Did the picture composition change when focus changes? and why?

[Rollei35]

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I don't know where to put this question, but it's a generic question to all Leica rangefinder cameras.

I understand frameline moves along (from top left to bottom right) when the focus moves (from infinite to close), in order to compensate parallax.

But why does the whole picture composition changes too?

Pardon me if this topic has been discussed before, but I just recently noticed only when I put the camera on a tripod. I took one picture with infinite focus, and another one with close focus. Nothing else changes, the camera was mounted on tripod and tripod was not moved. The composition/view/frame of the picture changed slightly. Why?

I have tested on my M11, M10-R, with 4 different Leica lenses and 3 non-Leica lenses. All displayed same phenomena. I assume it's not camera and/lenses issue, but why?

Not that I really care because who uses M on tripod anyway. But I am just curious.

Edited March 6 by Rollei35

[jdlaing]

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

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[Warton]

26 minutes ago, jdlaing said:

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

I have to say Leica needs to find a good technical writer to polish their manual in English 

[RexGig0]

7 minutes ago, Warton said:

I have to say Leica needs to find a good technical writer to polish their manual in English 

I found this page to have been written quite well, technically.

[J S H]

1 hour ago, Rollei35 said:

I don't know where to put this question, but it's a generic question to all Leica rangefinder cameras.

I understand frameline moves along (from top left to bottom right) when the focus moves (from infinite to close), in order to compensate parallax.

But why does the whole picture composition changes too?

Pardon me if this topic has been discussed before, but I just recently noticed only when I put the camera on a tripod. I took one picture with infinite focus, and another one with close focus. Nothing else changes, the camera was mounted on tripod and tripod was not moved. The composition/view/frame of the picture changed slightly. Why?

I have tested on my M11, M10-R, with 4 different Leica lenses and 3 non-Leica lenses. All displayed same phenomena. I assume it's not camera and/lenses issue, but why?

Not that I really care because who uses M on tripod anyway. But I am just curious.

Assuming you aren't slightly moving the lens/camera when changing focus, then any other changes are probably due to focus breathing. The magnification of the image will change slightly from close focus to infinity with most lenses that aren't specifically designed for video/cine use. 

[Michael Geschlecht]

Hello Rollei35, 

Welcome to the Forum.

Writing as a person who does as much of their Photography as possible on a tripod. It is interesting that you noticed this aspect of range/viewfinder photography.   

1 of the reasons that the composition changes as you focus to different distances is the range/viewfinder that you are looking thru is seeing a slightly different scene than the lens that is capturing the image is.

The top left to lower right movement of the viewfinder frame, for the lens in use & the rangefinder patches, is designed to accommodate for the slightly different viewpoints, which themselves change, as the lens is focused.

When the lens is focused at Infinity the frame adjusts to cover the scene captured by the lens.

As the lens is focused closer the range/viewfinder system adjusts itself so that it is centered on the newly reconfigured scene at the closer distance. This is a slightly reconfigured scene from what was viewed & captured when the lens was focused to Infinity.

This scene is also slightly enlarged because lenses focus closer by moving the second nodal point of the lens further from the sensor/film plane. They do this mechanically, optically, or a combination of the 2. This lens extension (Whatever the form.) makes the effective focal length of the lens longer. As the focal length gets longer the angle of capture of the lens gets smaller. 

This produces a larger captured image than appeared at infinity. Being a larger image, it leaves out a portion of what was a part of the edges of the image when the lens was set at infinity. since the sensor/film size does not vary as the lens is focused

Some range/viewfinder cameras compensate for this change in angle of image capture by creating frame lines that get larger or smaller as lenses are focused further or closer.

Leica "M" cameras do NOT do this.

So, as you focus closer, you get a slightly reconfigured image of a slightly enlarged & slightly cropped version of what was captured at Infinity. In frame lines that stay the same size.

Best Regards,

Michael

 

Edited March 6 by Michael Geschlecht

[Al Brown]

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It is called FOCUS BREATHING. It is a lens' characteristics. Change in focal length when going from MFD to infinity. Tons of stuff on the web written and Tube videos.

https://petapixel.com/focus-breathing/

Edited March 6 by Al Brown

[adan]

On 3/5/2024 at 6:30 PM, Rollei35 said:

But why does the whole picture composition changes too?

Ever used any kind of image projector (overhead, slide, motion picture, video)?

What happens if you move the projector away from the wall or screen?

Correct - the projected image gets LARGER when you move the projector and lens away from the wall/screen. Move it far enough, and the image no longer even fits on the screen.

Same thing happens when you focus your M lens from far to close (watch it as you turn the focus ring) - it moves away from the film or sensor, and the projected image gets larger (but is still "cropped" to the fixed size of the shutter opening, thus the edge compositon changes).

It is focal-length-dependent - longer focal lengths (135/90/75mm) move out a lot to focus from infinity down to 0.7m, while a 21/24 barely moves at all.

[jdlaing]

I don’t think there is focus breathing in a rangefinder lens. They don’t work the same as a modern lens with internal focus.

[convexferret]

There absolutely is focus breathing in rangefinder lenses. In fact all lenses that do not have some sort of compensatory mechanism (floating elements or internal focussing) will display it. Leica M lenses are no different. 

[Rollei35]

On 3/8/2024 at 9:26 AM, jdlaing said:

I don’t think there is focus breathing in a rangefinder lens. They don’t work the same as a modern lens with internal focus.

Put a M body on a tripod, shoot it with a lens focus at infinite, and then shoot another one at same location with focus at MFD.

Tell me you don't see the two pictures' composition differ?

This happens to all M cameras with any M lenses.

If it's not breathing, what is it?

[adan]

On 3/8/2024 at 7:26 AM, jdlaing said:

I don’t think there is focus breathing in a rangefinder lens. They don’t work the same as a modern lens with internal focus.

I have seen "focus breathing" used with opposite meanings (such is the internet).

In one case it was complaints that a Nikon 75-200 zoom (or thereabouts) with internal focus did not "match" the framing/magnification of a 200mm prime lens when set to the same minimum focus distance (zoom produced too "loose and unmagnified" an image at 200mm and 5 feet or whatever.

But it is unitary focusing (whole lens moves in and out - as do all M lenses) that changes (tightens) composition somewhat when focusing. And it is that slight change in magnification that is correctly called "focus breathing."

If M lenses did not "breath," Leica would not have had to provide that "outside the lines/inside the lines" diagram in your post #2. The framelines would stay identically (in)accurate at all focused distances (except for parallax).

(Fortunately for me, M lenses do breath - giving me "even closer, tighter" close-ups with 75mms at 0.7m - even before Leica started reducing the CFL. 😃 )

It is a term from cinematography ("motion" pictures), where refocusing while in mid-shot (for example, "pulling" the focus from the actor in the background to the actor in the foreground during a conversation), or trying to match framing from take to take that need to be "cut together," makes the effect obvious and annoying.

[jdlaing]

9 hours ago, adan said:

I have seen "focus breathing" used with opposite meanings (such is the internet).

In one case it was complaints that a Nikon 75-200 zoom (or thereabouts) with internal focus did not "match" the framing/magnification of a 200mm prime lens when set to the same minimum focus distance (zoom produced too "loose and unmagnified" an image at 200mm and 5 feet or whatever.

But it is unitary focusing (whole lens moves in and out - as do all M lenses) that changes (tightens) composition somewhat when focusing. And it is that slight change in magnification that is correctly called "focus breathing."

If M lenses did not "breath," Leica would not have had to provide that "outside the lines/inside the lines" diagram in your post #2. The framelines would stay identically (in)accurate at all focused distances (except for parallax).

(Fortunately for me, M lenses do breath - giving me "even closer, tighter" close-ups with 75mms at 0.7m - even before Leica started reducing the CFL. 😃 )

It is a term from cinematography ("motion" pictures), where refocusing while in mid-shot (for example, "pulling" the focus from the actor in the background to the actor in the foreground during a conversation), or trying to match framing from take to take that need to be "cut together," makes the effect obvious and annoying.

I don’t think that’s focus breathing on the frame lines but parallax.

[jdlaing]

11 hours ago, Rollei35 said:

Put a M body on a tripod, shoot it with a lens focus at infinite, and then shoot another one at same location with focus at MFD.

Tell me you don't see the two pictures' composition differ?

This happens to all M cameras with any M lenses.

If it's not breathing, what is it?

Parallax