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  1. #1

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    Technique for focusing "into your scene"

    Hi all,

    Question about 4x5 focusing. But first, to set the stage, let's talk digital for a moment.

    When learning about focusing a digital camera I have read many times and in many places, to maximize overall image sharpness and depth of field, focus 1/3 of the way "into" your scene.

    By all accounts this works pretty well and reliable.

    Now, let's shift gears to 4x5. Here, I have learned from others and have read, basically do the following:
    1. Focus on the near/far
    2. Tilt for the near/far
    3. Note the standard position on the metric scale
    4. Then hunt around the scene and find the most out of focus area, focus on that area, then note that position of the standard on the metric scale
    5. Then, here's the catch....place the standard at the mid-point of the near and far focus points

    The last step is the one I want to talk about. Positioning the standard on the mid-point....doesn't that equate to focusing 50% "into" the scene? Shouldn't we be focusing at the 1/3 point "into" the scene? I know the math is harder, but, thoughts on that?

    Thanks!!
    Anything in life worth having is worth sharing.

  2. #2

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    Re: Technique for focusing "into your scene"

    ____________________________________________

    Richard Wasserman

    https://www.rwasserman.com/

    http://richardwassermanphotographer.tumblr.com

  3. #3

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    Re: Technique for focusing "into your scene"

    Quote Originally Posted by Richard Wasserman View Post
    Couple that with: https://www.largeformatphotography.info/fstop.html and you're good to go.

    A few observations:

    The "1/3-in" rule doesn't really work. The amount of depth of field in front of and behind the plane of sharp focus varies with the distance being focused on. There are better ways to work with a view camera.

    The "focus near - focus far and split the distance method" works well only if you use it intelligently. You have to get the proper f-stop to provide you with the desired depth of field and you need to consider where the plane of sharp focus will end up and adjust if needed. For example, you might want to cheat toward better focus for a distant horizon line at infinity and stop down more with many scenes, etc.

    And, the "near" and the "far" can end up being above and below the plane of sharp focus if you use tilts; you really need to be able to visualize where that plane of sharp focus is in order to effectively choose your near and far focus points.

    Mastering movements is an essential part of working with the view camera if you want to optimize sharpness and depth of field. You really need to be able to assess a situation, decide where you want the plane of sharp focus to lie in the scene so you can use the optimum f-stop, and then know how to best achieve that with movements. Choosing focus points for your plane of sharp focus and applying movements is equally, if not more, important that "focusing" your camera.

    Knowing how to deal with out-of-focus areas is important too. Sometimes, they are unavoidable; sometimes desirable (although I don't really like glaring out-of-focus areas in my work). Knowing how to tweak movements and focus so an unavoidable soft area is placed unobtrusively in the scene is important too.

    Best,

    Doremus

  4. #4

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    Re: Technique for focusing "into your scene"

    Quote Originally Posted by Doremus Scudder View Post
    Couple that with: https://www.largeformatphotography.info/fstop.html and you're good to go.

    A few observations:

    The "1/3-in" rule doesn't really work. The amount of depth of field in front of and behind the plane of sharp focus varies with the distance being focused on. There are better ways to work with a view camera.

    The "focus near - focus far and split the distance method" works well only if you use it intelligently. You have to get the proper f-stop to provide you with the desired depth of field and you need to consider where the plane of sharp focus will end up and adjust if needed. For example, you might want to cheat toward better focus for a distant horizon line at infinity and stop down more with many scenes, etc.

    And, the "near" and the "far" can end up being above and below the plane of sharp focus if you use tilts; you really need to be able to visualize where that plane of sharp focus is in order to effectively choose your near and far focus points.

    Mastering movements is an essential part of working with the view camera if you want to optimize sharpness and depth of field. You really need to be able to assess a situation, decide where you want the plane of sharp focus to lie in the scene so you can use the optimum f-stop, and then know how to best achieve that with movements. Choosing focus points for your plane of sharp focus and applying movements is equally, if not more, important that "focusing" your camera.

    Knowing how to deal with out-of-focus areas is important too. Sometimes, they are unavoidable; sometimes desirable (although I don't really like glaring out-of-focus areas in my work). Knowing how to tweak movements and focus so an unavoidable soft area is placed unobtrusively in the scene is important too.

    Best,

    Doremus


    Doremus, this is all very well said. But this is what I'm trying to understand better.

    How about this....here's a link to 4 shots I just took the other day. You can download them and zoon in further than SmugMug will allow. Anyway, you will see soft spots in these images even though all of these areas fell within my near and far focus points on the rail. It would have been my expectation that everything should have been pretty much the same sharpness, but not so....I'm trying to understand why.

    Of course one possibility is that I THOUGHT all the areas were within the near and far focus points of travel, and maybe I was wrong. But I'm thinking by moving the standard to the mid-point of the near and far points on the standard rail markings that I caused the problem and I should have set the standard closer to the max extension point.

    Anyway....take a look at let me know if anyone can detect any potential causes.

    https://fountainphoto.smugmug.com/Fi...umb-3-27-2021/

    Image 1: 150mm Rodenstock f/5.6. 1/15 sec @ f/25 orange filter
    Image 2: 150mm Rodenstock f/5.6. 1/15 sec @ f/20 orange filter
    Image 3: 90mm Rodenstock f/6.8. 1/15 sec @ f/20 orange filter
    Image 4: 90mm Rodenstock f/6.8. 1/8 sec @ f/22 orange filter

    Arca-Swiss F-Line Classic with the MicroOrbix. Focus in the highest farthest point, MicroOrbix tilt for the nearest lowest. Image 4 was the easiest to get this clean.

    Any thoughts??
    Anything in life worth having is worth sharing.

  5. #5
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    Re: Technique for focusing "into your scene"

    Quote Originally Posted by AdamD View Post
    It would have been my expectation that everything should have been pretty much the same sharpness, but not so....I'm trying to understand why.
    DOF theory does not imply that everything within the calculated limits is uniformly sharp. Simply from the laws of optics, the degree of unsharpness necessarily increases as you move away from the plane of focus. However, depending on your circle-of-confusion criterion, up to the calculated distance limits the portions of the picture away from the plane of focus are judged acceptably unsharp. Again, not uniformly unsharp, just acceptably so to a varying degree as you move away from the plane of focus.

  6. #6

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    Re: Technique for focusing "into your scene"

    Image 1: 150mm Rodenstock f/5.6. 1/15 sec @ f/25 orange filter
    Looks good front to rear but soft top right, which implies to me that you had some swing in place as well.

    Image 2: 150mm Rodenstock f/5.6. 1/15 sec @ f/20 orange filter
    Same thing really. Good overall but soft on the left side.

    Image 3: 90mm Rodenstock f/6.8. 1/15 sec @ f/20 orange filter
    Looks like it's focused on the dead tree and no tilt has been used so the midground is slightly soft and the background is very soft.

    Image 4: 90mm Rodenstock f/6.8. 1/8 sec @ f/22 orange filter
    Foreground sharp, background sharp, midground soft. Classic effect you get when the shape of the terrain is like this. Your cone of focus expands as it moves away form the camera but it's not big enough to encompass the midground.

    I might not be right but as all these appear to have been shot wide open (or close to that, I'm not familiar with those lenses) I would not be surprised by any of the above.

    As an example of #4, here's one of mine I posted on the forum yesterday.



    I put the plane of focus as best I could through the heads of all the grass, those in the foreground are sharp as are those at the back, but in between, lower down on the grass stems, it's not in focus. And this is at f45.
    Rob Gray Ś Nature Photographer Extraordinaire
    www.robgray.com

  7. #7

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    Re: Technique for focusing "into your scene"

    Quote Originally Posted by AdamD View Post
    Doremus, this is all very well said. But this is what I'm trying to understand better.

    How about this....here's a link to 4 shots I just took the other day. You can download them and zoon in further than SmugMug will allow. Anyway, you will see soft spots in these images even though all of these areas fell within my near and far focus points on the rail. It would have been my expectation that everything should have been pretty much the same sharpness, but not so....I'm trying to understand why.

    Of course one possibility is that I THOUGHT all the areas were within the near and far focus points of travel, and maybe I was wrong. But I'm thinking by moving the standard to the mid-point of the near and far points on the standard rail markings that I caused the problem and I should have set the standard closer to the max extension point.

    Anyway....take a look at let me know if anyone can detect any potential causes.

    https://fountainphoto.smugmug.com/Fi...umb-3-27-2021/

    Image 1: 150mm Rodenstock f/5.6. 1/15 sec @ f/25 orange filter
    Image 2: 150mm Rodenstock f/5.6. 1/15 sec @ f/20 orange filter
    Image 3: 90mm Rodenstock f/6.8. 1/15 sec @ f/20 orange filter
    Image 4: 90mm Rodenstock f/6.8. 1/8 sec @ f/22 orange filter

    Arca-Swiss F-Line Classic with the MicroOrbix. Focus in the highest farthest point, MicroOrbix tilt for the nearest lowest. Image 4 was the easiest to get this clean.

    Any thoughts??
    Adam,

    Some thoughts :

    First, just because you choose near and far focus points and then set the focus halfway between them doesn't mean that you have enough depth of field for the extremes; that depends upon the aperture. The farther apart the focus points are (call it the focus spread distance) the smaller aperture you'll need to get everything acceptably sharp. That's all in the article that I linked to in my first post.

    Second, as Corran mentioned above, there's really only one sharp plane of focus; everything else is out of focus proportionally to how far it is from the plane of sharp focus and the aperture you've chosen. The object is to have the out-of-focus blurs (blurry circles/circles of confusion) to be so small in the final print that our eyes can't tell the difference between them and the really sharp points. You can see, then, that whether something ends up appearing out of focus also depends on the degree on enlargement. Make a contact print and it looks really sharp; enlarge it 10x and everything starts to look soft...

    So, the idea is to find the optimum aperture for the focus spread you have and the degree of enlargement you are planning on making (or, conversely, knowing how large a print you can make from a particular negative before it appears soft in areas you want sharp). Again, the article I linked to goes into this. Really, it's worth doing your homework here to save yourself a lot of headaches later.

    Lets talk about movements a bit while I'm at it: Movements are used for two reasons: image control (e.g., correcting converging parallels) and optimally positioning the plane of sharp focus in the scene. The latter is the important one here and is achieved with tilts and swings (note that rise/fall doesn't reposition the plane of sharp focus; just takes a different slice of the image circle).

    When positioning the plane of sharp focus with a view to getting everything in the scene as sharp as possible (which I think is what you're trying to do), the object is to get it as close as possible to the near and far focus points. The problem is, when you move the plane of sharp focus around, the points that are nearest and farthest change around too. If you, say, tilt the front forward a bit, which results in tilting the plane of sharp focus down in the scene a bit more in that same direction, the points you choose to focus on are no longer the ones nearest to and farthest from your camera position. Let's say you tilt so that the top of a near rock and a far mountaintop are in the plane of sharp focus. Now, the farthest point from the plane of sharp focus might be a spot at the base of the mountain, and there may be no point nearer than the top of that near rock you focused on. Note also, that the mountaintop is just as close to the plane of sharp focus as the top of the near rock. (This scenario is a common mistake made by people just learning camera movements.)

    You can see, in the above example, that the plane of sharp focus isn't at an optimal position between near and far points; it's intersecting the nearest point and some distance from the farthest point (which is at a point that seems counter-intuitive at first...). The solution is to choose better reference points; focus halfway down into that near rock and halfway down the mountainside so the tops of the near rock and the mountain are "closer" and the bottom of the near rock and the base of the mountain are "farther" from the plane of sharp focus.

    Now, you've positioned your plane of sharp focus well, but you still need to focus the camera (many think they are done at this point, but no!). Find the closest point, i.e. which point in the scene needs the most bellows extension to be sharp on the ground glass. Note this position; it's your "near" focus point. Now do the same for the far; search around in the scene and find the point that requires the least bellows draw. This is your far focus point.

    Once you have those, note the distance between the two points, set your focus halfway between them on the rail/camera bed and, importantly, choose the optimum aperture for your focus spread so that everything stays acceptably sharp.

    If you've done your homework, you've got a sticker or a table that you can easily reference to tell you what aperture to use for what focus spread.

    Alternately, you can set your focus and stop down, observing your focus points through your loupe until they become acceptably sharp and use that aperture. Many do this. The problems with the visual method, however, are that the ground glass can get too dark to view in many situations (low light, etc.), the grain of the ground glass can keep you from being able to tell when things are right, and you're not really balancing diffraction degradation with depth of field (unless you're using a really powerful loupe and a really fine ground glass, anyway). Still, many say, "stop down till everything is sharp enough, then stop down one more stop," and do fine. I like my focus-spread tables.

    Finally, let's look at one of your photos as an example. I don't know what you find unsharp about it; I can't see things on the website very well, but I can till you how I'd go about setting up for it. The photo is the second one, the one with the hillside and rock outcropping that slope up to the left.

    I'd want to place my plane of sharp focus diagonally in this scene, laying it down a bit with tilt and then tipping it sideways a bit with swing so that the near right corner of the plane of sharp focus was the lowest and the far left was the highest (hope that makes sense). I'd pick two points on the vertical center axis for my tilt reference points, say halfway up that cholla in the foreground and halfway up the rock outcropping. I'd apply the tilt first. Then, I'd choose two reference points for the swing on the horizontal axis, say halfway up the slope on the left and the middle of the bright rock on the right. I'd then apply the tilt.

    After that, I'd search around the scene, focusing on different things to find which are actually the "near" and "far" focus points, all the time keeping in mind where my plane of sharp focus lies. So, I'd check the tops of the rock outcropping and the tops of the near bushes/cacti for near points. Ideally, they should all be in focus at roughly the same position (if there are large discrepancies, I might rethink my movements). I'd find the one with the greatest bellows draw and call that "near" and note the position on the camera (my cameras all have scales on them). Then, I'd look around for the "far" (this time, something below the position of the plane of sharp focus), likely the hollow at the base of the outcropping or the ground near the camera. After finding the one that needs the least bellows draw, I'd note that position and then proceed as described above; finding focus spread and choosing aperture.

    Sorry this got so long; I didn't have time to write a shorter response

    Doremus

  8. #8

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    Re: Technique for focusing "into your scene"

    Quote Originally Posted by Doremus Scudder View Post
    Adam,

    Some thoughts :

    First, just because you choose near and far focus points and then set the focus halfway between them doesn't mean that you have enough depth of field for the extremes; that depends upon the aperture. The farther apart the focus points are (call it the focus spread distance) the smaller aperture you'll need to get everything acceptably sharp. That's all in the article that I linked to in my first post.

    Second, as Corran mentioned above, there's really only one sharp plane of focus; everything else is out of focus proportionally to how far it is from the plane of sharp focus and the aperture you've chosen. The object is to have the out-of-focus blurs (blurry circles/circles of confusion) to be so small in the final print that our eyes can't tell the difference between them and the really sharp points. You can see, then, that whether something ends up appearing out of focus also depends on the degree on enlargement. Make a contact print and it looks really sharp; enlarge it 10x and everything starts to look soft...

    So, the idea is to find the optimum aperture for the focus spread you have and the degree of enlargement you are planning on making (or, conversely, knowing how large a print you can make from a particular negative before it appears soft in areas you want sharp). Again, the article I linked to goes into this. Really, it's worth doing your homework here to save yourself a lot of headaches later.

    Lets talk about movements a bit while I'm at it: Movements are used for two reasons: image control (e.g., correcting converging parallels) and optimally positioning the plane of sharp focus in the scene. The latter is the important one here and is achieved with tilts and swings (note that rise/fall doesn't reposition the plane of sharp focus; just takes a different slice of the image circle).

    When positioning the plane of sharp focus with a view to getting everything in the scene as sharp as possible (which I think is what you're trying to do), the object is to get it as close as possible to the near and far focus points. The problem is, when you move the plane of sharp focus around, the points that are nearest and farthest change around too. If you, say, tilt the front forward a bit, which results in tilting the plane of sharp focus down in the scene a bit more in that same direction, the points you choose to focus on are no longer the ones nearest to and farthest from your camera position. Let's say you tilt so that the top of a near rock and a far mountaintop are in the plane of sharp focus. Now, the farthest point from the plane of sharp focus might be a spot at the base of the mountain, and there may be no point nearer than the top of that near rock you focused on. Note also, that the mountaintop is just as close to the plane of sharp focus as the top of the near rock. (This scenario is a common mistake made by people just learning camera movements.)

    You can see, in the above example, that the plane of sharp focus isn't at an optimal position between near and far points; it's intersecting the nearest point and some distance from the farthest point (which is at a point that seems counter-intuitive at first...). The solution is to choose better reference points; focus halfway down into that near rock and halfway down the mountainside so the tops of the near rock and the mountain are "closer" and the bottom of the near rock and the base of the mountain are "farther" from the plane of sharp focus.

    Now, you've positioned your plane of sharp focus well, but you still need to focus the camera (many think they are done at this point, but no!). Find the closest point, i.e. which point in the scene needs the most bellows extension to be sharp on the ground glass. Note this position; it's your "near" focus point. Now do the same for the far; search around in the scene and find the point that requires the least bellows draw. This is your far focus point.

    Once you have those, note the distance between the two points, set your focus halfway between them on the rail/camera bed and, importantly, choose the optimum aperture for your focus spread so that everything stays acceptably sharp.

    If you've done your homework, you've got a sticker or a table that you can easily reference to tell you what aperture to use for what focus spread.

    Alternately, you can set your focus and stop down, observing your focus points through your loupe until they become acceptably sharp and use that aperture. Many do this. The problems with the visual method, however, are that the ground glass can get too dark to view in many situations (low light, etc.), the grain of the ground glass can keep you from being able to tell when things are right, and you're not really balancing diffraction degradation with depth of field (unless you're using a really powerful loupe and a really fine ground glass, anyway). Still, many say, "stop down till everything is sharp enough, then stop down one more stop," and do fine. I like my focus-spread tables.

    Finally, let's look at one of your photos as an example. I don't know what you find unsharp about it; I can't see things on the website very well, but I can till you how I'd go about setting up for it. The photo is the second one, the one with the hillside and rock outcropping that slope up to the left.

    I'd want to place my plane of sharp focus diagonally in this scene, laying it down a bit with tilt and then tipping it sideways a bit with swing so that the near right corner of the plane of sharp focus was the lowest and the far left was the highest (hope that makes sense). I'd pick two points on the vertical center axis for my tilt reference points, say halfway up that cholla in the foreground and halfway up the rock outcropping. I'd apply the tilt first. Then, I'd choose two reference points for the swing on the horizontal axis, say halfway up the slope on the left and the middle of the bright rock on the right. I'd then apply the tilt.

    After that, I'd search around the scene, focusing on different things to find which are actually the "near" and "far" focus points, all the time keeping in mind where my plane of sharp focus lies. So, I'd check the tops of the rock outcropping and the tops of the near bushes/cacti for near points. Ideally, they should all be in focus at roughly the same position (if there are large discrepancies, I might rethink my movements). I'd find the one with the greatest bellows draw and call that "near" and note the position on the camera (my cameras all have scales on them). Then, I'd look around for the "far" (this time, something below the position of the plane of sharp focus), likely the hollow at the base of the outcropping or the ground near the camera. After finding the one that needs the least bellows draw, I'd note that position and then proceed as described above; finding focus spread and choosing aperture.

    Sorry this got so long; I didn't have time to write a shorter response

    Doremus

    Doremus,

    You totally outdid yourself. I love this post. So thoughtful and I totally followed you. I can see why you are suggesting swing, but that didn’t even occur to me in the moment.

    Thank you so much. This is a post I will be saving to reread over a few more times.

    Adam
    Anything in life worth having is worth sharing.

  9. #9
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    Re: Technique for focusing "into your scene"

    2022

  10. #10

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    Re: Technique for focusing "into your scene"

    Quote Originally Posted by Richard Wasserman View Post

    Which essentially says the same thing..."Focusing at the median of (A,B) will make the closest point and the furthest point equally sharp." which is essentially the 50% mark. How you get there will vary depending on your camera, but in essence, the instructions (which btw, I have read and re-read many times) gets you to a point where your min/max focus extension determines where we split the difference.

    Why is that when the strategy for a non-movement camera is to focus 1/3 of the way into the scene? Shouldn't this hold true when using a camera with movements? Why would it be different?

    When you think about it, the max extension focus point in many cases will be your most important subject material. Further, if using tilt, the max extension point establishes the plane of focus which, to me is a pretty darn important aspect of the photo, right? So, if you focus 50% into the scene or focus at the "median of (A,B)" you are in effect moving the plane of focus further away from the initial focal plane.

    I guess forget all that noise....why "median of (A,B)" and not 1/3 towards the minimum extension or 1/3 of (A,B)?
    Anything in life worth having is worth sharing.

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