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Thread: Long Lenses Don't Compress Foreground and Background?:Still Confused.

  1. #1

    Join Date
    Nov 1999
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    Long Lenses Don't Compress Foreground and Background?:Still Confused.

    About one week ago I raised the question of whether "telephoto-design" lenses pr oduce pictures that look in any way different than "normal-design" lenses in the same focal length. The answer to my question was understandably universal: no. But in the course of answering the question some people pointed out that I was w rong in my perception of the effects of long lenses, in that LONG LENSES DO NOT COMPRESS FOREGROUND AND BACKGROUND, BUT (FOR LACK OF A MORE PRECISE WAY FOR ME TO PUT IT) MERELY "CROP THE IMAGE AND ENLARGE IT". Well, at the time I first re ad this, I didn't think much of it because I was much more concerned with the po ssible differences between telephoto and normal-design lenses. But since then, I have gone back and reflected on this other aspect of their answer, and simply can't understand, for the life of me, how this could possibly be true. If long lenses do not compress foreground and background space then why is that when I have used a 105mm lens (or a 135mm, or a 200mm for that matter) in a 35mm format to photograph people, for example, did the space between the subjec t and the background seem to shrink, and the things in the background seem to mo ve closer to the foreground subject--or vice versa? And why is it that when I a m watching a movie that takes place in a city and the camera has a long lens foc used on a busy sidewalk full of people walking in one direction, do all the peop le appear to be walking on top of each other? And why is it that if a long lens was focused on two cars in the distance following each in a car chase would the two cars--even if they were separated by a great distance, be seemingly brought closer together by a long focal length lens--and the longer the lens, the greate r the closeness? Or is this effect due exclusively to the illusion of diminishi ng perspective (inherent in our own unaided eyesight), and the fact that the lon g lens merely crops the portion of this diminished perspective, and appears to h eighten it by presenting just a small piece of it? I am only really interested in answers to these questions, insofar as they rel ate to THE PROPER LENS SELECTION FOR LARGE-FORMAT CAMERAS. Basically my problem is this: I own 150mm, 210mm, 240mm, and 305mm lenses for my 4 x 5 camera, but I would like to get a longer lens that hopefully will provi de greater "compression of space" in my portraits, making my pictures of people "more dramatic" by "exaggerating their size or presence". So far, neither the 24 0mm nor the 305 have really accomplished this effect for me. Is it true that the 210mm will yield a perspective that is IDENTICALLY THE SAME, for example, as a 480mm, as long as I move close enough to create the same cropping between the tw o lenses? But if this were the case, then why do people recommend long lenses, such as the 300mm or 360mm for 4x5-format portraiture? Isn't it true that the l onger lenses alter the space, volume, perspective (call it whatever you like) an d "flatten" the face, reducing any possible exaggerations of nose and chin etc, thereby effecting a more complimentary look?

    But, then again, I have become quite confused lately because I recently compared pictures taken of a person with a 360mm and a 210mm, and the pictures taken wit h both lenses DID look almost the same (or perhaps exactly the same, but I can't quite believe it nonetheless), if I simply moved closer to the subject when I u sed the 210mm.

    Is there any point in purchasing a long lens if one is able to move close enough with a 210mm, to produce the same cropping with the shorter lens?

    Am I wasting my money on a huge misapprehension--if this is all I "plan" to acco mplish with a longer lens? (In this case, the 360mm lens in question is about $ 1400--so the answer is really important.)

    Will a 420mm or a 480mm lens not produce pictures that are in any way more "dram atic" or "foreground-and-background-compressing" than say a 210mm lens positione d much closer (to produce the equivalent cropping)?

    Is the purpose of a long lens merely to bring distant objects closer that might otherwise be too small because they are too far away (as in the case of a nature or sports photographer)--WITHOUT EFFECTING ANY CHANGE IN THE SPACE OR VOLUME BE TWEEN FOREGROUND AND BACKGROUND?

    I have taken pictures for many years--albeit with 35mm more than large-format--a nd I am really embarassed that I don't know the answers to these seemingly basic but admittedly elusive questions. Embarassingly, they have dogged me for some time, now that I am shooting exclusively in large format and seeking to achieve a certain "look" or "effect" with my portraiture--and I've yet to grasp it or co me to a clear answer in my head still in all the hours I have spent studying my prints. The answer is important because it determines which lenses it is necessa ry--or pointless--to buy.

    Anybody's help would be much appreciated.

    Thanks again.

    Nick Rowan

  2. #2

    Long Lenses Don't Compress Foreground and Background?:Still Confused.

    The spatial "compression" you are after is a perspective effect determined by the distance of the lens from the objects being photographed. A simple example: imagine two people 10 feet apart. Case 1: position the camera 5 feet in front of one person and 15 feet in front of the other and use a short focal length lens. In the resulting photograph the people will look like they are at quite different distances because of visual clues such as their relative sizes.

    Now position the camera 100 feet from the first and 105 feet from the second person. Case 2A: select a long lens to include the same cropping as in case 1 and take a photograph. The people will now look to be at the same distance (the fractional difference in their distance is 5% instead of 50%), except for visual clues such as the front person perhaps blocking the view of parts of the second person. This is the "telephoto compression" effect. The name is a misnomer since the lens need not be a telephoto, nor, as the next case shows, a long lens. Case 2B: imagine that you have extremely fine-grained film and only one lens, the short focal length lens of Case 1. Take the photograph and then enlarge a small portion of it to obtain the same cropping as before. With perfect film the image would be the same as Case 2A.

    Perspective is controlled by camera position. The "compressive" effects you seek are obtained by placing the camera far from the subject. The compressive effects are associated with long lenses because they are generally used to overcome the small subject size created by the large camera/subject distance.

    In your example of portraits with 210 and 360 lenses, the relative distance we are considering is between the tip of the nose and perhaps the ears. With these lenses you are far enough away that the change in relative distances will be small. Now if you compared an image taken with a 90 mm lens and a 210 lens, both with a camera position filling the 4x5 negative, you should see a big difference.

    If you want to experiment with what a long lens would produce, position your camera at the distance you would use for that lens and then use only the central portion of the negtive. E.g., to simulate a 600 mm lens with a 300 mm lens, move the camera twice as far away and use only the central 50% of the negative (50% linear, 25% area).

  3. #3

    Long Lenses Don't Compress Foreground and Background?:Still Confused.

    Nick, you have it figured out, but think of it this way. If you stand next to a buildiing and are looking at another building, doesn't the nearer one looke bigger?even if it isn't physically bigger? and don't they look far apart from one another? (think wide angle here) now, if you are a mile away from both buildings, don't they look as it they are right on top of each other? (think telephoto here).

    The theory of using long lenses for portraiture still holds, if I am one inch away from your nose and take a picture, and your nose sticks out one inch from your face, then your nose is halfway between your face and the lens. If I stand 20 feet away and take a pic, your nose is still an inch away from your face, but is much further away from the lens. Its all relational. You could do this with your naked eye and get the same effect, only when you are far away from your subject you can't crop out the useless areas like you can with a telephoto lens.

    So, yes to make a long story short (too late) the telephoto lenses only crops out the extra space around the subject, the foreshortning effect is caused by the distance from the subject.

    So the longer lens purchase isn't pointless, you are seeing the cure as the cause-- the telephoto lens doesn't cause the foreshortning, it only makes you move back to get more in the picture--the moving back is what causes the effect?

    sometimes my explanations tend to ramble, so I hope that I didn't confuse you even more.

  4. #4

    Long Lenses Don't Compress Foreground and Background?:Still Confused.

    Jeez Michael, you beat me to it, and I thought that I was going to be the first to answer!

  5. #5

    Join Date
    Nov 1999
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    59

    Long Lenses Don't Compress Foreground and Background?:Still Confused.

    Thank you both for your very detailed answers, but I am still struggling to understand what you said.

    Are you saying that the "compression" one senses (and won't you at least grant the fact that there is at least an APPARENT sense of compression caused by the view-cropping effect of long lenses?) in a photo taken with a long lens is due to the natural condition of foreshortening which the human eye is subject to simply being replicated--and, if you will, exaggerated--by the way a long lens crops out the "outside" portion of a frame and highlights one "center" portion, thereby removing the spatial-context for that center portion to relate to, giving all objects at whatever distance (both from each other as well as from the lens) within that central portion the appearance/illusion of being compressed or brought closer together, in relation to the lens/eye?

    I'm sorry--that's probably way too convoluted...but I think I may be getting it, I'm not sure--I've been conditioned to think about this very simple idea very differently all these years, and I have to "unlearn" it now (I never thought about it from the perspective of how our eyes actually "do the compressing" naturally every time we see distant objects and diminish their perspective), but I still have some very practical questions, as they relate to lens purchases, which are really the most important in the end.

    Having said all that both of you said: can you both (or anyone else for that matter) please offer me some guidance and recommendations as to what focal-length long lens(es) you think I should get for trying to achieve this "appearance" of compression that I am trying to attain? I have now a 150, 210, 240, and 305. I don't feel that the 210, 240, or 305 are capturing enough compression; I have recently considered purchasing a 360mm, aware that is the "high-end" of the traditional spectrum of 4x5 portrait lenses, but have tried it out and still feel it is too much like my 210mm (can barely see a difference when I simply move closer with the 210--is that possible?). I also tried out a 420mm (Red Dot Artar) and felt that focal-length came ALOT closer in increasing the "claustrophobic effect" of compression I am looking for--does that reaction make sense (it's only 60mm longer than the 360, and yet seems to yield a bigger difference than exists between the 210mm and 360mm [a 150mm difference])? And what about a 450mm, or 480mm? Would those be good choices too? (Forget about issues of bellows requirement; I have enought for all up to at least 480mm) Have either of you ever heard of using such long lenses in a studio setting to shoot a portrait with a 4 x 5 camera? Or SHOULD I JUST ABANDON THE WHOLE PROSPECT OF PURCHASING THESE LONGER (ie 360, 420, 450, and/or 480mm) LENSES, AND SIMPLY PHOTOGRAPH AT A CLOSER LENS-TO-SUBJECT DISTANCE WITH MY EXISTING 210MM or 305MM LENS?

    Will I really capture the "dramatic" illusion of "compression" I am so desiring with any of these longer lenses, filling all frames HALF- FIGURE? Or do you think the effects will be inconsiderable, in relation to simply moving closer with one of the focal lenths I already have?

    Thanks again--

    Nick

  6. #6

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    Long Lenses Don't Compress Foreground and Background?:Still Confused.

    Nick, Generally, you probably won't get the dramatic telephoto shots with large format that you can with smaller formats (e.g. 35mm) simply because lenses proportionally as long for the formats aren't available, practical or used very often. For instance, a 600mm lens on a 35mm camera is equivalent to 1800mm on 4x5 (multiply your 35mm focal lengths by 3 to arrive at a rough comparison). You just won't find one of those beasts! However, there are lots of "longer" lenses for LF in the 300 to 600+mm range. These are equivalent to 100-200mm on 35 mm. This is about as long as practical and affordable for most of us. So, when choosing your lenses, and in view of the above discussions, (which should have you coninced by now that the so- called "telephoto effect" is a function of distance and angle of view, not lens design), and, taking into consideration that LF offers lots of leeway to crop and still have relatively sharp and grain free enlargements, I would suggest that you purchase shorter lenses at first and crop when necessary for the shots that you need a really narrow angle of view for. This has several advantages: First, shorter lenses are cheaper. A 300mm Nikkor M or equivalent covers up to 8x10 and is downright affordable when compared to telephoto designs. Second, extremely long normal design lenses require appropriately longer bellow draw, requiring a larger, more cumbersome camera.(To circumvent this problem there are telephoto designs for LF. These, as you already know, trade shorter bellows draw for reduced performance and increased price!) Keep in mind that you can use one-half of your 4x5 sheet (i.e. crop to 2x2.5 inches) with a 300mm lens and still have a nice telephoto medium-format negative (equivalent to a 150mm lens on a 6x7 or a 100mm lens on 35mm)! Of course, if you find yourself cropping this small regularly, then you should consider shelling out for something longer and more exotic. Remember, your camera position (camera-to-subject distance) determines the perspective (large to small) relaionships in the scene and the longer lenses just narrow the field of view (which is the same as cropping). That means you don't "move closer" with a shorter lens to get the desired effect, you set up the camera at a distance where the perspective is correct and choose your lens or cropping to give the desired framing (angle of view). A rectangular opening cut in a piece of cardboard or a Zone VI viewing filter or the like can be helpful when composing. Hope all this helps, ;^D)

  7. #7

    Join Date
    Nov 1999
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    59

    Long Lenses Don't Compress Foreground and Background?:Still Confused.

    I am losing it again...I don't get it...if what you say is true, then all a longer lens does is CROP a view and make that portion of view full-frame: so why is that cropped view DIFFERENT than if I simply move closer to the subject and crop the picture to the same dimensions?

    I don't want to merely "crop a picture closer", I want to alter the relationship between the ground and the subject--or the foreground and the background--

    Either a long lens does that or it doesn't--

    If it doesn't do that, then I'd just as well use a shorter focal length and move closer--

    If it does do it, then I would like to find a lens longer than 360mm that will accomplish this "effect"--

    I think the central idea in all these explanations is getting lost, that a long lens causes at least some perceived/relative--call it what you like--CHANGE IN "RELATIVE SPATIAL PERSPECTIVE"--I like to call it "compression", you may call it "cropping"--but "cropping" to me implies NO SPATIAL/DIMENSIONAL CHANGE--and I just can't see how that could be the case--

    But if it is the case, then I don't see any argument for purchasing/ using a longer lens.

    I mean: either a long lens produces a different-looking picture than a normal focal length or it doesn't--

    You have to concede that the relationship between foreground and background within the frame undergoes SOME change by using a really long lens, or not-- -------------------

    On another note, I don't have the option to crop my 4 x 5 negatives, as I am making mural-size prints and need to utilize the full frame-- to keep the enlargement ratio to a minimum (approx 12x).

    I am already well aware of the bellows issues with regard to telephoto vs. normal design--I am not concerned with that--but are you implying that the view of a telephoto lens is DIFFERENT than a normal-design long lens, AT THE SAME LENS-TO-SUBJECT DISTANCE? Ie: if I stand 7 feet from a person with a telephoto lens, and then stand 7 feet from that same person with a normal-design long lens in the same focal length, that the two "cropped views" are different?

  8. #8

    Long Lenses Don't Compress Foreground and Background?:Still Confused.

    Nick:

    1. Forget the design of the lens... all that matters is focal length.

    2. Compression is a particular perspective caused by long film to subject distance ONLY. Focal length doesn't matter, only subject-film geometry.

    3. We usually use long focal length lenses for distant subjects, thus we observe compressed perspective most commonly with long focal length lenses.

    4. If you take 2 shots of the same subject, from the same distance with two focal length lenses, and crop the image shot with the shorter lens to match the image made with the longer lens, the perspective will be identical. Same subject-film geometry, thus same compression for distant objects. Obviously, the cropped image will be grainier and less sharp.

    5. In addition to the geometric perspective issue, part of what you see in long focal length shots is less depth of field which accentuates the compression effect by rendering only a narrow range of distances in sharp focus.

  9. #9

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    Nov 1999
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    Long Lenses Don't Compress Foreground and Background?:Still Confused.

    Glenn,

    Are you saying that if I stand, for example, 10 feet away from a person and point a 480mm lens at them and then stand 5 feet (or whatever distance would be necessary to create the same cropping of view as the 480mm creates) from the the same person and point a 210mm lens, that the photographs taken with these 2 lenses at these 2 distances would be exactly identical?

    Then why should I shell out $1500. for a long lens, when I can just use the 210mm I have now, and simply MOVE CLOSER to my subject when I photograph them?

  10. #10

    Long Lenses Don't Compress Foreground and Background?:Still Confused.

    Nick: Moving closer has the opposite effect on the "compression" factor. The distance from the lens to the subject is what causes the compressed look. As previously said, it is easier to achieve with 35mm than 4x5. A 360mm is not going to give you much more of a compression look than a 300 on 4x5 film. You would need to go above 500 mm and back off to get the compression look you want. The cropping that seems to be confusing you occurs after the image is on the negative, not cropping in the camera. For instance, if you make a photograph at 50 feet with a 300mm lens and a 90mm at the same 50 feet, naturally the 90 will take in much more area. However, if you enlarge the full negative from the 300mm to 8x10 and a small section of the 90 mm to match the print from the 300, the images will appear identical. Hope I haven't added to the confusion. Doug.

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