[Edvinas]

I agree. The focusing screen must be the same size as the sensor. To make an APS-C slr viewfinder look as large as that on a full-frame film slr would require a magnifyer in the prism, between the focusing screen and the eyepiece. This would probably make the prism bulge even larger than it is.

Also this would make viewfinder much darker....

[simico]

O-ME53, problem solved. With that I get the same VF size on my K-5 as my MZ-50's VF. It's a bit darker though (as explained by others), but that doesn't bother me.

[grhazelton]

One reason I chose my K10d was that, compared to the Canon and Nikon, its viewfinder image was huge. Theirs are absurdly small. Of course compared to my MX, ME Super and LX, not so good. As far as frame rate goes, the LX with motor will do 5 fps. Autofocus - didn't the late Pentax, Canon and Nikon manage autofocus with good sized VF's? Flash stuff - the LX and comparable Nikon FF's manage TTL with large VFs. Size of the viewfinder bulge? Do we really care?

Could it boil down to good old greed? Cheaper to use a small prism or even mirrors? In all fairness the slow lenses which dominate today do mitigate against big finders, via the need to cover a larger area. But still....

I wandered into my local Fox Photo with my ME-Super dressed out with winder and f1.2 50mm. The staff was amazed by the viewfinder. Poor Canon and Nikon shooters. Mike, an associate there, does have a F3 so he knows about good finders.

[Edvinas]

O-ME53, problem solved. With that I get the same VF size on my K-5 as my MZ-50's VF. It's a bit darker though (as explained by others), but that doesn't bother me.

No, it's not solved. O-ME53 improves the situatio, but view through APS-C viewfinder + O-ME53 is still wors than of any FF camera.

For example, K-5 has viewfinder which covers 100 of the sensor, it's magnification is 0.92x. O-ME53 magnification is 1.2

So, viewfinder of K-5 is 23.4×15.6×1×0.92×1.2=403mm²
MZ-50: 36×24×0.92×0.77=612mm²

[simico]

No, it's not solved. O-ME53 improves the situatio, but view through APS-C viewfinder + O-ME53 is still wors than of any FF camera.

For example, K-5 has viewfinder which covers 100 of the sensor, it's magnification is 0.92x. O-ME53 magnification is 1.2

So, viewfinder of K-5 is 23.4×15.6×1×0.92×1.2=403mm²
MZ-50: 36×24×0.92×0.77=612mm²

Before I wrote my post, I took my MZ-50 to my left eye and the K-5 (with O-ME53) to my right eye. I couldn't really see a difference in size, so any difference between the two is unnoticeable to me - and that's what matters to me.

[contrabass]

The K-5 was my first dSLR and I the relatively tiny viewfinder has been quite disappointing, compared to my old film SLRs. I would love to have a FF camera more to get a proper sized VF more than I necessarily care about the exact sensor dimensions.

But for what it is worth, the K-5 is still much bigger than the miniscule VF in the (entry-level) Canikons. I cannot imagine trying to manually focus using one of those little plastic children's toys.

Indeed. I have a Canon Rebel XTi (entry level crop-sensor DSLR from '07), a Pentax MX and a K-5.

Comparing the XTi and MX's viewfinders-- talk about your polar opposites. There are many reasons I opted for a K-5 rather than getting a new Canon body, but one of them is that the K-5 viewfinder is so far superior to any crop-sensor Canon out there. While the K-5's viewfinder isn't the expansive awesomeness of an MX, it's still the best crop-sensor DSLR finder I've ever looked through.

My wife isn't much of a gear-head with the camera stuff, but unprompted, she commented on how much better the K-5's finder is than what she's used to looking through on the old Canon.

I think there's a lot of Canikon shooters who simply don't know what they're missing.

[Edvinas]

I think there's a lot of Canikon shooters who simply don't know what they're missing.

Well, you have compared K-5 to entry level Canikons. Compare it to their top APS-C models and you'll see that their viewfinders are not worse than K-5's.

[Edvinas]

Before I wrote my post, I took my MZ-50 to my left eye and the K-5 (with O-ME53) to my right eye. I couldn't really see a difference in size, so any difference between the two is unnoticeable to me - and that's what matters to me.

Well, I've tried to do the same with K-5 vs D700 and I must admit that you're right - there's a little visual difference in viewfinder size between K-5 with O-ME53 and D700.

However D700 viewfinder is much brighter.

And another thing - other cameras have magnifying eyecups too. So, I screwed on DK-17M to D700 and then I definitely felt big difference between K-5 with O-ME53 and D700 with DK-17M

[Marc Sabatella]

Entry level Canon's have tended to be worse than entry-level Pentax's, though.

[Marc Sabatella]

And another thing - other cameras have magnifying eyecups too. So, I screwed on DK-17M to D700 and then I definitely felt big difference between K-5 with O-ME53 and D700 with DK-17M

While this is true, there is something rather special about the magnification you get with a typical FF viewfinder right out of the box: it gives you 100% magnification with a "normal" lens. This fact was so much taken for granted by many that it gave rise to the mistaken notion that normal might be *defined* in terms of the lens that gives 100% magnification. No, that only happens to be true on FF. For a typical APS-C viewfinder, a "normal" lens provide a much less than 100% magnification. For a typical 4/3 viewfinder, it's even worse. Conversely, larger formats such as 645 typically provide *greater* than 100% magnification with a "normal" lens. While to some extent bigger is better, there is also something kind of "right" about having 100% magnification with a "normal" lens.

I think it might be *possible* to design an APS-C camera this way even without additional magnifying elements, but you'd need to get the focus screen that much closer to your eye. Just speculating, though.

[RioRico]

Well, I've tried to do the same with K-5 vs D700 and I must admit that you're right - there's a little visual difference in viewfinder size between K-5 with O-ME53 and D700.

Just for ducks, I put my Cosina-made Vivitar Series 1 19-35 onto my K20D at 30mm, and onto my ZX-M and K1000 at 20mm. VF difference to my eye? None. I *do* recall that when I had an Olympus PEN-FT 135/HF (half-frame, ~same size as APS-C) SLR, its porroprism VF definitely looked smaller than that of a FF pentaprism SLR. But that's another can of worms.

[bwDraco]

Digital has nothing to do with it. Autofocus is the thing to blame

Yes. The mirror needs to transmit 30-40% of the light to an AF submirror, which directs light to the AF system. Manual focus cameras don't need a partially transparent reflex mirror.

--DragonLord

[contrabass]

Well, you have compared K-5 to entry level Canikons. Compare it to their top APS-C models and you'll see that their viewfinders are not worse than K-5's.

That's true... the 7D does have a 100% viewfinder. Of course, that's 100% of a 1.6 crop rather than a 1.5 crop, for what little difference that makes. It's not better than on a K-5. (I've messed around a bit with a friend's 7D.)

Of course, a 7D costs about $500 more than a K-5 and is a boat-anchor, size-wise, in comparison. The K-5 is only marginally larger than the Rebel we're slowly phasing out. The K-5 is exactly what I want.

[chhayanat]

....I'd gladly give up the OBF to return to a better VF and a clear view of the aperture ring of older lenses. ....
H2

I second this opinion heartliy. About the only reason I would buy another Pentax DSLR, even if it were not FF, would be for a film SLR sized viewfinder with the aperture ring of the old lenses inside that viewfinder. The small viewfinder was a step backwards and the higher frame rate was not, in my personal opinion, a large enough gain to justify the removal of the 35mm sized viewfinder. This is not the only example of its kind in the history of technological development.
Chhayanat

[keyofnight]

I've owned an *ist D for about 7 years, and I just bought an MX this week. The first time I looked through the viewfinder of the MX, it was like looking at an IMAX screen for the first time—and the *ist D was like a wide-screen 28" HDTV as far as I was concerned. Honestly, it took a little getting used to—the MX screen made my eyes watery! It's a lot brighter, a lot bigger, and the microprism collar / split image in the center is strange.

(I can't believe I have to get used to better stuff.)