Talk to me about RF Viewfinders...

Discussion in 'Rangefinder Forum' started by mtbbrian, Nov 21, 2006.

  1. mtbbrian

    mtbbrian Member

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    So what's the deal about RF viewfinders?
    In my research I see that they come in different shapes and sizes, as it were.
    From Lieca's .72 and .85 to the Besa 1:1.
    I don't quite understand all this.
    I wear glasses and have shot with two different Nikon SLR's over the course of my photographic experience, F3 and F100, and I also shoot with a Holga, so I am quite accustom to not seeing everything through the viewfinder.

    Thanks!
    Brian
     
  2. Biogon Bill

    Biogon Bill Member

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    The viewfinder has a lens which renders what you see at a certain level of magnification. A viewfinder with 1.00 magnification like the Bess R3 renders what you see at life size - or as your eye would see it if it were not looking through a viewfinder or if you were looking through any other piece of glass. One of the advantages of such a viewfinder is that you can put the camera up to one eye & keep the other eye open since both eyes will be seeing the same image.

    Other viewfinders present the viewfinder image at a level of magnification somewhat reduced from life size but to varying degrees. With an SLR, you are looking through the lens so you are seeing exactly what the lens sees. However, with a rangefinder you are looking through a separate window with a fixed size that is unrelated to the view of the lens you are using. The difference is that everything in the window is clear, but what you see through an SLR is distorted by the depth of field rendered by the lens & its maximum aperture, which is the aperture through which you are viewing regardless of what aperture you are using to shoot.Everything in the SLR is not necessarily in focus. If you want to see through the aperture you are shooting, you have to press your depth of field preview button if your camera has one & you have to try to discern a darker image as the lens is stopped down. with an RF, you must learn to imagine the depth of field for your lens & setting in your mind's eye. In contrast, you must add depth of field to what you see in your SLR as you stop down from maximum aperture.

    The various reduced magnification images enable the viewfinder to adape to different lens focal lengths. The higher the magnification, the better for longer lenses because the field of view as represented by the frame lines in the view finder is smaller than that for wide angle lenses. However, increased magnification - anything approaching 1.00 - leaves less room for wide angle frame lines. The only way to provide enough room for a wide angle field of view is to reduce the magnification, thereby also reducing what you can see with longer lenses.

    It seems to be generally agreed that a magnification of somewhere around 0.7 is the best for general use. Higher than that favors longer lenses. Lower than that favors wide angle lenses.

    Because higher magnification gives a better view at what you are seeing, it is also considered an aid to accurate focusing. This is of greatest importance with longer lenses & with wider apertures because of the reduced depth of field. Longer base lines also improve accurate focusing because of the mechanical advantage. The combination of base line & magnification is often expressed as effective base length. The longer the effective base length, the more accurately the camera can focus - at least within the limits of the visual acuity of any particular photographer.

    Frame lines are important for composition so you know what is in &/or out of the picture you are shooting. This will never be the same issue with an SLR because you will never get less than what you can see through the viewfinder - although you may get more if you can't see everything. If you ignored the frame lines in an RF viewfinder, the result can be chopping off some part of what you are shooting - like your mother-in-law's head. Not recommended.

    SLR viewfinders actually have their own magnification, which is available in the camera specs. Because you are seeing what you get with an SLR, it is easier to focus longer lenses on an SLR as the lens itself increases the magnification of what you see. In contrast the fixed magnification of a RF makes wide angle lenses easier to focus than on an SLR because the lens itself reduces the manification in an SLR viewfinder when you use a wide angle lens.
     
  3. mtbbrian

    mtbbrian Member

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    So would the R3A not be a good choice if I were intending to use a wider angle lens?
    Brian
     
  4. tim elder

    tim elder Member

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    The Bessa R2A was designed for photographers who prefer wide angle lenses and has built-in frame lines for the 35mm focal length. Many rangefinder photographers use external, hot-shoe mounted viewfinders for 28mm and wider lenses.

    If you haven't already, I'd recommend going to Steven Gandy's website, www.cameraquest.com, as he is a Cosina / Bessa dealer and presents a wealth of information on his site about their cameras.

    Tim
     
  5. Lee L

    Lee L Member

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    Brian,

    That depends on what lenses you plan to use. As others have mentioned, there are auxiliary finders that fit in the hot shoe and work with almost any focal length lens you can find, from 200mm down to 12mm. New Cosina finders run in the US$129 to US$150 range, and others can be found second hand. I'd second the recommendation to visit the cameraquest site for info on specific cameras and viewfinders. They have a nifty, tiny 35/28mm combo hot shoe finder with 0.50 magnification that I use on finderless bodies and my R3A.

    The R3A/M in the C/V Bessa line has frames for 40/50/75/90mm lenses at lifesize or 1:1. The R2/R2A/M models have 35/50/75/90mm framelines at 0.7 times lifesize. So the R2 models only get you from 40mm to 35mm compared to the R3 models.

    If you like to shoot almost all wides, the recently announced C/V Bessa R4A/M bodies coming in the spring with 21/25/28/35/50mm framelines built in might work well for you, but at about 1/2 lifesize or 0.52 magnification.

    Smaller magnification finders mean less accurate focusing in absolute terms, but with wides the DOF will cover you.

    There are built in finders in other rangefinder brands that cover as wide as 28mm. You'll need to follow up on specific models there.

    Leica makes a 1.25X(?) screw-in finder magnifier that can get their recent finders closer to 1:1. It brings their 0.85 finder back to 1:1.0625.

    The advantage of 1:1 is that both eyes match, and the frame floats in your field of vision with both eyes open. If you shoot left eyed, that doesn't do you any good, as the body will block your right eye. You have to give up magnification to get a wider view. Built in finders have more design restrictions than hot shoe finders.

    Lee
     
  6. Pinholemaster

    Pinholemaster Member

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    I find having different magnifications helpful. I have two Leica M6 TTL cameras. One is a .58, and the other a .85 magnification.

    Why, well with my 75 mm lens having a .85 viewfinder makes focusing easier. With the .58 viewfinder I can use my wide angle lenses without an auxillary viewfinder.

    Haven't use a Bessa. I'm blind in my left eye, so having a 1:1 viewfinder isn't important to me.
     
  7. Biogon Bill

    Biogon Bill Member

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    Correct.

    Auxiliary viewfinders require you to compose & focus in 2 sifferent viewfinders. Certainly less than ideal - & not recommended for anything that's going to be your general use or all-purpose lens as a 35 or 28 is for many people. If you prefer 40 or longer as your main lens & will only use wider occasionally, then the R3 is fine.
     
  8. Samuel Hotton

    Samuel Hotton Member

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    How can one know by looking at the camera what magnification it is? For example, my M6 view is smaller than 1:1, but is it a .85 or .75. Is it marked anywhere on the camera body? This info might help when looking at a camera you wish to purchase.

    Sam H.
     
  9. mtbbrian

    mtbbrian Member

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    From the Leica's I have looked at, the M6 and M7, that information is engraved on the viewfinder on the front.
    Brian
     
  10. John Shriver

    John Shriver Member

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    With glasses, you should expect to have "problems" with the widest frameline on any of the M6 frameline sets. Same thing with the 40mm framelines on the Bessa R3 family.
     
  11. mtbbrian

    mtbbrian Member

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    I am seriously considering an R3 or R4, so if I understand you. I should expect some "problems" with lenes wider than 40?
    I think I can compensate for those short comings with my experience with working with a Holga.
    Thanks!!
    Brian
     
  12. Biogon Bill

    Biogon Bill Member

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    Thgere are no frame lines on the R3 for for lenses wider than 40. You'll have to use an auxiliary viewfinder to use anything wider than 40 on this camera. The 40 mm frame lines themselves are a problem. I can't see them on this camera when I put my eye right up to the viewfinder. Many have reported the same problem.

    The M4 is a different beast altogether. No one can tell you about their experience with the viewfinder on this camera because it doesn't exist yet. Due out in about 5 months. It's designed for use with wide angle lenses - low magnification. Short effective base length, so it won't be useful for focusing fast 50s & the like.
     
  13. Roger Hicks

    Roger Hicks Member

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    Umm.... Yes it does. I handled one at photokina several months ago. Mr. Kobayashi reckoned it would probably be all right for a 50/1.5 but it wasn't designed or recommended for that.

    It's pretty much exactly what you'd expect. From memory the frames are 21-28-35-50 and I think the vf magnification is 0,4-something, for an effective base length of around 20mm, though I may be misremembering. My report on the show should be in the next Shutterbug.

    Cheers,

    R. (www.rogerandfrances.com)
     
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  15. Lee L

    Lee L Member

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    From my post (about 8 back), info from Stephen Gandy @ cameraquest.com:

    If you like to shoot almost all wides, the recently announced C/V Bessa R4A/M bodies coming in the spring with 21/25/28/35/50mm framelines built in might work well for you, but at about 1/2 lifesize or 0.52 magnification.

    Lee
     
  16. mtbbrian

    mtbbrian Member

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    This whole issue is so confusing to me!
    I guess with RF's you can't have it both ways with one body.
    Right?
    How many bodies does your "average RF shooter" have?
    As I have stated, I'd like to have lenes from 25 to 75 or 90.
    Brian
     
    Last edited by a moderator: Dec 4, 2006
  17. Roger Hicks

    Roger Hicks Member

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    Dear Lee,

    Thanks, and sorry for not reading more carefully. Was distracted by testing a prototype emulsion which may be announced as a production item next year.

    Cheers,

    R.
     
  18. Lee L

    Lee L Member

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    Roger,

    Just a bump. No one can keep up with reading everything on APUG anymore. The main point is that the R4A/M is a "known quantity".

    You're going to file a full report on the emulsion here first, right? :smile:

    Lee
     
  19. keithwms

    keithwms Member

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    It varies very much depending on your tastes, some people are very productive with one body and one lens. Cartier-Bresson comes to mind, much of his stuff was shot with the same field of view. With RFs one is usually thinking of doing one particular thing (e.g. wide) and doing it extremely well... an RF is a much more specialized tool than an SLR. You will learn to love that aspect, you almost certainly won't feel limited by lens selection.

    Back on the VF issue, one thing you may or may not know already is that the VFs typically display more than the captured area. This is a wondeful feature that really helps with composition. Of course you get framelines to show you what will ultimately go on film, but being able to see around those edges really helps. When I go back to an SLR now I feel like I have to wave the camera around to verify that I have the optimal composition, that is annoying to me.

    Also, for some people, being able to keep both eyes open while focusing is a big bonus; RFs already give you more of a 3D impression of the scene, but with both eyes open it feels very natural and of course there's no shutter blackout so... to make a long story short you're really going to enjoy this.
     
  20. Biogon Bill

    Biogon Bill Member

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    Prototype or pre-production model.
     
  21. Biogon Bill

    Biogon Bill Member

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    How can it be a "known" commodity when no one has had the opportunity to use one yet? We know some stats about it & we know its siblings, but we don't really know this camera yet.
     
  22. Biogon Bill

    Biogon Bill Member

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    Yes it is confusing . . . at least when it's new to you.

    You can have it both ways with one body. A split image rangefinder is is an instrument that determines the distance of an object from the camera by taking two different images of the object at separated points equidistant from the object & by then merging those images through an optical system in the camera. When they merge into one image, the distance & therefore accurate focus has been determined. Accuracy of rangefinder focusing depends on two factors: how widely spaced the two images are & how highly magnified the image in the viewfinder is. The wider spaced the two images are, the easier it is to make fine adjustments & therefore to be more precise in determining the exact right point for focus. The higher the magnification, the easier it is to see the image & therefore to edetermine when the two images are exactly merged in the viewfinder.

    Telephoto lenses have shallow depth of field & therefore require greater precision to focus. Wide angle lenses have much more depth of field & with so much of the subject in focus, less precision is requirted.Wide apertures have less depth of field, so greater precision is also required to focus at very wide apertures (greater than f/2) than at smaller apertures. A more precise rangefinder is always an asset because it is easier to focus at any focal length.

    Versatile rangefinder cameras that can work well with both wide angle & telephoto lenses usually use a magnification of about 0.7 magnification, i.e. the image that you see in the viewfinder will be reduced to .7 times the size that you would see with the naked eye. magnifications greater than .7 will make it easier to focus but the size will be too great to view the entire field of view that the camera sees with a wide angle lens. Magnifications less than .7 will accomodate an increased field of view but will be harder to focus because you will be viewing a smaller image. Using .7 as a compromise allows for the use of a wide range of focal lengths, such as the range in which you are interested.

    Leica has long been the standard in rangefinder photography & uses a magnification of .72 & a rangefinder with a base line 49 mm long on its basic model. Its viewfinder includes frame lines for focal lengths from 28 mm to 135 mm. The Zeiss Ikon, which was introduced a year ago, tweaked this formula by lengthening the base line to 75 mm & increasing the magnification to .74 to obtain greater focusing precision. By using an oversized eyepiece, they were still able to include frame lines for the 28 mm focal length.

    The Voigtlander Bessa cameras which have been discussed in this thread start with a limitation in that the base line of their rangefinder is only 37 mm long, or half the length of the one on the Zeiss Ikon. This saves on cost, but limits the accuracy of focus - especially under certain conditions (telephoto lenses & wide apertures) when using their basic R2 camera with .68 magnification. To offer an alternative to their customers, two years ago they introduced the R3 with 1.0, or life size, magnification to improve focusing precision. However, the widest frame lines they could fit in their viewfinder was for the 40 mm focal length & most have found even those to be very difficult to see. In April, they will offer the R4 with magnification reduced to .52 to accomodate lenses as wide as 21 mm.

    Leica does offer an option of .58 magnification to make the 28 mm frame lines easier to see, which is especially useful for those with glasses. However, they have not attempted to introduce 24 or 21 mm frame lines into such a viewfinder. So, what Cosina is attempting will be an innovation. When the camera is available, photographers will be able to report how difficult or easy it is to work with these wider frame lines. What is currently availbale on rangefinder cameras for focal lengths wider than 28 mm is the use of an auxiliary viewfinder that is added to the camera by mounting it on the hotshoe. This requires that the lens be focused through the camera's built in viewfinder & that the photographer then switch to the auxiliary finder to compose the picture. This two-step process is obviously not as efficient as doing both through the same viewfinder, so photographers often estimate focus & set the focus by the distance scale on the lens - often in advance of actually taking the picture. Because there is great depth of field at these focal lengths, such estimates can achieve accurate focus & leave the photographer free to compose through the auxiliary finder & with focus pre-set, ignore the camera's viewfinder. Photographers have been using this method for 50 years & auxiliary viewfinders are so basic on lenses wider than 28 mm that they are often included with the lens for the purchase price.

    You can find more information on rangefinder cameras & their viewfinders at the following websites:

    www.photozone.de/3Technology/camtec2.htm

    www.photoethnography.com/ClassicCameras/focusing.html

    www.cameraquest.com/leica.htm
     
  23. Roger Hicks

    Roger Hicks Member

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    Well, probably www.rogerandfrances.com with a cross-link here. On VERY limited acquaintance (a couple of square feet or so) it looks like sheer magic. I'm waiting for a lot more line-coated film for a better test.

    Cheers,

    R.
     
  24. Roger Hicks

    Roger Hicks Member

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    Not a lot of difference. The only real variation is the vf (the rest of the body is totally known) and there's not a lot to change between the prototype/pre-production camera and the final production version.

    Personally -- and I speak as someone who regards 35mm as a 'standard' lens -- I'd only buy one if I never used 75mm or 90mm, or switched to reflexes for 50mm and above. If that applies to you (or anyone else), it's an easy choice.

    Incidentally, superb analysis of effective base length/frame size. I'm sure many will find it invaluable.

    Cheers,

    R.
     
  25. elekm

    elekm Member

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    True -- from prototype to actual camera, things change, although maybe it's very close to being a production model.

    The point is that it probably hasn't been in anyone hands long enough for people to offer significant opinions or at least to offer more than "first impressions."

    I look forward to some in-depth reviews.
     
  26. Samuel Hotton

    Samuel Hotton Member

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    Brian, I've been looking carefully at my M6 and I cannot see any engraving on the viewfinder on the front. I would like to find out what I have.

    All the best,
    Sam H.