Viewfinder magnification & FoV

[olakiril]

Why don't manufacturers mention the field of view of their viewfinders together with the magnification?
Isn't it something that buyers should care?
I remember the large viewfinder from R-D1 that in addition to its large magnification of 1X it had a large FoV that could even support a 35mm FF FoV.
Fuji has a 0.6X magnification that does not even cover a 35mm FF FoV. That is tiny compared to R-D1.
Do you have any thoughts on this matter?

 

[stevebrot]

Why don't manufacturers mention the field of view of their viewfinders together with the magnification?

For rangefinder cameras such as the R-D1 and Leica offerings the makers generally indicate the provided viewfinder frame lines. Native field of view is usually not pertinent.

Fuji has a 0.6X magnification that does not even cover a 35mm FF FoV.

Is it safe to assume you mean the field of view for 35mm focal length to a 24x36 (FF) frame (43.2° diagonal)? If so, it would be good to note that the shortest focal length supported by the R-D1 was 28mm on APS-C (54.5° diagonal). If you needed a frame for a lens shorter than 28mm, an auxiliary viewfinder would be required. This is fairly typical for 1x magnification finder cameras.

In regards to Fuji and assuming you mean the X-Pro1 or X-Pro2, the optical viewfinder will automatically support (appropriate magnification and frame lines) down to 18mm on APS-C (77° diagonal) and up to 60mm (27° diagonal) when using Fuji lenses. It does this using two viewfinder magnifications (0.37x and 0.6x). I have not used the Fuji product, but according to their literature and available reviews, manual selection of both magnification and frame lines is possible. At both 0.37x and 0.6x, 35mm frame lines provided and are fully supported.


Steve

 

[redsky]

One thing I quite never understood precisely, mathematically, is how the magnification, the sensor size and the FoV all together define how big is the "rectangle" through which you look, whether for rangefinders or SLRs, 35mm or MF.

Would anyone explain that using numbers?

Thanks.

Why don't manufacturers mention the field of view of their viewfinders together with the magnification?
Isn't it something that buyers should care?
I remember the large viewfinder from R-D1 that in addition to its large magnification of 1X it had a large FoV that could even support a 35mm FF FoV.
Fuji has a 0.6X magnification that does not even cover a 35mm FF FoV. That is tiny compared to R-D1.
Do you have any thoughts on this matter?

 

[redsky]

Not sure whether this is a boring topic or nobody really knows, so I searched around and found this post:

http://www.dgrin.com/showpost.php?p=670119&postcount=12

Following this logic for a Leica M, for example, results in this:

Magnification rate (0.68x) is for 50mm, which is 39 degrees.
Viewfinder covers 28mm, which is 65 degrees.
So the viewfinder (28mm) covers 165% of the field of view of a 50mm lens.

Therefore:
the horizontal length of frame (the actually size of the rectangle you look through) is 165% * 0.68 * 36mm == 40mm

Which is significantly larger than the viewfinder of a D800 for example.
Does this make any sense?

One thing I quite never understood precisely, mathematically, is how the magnification, the sensor size and the FoV all together define how big is the "rectangle" through which you look, whether for rangefinders or SLRs, 35mm or MF.

Would anyone explain that using numbers?

Thanks.

 

[Denverdad]

There seems to be a fair amount of confusion regarding terms like magnification and coverage as applied to viewfinders. This short article is consistent with my understanding at least, and provides what I think is a pretty good overview of the subject with clarification of the terms.

In short, coverage describes what fraction of the scene to be recorded is actually visible through the viewfinder. For example I've discovered that many of the old medium format cameras I like to play around with have surprisingly poor coverage, showing a narrower field of view than what the camera ultimately captures. In addition, the line of sight through the viewfinder may sometimes be off a bit meaning you are effectively mis-pointing from where you want, and they can also be noticeably rotated from what the camera actually sees. These issues are something of a pet peeve of mine since I like to compose fairly precisely, so I sometimes feel like I am shooting with blinders on with these cameras. Of course there's the opposing argument to all of this which says you can always just crop the final result when you're done. so having some margin against clipping the edges of your subject is really a good thing.

Magnification really means something completely different from this. It is a measure of how the apparent size of objects appear in the viewfinder relative to their size when viewed directly. The article explains this and other terms in better detail than I would care to try, but I will just say that personally I value full (100%) coverage much more than I value 100% magnification.

Jeff

 

[pvdhaar]

Why don't manufacturers mention the field of view of their viewfinders together with the magnification?
Isn't it something that buyers should care?

Agreed. All the common numbers, like magnification and coverage, fail to address the real differentiator between viewfinders: ease of viewing. You can have all the 100% coverage you want but still not make out a thing if the magnification is crud (like the 0.35x of the Leica Minilux), and vice versa.. What also doesn't help, is that 100% coverage for an APS-C DSLR means something entirely different than 100% coverage for a FF one. With field of view, you have at least a notion of how large the apparent size of the view in the finder is; but this road is also paved with obstacles..

There's no point in having an enormous apparent FOV if the edges have large distortion. The typical barrel distortion in external OVFs for ultra wides comes to mind here. Basically, whatever metric you decide upon, manufacturers can take shortcuts and hide behind the numbers. Ultimately, there's only one solution: try before you buy..

 

[olakiril]

Coming back to this thread here is an example that compares the xpro2 with M4 :

7:22
https://m.youtube.com/watch?v=ziMH8u0oQdM&feature=youtu.be

The magnification is almost the same but the field of view is nearly double.

35mm on the xpro2 and 50mm on the leica from here:

http://rangefinderforum.com/forums/showthread.php?threadid=154128