A couple of questions from a beginner...

[Lizziejane]

So, I picked up the book everyone recommended by Bryan Peterson, Understanding Exposure. Anywhoo, great so far, made some lightbulbs go off, for sure. Buuuuut, he keeps talking about metering - specifically when he talks about how he took a particular shot. "... metered off (the sky, the horizon, the clouds, whatever), recomposed the frame, then shot the frame". What?!?!! Sorry, I know it probably sounds very obvious to some of you, but I don't get it.

From what I understand from my Rebel XTi manual, there are 3 settings for metering, and mine is set at evaluative. The book also mentions that this is where he recommends it should be most of the time anyway. So I haven't made any conscious effort to meter. What should I be doing?

The other question pertains to DOF. He talks about a distance scale, and if anyone has the book, what confuses me the most is the side-bar on page 39 - "...I preset my focus so that the distance of two feet is aligned directly above the center mark near the front of the lens..." scared1 and then further down, "...I obtained the desired DOF not by refocusing the lens, but by combining a wide-angle lens with a story telling aperature and with the focus pre-set via the distance scale". I guess it's the distance scale thing that's throwing me off. In other parts of the book he talks about adjusting the scale distance using the setting on the lens. I can't find anything in the manual about a distance scale.

And my final question (for tonight anway!), what do you do with your gear when you ride Splash or Kali?! I've got a great bag that's supposed to be waterproof. Do I dare chance it?

 

[DVC Jen]

hit the wrong button - skip this post

 

[DVC Jen]

OMgosh - I could have been asking that same question last week.

When you look into your eye piece you will see that little meter at the bottom. That is what he is talking about as checking the meter.

The way I figured it out and had me light bulb moment was to read what he was saying and cross reference my handbook for the camera and also try out what he was saying.

Pay special attention to the Manual mode instructions - AV mode and TV mode. I can't tell you right off the top of my head but if your exposure is not correct in AV mode - you will need to change the shutter speed. You know you are at the correct shutter speed when the meter is centered or on 0. And when you are in TV mode you need to adjust your aperature until the meter is centered - or on 0.

Does that make sense?

When I actually tried this with the camera the photos turned out right.

When he said he metered off the sky - he turned his camera to the sky - checked his meter and adjusted it to get to the 0 at the centere of the meter (adjusting his shutter speed for the AV mode and or the aperature for the TV mode). Then when he recomposed his shot - he repositioned the camera for what he actually wanted to take the picture of (not the sky) and then the actually took the picture.

OK - with that all said.... there is a very good chance that I totally misunderstood and my light bulb moment was dim.


I am hoping one of the people who really know what they are talking about can either back me up on this (so I feel better as well).. or tell me I am wrong and point both of us in the right direction.

 

[Lizziejane]

OMgosh - I could have been asking that same question last week.

When you look into your eye piece you will see that little meter at the bottom. That is what he is talking about as checking the meter.

The way I figured it out and had me light bulb moment was to read what he was saying and cross reference my handbook for the camera and also try out what he was saying.

Pay special attention to the Manual mode instructions - AV mode and TV mode. I can't tell you right off the top of my head but if your exposure is not correct in AV mode - you will need to change the shutter speed. You know you are at the correct shutter speed when the meter is centered or on 0. And when you are in TV mode you need to adjust your aperature until the meter is centered - or on 0.

Does that make sense?

When I actually tried this with the camera the photos turned out right.

When he said he metered off the sky - he turned his camera to the sky - checked his meter and adjusted it to get to the 0 at the centere of the meter (adjusting his shutter speed for the AV mode and or the aperature for the TV mode). Then when he recomposed his shot - he repositioned the camera for what he actually wanted to take the picture of (not the sky) and then the actually took the picture.

OK - with that all said.... there is a very good chance that I totally misunderstood and my light bulb moment was dim.


I am hoping one of the people who really know what they are talking about can either back me up on this (so I feel better as well).. or tell me I am wrong and point both of us in the right direction.

Hi Jen!

Ok, I did manage to figure out the Av-/+ settings in manual this morning, so good so far. From what you're saying then, I meter off the sky (or whatever), aim back at my subject but ignore the camera when it's telling me to re-set everything again?

Which leads to another question - because I haven't picked up on the answer from the book yet - why would I meter off the sky, or my hand, or the horizon instead of my subject?

Sorry people - you've unleashed a maniac here! I would have been quite content to go to WDW with a P&S until ya'll started posting some of those fabulous pictures! Now, the kids have threatened to leave home if I point "that" thing at them one more time! Time to borrow a dog!

 

[handicap18]

I believe that you are mostly right Jen. I don't know the Canon bodies so I don't know in which modes they do and do not show the actual meter. I know with my Nikon D50 in "P" mode it doesn't show the meter, nor does it show in Shutter or Aperture priority if a "correct" exposure can be had using the option you set and the option the camera will give for the other.

That being said, in the view finder you should see a bunch of tiny rectangles and also a large circle. The rectangles are for focusing. The large circle is part of the metering system. I believe that in evaluative metering mode the entire view finder is used to meter what you are pointing the camera at. In Center Weighted uses the what the meter see's in that large circle. So center weighted can be a more specific meter. This is where that little line on the bottom of the view finder with the '0' gets its info from. So if you want to get someone's face exposed correctly you can either zoom way in or walk towards the person till their face fills the view finder in evaluative mode, or in Center weighted mode, their face only has to fill the circle.

 

[handicap18]

You would meter off the sky for a sunset or a sunrise but want part the earth (trees, buildings, and stuff) in the pictures as well. In this case those objects would show up as black sillohetts (sp?). If you included a lot of trees in your meter reading then the sky wouldn't show up with as much color and the trees or other object would show more detail and color. This is one example.

Lets say you want to take a picture of someone using only candle light. Their face is light by the candle, everything else is dark. You would want to meter off just their face to get that exposed correctly and everything else would be very dark. If you stepped back and metered their face, and body and background, the camera would take that into considertion and its reading would be quite different.

 

[handicap18]

There are huge algebra equations to figure "distance scale". I remember learning some of it in HS photo class. If you want to have everything in your picture in focus, where you focus on does make a difference. If you focus on something very close to you or very far away from you you might not get the full sharpness across the whole image. I generally try to focus on something that is just below the center point in my view finder. Even if that means finding the composure I want, then moving the camera to focus on an area, then moving the camera back to my original composure. You will have to use your AF/AE (auto focus/auto exposure) lock button or briefly switch to manual focus once you have your focus point. Otherwise when you press the shutter release to actually take the picture the camera will try to refocus.

Trying to understand the math behind depth of field can drive one crazy, plus it just way to complicated. Try doing a search for "Defination of Depth of Field" at wikipedia.com. Don't let it get to you. I try not to worry about it and go with a general feeling and a lot of trial and error in where to focus. Then keeping mental notes of my results for future referance. I find it less stressful that way.

 

[DVC Jen]

He doesn't say to meter off the sky for every photo - just for a few. In once case (on page 41) he actually didn't look to the sky to meter because of the intense sun. I LOVE that pic btw - the one of the farmhouse through the icy fence.

On page 69 the top pic he set his exposure for the sky - just above the sunrise. Now if you look at that pic the dandelion is just a silhouette. He wanted the sunset to be the main focus (as far as color) not the flower.

On page 77 I think he did it because of the glare off the ocean maybe? If he set the exposure to the sky it was a more consistant thing to set it to than a moving and changing ocean (again I am purely guessing here - I maybe wrong).

He did the same thing on pages 80 and 81 - setting his exposure to the sky instead of the bright yellow flowers. Maybe it is because the sky is brighter and he gets a great exposure for all of the bright colors and light this way.

Does anyone have any ideas why Bryan Peterson sets a lot of his bright day time shots at the sky before he actually focuses in on what he intends to take a photo of?

I totally understand when he is doing a silhouette against a sunset or sunrise... but why during a daytime shot?

 

[DVC Jen]

There are huge algebra equations to figure "distance scale". I remember learning some of it in HS photo class. If you want to have everything in your picture in focus, where you focus on does make a difference. If you focus on something very close to you or very far away from you you might not get the full sharpness across the whole image. I generally try to focus on something that is just below the center point in my view finder. Even if that means finding the composure I want, then moving the camera to focus on an area, then moving the camera back to my original composure. You will have to use your AF/AE (auto focus/auto exposure) lock button or briefly switch to manual focus once you have your focus point. Otherwise when you press the shutter release to actually take the picture the camera will try to refocus.

Trying to understand the math behind depth of field can drive one crazy, plus it just way to complicated. Try doing a search for "Defination of Depth of Field" at wikipedia.com. Don't let it get to you. I try not to worry about it and go with a general feeling and a lot of trial and error in where to focus. Then keeping mental notes of my results for future referance. I find it less stressful that way.

The guy who wrote this book that Lizziejane and I have both read says to set your aperature for f/22 when you want great depth of field. And throughout his books he shows photos he has taken (mostly landscapes) using this aperature. They are fantastically clear and focused throughout the entire landscape, unless something is very close to the actual camera - like grass or a tree branch with leaves.

Does this sound right to everyone else?

 

[handicap18]

He doesn't say to meter off the sky for every photo - just for a few. In once case (on page 41) he actually didn't look to the sky to meter because of the intense sun. I LOVE that pic btw - the one of the farmhouse through the icy fence.

On page 69 the top pic he set his exposure for the sky - just above the sunrise. Now if you look at that pic the dandelion is just a silhouette. He wanted the sunset to be the main focus (as far as color) not the flower.

On page 77 I think he did it because of the glare off the ocean maybe? If he set the exposure to the sky it was a more consistant thing to set it to than a moving and changing ocean (again I am purely guessing here - I maybe wrong).

He did the same thing on pages 80 and 81 - setting his exposure to the sky instead of the bright yellow flowers. Maybe it is because the sky is brighter and he gets a great exposure for all of the bright colors and light this way.

Does anyone have any ideas why Bryan Peterson sets a lot of his bright day time shots at the sky before he actually focuses in on what he intends to take a photo of?

I totally understand when he is doing a silhouette against a sunset or sunrise... but why during a daytime shot?

He goes into more of an explination when he talks about the sky brothers on page 122. Keep in mind that they are guidelines and YMMV. Also there are now shadows in the sky. Just an additional though.

 

[handicap18]

The guy who wrote this book that Lizziejane and I have both read says to set your aperature for f/22 when you want great depth of field. And throughout his books he shows photos he has taken (mostly landscapes) using this aperature. They are fantastically clear and focused throughout the entire landscape, unless something is very close to the actual camera - like grass or a tree branch with leaves.

Does this sound right to everyone else?

Thats usually where I start. This goes back to the story of me and my eye doctor when I was a kid. Him telling me if I lose or break my glasses and need a quick temporary fix. Put a pin hole in a piece of paper and look though it, things will be in focus. It works.

 

[Lizziejane]

I'm so glad I posted the questions... I'm learning a little more, bit by bit! Thanks for the replies everyone, I really appreciate it.

Jen - did you notice any mention of a distance scale in your manual when you got your XTi? I'm not going to worry about it too much, just wondering if I missed something.

Jane

 

[jann1033]

i think the distance scale ( dof scale)is usually on the lens...

i am not sure how the xti is set up but with the xt the little light to the far right of the exposure level indicator stays green when the exposure is ok, flickers when it isn't. unless it's an unusual situation( ie snow) it's seemed pretty accurate. if you are unsure you can also set the exposure bracketing

 

[MarkBarbieri]

The guy who wrote this book that Lizziejane and I have both read says to set your aperature for f/22 when you want great depth of field.
...
Does this sound right to everyone else?

I wouldn't use f/22 on a typical modern DSLR unless I really, really had to. Two things happen as you shrink your aperture. The often desirable one is that more of your picture is in focus (increased depth of field). The undesirable one is that you increase the effects of diffraction. Diffraction is the scattering of light when it goes through a really small whole. The distortion caused by diffraction is related to the size of the sensor used to capture the image. On an APS-C sized sensor (like most DSLRs use), diffraction starts to blur an image somewhere around f/22. If you experiment, you'll probably find that an in-focus image taken at f/16 is sharper than one taken at f/22. The problem quickly gets worse the smaller the aperture.

The rule listed above was written back when people used 35mm film. As a consequence, the "sensor" size was larger and diffraction wasn't a problem at f/22.

 

[MarkBarbieri]

From what I understand from my Rebel XTi manual, there are 3 settings for metering, and mine is set at evaluative. The book also mentions that this is where he recommends it should be most of the time anyway. So I haven't made any conscious effort to meter. What should I be doing?

An image has lots of different brightness levels in it. The sky is probably bright. The shadows are darker. The metering modes are different ways for the camera to decide what to consider when it determines the overall brightness of the scene.

The simplest is the partial metering mode. It just uses the average brightness for what it sees in the middle of the image.

Center-weighted average is similar. It uses the average brightness for everything in the picture, but it considers the stuff in the middle much more strongly.

Evaluative metering looks at the entire image and tries to pick an exposure level that will properly expose as much as possible. I think some evaluative metering algorithms attempt to determine the subject (by looking at focus points and camera orientation) and put extra emphasis on those areas.

One metering mode that your camera does not have is called spot metering. It works like the partial metering method except that it uses only a very small spot in the middle. This is useful if there is something in the scene that you want to be perfectly metered, such as a person's face. It can also be useful to use the spot meter to check the brightness of various parts of the scene and then manually set an exposure that you think best covers the range. Using it that way is essentially the same as evaluative metering except that instead of the camera guessing at what is important, you are doing the work yourself.

One important thing to understand about camera meters is that they think the entire world is grey. Things that are lighter or darker than grey confuse the meter. When you take a picture of snow, your camera meter will not realize the snow is white. Instead, it thinks that it is brightly lit grey snow and it will underexpose your picture so that the snow looks grey. On the flip side, if you take a picture of someone in a black evening gown in front of a dark night sky, the camera will think that it sees someone in a poorly lit grey gown in front of a poorly lit grey sky. It will overexpose so that the gown and sky look grey.

If the scene you are shooting is substantially lighter or darker than grey, you should adjust the exposure (using exposure compensation) so that you get a better exposure. The most common real-world example I run into is shooting in snow. In those cases, I usually tell the camera to overexpose by 2/3 stops.

 

[MarkBarbieri]

The other question pertains to DOF. He talks about a distance scale, and if anyone has the book, what confuses me the most is the side-bar on page 39 - "...I preset my focus so that the distance of two feet is aligned directly above the center mark near the front of the lens..." () and then further down, "...I obtained the desired DOF not by refocusing the lens, but by combining a wide-angle lens with a story telling aperature and with the focus pre-set via the distance scale". I guess it's the distance scale thing that's throwing me off. In other parts of the book he talks about adjusting the scale distance using the setting on the lens. I can't find anything in the manual about a distance scale.

Distance scales are becoming a thing of the past. My advice is to just guess at what aperture you need. When a picture is important, try several different apertures. As a general rule, focus at a point about one third of the distance between the closest and farthest thing that you want in focus.

 

[MarkBarbieri]

what do you do with your gear when you ride Splash or Kali?!

I use it to take pictures.

Seriously, cameras and lenses differ in their resistance to water. Some are waterproof. Some are water resistant (aka weather sealed). Others aren't. Before shooting with a weather sealed body and lenses, I used to bring along a plastic grocery bag. Just before getting splashed, I'd shove it in the bag. When I was feeling gutsy, sometimes I'd just shove it inside my jacket or shirt.

Even if you have a weather sealed or waterproof camera, you still want to take care not to get water on the front of the lens. It might not hurt the camera, but pictures with big blobs of out-of-focus water in them aren't that appealing.

 

[mabas9395]

I use it to take pictures.

So do I.

I just put my XT in a one gallon zip loc bag and fired the whole way down.

 

[jann1033]

So do I.

I just put my XT in a one gallon zip loc bag and fired the whole way down.

nice ! i notice at the end some splashes/ spots but that kind of adds to the fun since my glasses always end up like that anyway...was wondering about the possiblitly of doing this for snow etc...do you do anything else? i was thinking i might need to rubber band around the lens or something to keep the plastic relatively smooth across the lens or wasn't that necessary

 

[wannabatwdw]

The pictures are great. I am suprised the plastic bag does not distort the quality. How do you hang onto the camera in a plastic bag? I would be afraid I would lose my grip...