Musings on Photography

Stupid Holdover from the Film Era – Viewfinders

Posted in equipment by Paul Butzi on May 3, 2007

It’s not just exposure meters in digital SLR’s that are derived directly from their counterparts in film SLR’s, and as a result have properties which no longer are desirable in the world of digital photography.  SLR viewfinders also come directly from the film era, without update, and as a result, we have a whole raft of digital SLR’s with a major defect.  That major defect is the ‘less than 100% viewfinder’. 

In a film camera, there are several possible destinations for the film.  The first, and most common, was that the photographer was exposing negative film, intending to make prints.  In this case, a little loss of image area around the edge of the frame was pretty much a given, because the enlarging equipment typically cropped a bit off so that raw edges wouldn’t show.  The second most common was probably color slide film, for projection.  Again, the photographer needed to allow for a slight crop around the edges, because the standard slide mount cropped a bit off (again to avoid raw edges).  The third most common, but the most common among pros, was that the film was intended for a professional postproduction workflow, and in this case, it was perfectly possible that the cropping at the edges would be minimal.  So we had ‘amateur cameras’ which had viewfinders which reflected cropping around the edges (usually around 95%), and then we had ‘pro’ cameras, which had ‘100% viewfinders’, so that the pros could see everything they were going to get.

And this distinction continues today.  The Canon Digital Rebel Xti, Canon’s entry level camera, has viewfinder coverage of 95%.  Canon’s EOS-5d, Canon’s high end ‘amateur’ workhorse (despite its appeal to pros) has 96% viewfinder coverage.  But the EOS-1ds mk II has a 100% coverage viewfinder.  It’s the same deal with Nikon.

But we don’t have negative carriers and slide mounts cropping off the edges of our photographs in the digital world.  So why do camera manufacturers insist on building cameras with (inappropriate) less than 100% viewfinders?  It’s as if camera designers are trapped in the past.  Let’s design a high end amateur camera, they say.  For decades, amateur cameras had 95% viewfinder coverage, and they never stop to think that in the digital world, maybe this no longer makes sense.

It’s time for that misfeature to go the way of the dodo.

10 Responses

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  1. Andy Chen said, on May 3, 2007 at 6:55 pm

    I thought that 100% coverage viewfinders required more expensive parts and were harder to assemble. Thus they were reserved for “pro” gear. Or, have I just been suckered by marketing speak?

  2. paul said, on May 3, 2007 at 7:41 pm

    Well, I agree with you, but I can’t complain. My D2X has 100% coverage. 🙂

  3. Martin Doonan said, on May 4, 2007 at 12:45 am

    I don’t see how a 100% view finder can be expensivev. My old, cheap EOS 500 has a 95% view-finder for 35mm. that’s 150% for APS-C digital. the mirror box is the same size it always was (which would be a limit) so why can’t he viewfinder be, too. Plus, the old VF I can read the entire display with glasses, on my 20D it’s almost impossible to read the numbers along the bottom.
    I agree with Paul, it’s laziness on the part of the designers.

  4. John McLaughlin said, on May 4, 2007 at 2:03 am

    And while on the topic, don’t forget that other lovely trait of SLRs in the digital era, the small dim viewfinder. I weep when comparing the lovely bright viewfinder on my wife’s Nikon film body to the pinhole on my 300D (or am I weeping from trying to squint through it?)

  5. Mike Johnston said, on May 4, 2007 at 6:20 am

    And don’t forget the really annoying legacy assumption, which is that “good” and “serious” and “pro” cameras have to be BIG, whereas small cameras have to be for “amateurs” who tolerate compromises. Thus, while not all big cameras have good viewfinders, all small cameras have bad ones. I can hardly wait for this particular fashion to change.

    (And BTW, from what I understand, 100% finders are considerably more expensive to make. The reason is that smaller-percentage finders don’t have to be precise–the lower coverage masks a fair amount of slop.)

  6. Guy Tal said, on May 4, 2007 at 7:39 am

    As others suggested, in terms of design and accuracy 100% is not just a couple or percentage points from 96%. The real deal is that it’s either an accurate/precise/measured 100% or it’s less-than 100% (and here manufacturers can take some freedoms to cut on cost and size). I take it to mean that anything less than 100% is the manufacturer’s way of saying “it’s inaccurate”. I don’t believe this has anything to do with the film days, it’s just a quality/tolerance issue for cost control.

    As for dim viewfinders – that’s what you get with a smaller reflex mirror (less light reflected up into the prism).

    Guy

  7. Olli Wendelin said, on May 4, 2007 at 9:17 am

    I wish Digital SLR viewfinders were like the old 35mm finders. I find current viewfinders to be way behind my Nikon F2 Viewfinder. Most have less than 100% coverage. No user changeable focusing screens. No interchangable viewfinders (I miss my BIG action finder).

    DX size mirrors mean dimmer viewfinders. In an effort to mitigate this the manufacturers use fresnel focusing screens. The end result is a brighter viewfinder but no change in depth of field below f2.8. With an f1.4 lens wide open you see more depth of field through the viewfinder than you see in the photograph.

    Olli

  8. Darren said, on May 4, 2007 at 9:42 am

    This is a great Photography blog, thanks for the info.

  9. Doug said, on May 4, 2007 at 11:05 am

    I think that this article is getting closer to the real pinch-point of the situation, which is that reflex viewing is sub-optimal for digital photography.

    We continue to use reflex viewing because electronic viewfinders haven’t yet measured up to optical viewfinders. Maybe instead of trying to make better reflex viewfinders, we should be trying to make electronic viewfinders more acceptable.

    Once the reflex mirror is out of the way, we can use the main sensor for exposure measurement. The EVF could show the exact framing, the exact white balance, the exact exposure, and the exact depth of field (the latter two are assuming that the lens is stopped down during viewing, rather than kept wide open). Live histograms and/or blown highlight indicators are possible. EVF “zoom” can help with getting manual focus dead-on. And of course live view on the back LCD or a remote display are possible.

    A number of advanced features also become possible. A choice of aspect ratios could be provided, either with crop lines or with the cropped areas completely blacked out. “Freeze frame” in the viewfinder could be useful for evaluating preflash results when making flash exposures—although the camera would have to calculate the increased effects of the full flash power.

    For the Raw shooter, an automatic “Expose (to the) Right” mode would probably be a big hit.

    Many more advanced features become possible for the JPEG shooter, where the camera can show the results of the processing that it will do. How about color gamut warnings? How about seeing the effects of various “virtual film types” right in the viewfinder? The B&W enthusiast might like to see what the effects of various filter effects in the viewfinder. Maybe a Levels or Curves feature could be added which affects the Raw-to-JPEG conversion. For many people, the need to shoot Raw is reduced if they could predict how the JPEGs would look.

    The big change is that previsualization would be replaced with visualization. The photographer wouldn’t need to imagine what the photo will look like with various settings—the result will be right there in the viewfinder (or on the LCD screen).

    Okay, aside from the need to develop a really GOOD electronic viewfinder system, there’s also the question of how to deal with autofocus.

    Still, I’m pretty much convinced that the so-called EVIL—electronic viewfinder, interchangeable lens—camera is going to push SLR out of the picture for most serious digital photography… once a good one arrives. There will still be those of us who use SLRs, just as there are those who still shoot medium format and view cameras. But reflex viewing will be considered to be just as quaint as direct viewing already is.

  10. Martin Doonan said, on May 4, 2007 at 11:10 am

    I’m just not buying the “100% is expensive due to precision” argument.

    the manufacturing & placement accuracy required for virtually every other component is far higher. just look at the ground glass versus focus precision, fore/aft alignment of sensor, rotation of sensor.

    That level of accuracy comes cheap and easy these days, and even a 100% VF wouldn’t need anything like that level of accuracy.

    Maybe 30/40 years ago that was the case but modern manufacturing is precise and cheap.


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