the reflections were not bad.

I kept getting a shift in WB depending with each half-press of the button, so I metered a grey card and locked the exposure and WB against it, then flipped over to manual mode to adjust the exposure while keeping the WB locked. At least the shifts are all equally off now. The cup, saucer and spoon should be white and the counter should be grey, but everything is brown. :( Anyway, bracketing 1/3 stop around the grey-card reading I ended up using the center bracket.

To duplicate the Aperture priority as best I could under the conditions, I set the aperture to f4.5 and adjusted the shutter speed to compensate for the change in ISO.

Resize only (ISO: 100, 200, 400)
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100% crop (ISO: 100, 200, 400)
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What I learned:

Stay at ISO100! I know, it's a matter of taste, but to me digital noise is just plain ugly.

My camera's settings are not exact. There should be no difference in tone between the three images, but the higher the ISO, the darker the image. But I don't know which is off, the ISO or the shutter speed as both are adjusted for each image -- either the ISO is slightly less than 1 stop more sensitive at each step or the shutter speed is slightly more than 1 stop faster or both. :(

I'll work on ISO400 when I get home from work and see what I can do with it -- but I'm also going to work on ISO100 because I like this pic and want to see what I can do with it. :p

Added (7/27/5): I worked with the ISO400 image in PS last night. In the process of working with it I developed what has become my newest noise reduction workflow -- basic steps are to extract the noise for each channel to a seperate layer and then use that layer to remove the noise from the original. What follows is my first attempt. While it did a good job, I was a bit sloppy in a number of things and will have to get better at controlling it. As it is, I think I went overboard on some of it.

ISO400 (original, noise reduced):
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100% Crop (original, noise reduced):
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Ignore the color cast on both the original and the noise reduced versions -- I did no color correction on either and it shows. :D

David

Message edited by author 2005-07-27 15:21:17.
07/26/2005 03:50:35 PM · #85
I originally shot all the ISOs I had: 100,200,400,800,1600,3200. I am posting these three: 200, 800, 3200

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I grabbed these shots early today before the rain came. My sweet, but pesty dog, was under the bush and kept jostling it, so it is not as sharp as it should be (I was using a tripod, but shutter was slow at 100ISO).

Oh, there is that relationship between ISO and shutter speed. You will have noticed that it increases (is faster) as the ISO rises, assuming the aperture value is the same.

I do not like to go over ISO400 and avoid it at all costs! Of course, the higher the ISO number, the noisier it is. This would be far more noticeable on a solid color. If you are planning to resize an image much smaller, then you could get away with the highter ISO as the noise will not be so noticeable. On the flip side, if you plan to crop and enlarge a portion of your image, keep that ISO low!

End of my contribution :)


07/27/2005 06:07:12 PM · #86
Originally posted by tolovemoon:

This is kind of extra to recap 1,2 and 3 exercises....
OK for me to understand EV exposure or bracketing, last night I tried some more shots of my son... Wich manually I can bracket. My camera doesnt take the shots of 3 or more for assurance... Unless I have read my manual wrong.. Anyways yall dont have to comment on these unless you want too.. I just thought I share becasue I thought they were rather good with the explanation of how I took them..

Something else though I am wondering....On my 35 mm film slr camera its a digital in a sense it gives me warnings too when something isnt right with the settings.. I get them a lot.. specially in dark situations..Does this mean its sord of bracketing for my assurance.. Maybe a silly question I am just curious...Everyone has a wide range of light colors like in their images and that I am sure to the difference of cameras and light. So what if an area is so poorly lit and we all were shooting there at the same time using the same settings would the images everyone took still be different.. ? I could probably answer this but wanted assurance....:)
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Tracy, you said something in your post I'd like to reiterate and that related to film. All the things we have been learning about exposure apply to film, too. But unlike digital, film gives you no instant feedback. No real time histogram. Limited ability to vary ASA (ISO) shot-by-shot. So the notion of buying insurance by bracketing may be even more important in film.

No your film camera isn't bracketing when it gives you the warnings. It is programatically analyzing the light compared to the camera settings and warning you about issues in the exposure. You can adjust one or more of your degrees of freedom tuntil it stops warning you. Your exposure will probably be better if you.

Left comments on the photos.

Message edited by author 2005-07-27 19:05:55.
07/27/2005 06:41:36 PM · #87
Originally posted by Britannica:

Exercise 4:
Resize only (ISO: 100, 200, 400)
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100% crop (ISO: 100, 200, 400)
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What I learned:

Stay at ISO100! I know, it's a matter of taste, but to me digital noise is just plain ugly.

ISO400 (original, noise reduced):
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100% Crop (original, noise reduced):
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David, firstly I am impressed with your "scientific method" of investigating our exercises. We all are learning from you here.

Second, let me make a coupld of additional points:

1) You will notice in the full size image the noise (grain) isn't as noticable as it is in a 100% crop. This gives us a hint about when to avoid high ISO. If you intend to use the whole frame, noise will be less of a factor than if you intend to crop severly. In other words, the more of the frame you use, the higher the ISO you can "get away with."

2) Digital tends to be noiser than film. If you have not invested in noise reduction software and want to shoot higher ISOs, you should run (not walk) to get a noise reduction capability for your photo editing suite. Photoshop CS/CS2 has a noise reduction capability built in. Third party vendors offer well integrated noise tools such as Neat Image (my choice) and Noise Ninja. (Google Digital Noise Reduction for more options.) And you can reduce noise by using multiple layers and gaussian blur. In your post processing workflow, you should always evaluate the need for noise reduction just as you would evaluate the need for sharpening. But go easy on the noise reduction. It's easy to overdue it.

In my "At the Zoo" photo, I was shooting (center-weighted metering) at ISO 800 and a pretty open lens in order to push my shutter speed to stop motion. You can clearly see the grain in the full frame image. The submitted photo represents a very severe crop. Noise reduction saved my butt!
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Pardon the shameless self-promotion!

Message edited by author 2005-07-27 19:03:34.
07/27/2005 06:55:19 PM · #88
Originally posted by papagei:

I originally shot all the ISOs I had: 100,200,400,800,1600,3200. I am posting these three: 200, 800, 3200

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I grabbed these shots early today before the rain came. My sweet, but pesty dog, was under the bush and kept jostling it, so it is not as sharp as it should be (I was using a tripod, but shutter was slow at 100ISO).

Oh, there is that relationship between ISO and shutter speed. You will have noticed that it increases (is faster) as the ISO rises, assuming the aperture value is the same.

I do not like to go over ISO400 and avoid it at all costs! Of course, the higher the ISO number, the noisier it is. This would be far more noticeable on a solid color. If you are planning to resize an image much smaller, then you could get away with the highter ISO as the noise will not be so noticeable. On the flip side, if you plan to crop and enlarge a portion of your image, keep that ISO low!

End of my contribution :)


Ingrid, thanks for posting these and for posting all the way up to ISO 3200. You all will notice that the amount of grain will vary not only with ISO but also with the camera. My Nikon (sadly) is noisier than Ingrid's Canon. So as you bond with your camera, some of our lessons will need to be adapted to the ideosyncracies of your particular camera.

Also thanks for making the point that your tolerance for high ISO will vary with your intentions for your picture. Resizing, cropping et al will emphasize or de-emphasize the noise.

In the set up for this exercise, I said there is a dark side to every degree of freedom related to exposure. I cited noise (grain) as the dark side of ISO. Ingrid correctly points out that shutter speed will also vary if you keep the same aperture. I'd like you to think about whether, if, or when shutter speed might be a dark side of adjusting ISO. No need to post your conclusions here. I have an exercise in mind that will explore this. But think about it.

Are we having fun yet?

Message edited by author 2005-07-27 18:56:58.
07/27/2005 07:16:44 PM · #89
I am sorry, I have been trying to figure this out the last 2 days about ISO changes in my camera. I am going to be a little late on the exercise, please dont let me hold anyone up I will catch up as soon as I understand the functions on this camera and do this exercise right...
The ISO available in my camera is
(As stated in a review..manual says nothing about ISO)Light sensitivity is nominally rated as equivalent to ISO 100, and is not adjustable. However, the manual states that the sensitivity will be automatically adjusted from 64 to 250 ISO equivalents as the shooting conditions dictate. When shooting in Manual exposure mode, exposure compensation is adjustable from -2.1 to +1.5 exposure equivalents (EV) in one-third-step increments.)

I have managed to only take 1 photo and have the ISO change.. So I am going to try what I did with the EV in the last assignment.... Any suggestions would be appreciative......
I am also using my Canon with this experiment it does change ISO..so I will have a good example to see what ISO does when I get my prints back hopefully by the weekend.....

Thank you Charles for answering my question and for all the comments on my photos as well as everyone else they really help and it confirms my knoweledge that is sinking in about all of this...
07/27/2005 09:55:30 PM · #90
These are my four photo's
Iso 80, 100, 200 and 400

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I seem to like the iso at 80 the best.


Message edited by author 2005-07-27 21:57:42.
07/27/2005 10:46:39 PM · #91
Exercise 4
ISO is one of the few controls I've learned to keep an eye on so I've already realized I don't want to go above 400 - or 800 if I'm really desperate. From what I've read, the 20d is one of the better dslr's for low noise at higher ISO's, but I don't usually like the results. Neat Image has saved me lots of times though.
I noticed that Ingrid shot at 200, 800 and 3200 with her 20d so I opted to shoot at 100, 400 and 1600 with mine.
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The noise is very noticable, especially on the left hand side, at ISO 1600.
This is the 1600 shot ran through Neat Image. The noise level has been reduced (at least to my eyes) back to the level of the ISO 100 shot.
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Message edited by author 2005-07-28 16:59:17.
07/28/2005 03:07:42 PM · #92
Originally posted by tolovemoon:

I am sorry, I have been trying to figure this out the last 2 days about ISO changes in my camera. I am going to be a little late on the exercise, please dont let me hold anyone up I will catch up as soon as I understand the functions on this camera and do this exercise right...
The ISO available in my camera is
(As stated in a review..manual says nothing about ISO)Light sensitivity is nominally rated as equivalent to ISO 100, and is not adjustable. However, the manual states that the sensitivity will be automatically adjusted from 64 to 250 ISO equivalents as the shooting conditions dictate. When shooting in Manual exposure mode, exposure compensation is adjustable from -2.1 to +1.5 exposure equivalents (EV) in one-third-step increments.)

I have managed to only take 1 photo and have the ISO change.. So I am going to try what I did with the EV in the last assignment.... Any suggestions would be appreciative......
I am also using my Canon with this experiment it does change ISO..so I will have a good example to see what ISO does when I get my prints back hopefully by the weekend.....

Thank you Charles for answering my question and for all the comments on my photos as well as everyone else they really help and it confirms my knoweledge that is sinking in about all of this...


Tracy, don't sweat it. Not all cameras have all the same settings as others. If you can't choose ISO except by varying EV Comp, then just be aware that by changing EV Comp on your camera you may be pushing up ISO with a possible side effect of added noise (Grain). I am about to post the next exercise, which I think you'll enjoy.
07/28/2005 03:29:28 PM · #93
Originally posted by bcoble:

These are my four photo's: Iso 80, 100, 200 and 400
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I seem to like the iso at 80 the best.

Bill, I agree. There is noticably less grain on your 80 than the others.

For all: Entirely optional extra credit exercise. Try printing a 100% crop of a low ISO and a high ISO photo. We have seen there is a clear difference on the screen. What do you see on paper? When you print it, try to use a good quality photo printer or print it at Costco, Wallmart, DPC or other. I live 15 minutes from a Costco. I can log on to their website, upload a picture and pick it up in an hour. Did this a few weeks ago to print passport pictures. Total cost was $0.36.
07/28/2005 03:42:06 PM · #94
Originally posted by sheapod:

Exercise 4
ISO is one of the few controls I've learned to keep an eye on so I've already realized I don't want to go above 400 - or 800 if I'm really desperate. From what I've read, the 20d is one of the better dslr's for low noise at higher ISO's, but I don't usually like the results. Neat Image has saved me lots of times though.
I noticed that Ingrid shot at 200, 800 and 3200 with her 20d so I opted to shoot at 100, 400 and 1600 with mine.
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The noise is very noticable, especially on the right hand side, at ISO 1600.
This is the 1600 shot ran through Neat Image. The noise level has been reduced (at least to my eyes) back to the level of the ISO 100 shot.
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Nice shots Laura. You can certainly see the difference in the grain (noise).

As we draw this exercise to a close, let me summarize a few lessons:
Lesson 1: The bright side of increasing ISO is that it makes the camera more sensitive to light and gives you a chance to get a good exposure when you otherwise couldn't.
Lesson 2: The dark side is that as the ISO increases, so does the grain (noise) in the photo. In some cases, for some subjects and some purposes, grain is fine. (I know of photographers who intentionaly ADD noise on occasion to get the look they want. A good example of a very good high noise photo is jmsetzler's Strike! image in Sports II Challenge.) But in general,we would prefer less grain rather than more.
Lesson 3: There are some situations where grain can be minimized or virtually eliminated. If you intend to use the full frame, and/or resize to a smaller image, grain may not be a noticible problem. Grain is less of a problem against a detailed background than against a solid background. Grain is a bigger problem when you are severely cropping a photo.
Lesson 4: Let's not throw the baby out with the bathwater. If you end up with grain, you can use noise reduction tools or blur techniques to reduce the noise.

Grain resulting from high ISO settings isn't something to be afraid of. But it is something to be aware of and to consider as you set up your camera for a shot.

Message edited by author 2005-07-28 16:12:12.
07/28/2005 03:56:14 PM · #95
Time to move along.

In a prior post I said we have several degrees of freedom to control exposure. All have advantages and disadvantages. We have explored Metering Mode, EV Comp, Bracketing, and ISO. The last 3 degrees of freedom are Shutter Speed, Aperture, and White Balance.

I won't be proposing an exercise about Shutter Speed. It is obvious that the longer the shutter is open the more light we let into the camera. (Which means we can shoot at a lower ISO and get less grain.) However, the disadvantage is that the longer it is open, the more likely we will get blur as a result. Motion blur from the subject (possibly desireable) and motion blur from camera shake (never desireable). If you want to play with this, knock yourselves out. But I don't think we need an exercise for this.

The next exercise I will post is about Aperture. As you open up the lens (smaller F Stops) you let more light into the camera and you can shoot with a faster shutter speed (to reduce motion blur) and a lower ISO (to reduce grain). But there is a dark side to Aperture and that is called Depth of Field (DOF). Simply put, DOF is the range of distance from the camera that will be in focus in the image the camera records. This will be the subject of Exercise 5. Coming soon to a Thread near you.

Message edited by author 2005-07-28 19:54:35.
07/28/2005 05:00:21 PM · #96
Exercise 5 -- Aperture

Our quest regarding exposure is to allow exactly the right amount of light into the camera to yield an image with no blown whites, no lost blacks, and good tonal range in the area of the photo we intend to use for our purpose.

One degree of freedom we control is Aperture. We can choose a wide open lens (F/2.8 on the lens I currently have mounted on my D70) to let in a lot of light. Or we can choose to close the lens (say to F/32 in my case) to dramaticly reduce the light entering the camera. The unintended consequence of changing Aperture is that in the process we change the Depth of Field (How much of the scene is in focus.) Nothing to be afraid of, but something you will want to be aware of and something you'll need to manage to get the photo you intend.

Exercise 5 This will be a set shot like my image below. This is a photo of a ruler pointed directly away from the camera. (I couldn't find a regular ruler so I used my old drafting ruler. Use a regular ruler if you can find one.)

Set your metering mode according to the conditions and your composition. Set your ISO according to the light you have available. Set your EV Comp to 0. And set your camera to Aperture Priority mode (remember we have divorced Auto for now.) Manually focus on the 6 inch mark as precisely as you can. Now shoot 5 identical photos varying only Aperture. Photo 1 should be at your most wide open aperature (smallest F/Stop number). Photo 5 should be at your most closed lens aperture (highest F/Stop number.) Spread photos 3, 4 and 5 across the range with 3 being about in the middle. If you are shooting with a zoom lens, do NOT change the focal length of your lens for these 5 photos. With each photo your shutter speed will vary and that's okay. Make me proud of your resulting exposures. And strive for a Britannica like series of images.
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Observation: Notice the ends of the ruler are out of focus. In my example, the DOF was less than the focal point +/- 6 inches. Oh, and I focused on the 5 by mistake. Opps.

Tip: It may help to put push pins, or marbles or sugar cubes (or pellet gun pellets in my case) next to the inch marks to help you focus and to highlight DOF. Just an idea. Not required.

Post your 5 photos to this thread and comment on what you've learned about the relationship between Aperture and DOF.

Deadline: End of Day Sunday

Message edited by author 2005-07-28 20:13:59.
07/28/2005 08:21:19 PM · #97
I used my 24-70 2.8L lens for this, which ranges from 2.8 to 22.

F stops posted are: f2.8 (1/1000s), f5.0 (1/320s), f8.0 (1/125s), f13 (1/40s), f22 (1/15s).
ISO 200

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The lower the f-stop (aperture), the shallower the depth of field, the less surrounding area is in focus. This increases as the f-stop increases in number. More is in fous at 5.0, even more at 8.0, and so on.

There is also a relationship between this aperture setting and the shutter speed (given all other variables are the same). The lower the f-stop, the faster the shutter speed.

In summary, this is yet another way to allow us to take a shot: if we don't have enough light, we can raise the ISO, we can lower the f-stop, lower the shutter speed (and use a tripod).

If we have too much light, we can lower the ISO, we can raise the f-stop (stop down), we can increase the shutter speed.



Message edited by author 2005-07-28 20:24:20.
07/29/2005 12:27:31 AM · #98
Originally posted by papagei:

I used my 24-70 2.8L lens for this, which ranges from 2.8 to 22.

F stops posted are: f2.8 (1/1000s), f5.0 (1/320s), f8.0 (1/125s), f13 (1/40s), f22 (1/15s).
ISO 200

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The lower the f-stop (aperture), the shallower the depth of field, the less surrounding area is in focus. This increases as the f-stop increases in number. More is in fous at 5.0, even more at 8.0, and so on.

There is also a relationship between this aperture setting and the shutter speed (given all other variables are the same). The lower the f-stop, the faster the shutter speed.

In summary, this is yet another way to allow us to take a shot: if we don't have enough light, we can raise the ISO, we can lower the f-stop, lower the shutter speed (and use a tripod).

If we have too much light, we can lower the ISO, we can raise the f-stop (stop down), we can increase the shutter speed.


Ingrid, very nice study. Well Done! You have drawn all the right conclusions.

Your images have interesting histograms. Have a look at the first one and critique the exposure, okay? You can simply add the critique as a comment on that shot. Try to be objective and analytical and tell me everything you can about the quality of your exposure. PM me when you're done and I'll have a look, too.
07/30/2005 06:34:27 PM · #99
I used my Canon 50mm 1.8 lens which ranges from 1.8 to 22
ISO 200
Manual focus
F-Stops used 1.8 5.6 10 16 22
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The higher the f-stop the greater the DOF, but that means the shutter speed is slower. I would have had major problems holding the camera steady at F16 and F22 if I hadn't used the tripod and timer.
I could have increased the ISO to allow more light in while maintaining the desired DOF. Also, for me at least, I tend to want a deep DOF primarily outside on landscape shots so had I been outside I would have had more natural light to work with which would have allowed for a faster shutter speed.
The lower the f-stop number the more shallow the DOF; perfect for portraits.

By the way, ever since Chuck agreed to mentor and we began this program I've tried to keep my camera in the Aperture setting. I've decided it's past time to learn to control the DOF. I'm amazed at how much I've learned about my camera in such a short amount of time. This mentorship program was a great idea!
I'll tackle the shutter speed eventually. Baby steps....right?
-Laura
07/31/2005 05:36:38 PM · #100
Originally posted by sheapod:

I used my Canon 50mm 1.8 lens which ranges from 1.8 to 22
ISO 200
Manual focus
F-Stops used 1.8 5.6 10 16 22
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The higher the f-stop the greater the DOF, but that means the shutter speed is slower. I would have had major problems holding the camera steady at F16 and F22 if I hadn't used the tripod and timer.
I could have increased the ISO to allow more light in while maintaining the desired DOF. Also, for me at least, I tend to want a deep DOF primarily outside on landscape shots so had I been outside I would have had more natural light to work with which would have allowed for a faster shutter speed.
The lower the f-stop number the more shallow the DOF; perfect for portraits.

By the way, ever since Chuck agreed to mentor and we began this program I've tried to keep my camera in the Aperture setting. I've decided it's past time to learn to control the DOF. I'm amazed at how much I've learned about my camera in such a short amount of time. This mentorship program was a great idea!
I'll tackle the shutter speed eventually. Baby steps....right?
-Laura


Laura, like Ingrid's, this is a nice study. I am intrigued that your ruler is 11 inches long on one side and 12 inches long on the other. What's up with that?
Lesson 1: Clearly as your F Stops decrease, your aperture becomes smaller and your depth of field (DOF) increases. And vice versa. This was the key point of this brief exercise. Not something to be afraid of, but something to be aware of and manage.
Lesson 2: Note also that everything the same distance from the lens is has the sam DOF characteristics. So in this case, the 5, the 6 and the candy(?), being the same distance from the lens are all in focus.
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