viewfinder magnification

[msbarnes]

why don't many cameras have 1:1 viewfinder magnification? Is it difficult to achieve? This is on both RF's and SLR's. What gives?

[polka]

Anyway, for the SLRs, the viewer magnification depends on the focal of the lens attached : with wide-angles the image seems smaller, with the teleobjectives they are larger. With my Topcon, the magnification is 1:1 for my standard 58mm lens. It is also the case of my Spotmatic with the Zenit Helios44 (which focal is also 58mm).

Maybe the magnification is a little less than 1:1 on SLRs with 50mm lenses, because otherwise the viewing angle of the viewfinder would be to wide for comfortable viewing ?

Paul

[Markster]

The viewfinder has to be smaller by definition. It has to have a moving mirror. That means its dimensions fit inside the normal "view" dimensions inside the mirror chamber...

It's just one of the issues with splitting a view off in a separate direction (the viewfinder) from where it needs to go naturally (the film plane).

[ic-racer]

Back in the day when you had to actually focus an SLR yourself, the focusing screen image was quite large and wide and frequently gave a 1:1 image when a 50mm lens was on the camera. I notice that post 1980s autofocus cameras, like Nikon f100 and n75 have what I call 'tiny' focus screens. I presume because the camera will focus for you and you don't need to see the image 'close up.' In fact the n75 gives a 1:1 view only with an 85mm lens. So I wouldn't even try to use that camera (or the F100) with manual focus lenses.

[Markster]

Forum ate my post! Gah!

Second try: Even ones in the 80s never had 1:1 zoom. They have at best 0.97x zoom or something close. The only way to get full 1:1 zoom would be to have no viewfinder at all -- like one of those glass plate cameras from the 1800s. Otherwise, any diversion of the light stream is going to cost some small margin of viewing area just because of the framework of the mirrors and the reflexive prisms in the viewfinder.

[Ralph Javins]

Anyway, for the SLRs, the viewer magnification depends on the focal of the lens attached : with wide-angles the image seems smaller, with the teleobjectives they are larger. With my Topcon, the magnification is 1:1 for my standard 58mm lens. It is also the case of my Spotmatic with the Zenit Helios44 (which focal is also 58mm).

Maybe the magnification is a little less than 1:1 on SLRs with 50mm lenses, because otherwise the viewing angle of the viewfinder would be to wide for comfortable viewing ?

Paul

Good morning;

As Paul has said, with most of the SLR cameras where you still could do some of the work yourself (other than just aiming it and pressing the shutter release button), the lens focal length that seems to produce a true 1:1 viewing image with true perspective as you see with your eye, seems to be right at about 58mm. Many of the major SLR camera manufacturers back in the early and middle 1960s made available a 58mm lens as one of their premium and professional offerings. There must be some reason why they departed from the "normal" 35mm film focal length for a "standard" lens of only 50mm.

And, I can add both Nikon and Minolta to the list of manufacturers Paul provided. Minolta was still offering a 58mm focal length lens at least into the late 1970s.

[Bob-D659]

58mm lenses, ie, the Nikon 5.8cm f1.4 were not retrofocus lenses.

[Markster]

I thought he was talking about usable area in the viewfinder vs what shows up on film?


Color me confused then.

[AgX]

Markster, these are two issues: the finder image magnification, and the ratio (given as percentage) between finder image area and film gate area.
The latter often differs due come up for the reduced size of image area in a framed slide. Furthermore is gives some reseve in case of misalignement between finder and film gate.

[lxdude]

I thought he was talking about usable area in the viewfinder vs what shows up on film?


Color me confused then.

Your assertion that no viewfinder showed 100% of the final image is incorrect. The Nikon F, F2, F3, etc. show 100%.