Nick:
No! I said that the image produced by different lenses given the SAME subject-film geometry has the same perspective.
If you shoot with a shot with a 240, then move twice as far away and shoot the same shot with a 480, the second shot WILL have a more compressed perspective. But the REASON is that you moved twice as far away, NOT that you used a longer focal length lens.
So, since we use longer focal length lenses at greater distances, we associate them with compressed perspective.
Doug,
Thank you for saying what you did about long lenses on 35mm vs.long lenses on 4 x 5.
I have noticed the same difference--but correct me if I'm wrong in what I am about to say.
Part of my frustration over this whole issue stems from the fact that I am conditioned to being able to achieve a certain amount of "compression" using long lenses in a 35mm format, which I have been consistently unable to achieve in a 4 x 5 format.
Long lenses in 35mm seem to produce greater compression--or at least the feeling/appearance of greater compression--than long lenses in a 4 x 5 (or 8 x 10) format.
But is this exactly right? I mean if I compare the "compression effect" of a 105mm lens vs a 50mm lens in a 35mm film format, against the "compression effect" of a 360mm lens vs.a 180mm lens in a 4 x 5 film format, are the two "compression effects" the same? Or would the photos taken with the 105mm on 35mm film cause greater compression than the photos taken with the 360mm on 4 x 5 film, as long as the two lenses were positioned at exactly the same distance from the subject?
If a smaller compressive change would occur between doubling the focal length within the 4 x 5 format vs. doing the same within a 35mm format, is this one reason why large-format cameras (in this case, 4 x 5 ones) are routinely built with such "short bellows"--ie bellows that usually only accomodate lenses up to about 300 or 360mm in focal length--because there is a recognition that using longer lenses doesn't alter a picture as radically as they do when used on 35mm cameras?
-----------------------
Also, do you think that I should avoid contemplating purchasing any lenses longer than the 305mm lens I already have, to create the effect of compression I am so desiring? (I mean I don't think I want to get a lens that's longer than 480mm--or should I? Ie: does anyone ever use such long lenses--lenses over 500mm--to shoot simple studio portraits?!)
Glenn,
Thank you for the clarification; I think that may have crystallized an understanding in my mind.
I still have more questions, but I hesitate to pose them, for fear that they are going to further confuse me--
Nick: The reason it looks different on 35mm is because of the negative size. If you put your 305mm lens from your 4x5 on your 35mm camera, the look will be the same as with your 300 telephoto from the same distance. Try this: set up your 4x5 next to your 35mm, both on tripods, and shoot the same subject with a 210 lens on the 4x5 and a zoom set at 210 on the 35mm. Shoot a negative with each. Then take the scissors and cut out a 35mm section of the 4x5 negative. The photos will be identical in size and perspective. 400 mm on a 4x5 is just about pushing the limits of the bellows even on studio stand cameras for head and shoulders portraits. To fill the negative, you will need 800mm of bellows extension if you go to a 1-1 ratio. It becomes impractical. I learned studio portraiture on a stand camera which had about 36 inches of bellows. We used a 12" (305) or 14" lens (360) for head and shoulders. It took quite a bit of bellows extension. Doug.
Think about it this way. Perspective is essentially a function of relative sizes of objects at different distances. Something further away looks smaller than something closer. The ratio of their 'apparent' sizes is in direct proportion to the ratio of their distances to the lens (object A to lens divided by object B to lens). Focal length only alters magnification. A longer focal length will give you more magnification than a shorter focal length. However, the relative distances between the two objects (object A to lens divided by object B to lens) remains unchanged and therefore the ratio of their apparent sizes remains unchanged i.e., perspective does not change and all that the longer lens is doing is allowing you to crop out portions of the scene 'in camera' (which is why you will get the same effect by cropping the center of the image from the negative taken with the wider i.e., shorter lens while printing).
The 'compression effect' you refer to is a function of many things 1/ typically long lenses in 35mm are used to isolate specific elements i.e., to isolate one subject and crop out the rest of the scene (by doing that, you of course delete depth cues associated with those things you've cropped out like the foreground) 2/ smaller DOF which essentially does the same - if it is not sharp, your eye has trouble focusing on the edges to separate figure from ground 3/ most importantly, you use long lenses at a distance and therefore all the objects in the picture are at more or less the same distance to the lens i.e., there are not much perspective cues in the picture.
Technically, the compression effect of a 300 vs 150 on 4x5 should be similar to the 100 to 50 on 35mm but keep in mind that their aspect ratios are somewhat different which may play a role also. In my opinion, the whole thing is moot. The biggest depth cues in a picture are the relative sizes of various objects that you want in the picture. If a particular element does not add to the picture, it should probably not be there anyway. Now, if you graph the apparent size i.e., size of image on ground glass against distance to object (i.e., as you back away from it), you see that size diminishes rapidly and approaches an asymptote quite rapidly i.e., you need to back off huge distances to reduce the size appreciably. In other words, the relative sizes of two same sized objects at different distances to the camera rapidly approaches 1 as you increase the distance to both of them. There is really not too much to gain beyond this by backing off even further and using even longer lenses because they are so close to being the same size as makes no difference. So the 'compression effect' levels out quite quickly also. Longer lenses in 35mm are really more for reach i.e., because you cannot get closer to the bird or the lion and are forced to shoot at a distance - and not so much for the perspective compression they produce. In other words, if you're using a 300mm lens for portraiture on a 4x5, thats pretty close to what you're going to get. The relative sizes of nose (which appears bigger since it is closer than the ear)and ear are pretty close at the kind of ditance you would use a 300 at and you're going to have to go to huge increases in focal length to equalize them further (and its doubtful that you can make out this further equlaization anyway). If a 135mm is regarded as an ideal portraiture lens in 35mm, its equivalent is roughly a 15" lens. A 300mm lens on 4x5 is roughly a 105mm on 35mm and I think it should allow you to operate far enough back as to prevent any unpleasant 'large' noses. DJ
Hi Nick,You are struggleing with one of the problems I have found on this site; and that is every one wants to get too precise with all this. We are making pictures, that's all. Why make it sound like a big deal. Doremus above has it right. 4X5 AND 35mm are different animals. A long lens on a 35mm is a long lens indeed, and the compresson of the image is great. This is a 35mm "thing". This is part of the "distortion" 35mm is famous for. 4x5 has not the long lens "thing" and this is why the same effect is not possible.
When someone askes a question on this page, we need to answer as simply as possible. This is not a time to show off all the knowledge we have (or have not!) of large format. I have seen too much trying to "out do" the next guy or gal! Lets "Show off" our work and not try to impress each other with our expertise (or lack thereof). Come on Photography is Fun, Fun, Fun. Lets not turn it into an intellectual exersise!!
Nick, Here's something to try to get your brain around this, and overcome the misinformation you were fed (before coming here). Take a piece of paper and make a side view of your camera and scene. Put a foreground and background object, and a large simplified camera. Draw lines from the top of the frame (highest point in the final picture) to the bottom of the film plane, and another from the bottom of the frame to the top pf the film plane through the middle of the lens. (These should be symmetrical about the camera). Now draw similar lines for the tops and bottoms of the foreground and background objects. This should enable you to construct a rough guess at what the picture will look like (and get an idea about the 'compression effect'.
The angle between the first two lines you draw represents the focal length of the camera.
Now if you can make more pictures varying the size of the film plane, subject to camera distance, and focal length. This should give you a visual means of comparing different changes.
You should find that 1) moving the camera closer and farther from the subject changes the 'compression'; 2) Changing the focal length enables you to move to the appropriate distance to get the 'compression' you want, and still not have to crop the picture to the point of graininess, 3) increasing the film size means the longer focal length is needed to get the same level of cropping (not compression).
Hope This Helps,
-- Topher
Nick, If you take a piece of cardboard and cut a frame into it and then place it before your eyes, you will be able to view exactly what effect the different lenses will produce on your su bject by simply moving the frame back and forward. Now, if you take a picture with, say a 90 mm and then de cide to crop it, the result will be exactly the same as if the shot had been taken with a longer lens provided it was taken FROM THE SAME POINT! But of course, if you move forward to your subject to restr ain the image, the picture you will get WILL HAVE AN OTHER PERSPECTIVE than the cropped image from the first place. This is simply because a lens is made to include a certain angle of view. Whatever yo ur distance from the subject, this angle will always remain the same. If you take a portrait with a 9 0 mm wide-angle from a distance of 3 meters, the person will be entirely included in your shot, and the background will be included with an angle of 83 degrees. So you will see on each side of your subject a lot of scenery, sky, ground, other people, which can produce a very rich picture, but can also be very distu rbing. Now, you move forward to your subject to a distance of 1 meter and with the same lens take a h alf body portrait. The way your subject looks in the picture will change dramatically! The person will fill half of your image, but if you look at the background, it will still be there included with the same ang le as before. But now yourimage looks very DYNAMIC for the relation between the subject and the backgr ound has changed. The relation between different parts of the body will change also, producing some im pression of distortion in your subject's face (big nose).If the background was disturbing in the first pla ce, it might still be disturbing now even the subject has filled more space in your image. Now, if in stead of moving forward from your initial 3 meter stand, you take the shot with your 90 mm and once back home, decide to crop it to include only a half body portrait, you will do exactly the same as if you changed your 90 mm for, say a 300 mm. The space occupied by the subject on your image will be the same as wh en you had moved closer, but the background will then only be included with an angle of 30 degree s instead of the previous 83. So taking a shot with a 90 and cropping will give the SAME PERSPECTIVE and SAME IMAGE as a the shot taken with a 300 mm except for one thing: the DEPTH OF FIELD. Your shot t aken with the 90 mm at 3 meters will probably look sharp all the way through. Now, with the 300 mm, and although the THEORETICAL DEPTH OF FIELD REMAINS THE SAME, you will be able to make your subje ct sharp and keep the background out of focus by using selective focus and larger apertures. Also, if the background included is the same, being out of focus ISOLATES your subject, and concentrates the viewer attention on it. A way to take benefit of this rule is by using a roll film! Your same 90 mm will be approx. equivalent to a 24 mm small format lens on 4x5 and to a 35 mm on 6x9.
All this will certainly be obvious to you so far, but here is a word on the effe ct lenses have on perspectives. Imagine the face of your subject if you place your 90 mm 10 inches afar. You will see a huge nose, large chicks, large eyes, but as you move from the center to the edge s of the face, the parts will be reduced in great proportions: small chin, small ears, small forehead, sm all body. Never take a picture of your girl friend this way unless she has a great sense of humor! At t he opposite, if you use a very long tele for a portrait, the nose will be COMPRESSED and you will have lar ge ears, a large neck, kind of a "Rambo look". Of course, in your 210-360 case, the differences are probably very subtle and would produce perhaps an overall impression rather than a clear difference. An other c ase of figure is group photography. I once had taken a group with a 90 mm. The people in the center of the image where looking fine, but all the faces near the edges where STRETCHED WIDE resulting in a quite embarrassing situation. However, none of these three situations can be qualified of DISTORTED. It is sim ply a MATTER OF DISTANCE. A shot taken close should be viewed close, that means with the same an gle it was taken, and a shot taken from far should be viewed from far (something I have learned in this forum thanks to great contributors!). My 5x7 print from the group taken with a 90 mm on 4x5 looks good if viewed from a 5 inches distance! That means also an image should be taken according to the futur e enlargement and viewing distance it is designed to match. In this regard, portrait photographers have established that a focal of between 65 and 135 but usually 85 mm for small format, 150-200 for medi um and 210-300 for 4x5 will give acceptable results for a normal size normal viewing distance phot ograph. When you move beyond, you may make the viewer experiment some distortion. I hope this is of so me help! Did I get your question right?
To all,
I truly appreciate all that everybody has written in on this most vexing of subjects (at least it is to me), but I think it will take me literaly several days for me to digest and process everything that you have written. I confess that I don't understand quite alot of it on first reading. My head is literally reeling with dizziness; I have more questions now than answers...
Barring a full understanding of all the technical aspects to your answers, can someone simply provide some simple, practical advice. I currently have a 305mm lens as my longest lens for my 4 x 5 camera. Will I gain ANYTHING in terms of "drama", "impact", "compression", "heightened presence", "exaggerated imminence" --all non-technical adjectives I would use to describe the quality of a good 35mm "long- lens shot"--by stepping up to a lens LONGER THAN 300mm, such as a 360mm, 420mm, 450mm, or 480mm lens, and shooting from a greater distance? Yes or no?!!!!! (Remember: I am trying to produce in these pictures the most dramatic, eye-popping, half-figure portraits possible, that look like they are literally jumping out at you--) If the answer is yes, would the difference be 1) great, 2) medium 3) negligible, or 4) none. And if the answer is "great", "medium", or even "negligible", is there a particular focal length among the focal lengths I have mentioned above which YOU would choose--all issues of bellows requirement aside? Would you choose the highest focal length, or would the "dramatizing effects" level off after a certain focal length? Please accompany your choice with a brief explanation. Thank you!
Nick, I would like to know why you are going to 4x5 for portraits and not 2 1/4 ? 4x5 can be such a pain for portraiture (in many cases) and especially with as long of a lens as you want ( a 4x5 470mm only equals a 135mm lens on a 35mm camera). You would have to go into 8x10 lenses to get the focal length you want $$$$$$$ and how are you going to keep the shot composed correctly with such a static camera? My advice is against large format for what you are trying to do.
Posting Permissions
Reply With Quote
Bookmarks