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Digital Deal: Inquiring Minds Inquire


Canon EOS 1D
Canon EOS 1D
Canon Viewfinders
Note the size difference between a full frame sensor—from the Canon EOS 1Ds—on the left, compared to the smaller sized sensor of the earlier EOS D60 on the right.
Olympus Evolt E-330
Probably the dimmest of the viewfinders we’ve used is the Olympus Evolt E-330, which, as we described two issues back, siphons some of its light out of the viewfinder path and redirects it to the Live Viewer imager pickup.

Perhaps astute readers have noticed that Photo Trade News doesn’t have a “letters to the editor” section. Why that is so is unknown to yours truly, for the Digital Dude is seldom involved in decisions outside his own pages. However, if he were, he’d have plenty of good reasons to exclude a “reader’s” page from the publication.

For starters, according to surveys, 93% of all “reader letters” are actually composed by industry analysts on the cheap trying to learn what to say when their clients ask. Another 79% are written to trick the editors and expose them as being dumber than they think. An additional 83% are by out-of-work freelance writers, trying to start a relationship. That’s 255% altogether, but these were very casual surveys.

Don’t get us wrong, we love to hear from readers. And yours truly never believes surveys. But even real letters go against at least some of the grain of some publications. Those that have “News” in their titles, for example, have plenty to report, but few readers’ letters are really “news.” They may be insightful, cogent, and well-stated, and we may love answering them off-line, but they’re often about topics that were last issue’s news. They may all be good questions, but only some have the currency to be published in Photo Trade News.

Besides “news” in our title, there’s also the “photo trade” part. A letter that asks how to work a certain camera may be well-suited for a consumer publication, but the orientation here is different. Our readers being retailers, they already should know how to work every camera. We may love discussing that off-line again, but what gets printed for our readers might have more to do with how to present the camera.

That’s how the thinking would go if the Digital Dude ran things, and there would be no “letters” page. There would simply be letters, when and as they come up, which, besides being insightful and cogent and well-stated, bear also upon newsworthy things of interest to the trade. We receive quite a few.

It would be immodest for us to publish the sweet nothings some readers send us, or the cards that come with their bouquets of flowers and boxes of chocolates. But here are two of another order, perhaps of broader interest.

Seeing the Light

Probably the first thing most customers do when examining a new camera is put the viewfinder to their eye. This means that their first impression about working the camera is based upon the viewfinder, how comfortable and practical it is. That being the bedrock of all subsequent impressions, the seemingly simple viewfinder plays a surprisingly profound role in making the camera likeable or otherwise. In this regard, yours truly received the following e-mail from a reader identified only as Tracy.

“Very interesting article,” states Tracy in response to one recent camera review. “You are an excellent writer and the historical perspective you supply is so valuable.” And we promised we’d keep the flowers and chocolates out of this! But Tracy goes on: “You mentioned the bright digital SLR viewfinder, and I wonder if I could get your advice on this topic. My Nikon F2 was just stolen, and I am finally going to try a digital SLR. I am finding that the viewfinders on the Nikon D70 and the Canon 20D seem a bit dim. I just don’t feel that I am seeing the shot as well. Any thoughts? Do you think the viewfinder is likely to be improved in the next iteration of the Nikon prosumer DSLR? I realize you may not have the time to answer my question, but I thought I’d give it a try.”

For a question like this, we’d make the time to answer. It’s an important question indeed, as DSLRs sustain their juggernaut rampage across the photographic landscape. It suggests certain preparations for the demonstration of a DSLR, if conditions allow. For the through-the-lens viewing of a DSLR, the viewfinder is obviously influenced by the brightness of the lens. An f/2.8 lens on a given DSLR will create a brighter viewfinder image than an f/4.5 lens on that same camera.

Whether you actually demonstrate the camera with the faster lens, however, brings some considerations of an ethical nature into the formula. Will the customer be buying the camera with that particular lens? If so, go for it. But most of the “kit” lenses offered with the low- and mid-price DSLRs are more in the f/3.5 range, and the customer buying the kit should evaluate the package, viewfinder included, with the accompanying lens.

PTN readers are the world’s most ethical, of course, but even the readers of rival publications should take heed—for where ethics leave off, enlightened self-interest sometimes kicks in. That is, a customer ought to be satisfied from the beginning. For most retailers, the cost of losing a sale is still less than the cost of processing a return.

But the speed of the lens would not be the sole factor in the brightness of an SLR viewfinder. The viewfinder’s own construction must bring influences to bear. Tracy mentions the Canon 20D, whose attributes in this regard are matched by the new 30D. Both models use the same APS-C-size imager, which is smaller than a 35mm film frame. Would this require a smaller mirror and optical path? And would this in turn have an effect upon the amount of light transmitted through it?

We took the question to Canon, for two good reasons. First, they’re the only manufacturer of DSLRs offering both APS-C and full-frame cameras, so they’re the most likely to lack a favoritism either way. Second, they have Chuck Westfall on-hand, whose knowledge of such things is encyclopedic and his willingness to share quite generous. “Assuming identical lenses,” states Mr. Westfall, “the two biggest variables in AF SLR viewfinder brightness are: “1. Prism characteristics: SLRs with glass pentaprisms tend to deliver brighter images than SLRs with hollow pentaprisms, sometimes called ‘penta-mirrors.’ All EOS digital SLRs (including the 20D) have glass pentaprisms, except the Rebel series, which uses pentamirrors. And then there are some SLRs (Olympus comes to mind) that use roof prisms rather than pentaprisms. These have no particular advantage or disadvantage when it comes to viewfinder brightness.

“2. Focusing screen characteristics: There’s a lot of variety in focusing screen design. The old-fashioned ground-glass focusing screens of the 1960s and 1970s have largely been replaced by plastic screens, which are not only lighter and cheaper, but can also be made much brighter. In fact, by modifying the surface pattern, brightness can be optimized for specific aperture ranges. Standard focusing screens for consumer-grade digital SLRs tend to be optimized for consumer-grade zoom lenses that typically feature maximum apertures as small as f/5.6. But these screens are often difficult to focus manually, especially away from the center of the picture area. Professional SLRs like the EOS-1 series can be outfitted with screens that deliver more sharpness, albeit at the expense of maximum brightness.

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