Viewfinders

*sorry, ment pentamirror*

Jacob

Folks, viewfinder size is not inherently limited only by the in-camera flash. Look at the 1DsII and the 5D...neither have an in-camera flash but both have a dinky 0.7x viewfinder magnification, making the apparent size of the 24x36mm frame to be much less of an increase in the viewfinder compared to the 20D/30D, than would be the case if they both used 0.92x like the 20D and 30D!

Wilt wrote in post #2095048
Folks, viewfinder size is not inherently limited only by the in-camera flash. Look at the 1DsII and the 5D...neither have an in-camera flash but both have a dinky 0.7x viewfinder magnification, making the apparent size of the 24x36mm frame to be much less of an increase in the viewfinder compared to the 20D/30D, than would be the case if they both used 0.92x like the 20D and 30D!

Yes, but the .71X viewfinder of the 5D is still considerably larger than the .92X viewfinder of the 30D. Why? Because it's a .71X magnification of a 24 X 36 mm image (the size of a full-frame sensor), whereas the 30D is a .92X (.9X according to the Canon USA web site) magnification of a 22.5 X 15 mm image size(the size of a 1.6X APS-C sensor).

In other words, the format size is a factor in viewfinder size as well. As is cost, size, weight, and viewfinder brightness.

I won't even touch the fact that the same 50 mm focal length lens is used to determine viewfinder magnification on the XT, 30D, 1D2, 5D, and 1Ds2. Suffice to say that for a fair dimensional comparison, a comparable "normal" lens ought to be used on each format (50 mm on full frame, about 38 mm on the 1.3X, and about 31 mm on a 1.6X sensor). I'll link one discussion on the subject:

http://www.luminous-landscape.com/columns/​sm-mar-05.shtml

and a chart of comparable viewfinder magnifications that takes into account the lens and sensor size:

http://photo.pidcock.c​o.uk/dslr_viewfinders.​html

((Note: the 5D specification is not correct - the author erroniously placed a published figure of 0.96 instead of 0.71 in his chart, resulting in a vastly different result. It should be about 0.71, give or take a hundredth or so.))

guitarboy wrote in post #2094189
Are you serious!? My viewfinder is small because of the built in flash!?

yeah, you got a rebel XT - what do you expect?

Tom W wrote in post #2098881
Yes, but the .71X viewfinder of the 5D is still considerably larger than the .92X viewfinder of the 30D.

Tom my point was not that the 5D viewfinder is not larger than the 20D/30D, it is! My point was that the 5D viewfinder could be 260% the size if it used the same magnification factor in the viewfinder area compared to the 20D/30D (288 vs. 588 sq.mm), not just 200%!

15x22.5 * 95% * 0.9x = 288
24x36 * 96% * 0.71 = 588

Compare those figures with the specs of my Olympus OM-1 film camera that put the 1DsII and 5D viewfinder size to shame:

24x36 * 97% * 0.92x = 771

Wilt wrote in post #2098946
Tom my point was not that the 5D viewfinder is not larger than the 20D/30D, it is! My point was that the 5D viewfinder could be 260% the size if it used the same magnification factor in the viewfinder area compared to the 20D/30D (288 vs. 588 sq.mm), not just 200%!

Yes, it could, for a price!

Considering the 50 mm lens is used on both formats, I suspect that the "magnification" difference is much larger. Based on the chart in my second link (and the rant in the first link), the 30D is closer to a 0.56X magnification once the angle-of-view is equalized by lens choice.

My own experience with both is that the 5D is considerably larger, though I've never measured the two. I don't know if it's 2X as big or not, but it is a very obvious difference.

Regardless, I agree with you that an even larger viewfinder could be really nice, providing that it's bright enough. And a 0.9X on a full-frame sensor would be a big, sweet view.

Tom W wrote in post #2098996
Yes, it could, for a price!


Considering the 50 mm lens is used on both formats, I suspect that the "magnification" difference is much larger. Based on the chart in my second link (and the rant in the first link), the 30D is closer to a 0.56X magnification once the angle-of-view is equalized by lens choice.

My own experience with both is that the 5D is considerably larger, though I've never measured the two. I don't know if it's 2X as big or not, but it is a very obvious difference.

Regardless, I agree with you that an even larger viewfinder could be really nice, providing that it's bright enough. And a 0.9X on a full-frame sensor would be a big, sweet view.

288 / 588 = 0.49 . Yes, the 20D/30D apparent magnification is just under half. It could have been even more diminutive if Canon gave their flagships even 0.82x rather than 0.71x , but they didn't and the (lack of) on-board flash was not the explanation for it.

Wilt wrote in post #2099041
288 / 588 = 0.49 . Yes, the 20D/30D apparent magnification is just under half. It could have been even more diminutive if Canon gave their flagships even 0.82x rather than 0.71x , but they didn't and the (lack of) on-board flash was not the explanation for it.

Well, if you pull the lid off a 5D, you may or may not have your reason for the lack of a larger pentaprism and related optics. The prism housing on my 5D is considerably bigger than that of the 30D despite missing the flash. 1-series are similarly large. I know that the primary reason is that the dimensions of the pentaprism are larger due to the larger format. I don't know if the magnification reduction takes place before or after the prism, though I suspect that it's after since that is where the optics reside.

Can't say that I wouldn't like an even-larger viewfinder, but I would also consider that there would be a price in brightness. Remember that we auto-focus Canon users already give up 35-40% of our viewfinder light to the secondary mirror and AF system. The logic of the .71X magnification factor vs. a .8 or .9 on full frame might well be that manually focusing an f/5.6 lens in a fairly dark room might become futile (note also that the "0.9X" rating on smaller formats isn't quite what it says it is due to the use of the 50mm lens as noted in the links). If I remember my physics correctly, a 0.5X magnification essentially doubles light (1 stop), all other factors being equal. 0.71X should basically offset the losses that occur in the partial mirror.

Now I'm not saying that a dimmer, larger viewfinder wouldn't be very useful - in many (maybe most) shooting situations, a modest loss of brightness probably wouldn't be noticeable. I use the angle-finder C at 2.5X to manually focus bright objects with f/8 lenses so I know that even dim viewfinders are useable in many situations.

Just try looking through the viewfinder of a "A" or "F" series body (they're both manual focus, ya know, the FD lenses) sometime if ya get the chance. The manual focus cameras had mirrors that sent 100% of the light to the viewfinder, and with the introduction of auto-focus, the mirror sends 80 to 85% ? of the light up there, the rest going to the auto-focus sensor. Is it a stop?, maybe a half stop? I dont know, but I do know all digitals (EOS 1 included) are not the same as looking through a F1N or a Nikon F3HP

Moschero wrote in post #2099838
Just try looking through the viewfinder of a "A" or "F" series body (they're both manual focus, ya know, the FD lenses) sometime if ya get the chance. The manual focus cameras had mirrors that sent 100% of the light to the viewfinder, and with the introduction of auto-focus, the mirror sends 80 to 85% ? of the light up there, the rest going to the auto-focus sensor. Is it a stop?, maybe a half stop? I dont know, but I do know all digitals (EOS 1 included) are not the same as looking through a F1N or a Nikon F3HP

40% goes to the mirror and 60 to the prism.

I'd wanna see a full frame prism on top of the rebel bodies. You can have crop lines and since you're using full frame lenses, you'll be able to see more than you're actually capturing.

With a magnification close to 1x of course.

Moschero wrote in post #2099838
Just try looking through the viewfinder of a "A" or "F" series body (they're both manual focus, ya know, the FD lenses) sometime if ya get the chance. The manual focus cameras had mirrors that sent 100% of the light to the viewfinder, and with the introduction of auto-focus, the mirror sends 80 to 85% ? of the light up there, the rest going to the auto-focus sensor. Is it a stop?, maybe a half stop? I dont know, but I do know all digitals (EOS 1 included) are not the same as looking through a F1N or a Nikon F3HP

Looking through a Nikon F4 is like a picture window compared to the 20D's porthole.

If someone wanted to give Canon the spec for a redesigned viewfinder all they have to do is hand them an Olympus OM-1 and say "make it like that".

yep, or a Contax RTS-III

I checked out the Nikon D80 and D200 and their viewfinders blows away my 30D and the XT. D80 price is reasonable too.

bufferbure1 wrote in post #2101288
I checked out the Nikon D80 and D200 and their viewfinders blows away my 30D and the XT. D80 price is reasonable too.

You can't have your cake and eat it, too! Nice viewfinder, poorer handling of noise at higher ISO values. And you don't get to use L lenses (if that matters to you).