Fun with MF images - ARCHIVED - FOR VIEWING ONLY

[Thierry]

Dick,

with all due respect, it is wrong to say that the FL is in any way responsible or a factor having an influence on the perspective.

When one takes 2 images from the VERY SAME (to be able to compare) view point with 2 different FL, the 2 resulting images are exactly identical concerning the perspective (the horizontal and vertical converging or diverging lines in the image). The reproduction scale is not the same, obviously, but the perspective yes. Just enlarge the 2 images to exactly the same scale and you will see that the lines do overlap exactly, thus the perspective is the same.

Best regards
Thierry

He means the subtended angle... if the lens axis is perpendicular to the middle of a 20m subject 10m away the subtended angle is 2(arctan (10/10) or 90 degrees.

The angle of view would be the same if the subject filled the format (viewfinder).



It is obvious, but, in this context, I think it needs pointing out: We use lenses of different focal lengths to allow us to get the reproduction ratios we want from different subject distances.... the view point (or subject distance) required to fill the format to the required degree, at the required scale, is dictated by the focal length and format (angle of view).

Focal length affects perspective by allowing us to vary the subject distance.

If you use a standard focal length lens (focal length equal to the diagonal of the format) or a wide-angle, and fill the format with a face, perspective makes the nose disproportionately large... if you use double the focal length at double the distance with the same format you do not get this effect.

If there are no obstructions in the way, if you want a tall tower in the middle distance to produce an image similar in size to that of a much smaller (part of a) building in the foreground you can achieve this by an appropriate combination of angle of view and viewpoint.... this can be used to good effect on buildings like churches, with a tower at the far end.

On a Calendar picture there was a tractor in the foreground, framed by a tree, and a small hill in the distance - by using a longer lens (from a greater distance) I made the hill look considerably higher, giving a better composition.

 

[Shashin]

The two primary factors that impact (linear) perspective are object distance (true perspective) and viewing distance (apparent perspective). It is the viewing distance that shows differences in focal length and angle of view (if perspective, which is defined as the depth in a 2-D image, did not change, how could we notice what images were taken with wide angles and telephotos--they would look the same). So just as where you stand is important for creating the perspective, where you stand when viewing the perspective is important as well--perspective is a type of projection system.

Apparent perspective will be the same if the image is viewed in relation to the focal length and magnification of the image--you view wide-angle image closer and telephoto image further away (the would be defined as the "Correct" viewing distance). However, we usually view images at a fixed distance. If that distance is further away then the Correct viewing distance, then the apparent perspective is stronger. If it is closer, then it is weaker. "Standard" viewing distance is proportional to the diagonal of the image and so the standard and correct viewing distance are the same in that case, that is why we call a lens with a focal length equal to the format diagonal "Normal"--it has nothing to do with angle of view being the same as the eye, but rather giving the natural perspective when viewed at the standard distance.

When the actual viewing distance is very different from the Correct viewing distance, the image will appear distorted. The Wide-Angle Effect is well known where heads are stretched away from the optical axis, but if you place your eye close to the image at the correct viewing distance, the head will appear round--same thing with writing on roads. When you have very long focal lengths, you get very unnatural compression of features.

So to see changes in perspective related to focal length is real, but it is not the focal length per se that is causing it.

There are tons of books on perspective--I have read a whole bunch of them. There is also a link to one in an earlier post I made. Common references include The Focal Encyclopedia of Photography, Third Edition, Materials and Processes of Photography, and View Camera Techniques.

 

[Shashin]

But back to why we are here. Tom, sublime. Don't give up on this assignment yet...

Last December, I gave myself the assignment of taking one photo/day to be used in a printed collection. My intention is to keep this going for a year. As a non-professional and someone who often suffers from a lack of imagination, this has turned out to be more difficult than I thought. Most of the shots so far have been with a K-5, simply because of ease of use and high ISO performance. Only a few are with the 645D. Here's one I never would have taken without the self-imposed assignment forcing me out the door. The jpeg version loses some of the features I like in this image: the frozen water along the shore glows in a Gold Silk print and is somewhat subdued on the screen. 645D, 35 mm A.

Tom

 

[rem]

Some Portraits from the last Days with the H4D and 120mm Macro II. Any Critique? Thanks, rem

 

[Thierry]

Absolutely correct and a very good extensive explanation: I didn't dare to "plunge" in it.

We can define perspective with other words: it is the reduction in 2 dimensions on a plane (sensor, film or paper plane of the printed image) from the original 3-D dimensions of the subjects. The perspective is given by the horizontal and vertical (converging or diverging) lines in this 2-D projection.

Thanks and best regards
Thierry

The two primary factors that impact (linear) perspective are object distance (true perspective) and viewing distance (apparent perspective). It is the viewing distance that shows differences in focal length and angle of view (if perspective, which is defined as the depth in a 2-D image, did not change, how could we notice what images were taken with wide angles and telephotos--they would look the same). So just as where you stand is important for creating the perspective, where you stand when viewing the perspective is important as well--perspective is a type of projection system.

Apparent perspective will be the same if the image is viewed in relation to the focal length and magnification of the image--you view wide-angle image closer and telephoto image further away (the would be defined as the "Correct" viewing distance). However, we usually view images at a fixed distance. If that distance is further away then the Correct viewing distance, then the apparent perspective is stronger. If it is closer, then it is weaker. "Standard" viewing distance is proportional to the diagonal of the image and so the standard and correct viewing distance are the same in that case, that is why we call a lens with a focal length equal to the format diagonal "Normal"--it has nothing to do with angle of view being the same as the eye, but rather giving the natural perspective when viewed at the standard distance.

When the actual viewing distance is very different from the Correct viewing distance, the image will appear distorted. The Wide-Angle Effect is well known where heads are stretched away from the optical axis, but if you place your eye close to the image at the correct viewing distance, the head will appear round--same thing with writing on roads. When you have very long focal lengths, you get very unnatural compression of features.

So to see changes in perspective related to focal length is real, but it is not the focal length per se that is causing it.

There are tons of books on perspective--I have read a whole bunch of them. There is also a link to one in an earlier post I made. Common references include The Focal Encyclopedia of Photography, Third Edition, Materials and Processes of Photography, and View Camera Techniques.

 

[tsjanik]

But back to why we are here. Tom, sublime. Don't give up on this assignment yet...

Thanks Vincent Pramote and Shashin, I appreciate the comments. Not giving up yet.

Pramote: your beach looks more inviting

 

[Landscapelover]

Thanks Tom for your kind words.
Again, your photo is stunning! Please don't give up.
Pramote

 

[dick]

Dick,

with all due respect, it is wrong to say that the FL is in any way responsible or a factor having an influence on the perspective.

When one takes 2 images from the VERY SAME view point with 2 different FL, the 2 resulting images are exactly identical concerning the perspective.

Best regards
Thierry

Thierry...

What you say above is true, but...

If you had shown me due respect you would have read and tried to understand my post before trying to refute it.

I am not talking about taking two picture from the same view point with different focal lengths, I am talking about taking two pictures of the same subject, at the same subject-to-image scale with different lenses. This means different view points and different subject distances. I even put the relevant sentence in a bigger font to try to ensure that you got the point.

You should try to understand the rules and not just learn them parrot-fashion and quote them out of context.

He means the subtended angle... if the lens axis is perpendicular to the middle of a 20m subject 10m away the subtended angle is 2(arctan (10/10) or 90 degrees.

The angle of view would be the same if the subject filled the format (viewfinder).



It is obvious, but, in this context, I think it needs pointing out: We use lenses of different focal lengths to allow us to get the reproduction ratios we want from different subject distances.... the view point (or subject distance) required to fill the format to the required degree, at the required scale, is dictated by the focal length and format (angle of view).

Focal length affects perspective by allowing us to vary the subject distance.

If you use a standard focal length lens (focal length equal to the diagonal of the format) or a wide-angle, and fill the format with a face, perspective makes the nose disproportionately large... if you use double the focal length at double the distance with the same format you do not get this effect.

If there are no obstructions in the way, if you want a tall tower in the middle distance to produce an image similar in size to that of a much smaller (part of a) building in the foreground you can achieve this by an appropriate combination of angle of view and viewpoint.... this can be used to good effect on buildings like churches, with a tower at the far end.

On a Calendar picture there was a tractor in the foreground, framed by a tree, and a small hill in the distance - by using a longer lens (from a greater distance) I made the hill look considerably higher, giving a better composition.

 

[dick]

The two primary factors that impact (linear) perspective are object distance (true perspective) and viewing distance (apparent perspective).

¿The correct viewing distance is the viewing distance for which the observer-to-print angle of view is the same as the camera-to-subject angle of view?

It is possible to make a mural look like an extension of a room, with correct perspective, but only for one viewpoint.

A picture in a french window frame at the end of a passage could look as if you were looking through a window at Mont Blanc, but the viewing distance/angle-of-view would have to be correct... if the camera was looking up at the mountain... the picture viewer's eye should be at the same level as the eye level in the picture.

 

[Thierry]

Excuse me Dick, there was no disrespect meant in my post, and my apologies to you if you took is as such. I am not trying to put my knowledge here under any circumstance and out of context.

This being said, I read of course your post entirely and did well understand what you meant to say.

What I am saying is that perspective has to be compared from the SAME view point (shooting/viewing distance), if you don't then you don't compare the same things and cannot speak about comparing perspective objectively.

That is at least how perspective is defined.

Again, am sorry if I did hurt your feelings, this was just meant as a discussion.

Best regards
Thierry

Thierry...

What you say above is true, but...

If you had shown me due respect you would have read and tried to understand my post before trying to refute it.

I am not talking about taking two picture from the same view point with different focal lengths, I am talking about taking two pictures of the same subject, at the same subject-to-image scale with different lenses. This means different view points and different subject distances. I even put the relevant sentence in a bigger font to try to ensure that you got the point.

You should try to understand the rules and not just learn them parrot-fashion and quote them out of context.

 

[dick]

Excuse me Dick, there was no disrespect meant in my post, and my apologies to you if you took is as such. I am not trying to put my knowledge here under any circumstance and out of context.

This being said, I read of course your post entirely and did well understand what you meant to say.

What I am saying is that perspective has to be compared from the SAME view point (shooting/viewing distance), if you don't then you don't compare the same things and cannot speak about comparing perspective objectively.

That is at least how perspective is defined.

Again, am sorry if I did hurt your feelings, this was just meant as a discussion.

Best regards
Thierry

Thierry

We do appreciate contributions made by professionals like you to this forum, and I appreciate your apology, and I did not want to start a flame war.

You appreciate that you get different perspective from a different view point, and a different focal length would enable us to "fill the frame" from the different view point? ...Like if you take two portraits, one with a 60mm lens from 1m and one with a 120mm lens from 2m?

Subject distance is a simple concept on a simple camera, but with a technical camera the subject distance, for calculation of reproduction ratios, should be measured perpendicular to the image plane... the perpendicular distance can be changed using rear movements, giving an effectively different subject distance from the same view point?

This is all explained in Merklinger's "Focusing the view camera"... which I should re-read sometime.

 

[Paul66]

Isn't this thread titled FUN with medium format images? I feel that you are using it to argue and need to do that somewhere else just my opinion but...........

 

[Landscapelover]

I absolutely agree with Paul!
I visit here to have "FUN" and view breathtaking images from friends here.
Almost quitted this forum once when I was a new member! Disagreement is okay but I'd expect friendly and respectful atmosphere here.
Take it easy guys!
Thanks,
Pramote

 

[Quentin_Bargate]

Tulips, Hasselblad H4D-50, 120mm macro, first shot in a new project.

This shot works well printed on Epson Water Resistant Mate Canvas

And Rem, those portraits look great to me, particularly the middlw one, with the nicely used hair light and a cute expression on the model. I see you have the mark II macro. I still have the Mark 1 which I used for the tulips.

 

[gazwas]

Nice still life image Quentin!

It looks like a strobe/softbox reflection in the glass vase but the light it so soft its similar to diffused window lighting and wondered if you could share your technique?

 

[Quentin_Bargate]

Hi Gareth,

Thanks - and yes it is a strobe refelcted in the vase base. Quite a bit of post processing, obviously

Quentin

 

[rem]

Thanks Quentin, and I find your picture from the Tulips wonderful. I think its great printet! Yes I have the II, but I think there will not be a big difference if any. rem

 

[jerome]

Tulips, Hasselblad H4D-50, 120mm macro, first shot in a new project.



This shot works well printed on Epson Water Resistant Mate Canvas

And Rem, those portraits look great to me, particularly the middlw one, with the nicely used hair light and a cute expression on the model. I see you have the mark II macro. I still have the Mark 1 which I used for the tulips.

I love this Quentin !

 

[Shashin]

I shot this tonight for fun and the Pentax Day event on Feb. 4th. These are 3 minute exposures at ISO 400 at f/10 with the Pentax 645D and A 35mm lens. Kinda hard focusing without light.

 

[Swissblad]

Tulips, Hasselblad H4D-50, 120mm macro, first shot in a new project.



Quentin

Really lovely tulips - and I can imagine it looks terrific printed as indicated.

Any hints on the post-processing...?

Thanks for sharing,

Sinuhe