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Bryan Peterson's UNderstanding Exposure - A few questions
Howdy,.

I finally picked up UNderstanding Exposure this week and have read through about 2/3's of it. it's a great book! I didn't think it would offer much more since I've done a ton of reading on the net (but of course, by no means very good yet), but this book was definitely worth it and gave me some new perspectives. Anyway, I was kind of confused by a few things he said..

One is how he focuses. He seems to like to manual focus much of the time. He talks about using the distance scale, esp for the landscape type shots, to focus to infinity. He says to set focus to 2 feet on the distance scale and warns that it will look blurry in the viewfinder b/c the lens is wide opened at that point, but once you snap the pic, the lens stops down and it'll come into focus. That really kind of threw me. Does that mean you can't really trust manual focus then? If it's blurry, but will come out focuses, how could you ever manual focus? Or does this only apply to focus'ing to infinity, but he does mention the 2 ft scale if I remember correctly.

Is it b/c of DOF with the wide opened aperture and when it stops down it'll all come into focus, thus implying that you can still manual focus no problem but not everything will be in focus, however there will be something in focus..

Another question has to do with white balance. I guess I've misunderstood what WB is this whole time. I always thought WB didn't affect metering, that it just told the processor HOW to process the neutrals in the photo. BUt he seems to imply that it does affect metering. Is that right? Generally, I don't even worry about WB, I just set it to AWB and if I need to change it, I do so in post processing. But if it affects metering, then it is important to get it right from the start..

He gives the particular example of snow - which I understood. The camera, by itself, will make a snowy field gray. Makes sense, I understand that and how the meter works. So you set some EC to correct this and good to go. Understand so far. But he did talk about setting the white balance correctly and this to me seemed to imply it would affect the metering.



ANyway, it's a great read. Thanks to all on here who strongly recommended this book. I need to go out and try his techniques. I'm a little skeptical on some of his metering suggestions when it comes to the sky. BUt of course, I'm not the expert, so I'll give it a whirl. He says to meter off the blue sky, but for me, this usually tended to severly underexpose everything else.

For instance, if I were taking a picture of some building, currently, I would meter the building and sometimes this would blow the sky. But when I was practicing before, there were times, where I believe I metered the sky, and the building would come out as a silhouette. And this is not from "backlit sun", it's from "frontlit sun" Anyway, a bit counterintuitive for me, but I'm going to give it a whirl..

Just trying to learn.

Blog: http://novicephotog.blogspot.com/Flickr: http://www.flickr.com/photos/9778447@N07/..

Comments (32)

From what I understood about the focus, was that when you manually focus through the viewfinder you are focusing with a DOF that would be equal to your lens being wide open..

It's not until you press the shutter release that the lens stops down to your selected aperture. So by using the scale to infinity for landscapes your really taking any guess work out of what will be in focus. Or you can also use your DOF preview after you adjust your focus to see if you were right...

Comment #1

One is how he focuses. He seems to like to manual focus much of thetime. He talks about using the distance scale, esp for the landscapetype shots, to focus to infinity. He says to set focus to 2 feet onthe distance scale and warns that it will look blurry in theviewfinder b/c the lens is wide opened at that point, but once yousnap the pic, the lens stops down and it'll come into focus..

Two FEET? That will be hopeless for landscapes as you will get next to no depth of field and everything will be out of focus (except anything two feet in front of you, which isnt likely to be much for a landscape shot)..

The depth-of-field calculator at.

Http://www.dofmaster.com/dofjs.html.

Is really instructive: have a play with it. Suppose you have a typical crop-sensor DSLR like a Nikon D40 or a Canon EOS 400D or a Pentax K100D. Set the focal length to 25mm and the distance to the subject to 2 feet; aperture to f/16. The depth of field extends from 1.6 to 2.8 feet. At f/8 the situation is worse, with a depth of field from 1.75 to 2.33 feet. Not much use for a landscape!.

I haven't read this book but it is well known and reputable. Is it possible you have mis-interpreted something? It sounds like he is trying to explain about hyperfocal focussing..

If you are shooting a landscape and want everything up to infinity to be in focus, what most people would do is just focus on infinity. With the setup above (25mm lens, f/8) everything from 13.3. feet to infinity would be in focus. Fine. But if you focus slightly in front of infinity (to be precise, at 13.6 feet) - then everything from 6.8 feet to infinity will be in focus. The depth of field stretches from in front of the focus point to behind , and by using 13.6 feet (the hyperfocal distance under these conditions) as the focus point you are relying on the depth of field to bring infinity into focus, whilst getting some more depth of field close to you..

This explains the comment about the image looking out of focus in the viewfinder. When looking through the viewfinder the lens is wide open (say, at f/2 if you are using a prime lens, or f/3.5 if you are using a kit zoom lens). Under these conditions (25mm, f/3.5, 13.6 feet focus distance) the background WILL be out of focus because the depth of field stretches from 9.5 to 23.5 feet and 'infinity' is not in focus. But as soon as you take the picture, the lens stops down to your selected aperture and the depth of field will extend to infinity..

Another question has to do with white balance. I guess I'vemisunderstood what WB is this whole time. I always thought WB didn'taffect metering, that it just told the processor HOW to process theneutrals in the photo. BUt he seems to imply that it does affectmetering. Is that right?.

Possibly but it won't have much effect. As you say is just affects the colour balance in the photo from warm (yellowish) to cool (bluish). I haven't noticed it having any significant effect on exposure and I can't see why it should..

Generally, I don't even worry about WB, Ijust set it to AWB and if I need to change it, I do so in postprocessing..

Me too, except in artifiical light (tungsten or fluorescent lights) where AWB doesn;t work well..

Best wishesMike..

Comment #2

Riceowl wrote:.

Howdy,One is how he focuses. He seems to like to manual focus much of thetime. He talks about using the distance scale, esp for the landscapetype shots, to focus to infinity. He says to set focus to 2 feet onthe distance scale and warns that it will look blurry in theviewfinder b/c the lens is wide opened at that point, but once yousnap the pic, the lens stops down and it'll come into focus. Thatreally kind of threw me..

For this, I guess what he is trying to explain is about the hyperfocal distance and DOF..

If you set your focus >= hyperfocal distance, anything at and beyond this focus distance will be "acceptably" sharp. Just like you get the DOF up to infinity, which you need this for landscape shooting. No matter you set your focus at hyperfocal distance or larger than hyperfocal distance, you still get DOF up to infinity. Let say for his case, the hyperfocal distance is 2 feet. So you can get sharp focus till infinity whether you set your focus at 2 feet, 3 feet, 10 feet or anything larger..

But if you set at 10 feet, you only get anything from 10 feet to infinity sharp. Closer thing will be blur. So, it would be better to set at 2 feet to get everything from 2 feet to infinity sharp..

One thing to note here is that if you set your focus smaller than hyperfocal distance, you can't get the depth till infinity. So, it is adviceable to set your focus slightly larger than hyperfocal distance, but yet not too large to get the advantage above. This is to avoid the risk that if you slightly go below hyperfocus distance, the very far object will be blurred..

However, the problem here is that hyperfocal distance is a function of a few things including aperture (the f-number). The smaller the f-number, the longer the hyperfocal distance. For his case, when the aperture is wide open using viewfinder, the hyperfocal distance is larger than 2 feet, but your focus distance is 2 feet (less than hyperfocal distance), so you don't get the depth till infinity and see blurred background. When you snap, the aperture stop down, and the hyperfocal distance just change to slightly lower than 2 feet, hence you get the depth till infinity > sharp landscape...

Comment #3

Skylark_khur wrote:.

Riceowl wrote:.

For this, I guess what he is trying to explain is about thehyperfocal distance and DOF..

If you set your focus >= hyperfocal distance, anything at and beyondthis focus distance will be "acceptably" sharp. Just like you getthe DOF up to infinity, which you need this for landscape shooting.No matter you set your focus at hyperfocal distance or larger thanhyperfocal distance, you still get DOF up to infinity. Let say forhis case, the hyperfocal distance is 2 feet. So you can get sharpfocus till infinity whether you set your focus at 2 feet, 3 feet, 10feet or anything larger.But if you set at 10 feet, you only get anything from 10 feet toinfinity sharp. Closer thing will be blur. So, it would be betterto set at 2 feet to get everything from 2 feet to infinity sharp..

Sure... but I think that '2 feet' is a mistake (somewhere). The only way to get a hyperfocal distance that short is to use an ultra-wide angle lens stopped right down. With an 18mm lens (widest setting of most standard zooms on a crop-sensor camera) you'd need to use f/32 to get a hyperfocal distance of 2 feet, which would give everything from 13 inches to infinity in focus... and a very soft image due to diffraction effects. Maybe the book said 20 feet, which would work fine in many cases..

Best wishesMike..

Comment #4

Mike703 wrote:.

One is how he focuses. He seems to like to manual focus much of thetime. He talks about using the distance scale, esp for the landscapetype shots, to focus to infinity. He says to set focus to 2 feet onthe distance scale and warns that it will look blurry in theviewfinder b/c the lens is wide opened at that point, but once yousnap the pic, the lens stops down and it'll come into focus..

Two FEET? That will be hopeless for landscapes as you will get nextto no depth of field and everything will be out of focus (exceptanything two feet in front of you, which isnt likely to be much for alandscape shot)..

The "two" sounds like it cold be a confusion with Hyperfocal Distance DoF nearpoint..

When hyperfocal focusing is used, Depth of Field extends *up to* infinity behind the hyperfocal distance focused, and *from* a nearpoint that is HALF hyperfocal distance......

..... which could be expressed as " hd/2 " ... possibly [?].

I haven't seen the book, but I think I might be on the right track regarding where that anomalous "two" came from.Regards,Baz..

Comment #5

I missed something up there. Correction here..

When you set your focus at hyperfocal distance, everything behind the hyperfocal distance until infinity is "acceptably" sharp. But something slightly infront of the hyperfocal distance is also "acceptably" sharp. About HD/2 I guess..

But if you set your focus to infinity, you only get "acceptably" sharp from hyperfocal distance to infinity. You lose the extra that you can get by setting it at hyperfocal distance..

Example, if hyperfocal distance is 2 feet and you set focus at infinity, you get "acceptably" sharp from 2 feet to infinity. But if you set focus at 2 feet, you get "acceptably" sharp from 1 feet (I randomly choose a small number here, you can get it calculated out with some DOF calculator) to infinity...

Comment #6

Mike703 wrote:.

Sure... but I think that '2 feet' is a mistake (somewhere). The onlyway to get a hyperfocal distance that short is to use an ultra-wideangle lens stopped right down. With an 18mm lens (widest setting ofmost standard zooms on a crop-sensor camera) you'd need to use f/32to get a hyperfocal distance of 2 feet, which would give everythingfrom 13 inches to infinity in focus... and a very soft image due todiffraction effects. Maybe the book said 20 feet, which would workfine in many cases..

I think you are right here, I also tried calculate and if use f/16, you will need 16mm lens to get hyperfocal distance at 1.8 feet. Lol..

If set focus to infinity, get depth from 1.8 feet to infinity.If set focus at 2 feet, get depth from 1 feet to infinity...

Comment #7

Skylark_khur wrote:.

Example, if hyperfocal distance is 2 feet and you set focus atinfinity, you get "acceptably" sharp from 2 feet to infinity. But ifyou set focus at 2 feet, you get "acceptably" sharp from 1 feet (Irandomly choose a small number here, you can get it calculated outwith some DOF calculator) to infinity..

The nearpoint distance of hyperfocal distance DoF isn't randomIt is ALWAYS HALF hyperfocal distance whatever that happens to be for the actual aperture in use. (See my post made a short while ago....).

So your guess of 1 foot for a 2 foot HD, is bang on! Well done! .

The point about using hyperfocal distance is that it doesn't extend DoF BEYOND infinity, where it is absolutely useless....

... well, to anybody but Buzz Lightyear* that is! .

* See excellent animated movie "Toy Story"Regards,Baz..

Comment #8

Barrie Davis wrote:.

Skylark_khur wrote:The nearpoint distance of hyperfocal distance DoF isn't randomItis ALWAYS HALF hyperfocal distance whatever that happens to be forthe actual aperture in use. (See my post made a short while ago....).

So your guess of 1 foot for a 2 foot HD, is bang on! Well done! .

Lol, I guess it was something there but not entirely sure, so just randomly put a number. Guess I'm lucky to day..

So, essentially, why the author go through the trouble (not really very trouble) to set focus at hyperfocal distance instead of just set it at infinity is to get the extra depth in front of the hyperfocal distance..

If it is 20 feet, you get extra 10 feet by going through the "trouble"...

Comment #9

Barrie Davis wrote:.

The point about using hyperfocal distance is that it doesn't extendDoF BEYOND infinity, where it is absolutely useless....

... well, to anybody but Buzz Lightyear* that is! .

* See excellent animated movie "Toy Story".

Ahaaa... so THAT's what good ol' Buzz Lightyear was on about: he was answering the question 'how far does the depth of field extend when you focus beyond the hyperfocal distance?' There's obviously more to that movie than meets the eye..

Come to think of it, answers to commonly-asked photography questions on this forum crop up in many films. For example:.

Q: Should I buy a Canon or Nikon?A: Frankly my dear, I don't give a damn(Clark Gable, in 'Gone with the wind').

Q: I've just bought a Rebel XTi and want to turn professional. Any advice?A: Dave, this conversation can serve no purpose anymore. Goodbye.(from 2001, A Space Odyssey).

As you can tell, I'm bored at work today...Best wishesMike..

Comment #10

What page is your focus question and WB question on? I was also confused in a few places by his comments on focusing but I think I understood his comments on WB. You might also be interested in this thread on metering..

Http://forums.dpreview.com/...forums/read.asp?forum=1034&message=27439835..

Comment #11

RE>So you set some EC to correct this and good to go. <.

Nope..

How much snow will be in your shot? Will it fill the frame, or will there be lots of sky in the shot, too?.

People in the picture? How much of the frame will they take up?.

Themore snow, the greater the exposure compensation. The less snow, the less exposure comp. How much is more and how much is less? Beats me..

That's why smart people use manual exposure when taking pictures of subjects where the amount of snow varies from frame to frame..

Distance scales? You read about that because the author and the publisher have not done a half decent job keeping the book current..

White balance and metering? You've just confused me, because the author confused you. While everything is realted in photography aperture to depth of field to focus to blur from shutter speeds to ....there's not much connection the vast majority of the time between white balance and metering, although tehere are things like shadows going blue on snow, and the darkness of the shandows relating to the exposure settings..

But mostly, it doesn't matter..

BAK.

BAK..

Comment #12

You haven't said anything helpful. Sometimes it's difficult for a person new to photography to ask the "right" question when they don't understand the topic. Ask for clarification to try and understand what it is they are having difficulty with rather than just pointing out that they are confused...

Comment #13

One is how he focuses..

He is explaning why using the hyperfocal distance (2 feet is just to explain a point) will give you a picture that has more in focus than simply setting the lens to infinity..

Another question has to do with white balance.... affecting metering..

No, please reread..

I'm a little skeptical on some of his metering suggestions when it comesto the sky..

Don't forget that he uses Center-weighted Average metering exclusively. Won't work with matrix (multi-pattern) metering, so set your camera to center-weighted before you try this out...

Comment #14

Hey all,.

Thanks for all your responses. To answer the question many you have asked, "Could I have misread what the author stated?" My answer is absolutely and I probably did. When I get home, I'll look to see again what it is he said. On the focusing, I have heard of focusing to infinity, but I could have sworn he didn't say that, he gave a number and I thought the number was 2 feet. If this doens't sound logically, then I probably misread it or misunderstood..

On the WB question, he didn't say it affected the metering, but it seemed to be implicitly implied. Again, this is probably me misreading what he said. I'll reread this section and report back as well. From what I remember, he was talking about snow and how it turns to grayish if you listen to the metering. In the same area, he talked about setting hte white balance to help you by using a gray card (he also gave a trick about using hte palm of your hand and taking the difference or something like that, BUT don't take that as gospel, I remember that even less well). I'll have to look at it again, but in his steps it almost seemed to imply WB would affect metering..

I'm going to have to reread the book. I've read through it pretty quickly so I'm sure I've missed some stuff or misunderstood. I will say it's an excellent book, I enjoy it and have learned some good tips. Also, convinced me that I should get into manual mode sooner rather than later. I've been pretty content in Av mode and sometimes Tv, but after reading his book, I see there is more than meets the eye to the advantages of shooting in manual mode..

I'll take a look at what he says and repost here. More than likely, I misunderstood what he was saying..

Just trying to learn.

Blog: http://novicephotog.blogspot.com/Flickr: http://www.flickr.com/photos/9778447@N07/..

Comment #15

Mary, interesting thread on metering. I did take a read on that. I didn't take into account that Peterson does say he uses center weighted all the time..

For the distance stuff, in the book on p39, there is a picture and he has a description of how he took the picture. He used a wide angle lens "20-35mm" and set aperture to f/22 and preset his focus so that distance of two feet is set. He warns that in the viewfinder, it will look out of focus, but once the button is pressed to take the pic, the lens will stop down and it will all be in focus..

So I guess he gave the 2 feet as a particular example. I'm not sure if he'd always use 2 feet for this type of pic, he was doing a pic with great DOF. He has other mentions of presetting his focus using distance scale, but doesn't give the actual number, so I assume maybe at 2 feet?.

Okay, this is why I may have confused the WB with the metering. I've never used a gray card before, I have heard of them, BUT I always thought they were for setting the white balance. It seems that I may be wrong on this, but it appears that a gray card is used to aid in metering, which makes sense to me. Now, is that correct? Is a gray card used to help in metering? I guess the reason I thought it was for white balance was b/c I could have sworn I've seen instruction on setting Custom WB and it said to take a pic of a gray card and then follow certain steps depending on your camera, and viola, you have custom WB set. This is why I thought he was implying WB is affecting the metering, he says to shot a gray card to help with the metering (or meter off a gray card to be exact)..

Just trying to learn.

Blog: http://novicephotog.blogspot.com/Flickr: http://www.flickr.com/photos/9778447@N07/..

Comment #16

I too am almost done reading this book and am rather new to photography as a hobby. One thing I really don't understand is how he says he's always pointing his camera to something other than the subject to get a meter reading. Why???? He'll say something like, "I pointed to camera to the blue sky to get a meter reading." Why would he do that if he's taking pictures of flowers right in front of him?..

Comment #17

For the distance stuff, in the book on p39, there is a picture and hehas a description of how he took the picture. He used a wide anglelens "20-35mm" and set aperture to f/22 and preset his focus so thatdistance of two feet is set. He warns that in the viewfinder, itwill look out of focus, but once the button is pressed to take thepic, the lens will stop down and it will all be in focus..

So I guess he gave the 2 feet as a particular example. I'm not sureif he'd always use 2 feet for this type of pic, he was doing a picwith great DOF. He has other mentions of presetting his focus usingdistance scale, but doesn't give the actual number, so I assume maybeat 2 feet?.

Then he is just giving an example. When you using 20mm f/22 on full-frame, the hyperfocal distance is 2 feet. By focusing at infinity, you get the DOF 2 feet to infinity. By focusing at 2 feet, you get the DOF 1 feet to infinity. Hence, nearer limit and more coverage..

But you get this only when the aperture step down to f/22 when SNAP. When viewing, the aperture is wide open and the hyperfocal distance is much greater. For example, if it is f/2.8 when wide open, the hyperfocal distance is 15.5 feet, and when focusing at 2 feet, you get the DOF from 1.78 feet to 2.29 feet only. Thus, he tell you this doesn't matter because this "temporary" blurry landscape is not something that you are going to end up...

Comment #18

Rugby148 wrote:.

I too am almost done reading this book and am rather new tophotography as a hobby. One thing I really don't understand is how hesays he's always pointing his camera to something other than thesubject to get a meter reading. Why???? He'll say something like, "Ipointed to camera to the blue sky to get a meter reading." Why wouldhe do that if he's taking pictures of flowers right in front of him?.

Because he is trying to fool the metering? I presume he is using center-weighted spot metering. So, the choice is where he want the result to be correctly expose. If he is metering at the flower, he get the flower correctly expose with the risk of overblown sky. If he is metering at the sky, he get the sky correctly expose but the flower might slightly underexpose. In many case, you can't get everything in a frame correctly expose. It is your choice to balance it and get the effect you want..

When we use matrix-patterned metering, the camera will try her best to balance it. Although the camera may not be always success...

Comment #19

Thanks skylark. I guess I need to figure out how to calculate and use the distance scale then. So, if this is the case, can you ever really manually focus if it's going to be blurry when wide opened, ie before you press the shutter release? Why does autofocus work and it's clear and sharp before you press the shutter? I'm guessing that it's fine if you actually focus on the object you want to snap, since that'll be sharp, no matter what DOF is. DOF just determines how sharp and in-focus things are in front of and behind the object. So is this really the prefered way to focus landscapes or anything you want to shoot to infinity? I usually just find something to focus on, have a small aperture, and shoot away..

Another thing, the numbers for aperture he gives seem rather small (high in number). I guess from reading here, and again it may be my misperception, but I thought you really didn't want to go above f/16. Peterson is shooting f/22 and f/30! Certainly, I thought it was not recommended to go to f/30 b/c of issues. OR, is it the crop factor? Is he stating off a full frame and being that I'm shooting on a crop factor, I need to take that into account? I'm guessing this is the case b/c he does say P&S have the advantage of being able to have great DOF at a relatively smaller aperture..

Rugby - EXACTLY! This is counter to what I've been doing. I'm going to give it a try. I figured he'd say "do this and grab a flash" but he says he doesn't like flash. But yeah, I was confused about this as well, meter off the sky. And Mr. Green Jeans (aka meter off grass) if there is grass and no sky (using -2/3 EC).

I figure if I meter off the sky, and then am shooting a building, the building is going to end up severly underexposed with a nice exposed sky. When I first got my camera I played around with things and tried to be aware of the dynamic range (blown out sky, properly exposed subject vs properly exposed sky, and underexposed subject). His pictures seem to indicate it works. BUt yeah, I'm confused by this as well. I always thought you should meter on the most important subject, for the most part.

Just trying to learn.

Blog: http://novicephotog.blogspot.com/Flickr: http://www.flickr.com/photos/9778447@N07/..

Comment #20

Skylark, that's exactly right. He is using center weighted. Does that mean that is the preferred way? He says the reason he does it is b/c it's always worked well for him, but he'll do spot as well. So with that rational, will metering off sky work fine if you are using spot? I figure with spot, you want to meter the main subject. And he uses your words exactly for the most part "Fool the metering in the camera.".

Skylark_khur wrote:.

Rugby148 wrote:.

I too am almost done reading this book and am rather new tophotography as a hobby. One thing I really don't understand is how hesays he's always pointing his camera to something other than thesubject to get a meter reading. Why???? He'll say something like, "Ipointed to camera to the blue sky to get a meter reading." Why wouldhe do that if he's taking pictures of flowers right in front of him?.

Because he is trying to fool the metering? I presume he is usingcenter-weighted spot metering. So, the choice is where he want theresult to be correctly expose. If he is metering at the flower, heget the flower correctly expose with the risk of overblown sky. Ifhe is metering at the sky, he get the sky correctly expose but theflower might slightly underexpose. In many case, you can't geteverything in a frame correctly expose. It is your choice to balanceit and get the effect you want..

When we use matrix-patterned metering, the camera will try her bestto balance it. Although the camera may not be always success..

Just trying to learn.

Blog: http://novicephotog.blogspot.com/Flickr: http://www.flickr.com/photos/9778447@N07/..

Comment #21

Riceowl wrote:.

Mary, interesting thread on metering. I did take a read on that. Ididn't take into account that Peterson does say he uses centerweighted all the time..

For the distance stuff, in the book on p39, there is a picture and hehas a description of how he took the picture. He used a wide anglelens "20-35mm" and set aperture to f/22 and preset his focus so thatdistance of two feet is set..

He said the photo was taken at 20mm, f/22 and the focus was preset with the distance scale on the lens at two feet..

I don't know how to use the distance scale on the lens. Maybe someone can explain. I did not understand his comments on presetting focus as in this example but I'd really like to know..

He warns that in the viewfinder, itwill look out of focus, but once the button is pressed to take thepic, the lens will stop down and it will all be in focus..

Yes, that is my understanding. The view thru the viewfinder is with the lens wide open (in the picture on p 39 that was 2.8) but the image captured will be at f/22. When he talks about the picture being blurry I assume he is referring to the shallower DOF at 2.8 as compared to f/22 but I don't know for sure. Maybe someone can comment on this..

So I guess he gave the 2 feet as a particular example. I'm not sureif he'd always use 2 feet for this type of pic, he was doing a picwith great DOF. He has other mentions of presetting his focus usingdistance scale, but doesn't give the actual number, so I assume maybeat 2 feet?.

I thought that his preset focus here was specifically for this particular example. I don't understand this "preset focus" he is referring to..

Okay, this is why I may have confused the WB with the metering. I'venever used a gray card before, I have heard of them, BUT I alwaysthought they were for setting the white balance..

My understanding is that if you are going to use a custom white balance you need to set it using a neutral colored object such as a gray card. I think white can be used as well..

It seems that I maybe wrong on this, but it appears that a gray card is used to aid inmetering, which makes sense to me. Now, is that correct? Is a graycard used to help in metering?.

I'll comment on this later..

I guess the reason I thought it wasfor white balance was b/c I could have sworn I've seen instruction onsetting Custom WB and it said to take a pic of a gray card and thenfollow certain steps depending on your camera, and viola, you havecustom WB set..

Yes, thats correct..

This is why I thought he was implying WB is affectingthe metering, he says to shot a gray card to help with the metering(or meter off a gray card to be exact)..

The gray card serves different purposes in setting a custom white balance and in the calibration of the light meter..

I'm just learning this myself so if something I said was incorrect maybe some can provide the correct info..

Just trying to learn.

Blog: http://novicephotog.blogspot.com/Flickr: http://www.flickr.com/photos/9778447@N07/..

Comment #22

Thanks Mary, I'm in the same boat, trying to learn everything. I thought I had a good grasp of things, then reading Peterson's book made me realize I missed a lot of htings too. Its a great read though and got me excited about trying out Manual mode now. I've been shooting about 9 months now, but not as much or as often as I'd like. I go in spurts. Sometimes I feel like I was shooting better at 3 months than I do now! Reminds me of golf: I'd get to a certain point, change something like my swing, and then my game would be worse for a while, but then would eventually get better.



Just trying to learn.

Blog: http://novicephotog.blogspot.com/Flickr: http://www.flickr.com/photos/9778447@N07/..

Comment #23

Riceowl wrote:.

Thanks skylark. I guess I need to figure out how to calculate anduse the distance scale then. So, if this is the case, can you everreally manually focus if it's going to be blurry when wide opened, iebefore you press the shutter release? Why does autofocus work andits clear and sharp before you press the shutter? I'm guessing thatits fine if you actually focus on the object you want to snap, sincethat'll be sharp, no matter what DOF is. DOF just determines howsharp and in-focus things are in front of and behind the object..

Your guess is right, if you actually focus on the object you want to snap, the object will be sharp, no matter what DOF is. DOF just determines how sharp things are in front and behind the main object. The true idea he is trying to say is that you can't see the "real" DOF when using viewfinder since the aperture is not what you set. For example, for some reason, you want to shoot a near object in focus and get all the background sharp, you can't depend on the viewfinder to "preview" the effect. You need to know what aperture to use to get the hyperfocal distance shorter than the near object. But after setting the aperture right, you still can't "preview" the DOF effect..

Some autofocus or even manual focus lens have this feature called "DOF Preview" which will stop down the aperture to what you set to let you "preview" the effect you really will get..

So, is this really the prefered way to focus landscapes or anything youwant to shoot to infinity? I usually just find something to focuson, have a small aperture, and shoot away..

For most people, I guess they will just set to infinity and small aperture and shoot. But when you know where your hyperfocal distance is (it is always fixed if you use the same focal length, same aperture, same circle of confusion), why don't set it at hyperfocal distance to get the extra HD/2 near limit?.

Also, small aperture is not always what you want when shooting night landscape. You will see the clear "star effect" on light source due to diffraction at night. But this really depends on what effect you want, sometimes you may find this "star effect" great, and sometimes you may just find this distracting..

Another thing, the numbers for aperture he gives seem rather small(high in number). I guess from reading here, and again it may be mymisperception, but I thought you really didn't want to go above f/16.Peterson is shooting f/22 and f/30! Certainly, I thought it was notrecommended to go to f/30 b/c of issues. OR, is it the crop factor?Is he stating off a full frame and being that I'm shooting on a cropfactor, I need to take that into account? I'm guessing this is thecase b/c he does say P&S have the advantage of being able to havegreat DOF at a relatively smaller aperture..

Yes, smaller aperture will introduce diffraction. Diffraction is always there when a light source pass through a small holes (like the lens aperture). But whether you can see it's effect in your photo depends on many factors including how contrast is the light compare to surrounding (very strong at night), how large is your sensor area per pixel (if your sensor are per pixel is very big, you can tolerate higher splitting effect of diffraction and hence, can use smaller aperture) and many other things..

So, the answer about your crop factor is generally true (but not always) because smaller sensor usually have smaller sensor area per pixel..

Yes, P&S have the advantage of having greater DOF as their "real" focal length is short and, thus, their hyperfocal distance is short. This also explains why it is so hard to get blurred background portrait in P&S because the subject can easily go beyond hyperfocal distance..

P/s Although the requirement for CoC is smaller in P&S due to their higher pixel per inch on small sensor, they still have much shorter hyperfocal distance as HD is approximately proportional to (focal length^2)/CoC...

Comment #24

Riceowl wrote:.

Skylark, that's exactly right. He is using center weighted. Doesthat mean that is the preferred way? He says the reason he does itis b/c it's always worked well for him, but he'll do spot as well..

It is self-preference. He used it because it worked well for him. One reason I guess that he prefers manual over automatic. Center-weighted spot metering is, somehow, less automatic than matrix-patterned metering (where camera AUTOMATICALLY select the metering area)..

So with that rational, will metering off sky work fine if you are usingspot? I figure with spot, you want to meter the main subject. Andhe uses your words exactly for the most part "Fool the metering inthe camera.".

Again, depends on the effect you like to create. If you want to end up with something like a silhoutte in front of a clear cloudy sky, meter the sky. If you want to end up with something like a well-exposed person face in front of a bright over-blown sky, meter the person face..

You have less control over this if you use matrix-patterned metering as the camera select it's own metering area...

Comment #25

Mike703 wrote:.

Q: Should I buy a Canon or Nikon?A: Frankly my dear, I don't give a damn(Clark Gable, in 'Gone with the wind').

Q: I've just bought a Rebel XTi and want to turn professional. Anyadvice?A: Dave, this conversation can serve no purpose anymore. Goodbye.(from 2001, A Space Odyssey).

Hmmm... those are rather good, aren't they? Highly appropriate! .

I'm wracking my brains trying to come up with a couple more. So far nothing has occurred to me that has your ring of quality.. .

[Any movie buffs out there.... ??]Regards,Baz..

Comment #26

Riceowl wrote:.

Howdy,.

I finally picked up UNderstanding Exposure this week and have readthrough about 2/3's of it. it's a great book! I didn't think itwould offer much more since I've done a ton of reading on the net(but of course, by no means very good yet), but this book wasdefinitely worth it and gave me some new perspectives. Anyway, I waskind of confused by a few things he said..

One is how he focuses. He seems to like to manual focus much of thetime. He talks about using the distance scale, esp for the landscapetype shots, to focus to infinity. He says to set focus to 2 feet onthe distance scale and warns that it will look blurry in theviewfinder b/c the lens is wide opened at that point, but once yousnap the pic, the lens stops down and it'll come into focus. Thatreally kind of threw me. Does that mean you can't really trustmanual focus then? If it's blurry, but will come out focuses, howcould you ever manual focus? Or does this only apply to focus'ing toinfinity, but he does mention the 2 ft scale if I remember correctly.It kind of confused me.



What Bryan is referring to is known as hyperfocal focusing On a landscape if you focus on infinity you will sacrifice some depth of field on the close end of the depth of field. On the lens there should be a focus point designated by a line. On each side are numbers: 32, 22, 16, 11, 8, 5.6, ^, 5.6, 8, 11, 16, 22, 32. If you place the infinity inside the f stop for the aperture you've selected instead of the focus marker on infinity you've done what he's referring to. You can verify DOF by pressing the DOF button. Even if you don't have this preview on your camera Hyperfocal focusing works.



Another question has to do with white balance. I guess I'vemisunderstood what WB is this whole time. I always thought WB didn'taffect metering, that it just told the processor HOW to process theneutrals in the photo. BUt he seems to imply that it does affectmetering. Is that right? Generally, I don't even worry about WB, Ijust set it to AWB and if I need to change it, I do so in postprocessing. But if it affects metering, then it is important to getit right from the start..

He gives the particular example of snow - which I understood. Thecamera, by itself, will make a snowy field gray. Makes sense, Iunderstand that and how the meter works. So you set some EC tocorrect this and good to go. Understand so far. But he did talkabout setting the white balance correctly and this to me seemed toimply it would affect the metering.



ANyway, it's a great read. Thanks to all on here who stronglyrecommended this book. I need to go out and try his techniques. I'ma little skeptical on some of his metering suggestions when it comesto the sky. BUt of course, I'm not the expert, so I'll give it awhirl. He says to meter off the blue sky, but for me, this usuallytended to severly underexpose everything else.

For instance, if I were taking apicture of some building, currently, I would meter the building andsometimes this would blow the sky. But when I was practicing before,there were times, where I believe I metered the sky, and the buildingwould come out as a silhouette. And this is not from "backlit sun",its from "frontlit sun" Anyway, a bit counterintuitive for me, butI'm going to give it a whirl..

Just trying to learn.

Blog: http://novicephotog.blogspot.com/Flickr: http://www.flickr.com/photos/9778447@N07/..

Comment #27

Riceowl wrote:.

Mary, interesting thread on metering. I did take a read on that. Ididn't take into account that Peterson does say he uses centerweighted all the time..

Thought you might be interested.http://forums.dpreview.com/...forums/read.asp?forum=1034&message=27664244..

Comment #28

Remember that no matter what the camera is using to determine exposure, whether set to matrix, center-weighted or spot, in the end it has to return two values: a shutter speed and an aperture..

For example, most cameras are defaulted to matrix metering, and you'll read this camera's matrix metering meters 1000 different spots in the scene, does a fantastic determination of the type of scene (it has a database of scenes), and gives good exposure: a shutter speed and an aperture..

It all comes down to: what shutter speed and aperture should I use?.

Shutter speed can be used to freeze action (fast shutter speed), depict motion (slow shutter speed), or you may be indifferent to it for a particular scene..

Aperture can be used to obtain lots of DOF e.g. landscape (small aperture), little DOF e.g. for a portrait (large aperture), or you may be indifferent to it for a particular scene..

Whichever shutter speed you decide to use, you then need to select the right aperture for correct exposure..

Likewise, if you fix the aperture, then you need to select the right shutter speed for correct exposure..

What is "correct exposure?".

That's where the book comes into play and Bryan is sharing his years of experience in how he meters (using center-weighted and his various rules) and how these have served him well, with examples to prove his point. The only way to understand them fully is to go out and try them..

Have fun!..

Comment #29

My wong wrote:.

Remember that no matter what the camera is using to determineexposure, whether set to matrix, center-weighted or spot, in the endit has to return two values: a shutter speed and an aperture..

For example, most cameras are defaulted to matrix metering, andyou'll read this camera's matrix metering meters 1000 different spotsin the scene, does a fantastic determination of the type of scene (ithas a database of scenes), and gives good exposure: a shutter speedand an aperture..

Forget Mr. Peterson: he's too cryptic to follow. Look up the "Zone System" on the web (a simplified version) and get yourself a "Spot Meter" and use that..

All you need for any shot is one "good" spot reading off a tonality of your choice -it doesn't have to be middle gray (in fact it's easier if it's not middle gray). (I personally use either "open shadow" -i.e. zone 4- or white with barely discernible detail -zone 7.).

Decide where you want that tonality to fall, adjust your (manual) exposure settings accordingly, frame, focus and shoot..

Simpler still: just spot-read the brightest highlight you want to keep, hit the "highlight" button on your spot meter and use the reading in you camera..

Its that easy..

(All the other tonalities in your scene will fall into place accordingly).

All that the "matrix/evaluative metering BS has achieved is total loss of control (let alone understanding what's going on) for the photographer..

Remember: KISS! ..

Comment #30

Mikelis wrote:.

All you need for any shot is one "good" spot reading off a tonalityof your choice -it doesn't have to be middle gray (in fact it's easierif it's not middle gray). (I personally use either "open shadow" -i.e.zone 4- or white with barely discernible detail -zone 7.).

Won't metering off white = underexposure?.

Decide where you want that tonality to fall,.

What do you mean?.

Adjust your (manual)exposure settings accordingly, frame, focus and shoot...

Comment #31

MaryGierth wrote:.

Mikelis wrote:.

All you need for any shot is one "good" spot reading off a tonalityof your choice -it doesn't have to be middle gray (in fact it's easierif it's not middle gray). (I personally use either "open shadow" -i.e.zone 4- or white with barely discernible detail -zone 7.).

Won't metering off white = underexposure?.

Meter whatever you like, the meter will interpret it in a way that will result in an exposure that renders whatever you have metered as "middle" grey..

OK, so you say to yourself, "I don't wnat that patch to be middle gray, I want it to be a shadow, highlight, whatever"..

So (using the meter reading as a baseline only) you simply add or subtract some exposure compensation in your manual setting of your exposure so that the patch in question would now be rendered at whatever tonality you want it to be (shadow, highlight, whatever you want)..

So, if a highlight, add +3 ev (almost but not quite washed out), +2 ev (some detail visible), +1 ev (all detail clearly visible) to your settings; if a shadow, -1 ev (light shadow, open shade) or -2 ev (dark shadow, deep shade), -3 ev (inkspot), and so forth..

Decide where you want that tonality to fall,.

What do you mean?.

You really should read up on the "simplified" Zone System to understand this..

The Zone System (co-invented by Ansel Adams) is a way of "visualizing" the brightness of any scene in terms of a range of 9, 10, or 11 steps (depending on whom you read). It gives you both a conceptual framework (Gestalt) and a vocabulary for dealing with exposure issues which are communicable to others and which work..

In my opinion, any book on "exposure" which doesn't mention the "Zone System" really has to be mainly BS and the author probably is "winging it"..

Now, if you really do have to take a shot "on the run", well, by all means use all the built-in help the camera can offer, and hope for the best ("spray and pray!"). Some good shots are bound to "happen"..

Nothing wrong with that: simply delete the failures and try again!..

Comment #32

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This question was taken from a support group/message board and re-posted here so others can learn from it.

 

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