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Old Feb 20, 2007, 9:41 AM   #11
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Prior to the advent of AutoFocus, SLR's had focusing screens designed for good (and hence easy) manual focus. The more advanced models of SLR's had interchangeable focus screens, so the user could select the type of focus screen best suited to the type of photography he/she engaged in.

However, since AF has pretty much taken over and especially since the dSLR replaced the film SLR, the focus screens in the new models are really only designed for viewing the scene and NOT for determining the correct focus.

While still significantly better than any EVF or LCD, they still pale in comparision to the old film cameras.
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Old Feb 20, 2007, 11:31 AM   #12
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There are some optional focusing screens for some dSLRs, but they're not user interchangeable like in the days of the Nikon F and the Mamiya-Sekor.
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Old Feb 20, 2007, 11:38 AM   #13
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My Minolta SRT-101 from the late 1960s didn't have the split prism but my Minolta X570 from thr 1980s did. It was just two prisms, side by side so that the thick ends were opposite each other.

The rangefinder in a Leica or similar camera is completely different. See Rangefinder camera
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Old Feb 20, 2007, 9:59 PM   #14
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BEECEE wrote:
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I've never had much luck with manual focus on my D50. The photos look in focus thru the viewfinder but are slightly out of focus when I get them home. Either there is something wrong with the lens or my vision is not what it used to be.
The matte focus screens are not quite as accurate for manual focus. Also, double check the setting of your diopter adjustment, concentrating on getting the VF displays sharp when first looking into the VF.

The image displayed in VF is intended to be that of the image on the sensor, with appropriate compensations. This makes it smaller than on a 35mm film cam. The difference is quite marked between my Minolta SR-t 102 and Pentax *IST D, and the pentax is considered to have one of the best VFs among the digitals (other than full-frame)

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Old Feb 21, 2007, 3:05 AM   #15
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VTphotog wrote:
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BEECEE wrote:
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I've never had much luck with manual focus on my D50. The photos look in focus thru the viewfinder but are slightly out of focus when I get them home. Either there is something wrong with the lens or my vision is not what it used to be.
The matte focus screens are not quite as accurate for manual focus. Also, double check the setting of your diopter adjustment, concentrating on getting the VF displays sharp when first looking into the VF.

The image displayed in VF is intended to be that of the image on the sensor, with appropriate compensations. This makes it smaller than on a 35mm film cam. The difference is quite marked between my Minolta SR-t 102 and Pentax *IST D, and the pentax is considered to have one of the best VFs among the digitals (other than full-frame)

brian
So, obviously, the D50 lacks the function of letting the camera show you what focuspoint is in focus while you turn the MF ring?

One starts to wonder why so many cameras have bad viewfinders. I mean, it gets bashed by all reviews and by all users, why not just make large and bright viewfinders in all DSLR's???
Pentax has had cheap entrylevel cameras with great viewfinders (or so I've read) so why cant everyone do it? Whats the catch?
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Old Feb 22, 2007, 6:12 AM   #16
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ASBR wrote:
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Whats the catch?
In a nutshell: cost.
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Old Feb 22, 2007, 7:15 AM   #17
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ASBR wrote:
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One starts to wonder why so many cameras have bad viewfinders. I mean, it gets bashed by all reviews and by all users, why not just make large and bright viewfinders in all DSLR's???
Pentax has had cheap entrylevel cameras with great viewfinders (or so I've read) so why cant everyone do it? Whats the catch?
The Pentax K100D uses a pentamirror instead of a pentaprism.

A pentaprism is a solid piece of glass that diverts the path of light by exactly 90 degrees. Light comes into the camera through the lens andis reflected up by the mirror that flips up out of the way when you press the shutter release. It then enters the bottom of the pentaprism and is reflected down and forward off a silvered surface on top, and then rearward toward the eyepiece off a silvered surface on the front.

Instead of the pentaprism's solid piece of glass, a pentamirror is a frame that holds two mirrors in place that reflect light in the same direction as the silvered surfaces of a pentaprism.

Pentamirrors are brighter, lighter and cheaper than pentaprisms but are subject to misalignment if the camera is not handled gingerly.

Sometimes, camera manufacturers will use pentamirrors instead of pentaprisms to save weight and/or cost, but at the expense of durability.

Edit: Also, pentamirrors are larger than pentaprisms.
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Old Feb 22, 2007, 12:24 PM   #18
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BEECEE wrote:
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I've never had much luck with manual focus on my D50. The photos look in focus thru the viewfinder but are slightly out of focus when I get them home. Either there is something wrong with the lens or my vision is not what it used to be.
Did you use the green dot that lights up when the subject where the focus point is at is in-focus? Or did you try to focus using just what you see in the viewfinder?


ASBR wrote:
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So, obviously, the D50 lacks the function of letting the camera show you what focuspoint is in focus while you turn the MF ring?
It does have that green light. See comment above.

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Old Feb 22, 2007, 2:13 PM   #19
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amazingthailand wrote:
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ASBR wrote:
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Whats the catch?
In a nutshell: cost.
Not according to TCav's explanation below your post.

Thanks you guys, interresting

Strange they cant just magnify the image someway, but I guess that would make it dimmer. Strange that old analog cameras had so extremely bright and large viewfinders as some people say, making it very possible to focus manually. Not THAT big difference between film/sensor sizes so I guess there must be some other explanation to why DSLR's has so small viewfinders that can hardly even be used to spot accurate focus.
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Old Feb 22, 2007, 4:07 PM   #20
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It depends on the DSLR. As a general rule, the smaller the sensor, the smaller the viewfinder. Go with a full frame (i.e., 35mm film size sensor) DSLR if you want a decent viewfinder (and you still may want a different focus screen). Of course, that's a pricey solution. lol

Here's one solution to aid MF (a split image focus screen):

http://haodascreen.com/sifs.aspx

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