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stradibarrius
21-Dec-2014, 14:04
When you decide to take a photo, how do you decide which lens in your bag to use? to be a bit more specific...ex. a table top shot where you could use a longer lens from a farther distance or a shot focal length and be closer to the subject.
You could use a 150mm at x distance away or a 300mm at x+ distance away.
Assuming both lenses are of equal quality, contrast, sharpness etc. I know that in portraiture shorter lenses will magnify certain features but subjects other than portraits.

Will Frostmill
21-Dec-2014, 14:31
The rule of thumb is in two parts:
1. The longer the lens, the further back you need to be to fit everything in.
2. The further back you are, the less difference you'll see in size between the things you are photographing. (This is a property of perspective, not lenses.)

So if you set up a bunch of identical bottles on a table for a still life, and frame it so that they fill the viewfinder/ground glass, with a "normal" lens, the bottles toward the front will seem a little bigger than the ones in the back. With a "short tele" lens, the bottles in the front and the ones in the back will seem to be the same height. This is why the convention is to use a short tele lens for portraits: you don't want to accidentally magnifiy someone's nose relative to the rest of their face. (This isn't always good advice.)

Another way to think about it is this: if you keep the framing the same, a shorter lens magnifies things in the foreground much more than a longer lens. The longer lens magnifies everything equally.

Using a longer lens can make some things look unnaturally flat and weird, particularly once you get beyond 200mm in 35mm film terms.

Heroique
21-Dec-2014, 14:46
When you decide to take a photo, how do you decide which lens in your bag to use?

Here's a great tool to help determine which lens is "best" for your image:

126990

This is AA using his viewing card in The Camera – it’s from the "Basic Image Management" chapter. He calls it the cut-out card. He can be so literal sometimes.

Forum members here also call it the "viewing frame."

Me, I've taken fewer & better shots because of it. Yet, some of my best shots happened because I didn’t bring it, or I put it aside. (Never would this cause me to abandon its use.)

I'll just say that the frame, on one hand, is supremely useful in isolating elements in a scene by imposing borders roughly corresponding to the field of view of a particular lens. It makes choosing the best lens a lot easier.

On the other hand, its usefulness potentially blinds me to additional means of pre-visualizing. If I’m not careful, it monopolizes too much of my attention – w/o my awareness that it's doing so.

I made mine w/ a mat cutter and leftover piece of mat board, so I’ll add "cheap" to tiny, light, and useful.

Old-N-Feeble
21-Dec-2014, 14:49
1. What are the limitations regarding camera placement?

2. How to I want the main area of concern (foreground or background)... to relate to the other?

3. After 1 and 2 are answered: What kind of effect best suits the subject?

Light Guru
21-Dec-2014, 14:56
You choose the one that will give you the image you have in your mind.

neil poulsen
21-Dec-2014, 15:16
I first determine the camera position, depending on the object, direction, near to far relationships, etc. I append this process with a Computar zoom, viewing frame to frame and compose the image. I have marks on the Computar to determine which lens to use. It's pretty straight forward.

The Computar is kind of neat. It's an optical zoom, versus the Linhof viewer, which is a mechanical zoom. The computar was designed for a 3x4 ratio. But by opening it up and masking it a little more tightly, I get a good 4x5 framing tool. In focal length range, the Computar gives me from about 110mm to close to 450mm.

One can also use the Linhof viewer as well.

What I absolutely hate is trying to frame with the camera, putting one lens on, focusing, changing to another lens, back again, etc., and it's taken me fifteen minutes (or more) to compose the image.

stradibarrius
21-Dec-2014, 15:34
It seems "Will" understood the question more in line with the way my crazy mind works. To state the question another way for example I can use 150mm lens to fill the frame at say 5 feet...or I can use a 300mm lens which at a great distance, say 15 feet, will give me basically the same framing... how would you select a lens?

Ken Lee
21-Dec-2014, 15:45
A web search for "lens perspective" or "focal length example" will result in a lot of images which illustrate the change of perspective we get by selecting focal length and then moving closer or farther to retain subject size.

Here's a nice one from https://bakerdh.files.wordpress.com/2012/05/allsmall.jpg

https://bakerdh.files.wordpress.com/2012/05/allsmall.jpg

mdarnton
21-Dec-2014, 16:06
Stand where you get the perspective you want, then choose the lens that will outline the boundaries of what you have decided you want in the photo, and will crop out what you don't want.

Mark Sawyer
21-Dec-2014, 17:02
Short answer: I consider how much I want to expand or compress the space.

Luis-F-S
21-Dec-2014, 17:07
There are entire books written on the subject................L

stradibarrius
21-Dec-2014, 17:50
Great thanks!

BetterSense
21-Dec-2014, 19:44
Have only one lens.

Ari
21-Dec-2014, 19:58
Have only one lens.

Alternatively, use only three lenses whose FLs are spread apart.
On 4x5, say, a 90, 210 and 360.

John Olsen
21-Dec-2014, 20:21
A web search for "lens perspective" or "focal length example" will result in a lot of images which illustrate the change of perspective we get by selecting focal length and then moving closer or farther to retain subject size.

Here's a nice one from https://bakerdh.files.wordpress.com/2012/05/allsmall.jpg

https://bakerdh.files.wordpress.com/2012/05/allsmall.jpg
What's strange here is that the shorter focal length lenses make his hair look messier. Great examples, otherwise.

uphereinmytree
21-Dec-2014, 20:28
I would add to the idea of limited lens choices and Ken's perspective illustrations, that when you use a few lenses enough or alot, you may find you instinctively know which lens a shot will need. It's taken me more shooting than I would have guessed to develop the 'lens sense' and i still start with the wrong one sometimes. Sometimes topography will dictate which lens to use. I remember way back when I would wonder 'how can I possibly know which aperture to use?" I'm now often confounded by "soft focus or sharp" and "which film and which paper for this shot?". Previsualization is the key. It seems my favorite shots are the ones where I didn't overthink things and just saw the image when I found it and then captured it.

John Kasaian
21-Dec-2014, 21:18
I mainly contact print so having everything I want in the frame is important and I also shoot with an 8x10 and seldom have more than one lens with me because most of them are so darned heavy to lug around, so that's the lens I'll use.
Usually a wide lens (240 or 250mm) for close up shots, a really wide lens (159mm) for table top, a long lens (19") for more distant views and a normal lens (12" or 14") for everything else.

Joe Smigiel
21-Dec-2014, 21:29
Actually, I think Heroique provided the answer. The viewfinder/framing card helps determine where in space the picture should be taken, and also the focal length that should be used. There is really only one best position in space to photograph the scene. That spot gives the best perspective. Once it is found using the framing device, that's where the lens should be placed.

If the viewfinder opening has the same dimensions as the film format (e.g., 4x5), when you have framed the scene with the card at that spot, then the distance from the card to your eye tells you what focal length lens will give you that perspective. A card held 6" (150mm) away from your eye indicates a 6" (150mm) lens should be used on camera. If the scene looks best when the card is 12" (300mm) away, then a 12" (300mm) lens is indicated.

All the other stuff about exaggerating nearer objects relative to further objects with shorter lenses will still be true, but the card lets you see that relationship directly and also informs about the appropriate lens focal length, how much background will be seen, etc. It doesn't matter if you are doing a landscape or tabletop, the card works in both situations.

Consider what happens to the scene when two somewhat overlapping bottles at different distances are photographed with lenses of different focal lengths. If the foreground bottle is to have a certain height in the picture with the shorter lens, the lens will be closer to it and the bottle will look larger than the one in the background. There will also be more background evident overall. If you maintain the same image size of the foreground object using a longer lens, several effects will occur as you will need to back up (i.e., increase the subject distance) and thus change the perspective. First, the relative sizes of the foreground and background bottles will become more similar. Second, less background will be seen within the format. Third, the top and bottom of the foreground bottle will appear to be closer together than they were with the shorter lens relative to the same areas of the background bottle. IOW, the top of the foreground bottle will appear to be lower relative to the top of the background bottle compared to the first situation and ditto with the bases. Fourth, since you've changed the perspective by changing the subject distance, the shape of the ellipses that visually result from the cylindrical shapes will change and alter the overall impression of the bottle shapes. The ellipses become more like lines than circles, the space between the bottles appears visually reduced and the whole scene seems flatter. Substitute a landscape with trees instead of bottles and the same things happen visually.

Another thing very nice about using the card is that the card will show you where the lens should be placed in physical space. Once that is found, the big camera can be placed there. That's a lot easier than trying to find the best spot by moving the camera and tripod around and looking under the hood at an inverted image. Also, you could use a 4x5 card to determine best focal lengths for an 8x10 or any other format with the same aspect ratio. If the shot looks good with a 4x5 opening 6" from your eye, doubling that distance will tell you that a 12" lens will give the same perspective with an 8x10 camera. If you really want to get fancy, a #90 Wratten monochrome viewing filter could be added to the card for b&w work to allow tonal relationships to be estimated as well. A similar device was once marketed by Fred Picker and his Zone VI Studios.

ic-racer
22-Dec-2014, 07:11
I only carry one lens when I got out with LF gear. I can create great images with all of my lenses. I usually choose a lens based on my mood that day.

prendt
22-Dec-2014, 07:45
Actually, I think Heroique provided the answer. The viewfinder/framing card helps determine where in space the picture should be taken, and also the focal length that should be used. There is really only one best position in space to photograph the scene. That spot gives the best perspective. Once it is found using the framing device, that's where the lens should be placed.

If the viewfinder opening has the same dimensions as the film format (e.g., 4x5), when you have framed the scene with the card at that spot, then the distance from the card to your eye tells you what focal length lens will give you that perspective. A card held 6" (150mm) away from your eye indicates a 6" (150mm) lens should be used on camera. If the scene looks best when the card is 12" (300mm) away, then a 12" (300mm) lens is indicated.

All the other stuff about exaggerating nearer objects relative to further objects with shorter lenses will still be true, but the card lets you see that relationship directly and also informs about the appropriate lens focal length, how much background will be seen, etc. It doesn't matter if you are doing a landscape or tabletop, the card works in both situations.

Consider what happens to the scene when two somewhat overlapping bottles at different distances are photographed with lenses of different focal lengths. If the foreground bottle is to have a certain height in the picture with the shorter lens, the lens will be closer to it and the bottle will look larger than the one in the background. There will also be more background evident overall. If you maintain the same image size of the foreground object using a longer lens, several effects will occur as you will need to back up (i.e., increase the subject distance) and thus change the perspective. First, the relative sizes of the foreground and background bottles will become more similar. Second, less background will be seen within the format. Third, the top and bottom of the foreground bottle will appear to be closer together than they were with the shorter lens relative to the same areas of the background bottle. IOW, the top of the foreground bottle will appear to be lower relative to the top of the background bottle compared to the first situation and ditto with the bases. Fourth, since you've changed the perspective by changing the subject distance, the shape of the ellipses that visually result from the cylindrical shapes will change and alter the overall impression of the bottle shapes. The ellipses become more like lines than circles, the space between the bottles appears visually reduced and the whole scene seems flatter. Substitute a landscape with trees instead of bottles and the same things happen visually.

Another thing very nice about using the card is that the card will show you where the lens should be placed in physical space. Once that is found, the big camera can be placed there. That's a lot easier than trying to find the best spot by moving the camera and tripod around and looking under the hood at an inverted image. Also, you could use a 4x5 card to determine best focal lengths for an 8x10 or any other format with the same aspect ratio. If the shot looks good with a 4x5 opening 6" from your eye, doubling that distance will tell you that a 12" lens will give the same perspective with an 8x10 camera. If you really want to get fancy, a #90 Wratten monochrome viewing filter could be added to the card for b&w work to allow tonal relationships to be estimated as well. A similar device was once marketed by Fred Picker and his Zone VI Studios.


+1, absolutely right.
I even considered it so obvious that in the first moment I couldn't get the sense of the OP's question.

john borrelli
22-Dec-2014, 08:53
The viewing card is very helpful. I make mine.

I make them using one side cut from a black three ring binder, the kind with black vinyl over cardboard. Take a piece of film trace it on the center of the binder. cut the hole. Get some superglue and glue thick black electrical tape over all the exposed cardboard overlapping the tape with the black vinyl of the binder. The thing is indestructible. Then take a string, or shoelace and a metric ruler. Attach the string to one side of the viewing frame. Wrap the string around the frame to the cleanest side of the viewing card. Take the ruler and put marks on the string according to the lens focal lengths: so for a 150mm lens measure 150mm and mark the string with something like paint(I used my wife's nail polish). Continue to mark all of your focal lengths on the string. I had been using one lens for a while but recently purchased two more, a slightly wide and slightly long one to go with my 150mm lens so I now have three marks on my shoe lace. To preview the image I touch the mark on the shoelace to my nose and view the three possibilities.

This card helps with the previsualization process. As a landscape photographer, the card also saves me time and effort as I can pick out where I want to place my camera and which lens to use without the trial and error of setting up the camera in multiple places, focusing with a variety of lenses before choosing the best one, and of course the image is brighter and sharper through the viewer than the camera. However, I am sure the card will help with any kind of photography.

DrTang
22-Dec-2014, 10:23
It seems "Will" understood the question more in line with the way my crazy mind works. To state the question another way for example I can use 150mm lens to fill the frame at say 5 feet...or I can use a 300mm lens which at a great distance, say 15 feet, will give me basically the same framing... how would you select a lens?

stand at 5' with one eye closed and look


then back up to 15' and stand and view the scene with one eye


- done


it's actually easier to walk back and forth until you find the sweet spot with re: to perspective..then plonk your tripod there.. then find a lens that covers what you want to include..the lens is the least important decision

hoffner
22-Dec-2014, 11:31
To preview the image I touch the mark on the shoelace to my nose and view the three possibilities.




Why on Earth do you put the mark to your nose? Do you have your nose at the same distance from the frame as your eye is? Why would anybody want to introduce such an error to this technique is beyond me.

sanking
22-Dec-2014, 12:13
Why on Earth do you put the mark to your nose? Do you have your nose at the same distance from the frame as your eye is? Why would anybody want to introduce such an error to this technique is beyond me.

As early as the 9th century Arab navigators used a device known as a kamal for celestial navigation to determine latitude. It was soon adopted by Indian navigators and then by the Chinese.

The kamal consists of a rectangular wooden board to which a string with several equally spaced knots is attached through a hole in the middle of the card. To use one end of the string is placed in the teeth, while the other end is held away from the body. By positioning with location to a star, usually Polaris, the angle to the horizon can be determined, and thus latitude. While crude, and less accurate than later instruments such as the back-staff and the cross-staff, the kamal served its purpose and probably saved the lives of many ancient sailors.

No pretense of accuracy or precision has been made for the viewing card, whether you adjust it with a string with knots, place it on your nose, hold it a certain distance away from your eyes, or affix it to your tongue jewelery. It is a guide, not the final image, and is used to roughly determine where to initially position the camera. In many cases that position is not exactly where we want it, and we move the camera.

There are certainly ways to more precisely visualize our compositions, such as viewfinders for smart phones. But in the end, the viewfinder on the smart phone is still only a guide, not the final image itself, and both potentially introduce a fair amount of error. Why should that matter, if the person using the guide is satisfied with it?

Sandy

Alan Gales
22-Dec-2014, 12:44
I pre-visualize what I want my image to look like before I do anything. The image in my head dictates if I need a wide, normal or long lens. By not carrying a bunch of lenses with me it's pretty easy to decide which lens I want to use. I also don't own a lot of lenses which helps me decide which lenses to take with me.

It's always worked for me but I'm sure it isn't the answer for everyone.

Leszek Vogt
22-Dec-2014, 12:52
There are many lens simulators out there, but nothing matches your own experience with the lens/es....to determine what's needed.


Les

Heroique
22-Dec-2014, 13:24
Why on Earth do you put the mark to your nose? Do you have your nose at the same distance from the frame as your eye is? Why would anybody want to introduce such an error to this technique is beyond me.

Once again, an armchair photographer's remark.

You may want to learn how to give a practitioner, John Borrelli in this case, the benefit of the doubt.

I bet how he positions his viewing card provides the desired guidance he needs for the lens in question, no matter how he tries to describe his technique.

hoffner
22-Dec-2014, 13:41
Once again, an armchair photographer's remark.

You may want to learn how to give a practitioner, John Borrelli in this case, the benefit of the doubt.

I bet how he positions his viewing card provides the desired guidance he needs for the lens in question, no matter how he tries to describe his technique.

Maybe you may learn a little bit of maths - adding 3-4cm to the string of your view frame strictly depending on its right length from your eye is not a question of good will. Describe your technique as you like but don't correct those who see errors in your description. Otherwise you can say whatever nonsense and add - trust me on that, I'm a practitioner.

BrianShaw
22-Dec-2014, 14:50
What's strange here is that the shorter focal length lenses make his hair look messier. Great examples, otherwise.

... and makes the background artwork look different.

Will Frostmill
22-Dec-2014, 15:32
As early as the 9th century Arab navigators used a device known as a kamal for celestial navigation to determine latitude. It was soon adopted by Indian navigators and then by the Chinese.

The kamal consists of a rectangular wooden board to which a string with several equally spaced knots is attached through a hole in the middle of the card. To use one end of the string is placed in the teeth, while the other end is held away from the body. By positioning with location to a star, usually Polaris, the angle to the horizon can be determined, and thus latitude. While crude, and less accurate than later instruments such as the back-staff and the cross-staff, the kamal served its purpose and probably saved the lives of many ancient sailors.

No pretense of accuracy or precision has been made for the viewing card, whether you adjust it with a string with knots, place it on your nose, hold it a certain distance away from your eyes, or affix it to your tongue jewelery. It is a guide, not the final image, and is used to roughly determine where to initially position the camera. In many cases that position is not exactly where we want it, and we move the camera.

There are certainly ways to more precisely visualize our compositions, such as viewfinders for smart phones. But in the end, the viewfinder on the smart phone is still only a guide, not the final image itself, and both potentially introduce a fair amount of error. Why should that matter, if the person using the guide is satisfied with it?

Sandy

THIS.
Excellent lesson Sandy. I learned something new!

Leszek Vogt
22-Dec-2014, 15:51
If necessary, you can use "director's viewfinder" (usually in 16/35mm) and reconfigure that into LF. At least you'll be close. They can be relatively inexpensive (below $100 used) or going over $3K new.


Les

hoffner
22-Dec-2014, 16:15
No pretense of accuracy or precision has been made for the viewing card, whether you adjust it with a string with knots, place it on your nose, hold it a certain distance away from your eyes, or affix it to your tongue jewelery. It is a guide, not the final image, and is used to roughly determine where to initially position the camera. In many cases that position is not exactly where we want it, and we move the camera.

There are certainly ways to more precisely visualize our compositions, such as viewfinders for smart phones. But in the end, the viewfinder on the smart phone is still only a guide, not the final image itself, and both potentially introduce a fair amount of error. Why should that matter, if the person using the guide is satisfied with it?

Sandy

Sandy,
while nobody doubts the obvious - that viewing guides are not the final image (did you think anybody ever thought otherwise?) and that any viewing guide can be misused in an error-full way (indeed it can) it surely matters where from you measure the distance of a viewing frame. Take a frame for 75 cm FL lens. If you put it at a distance of 75 cm from your eye or at a distance of 105/115cm (the length 3-4cm of a nose protruding ahead from your eye level) you suddenly have a frame for a 105/115 cm lens. Does it matter? Take a guess.

john borrelli
22-Dec-2014, 17:49
Apologies if putting the string to your nose introduces an inaccuracy. Perhaps a more accurate description could b provided by Sanking as to where to put the string.

uphereinmytree
22-Dec-2014, 19:48
who wants to carry a big piece of cardboard with a hole in it? i can hold my fingers up in something like a rectangle and add hashmarks to my arm, but there's less inaccuracy with a viewfinder in the mind when you know your lenses

Willie
22-Dec-2014, 20:01
If you own only one lens the choice is a bit easier. More than on good photographer has gone that route.

Jac@stafford.net
22-Dec-2014, 20:35
?????


127036

sanking
22-Dec-2014, 21:48
Apologies if putting the string to your nose introduces an inaccuracy. Perhaps a more accurate description could b provided by Sanking as to where to put the string.

To be clear, the purpose of my message was to suggest that great accuracy is normally not required when using a viewing card. If you need maximum accuracy you could adjust the distance of the marks on your string to compensate for where you place it on your face. The very best place, at the focal plane of the viewing eye, is not of course available.

Basically, I use a method very similar to yours, though to mark focal length I make a knot on the string so that I can hold it with my front teeth, similar to way the medieval Arab sailors used the Kamal. I do compensate, *roughly* in the place where I put the knot for viewing distance.

If you need greater accuracy and own an iPhone the Mark II app is capable of creating frames for virtually any format and lens imaginable. There is also a viewfinder app for Android devices, though much less sophisticated than the Mark II.

Sandy

hoffner
23-Dec-2014, 01:22
A viewing frame is the most precise and very precise "non optical" (not counting the optics of your own eye in this device) means of previewing framing of a picture taken by a lens on a given film format.
So called wire frames that were present on some film cameras were developed on the same principle. These wire frames had two parts - one was the wire (more distant from your face) framing the field of view, the other was a smaller wire frame, with a centre in it, which you were suppose to put your eye at - notice, that it was your eye that was centred there, surely not your nose. This smaller wire frame was added to help your eye being kept at the right distance and in the right position.

It surely is not important if the string of your view frame is hold by your teeth, by your finger under your eyes, by a chewing gum there or by the camera itself. What is important is the distance of the viewing frame from the pupil of your eye and its centred viewing position - important for obvious reasons that should not need to be explained. After all, if you keep the frame away from your eye at a distance of 100 mm or 140mm the view framing is very different! Try it if you don't believe it.

Now let the offended public start long wired posts about how the distance is not important and the tip of your nose is at the distance of your eye from whatever you put in front of your face. I'll once again enjoy all of that.

Drew Bedo
23-Dec-2014, 09:31
Haven't read any of the first four pages . . .sorry if this is a repetition.

"The Ground Glass is truth." If you don't see what you want on the GG, then try another lens. It is as simple as that. with experience you will develop a moe intuitive sense of what you want and how to get there.

Alan Gales
23-Dec-2014, 10:49
Haven't read any of the first four pages . . .sorry if this is a repetition.

"The Ground Glass is truth." If you don't see what you want on the GG, then try another lens. It is as simple as that. with experience you will develop a moe intuitive sense of what you want and how to get there.

Practice makes perfect. Well, maybe not perfect but practice does make you much better. :)

Old-N-Feeble
23-Dec-2014, 11:49
Oh, for Pete's sake. The distance between one's eyes and nose are EASILY compensated for. It doesn't require a genius intellect to understand that.


A viewing frame is the most precise and very precise "non optical" (not counting the optics of your own eye in this device) means of previewing framing of a picture taken by a lens on a given film format.
So called wire frames that were present on some film cameras were developed on the same principle. These wire frames had two parts - one was the wire (more distant from your face) framing the field of view, the other was a smaller wire frame, with a centre in it, which you were suppose to put your eye at - notice, that it was your eye that was centred there, surely not your nose. This smaller wire frame was added to help your eye being kept at the right distance and in the right position.

It surely is not important if the string of your view frame is hold by your teeth, by your finger under your eyes, by a chewing gum there or by the camera itself. What is important is the distance of the viewing frame from the pupil of your eye and its centred viewing position - important for obvious reasons that should not need to be explained. After all, if you keep the frame away from your eye at a distance of 100 mm or 140mm the view framing is very different! Try it if you don't believe it.

Now let the offended public start long wired posts about how the distance is not important and the tip of your nose is at the distance of your eye from whatever you put in front of your face. I'll once again enjoy all of that.

Alan Gales
23-Dec-2014, 12:01
Oh, for Pete's sake. The distance between one's eyes and nose are EASILY compensated for. It doesn't require a genius intellect to understand that.

Not necessarily. I've got a big nose so I have a longer distance than normal to compensate for.

djdister
23-Dec-2014, 12:03
I think I'll put the string up my nose and attach a wire frame to my glasses. How about that?
Duhhhhhhhhhhh.....

hoffner
23-Dec-2014, 12:42
Oh, for Pete's sake. The distance between one's eyes and nose are EASILY compensated for. It doesn't require a genius intellect to understand that.

Guess what - it's even EASIER to put the right length of the string to the right bloody spot in the first place! No calculation of any compensation, no worry what the compensation was, no nothing - just easy peasy. Go, wonder.

Old-N-Feeble
23-Dec-2014, 12:45
What difference does it make... other than to argue attempting to force one's opinion on others? You should measure from your eyes if that works best for you. I'll measure from my arse if that suits me.

hoffner
23-Dec-2014, 13:01
What difference does it make...

If you didn't get it see again the post n. 32. It's easy peasy, isn't it?

Kirk Gittings
23-Dec-2014, 13:14
To be clear, the purpose of my message was to suggest that great accuracy is normally not required when using a viewing card. If you need maximum accuracy you could adjust the distance of the marks on your string to compensate for where you place it on your face. The very best place, at the focal plane of the viewing eye, is not of course available.

Basically, I use a method very similar to yours, though to mark focal length I make a knot on the string so that I can hold it with my front teeth, similar to way the medieval Arab sailors used the Kamal. I do compensate, *roughly* in the place where I put the knot for viewing distance.

If you need greater accuracy and own an iPhone the Mark II app is capable of creating frames for virtually any format and lens imaginable. There is also a viewfinder app for Android devices, though much less sophisticated than the Mark II.

Sandy

Sandy, Are you also using one of the wide angle iPhone lens adapters also in conjunction with the app?

Old-N-Feeble
23-Dec-2014, 13:18
If you didn't get it see again the post n. 32. It's easy peasy, isn't it?

I get it, hoffner... more than you'll probably ever realize. We all "get it". Some of us just choose not to force our opinions on others insisting they agree with us. Get it?;)

Kirk Gittings
23-Dec-2014, 13:35
To keep it simple one can simply use you hands and fingers as I do-a little hard to describe with words-kind of like the cliched directors hand framing thing in movies. Basically I have two distances worked out for using my hands as a frame, one is for a 90 on 4x5 and the other is for a 210 on 4x5. From those two I can pretty accurately guess what lens I need if those two are too short or long. Its easy to set up a lens on the camera and then play around with your hands till you get a hands frame distance from your nose that approximates its view and then remember it. Its not perfect-but works, and requires no additional crap to carry. I'm always thinking of ways to simplify my work flow and gear and resist anything that requires more gear, more complexity or more time to get set up.

sanking
23-Dec-2014, 14:45
Sandy, Are you also using one of the wide angle iPhone lens adapters also in conjunction with the app?

Kirk,

Yes, I have an Olloclip three-in-one fast clip adapter. I believe the wide angle is 0.5X, which doubles the effective field of view of the camera of your phone. This gives an effective focal length of about 15mm - 17mm on FF depending on which device you are using. The only downside of using the adapter is that to use it one may have to remove the phone case.

An additional feature of the Mark II app is that it also functions as a camera, and if you snap the view frame GPS data will be recorded, which can be accessed directly through the app with either map, google earth or hybrid projection. This will work in any location, even where there is no phone signal, since it operates through GPS.

Sandy

john borrelli
23-Dec-2014, 14:59
Apparently, I somehow contributed to this thread going off on a tangent. Hopefully, there are some ideas for the OP to try. I appreciate Sanking taking the time to provide the details on his methods and will try his technique the next time I head out.

Ken Lee
24-Dec-2014, 08:48
When you decide to take a photo, how do you decide which lens in your bag to use? to be a bit more specific...ex. a table top shot where you could use a longer lens from a farther distance or a shot focal length and be closer to the subject.

Why has so much more music been composed and performed for Violin than Viola, Cello or Bass ?

stradibarrius
24-Dec-2014, 09:21
Ken, thanks for your photos. That helps.
As to why there is more music written for violin than the other three "bowed" instruments in the family is because the violin is basically a soprano voiced instrument which is a "lead" voice the others are supporting "voiced" instruments. The human voice is what has inspired the majority of music.
Modern convention is changing that to some degree but historically most music was written for the violin. many players today are playing Bluegrass, Rock and Jazz on cellos. The Avett Bros. for example. They are a very popular band currently and have a violin , which I made, a cello, a banjo along with electric guitars.
Bach did write the "Cello Suite" that is very popular and if you listen to the #1 you will immediately recognize it.
Good question and maybe a way to put and end to this thread...

Why has so much more music been composed and performed for Violin than Viola, Cello or Bass ?

stradibarrius
24-Dec-2014, 09:24
As an addition to my answer check this video out as to some of what is being done with the cello...
https://video.search.yahoo.com/video/play?p=Bach+cello+music&vid=58dd8c1c70f953e8fe5e4b8b1197f5a5&l=4%3A02&turl=http%3A%2F%2Fts3.mm.bing.net%2Fth%3Fid%3DVN.608051332388162338%26pid%3D15.1&rurl=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DRy4BzonlVlw&tit=The+Cello+Song+-+%28Bach+is+back+with+7+more+cellos%29+-+ThePianoGuys&c=3&sigr=11bg9a5f9&sigt=121lrokg6&back=https%3A%2F%2Fsearch.yahoo.com%2Fyhs%2Fsearch%3Fp%3DBach%2Bcello%2Bmusic%26ei%3DUTF-8%26hsimp%3Dyhs-001%26hspart%3Dmozilla&sigb=12s3l1gd2&ct=p&age=0&fr2=p%3As%2Cv%3Av%2Cm%3Asa&hsimp=yhs-001&hspart=mozilla&tt=b

Ken Lee
24-Dec-2014, 09:43
the violin is basically a soprano voiced instrument which is a "lead" voice the others are supporting "voiced" instruments. The human voice is what has inspired the majority of music.

I'm suggesting that in choice of focal length, there is something roughly analogous to the lead voice.

I'm not an expert in cinematography but wonder if anyone has ever made a survey in films: what is the typical ratio of wide to close shots etc. What is most comfortable or natural for the viewer ?

Wonderful video of the Cello player(s): thanks !

Old-N-Feeble
24-Dec-2014, 10:27
Ken, IMHO the cello and even bass viol are FAR closer to human voice than violin. I suspect more music has been composed for violin only out of habit.

That stated, I think I understand your point. There's a 'range of normal' that we human beings 'connect with' more easily. For me, a slightly wider than normal lens fits the bill. On 4x5 inch film, for me, a 110-120mm probably suits how I view my surroundings moreso than a 'normal' 150-155mm lens. I'm sure others view the world differently than I.

Alan Gales
24-Dec-2014, 11:11
What is most comfortable or natural for the viewer ?


I would think that a near normal perspective would be more comfortable for the viewer.

Sometimes you don't want the viewer to be comfortable though. :)

Ken Lee
24-Dec-2014, 11:54
For what it's worth I found an informal discussion of this topic on cinematography.com

See Most oftenly used lenses in cinema (http://www.cinematography.com/index.php?showtopic=59222)

Not surprisingly, my theory that there is one optimal length is true... but the optimal length varies with the individual :rolleyes:

hoffner
24-Dec-2014, 11:56
Why has so much more music been composed and performed for Violin than Viola, Cello or Bass ?

So, Ken Lee, in relation to the given OP question - what, in your opinion, is the equivalent of a violin or a cello among different lenses? And how do you decide if you take a violin or the cello? Is the violin a long lens or a short lens or a normal lens and why? And how that musical comparison answers the OP's problem of choice? I cannot find any answer to these questions in your post. Have a good day!

Ken Lee
24-Dec-2014, 11:58
Stradibarrius, the original poster, is a maker of musical instruments: violins and guitars. See http://www.dudleyviolins.com/.

I found his answer to be very substantial.

As I stated in post 55 (emphasis added), "I'm suggesting that in choice of focal length, there is something roughly analogous to the lead voice."

My suggestion is that lead instruments are analogous to lenses of moderately longer-than-normal length. Taking the analogy further, the fovea centralis of the eye is a small region of the retina: we normally see only small areas of the subject and "stitch" them together to make up our impression of a subject. In that sense, narrow vision paints the scene, or takes the lead, much as a lead instrument or singer carries the melody and the lyrics.

Analogies can only go so far of course, but it's a privilege to be able to ask such questions of musicians, who by nature can be open to circuitous thinking.

By presenting this topic as a question rather than a declaration, I hoped to invite varied opinions and learn from others.

hoffner
24-Dec-2014, 12:07
Stradibarrius, the original poster, is a maker of musical instruments: violins and guitars. See http://www.dudleyviolins.com/.

As I stated in post 55 (emphasis added), "I'm suggesting that in choice of focal length, there is something roughly analogous to the lead voice."

Ken Lee,
can you please enlighten me what exactly, if anything, rude you see in my question?
More over, can you explain the analogy about violin, cello etc. and different lenses? Because as I said (with no rude element whatsoever) I don't understand how such analogy helps in the decision the OP spoke about in his question. Thank you in advance for an explanation.

Old-N-Feeble
24-Dec-2014, 12:14
hoffner... Ken is trying to harmonize choice of lens focal length with the OP's other knowledge which is musical instruments.

Ken Lee
24-Dec-2014, 12:30
can you explain the analogy about violin, cello etc. and different lenses? Because as I said (with no rude element whatsoever) I don't understand how such analogy helps in the decision the OP spoke about in his question. Thank you in advance for an explanation.

I'm sorry if my thinking is fuzzy.

My suggestion is that lead instruments are analogous to lenses of moderately longer-than-normal length. Taking the analogy further, the fovea centralis of the eye is a small region of the retina: we normally see only small areas of the subject and "stitch" them together to make up our impression of a subject. In that sense, narrow vision paints the scene, or takes the lead, much as a lead instrument or singer carries the melody and the lyrics.

Analogies can only go so far of course, but it's a privilege to be able to ask such questions of musicians, who by nature can be open to circuitous thinking.

By presenting this topic as a question rather than a declaration, I hoped to invite varied opinions and learn from others.

Alan Gales
24-Dec-2014, 13:13
I'm sorry if my thinking is fuzzy.

It was clear to me but maybe I'm just fuzzy. ;)

That's the problem sometimes with the written word. It may be clear as blue sky to some and muddy as the Mississippi to others.

Jac@stafford.net
24-Dec-2014, 13:23
That's the problem sometimes with the written word. It may be clear as blue sky to some and muddy as the Mississippi to others.

Ahem! That would be the Lower (http://previews.123rf.com/images/sframe/sframe1007/sframe100700011/7294273-interstate-40-bridge-over-the-muddy-mississippi-river-connects-memphis-tennessee-with-west-memphis-a.jpg) Mississippi, not the river in my backyard (http://finance-commerce.com/files/2014/07/Winona-Bridge-Project-rendering-submitted-600x330.jpg). :)

Alan Gales
24-Dec-2014, 13:35
Ahem! That would be the Lower (http://previews.123rf.com/images/sframe/sframe1007/sframe100700011/7294273-interstate-40-bridge-over-the-muddy-mississippi-river-connects-memphis-tennessee-with-west-memphis-a.jpg) Mississippi, not the river in my backyard (http://finance-commerce.com/files/2014/07/Winona-Bridge-Project-rendering-submitted-600x330.jpg). :)

I've never seen the Mississippi that clean. I worked with three sheet metal workers from Minnesota a little over 20 years ago. They were in town just to pick up work at a Chrysler car plant remodel (lots of overtime). They described Minnesota as God's Country.

Luis-F-S
24-Dec-2014, 14:03
It's really not that difficult: You put a lens on the camera, any lens, then focus. You need more real estate, you go to a wider lens. You need less real estate, you go to a longer lens. You don't like the prespective, you move the camera & start over. It's not that difficult!

Leszek Vogt
24-Dec-2014, 14:31
The lens is usually determined by the story or project at hand. Each scene (or portion) will require certain look...and these can be broken down into visuals + consistency throughout. Ha, one has to be able to edit the process in one's head. It's a delicate dance between cinematographer and director....and one (as a norm goes) tries to squeeze out the most out of the scene as possible.....lighting, movement within the frame, what is included or often excluded (to give fuel to imagination), prod values, etc. etc. Video or mot pic requires little different sensibilities than creating stills....and different equipment, as well.

Les

Old-N-Feeble
24-Dec-2014, 16:30
Muddy Waters would set all yooz guys straight.

Jody_S
24-Dec-2014, 17:35
Once you know your lenses, you learn to 'see' with whatever lens happens to be in your kit that day. You will compose mentally by mentally looking through that lens at your subject, and set up the camera, compose the shot, etc., to take full advantage of that particular lens.

If you are a commercial photographer who has to produce a certain image with exact, well-defined characteristics, then you will go about this the opposite way, that is choose a lens that will render the scene the way you need it to be rendered. But that presupposes you can go lens- and film-shopping as you please to get that look. Most of us hobbyists tend to compose with what we happen to have on hand, I think. I could be wrong on that, I haven't seen a survey or anything to back it up.

Jac@stafford.net
24-Dec-2014, 17:49
I've never seen the Mississippi that clean.

Feel free to visit, Sir!

I am a newcomer to the Upper Big River, having lived on its riverbank for only twenty-seven years. My wife has been on the river for sixty-four years (She is a young one).

It has changed upon the surface but a profound undercurrent prevails.

Ari
24-Dec-2014, 20:13
It's really not that difficult: You put a lens on the camera, any lens, then focus. You need more real estate, you go to a wider lens. You need less real estate, you go to a longer lens. You don't like the prespective, you move the camera & start over. It's not that difficult!


The lens is usually determined by the story or project at hand. Each scene (or portion) will require certain look...and these can be broken down into visuals + consistency throughout. Ha, one has to be able to edit the process in one's head. It's a delicate dance between cinematographer and director....and one (as a norm goes) tries to squeeze out the most out of the scene as possible.....lighting, movement within the frame, what is included or often excluded (to give fuel to imagination), prod values, etc. etc. Video or mot pic requires little different sensibilities than creating stills....and different equipment, as well.

Les


Once you know your lenses, you learn to 'see' with whatever lens happens to be in your kit that day. You will compose mentally by mentally looking through that lens at your subject, and set up the camera, compose the shot, etc., to take full advantage of that particular lens.



Practice, practice, practice.

Randy
24-Dec-2014, 23:14
Have only one lens.I have often thought I would do better with just one lens. I am forcing myself to do that with my 5X7 camera.

stradibarrius
25-Dec-2014, 08:14
As so often happens with a question on a forum the original question and intent of the question gets lost. The question I was asking was basically answer way back when Ken Lee posted the comparison of facial features rendered with different focal lengths. The question was not about how much to include or exclude from the frame.
When it seems that more than one focal length would privide the "view" that you are trying to achieve, how do you choose between the focal lengths.
For Example, if I were photgraphing one of my violins on a table top, I could use a 150mm and position the camera say 5 feet from the subject. I could also use a 30mm lens but to achieve the "view" or framing I would have to stand further from the subject. In this example I have the room to move the camera closer or farther from the subject. Under that type of situation when it seems that more than one lens would give the same framing how would you choose between the lenses. I don't think this question applies to landscape "type" photography. It applies to product photography, portraiture, still lifes and probably some others. In the example that Ken Lee posted it was fairly easy to see the drastic difference that lens choice made. But what about when the difference is not so obvious??? I don't thnk using a string or a view finding aid would offer much help in this situation. You might want to refer to post #8 as being very close to the intent of my original question. Post #3 is a good method but I don't really think it applies in this example.

Randy I think that you may have hit the nail on the head...sometimes I suffer from analysis paralysis and only having one choice would certainly cure that...LOL!

Ken Lee
25-Dec-2014, 09:04
"...if I were photgraphing one of my violins on a table top, I could use a 150mm and position the camera say 5 feet from the subject. I could also use a 300mm lens but to achieve the "view" or framing I would have to stand further from the subject."

http://www.kenleegallery.com/images/forum/violin-scroll.jpg

Searching the web for photos of violins, I found only a few made at close range with a wide lens - and not too wide at that - like the one above. The intention was probably to highlight the "scroll" section of the instrument, rather than to make an artistic interpretation.

http://www.kenleegallery.com/images/forum/violin.jpg

Almost all photos of violins I found appear to have been made with lenses of normal to moderately long focal length: from far enough away that the proportions of the instrument are not attenuated, but not so far as to be compressed.

For a product shot this seems reasonable. I presume this is because violins are already so nicely proportioned that their inherent beauty only suffers when fattened or stretched.

Alan Gales
25-Dec-2014, 12:25
With portraiture I know what lens I want to use because of experience. Even then sometimes I have been forced to use a shorter lens due to lack of space. You make do.

I don't know much about product photography but the lens of choice of the pros was the 210mm. That's why you see all these monorails for sale with a 210mm f/5.6 lens. I suspect they liked the perspective and the coverage of the 210. If you only have the 150 and 300 then try both and see for yourself. If you are having trouble comparing by just looking at the ground glass then take a shot with each and compare your prints. Then you will know.

There was recently a fellow on APUG asking questions about lenses for an RB67. He was interested in a telephoto lens for portraiture. I used to shoot an RZ and like most on APUG recommended the excellent 180mm. He ended up buying the 127mm and thought it to be perfect. What I am getting at is there is usually no one right answer and we all have different taste.

Alan Gales
25-Dec-2014, 12:27
Feel free to visit, Sir!

I'd love to get up there one day. The guys I worked with told me that you can't go anywhere without running into a lake. Minnosota sounds beautiful!

Greg Davis
25-Dec-2014, 12:30
I am currently doing some tabletop stuff in my home with an 8x10. I am using a 240mm lens because I can't back up any further. I get what I want from it.

Joe Smigiel
25-Dec-2014, 22:50
...
When it seems that more than one focal length would privide the "view" that you are trying to achieve, how do you choose between the focal lengths.
For Example, if I were photgraphing one of my violins on a table top, I could use a 150mm and position the camera say 5 feet from the subject. I could also use a 30mm lens but to achieve the "view" or framing I would have to stand further from the subject. In this example I have the room to move the camera closer or farther from the subject. Under that type of situation when it seems that more than one lens would give the same framing how would you choose between the lenses!

'The "view" that you are trying to achieve' is the best perspective. Semantics... Perspective is viewpoint (aka view, POV, etc.). You are really asking a question about perspective and referring to it as "framing." Moving forward or back (or left,right,up,down) changes the perspective and that changes framing as well as image shape, size, apparent distortion and so on. You can only obtain the same framing by changing both the format and the focal length while keeping the perspective the same. Any other combination (subject distance + focal length, lens angle-of-view + image size, etc.,) will result in a different "view."

That being said, the resultant changes may not be important to you (e.g., more or less background) but they will still occur and change the appearance of the image/object/view.

The only way to use two (or more) different lenses of different focal length and get the same framing is to stay in the same spot and use for example, a 150mm lens on a 4x5 camera or a 300mm lens on an 8x10 camera or a 600mm lens on a 16x20 camera, etc., (assuming the same lens design formula and angle of view) and then enlarge the smaller format film(s) to match the image size of the larger formats. The perspectives ("framing") will be the same then (although depth-of-field, graininess, etc., will change, other things being equal). If you change only two variables such as focal length and subject distance, you will not have the same framing. (You will need to change the format as well.)

Here's a pic with a musical instrument that shows 3 different crops from the same position in space, i.e., the same perspective. If you consider the the central crop from the smaller sensor, it has an identical perspective and relative size and shape relationships from the machine heads to the bridge regardless of the sensor size. However, to match the absolute image size of the instrument and person between crops, you would have to enlarge the smaller sensor's image to match the full frame and the result would be less resolution (and less background).

http://mcpactions.com/wp-content/uploads/2014/03/FullFrame-vs-Crop-600x1000-600x360.jpg?ed563c

I think I fully understand your question and what you are curious about but as in the portrait example, to maintain the shape and size of any object in the frame (or any part of an object such as a violin), you have to stay at the same spot. If we use a violin as an example, if you photograph so the tuners (forgive my lack of knowledge in terminology here) are a certain size and shape, the rear of the violin will take on a certain size and shape based on the perspective and constraints in angle of view. Changing the focal length and subject distance (referenced here to the tuners) will result in the rest of the instrument assuming a different size and shape relationship. It will either elongate or compress visually with a change in distance. The amount of included background will also change as is clearly illustrated in the portrait example.

The two pictures of the violins a few posts previous illustrate the effects. In the first example taken with a short focal length lens, the head is exaggerated in size and distorted from a normal view of its shape. It is a striking effect but rest of the violin looks diminutive compared to the head. It analogous to the exaggeration of the nose in the portrait examples. In contrast, the second view of the violin appears more normal, less dramatic, and the relative size and shapes of the head and body of the instrument are more normal in proportion. It also helps that the viewing angle is more planimetric. The latter picture was probably taken with a longer lens from a greater distance.

The portrait example earlier changed subject distance and focal length to maintain the head size (object size on film). The violin examples show a change in perspective and focal length which altered the relative size and shapes of the instrument. The digital sensor crop shows identical perspective but a change in coverage and format and therefore magnification and image size affecting resolution. A change in focal length holding perspective and lens angle-of-view the same but allowing format to change affects things like depth-of-field and object size on the film. But, with the latter you can blow up the smaller format pic to identically match the view of the longer lens image taken from the same spot. Doing so changes the magnification and graininess of the image, but not the perspective or "view." You can see that effect as well as the background/foreground size and shape distortion caused by maintaining the object size and changing subject distance in this additional example :

http://media-2.web.britannica.com/eb-media/86/3486-004-D81AEC93.jpg

The key to all this really is the cutout viewfinder card (or having some familiarity in advance with a very limited number of focal lengths). Don't dismiss the card without giving it a try. It will only take a few minutes to make. Take a piece of matboard and cut an opening equivalent to your film format in it. Then place your violin on the surface of choice with the background you would like to use. Approach it using the viewfinder and moving it around forward and back, up and down, at different distances from your eye, etc., until you find the framing you want. That's it. You will now have the correct perspective, the preferred relative size and shapes of the instrument will be what you see through the opening and also have probably envisioned, and the distance of the card from your eye will tell you the focal length to use. It is much simpler to do than explain or debate. Give it a try and I think you will be amazed at how simple it makes the focal length decision and shows you the best POV.

hoffner
26-Dec-2014, 03:06
'The "view" that you are trying to achieve' is the best perspective. Semantics... Perspective is viewpoint (aka view, POV, etc.). You are really asking a question about perspective and referring to it as "framing." Moving forward or back (or left,right,up,down) changes the perspective and that changes framing as well as image shape, size, apparent distortion and so on. You can only obtain the same framing by changing both the format and the focal length while keeping the perspective the same. Any other combination (subject distance + focal length, lens angle-of-view + image size, etc.,) will result in a different "view."

That being said, the resultant changes may not be important to you (e.g., more or less background) but they will still occur and change the appearance of the image/object/view.

The only way to use two (or more) different lenses of different focal length and get the same framing is to stay in the same spot and use for example, a 150mm lens on a 4x5 camera or a 300mm lens on an 8x10 camera or a 600mm lens on a 16x20 camera, etc., (assuming the same lens design formula and angle of view) and then enlarge the smaller format film(s) to match the image size of the larger formats. The perspectives ("framing") will be the same then (although depth-of-field, graininess, etc., will change, other things being equal). If you change only two variables such as focal length and subject distance, you will not have the same framing. (You will need to change the format as well.)



The key to all this really is the cutout viewfinder card (or having some familiarity in advance with a very limited number of focal lengths). Don't dismiss the card without giving it a try. It will only take a few minutes to make. Take a piece of matboard and cut an opening equivalent to your film format in it. Then place your violin on the surface of choice with the background you would like to use. Approach it using the viewfinder and moving it around forward and back, up and down, at different distances from your eye, etc., until you find the framing you want. That's it. You will now have the correct perspective, the preferred relative size and shapes of the instrument will be what you see through the opening and also have probably envisioned, and the distance of the card from your eye will tell you the focal length to use. It is much simpler to do than explain or debate. Give it a try and I think you will be amazed at how simple it makes the focal length decision and shows you the best POV.

Man, did you mean, it's all independent of the fact that you produce violins or collect butterflies?
I don't know if you're confrontational and live dangerously on this forum but you're surely right, that much I know.
Hopefully the matter is put to the rest now.

Joe Smigiel
26-Dec-2014, 06:59
Sorry if my post is coming off as "confrontational." That's not my intent. I'm just trying to give enough technical detail to clearly identify the variables.

Post #3 of the thread which the OP noted was "a good method" but for some reason didn't think relevant was in fact the correct answer to the problem. The rest that followed has either been humor, clarification, or obfuscation, depending of course on your POV. :)

hoffner
26-Dec-2014, 07:13
Nothing confrontational at all, Joe,
it was just a humours note - when I started to express the same thought, I was immediately accused as being confrontational. That accusation was then deleted by its overzealous author.
Live well and don't be afraid to express what is correct - life is defended in the same way. Cheers.

John Kasaian
26-Dec-2014, 10:15
If you own only one lens the choice is a bit easier. More than on good photographer has gone that route.
So true!

stradibarrius
26-Dec-2014, 16:41
Joe, Thank you for going to the effort to provide such a good answer! I am going to do just what you have explained. I am certain it will improve my results.

'The "view" that you are trying to achieve' is the best perspective. Semantics... Perspective is viewpoint (aka view, POV, etc.). You are really asking a question about perspective and referring to it as "framing." Moving forward or back (or left,right,up,down) changes the perspective and that changes framing as well as image shape, size, apparent distortion and so on. You can only obtain the same framing by changing both the format and the focal length while keeping the perspective the same. Any other combination (subject distance + focal length, lens angle-of-view + image size, etc.,) will result in a different "view."

That being said, the resultant changes may not be important to you (e.g., more or less background) but they will still occur and change the appearance of the image/object/view.

The only way to use two (or more) different lenses of different focal length and get the same framing is to stay in the same spot and use for example, a 150mm lens on a 4x5 camera or a 300mm lens on an 8x10 camera or a 600mm lens on a 16x20 camera, etc., (assuming the same lens design formula and angle of view) and then enlarge the smaller format film(s) to match the image size of the larger formats. The perspectives ("framing") will be the same then (although depth-of-field, graininess, etc., will change, other things being equal). If you change only two variables such as focal length and subject distance, you will not have the same framing. (You will need to change the format as well.)

Here's a pic with a musical instrument that shows 3 different crops from the same position in space, i.e., the same perspective. If you consider the the central crop from the smaller sensor, it has an identical perspective and relative size and shape relationships from the machine heads to the bridge regardless of the sensor size. However, to match the absolute image size of the instrument and person between crops, you would have to enlarge the smaller sensor's image to match the full frame and the result would be less resolution (and less background).

http://mcpactions.com/wp-content/uploads/2014/03/FullFrame-vs-Crop-600x1000-600x360.jpg?ed563c

I think I fully understand your question and what you are curious about but as in the portrait example, to maintain the shape and size of any object in the frame (or any part of an object such as a violin), you have to stay at the same spot. If we use a violin as an example, if you photograph so the tuners (forgive my lack of knowledge in terminology here) are a certain size and shape, the rear of the violin will take on a certain size and shape based on the perspective and constraints in angle of view. Changing the focal length and subject distance (referenced here to the tuners) will result in the rest of the instrument assuming a different size and shape relationship. It will either elongate or compress visually with a change in distance. The amount of included background will also change as is clearly illustrated in the portrait example.

The two pictures of the violins a few posts previous illustrate the effects. In the first example taken with a short focal length lens, the head is exaggerated in size and distorted from a normal view of its shape. It is a striking effect but rest of the violin looks diminutive compared to the head. It analogous to the exaggeration of the nose in the portrait examples. In contrast, the second view of the violin appears more normal, less dramatic, and the relative size and shapes of the head and body of the instrument are more normal in proportion. It also helps that the viewing angle is more planimetric. The latter picture was probably taken with a longer lens from a greater distance.

The portrait example earlier changed subject distance and focal length to maintain the head size (object size on film). The violin examples show a change in perspective and focal length which altered the relative size and shapes of the instrument. The digital sensor crop shows identical perspective but a change in coverage and format and therefore magnification and image size affecting resolution. A change in focal length holding perspective and lens angle-of-view the same but allowing format to change affects things like depth-of-field and object size on the film. But, with the latter you can blow up the smaller format pic to identically match the view of the longer lens image taken from the same spot. Doing so changes the magnification and graininess of the image, but not the perspective or "view." You can see that effect as well as the background/foreground size and shape distortion caused by maintaining the object size and changing subject distance in this additional example :

http://media-2.web.britannica.com/eb-media/86/3486-004-D81AEC93.jpg

The key to all this really is the cutout viewfinder card (or having some familiarity in advance with a very limited number of focal lengths). Don't dismiss the card without giving it a try. It will only take a few minutes to make. Take a piece of matboard and cut an opening equivalent to your film format in it. Then place your violin on the surface of choice with the background you would like to use. Approach it using the viewfinder and moving it around forward and back, up and down, at different distances from your eye, etc., until you find the framing you want. That's it. You will now have the correct perspective, the preferred relative size and shapes of the instrument will be what you see through the opening and also have probably envisioned, and the distance of the card from your eye will tell you the focal length to use. It is much simpler to do than explain or debate. Give it a try and I think you will be amazed at how simple it makes the focal length decision and shows you the best POV.

chassis
3-Jan-2015, 07:22
It's a matter of perspective, since the stated assumption is the lenses are "equal" in performance. If you have access to a CAD program or 3D viewer software, a test can be made to simulate the OP's question, by setting the focal length of the viewing software at different values, and setting the camera location at different locations in order to achieve roughly the same image framing. Another, more practical, way to do this is to study images on this site and others to understand lens selection for different situations.