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08-23-2013, 12:36 PM   #16
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I don't get the article. Why is it important for things in the viewfinder to look the same as with the naked eye? Even film SLRs had different viewfinder magnifications, and AFAIK, nobody ever complained "my ME Super viewfinder is too big, it is causing me to use the wrong lens, because my perspective is all wrong!"

What about medium format waist-level viewfineders, are those unusable because the screen is way down from your eye and so small?

Is the author complaining that the viewfinder is too small? I would agree that is generally true on DSLRs. But is that forcing him to make bad lens choices, compose his photos incorrectly, or making him a bad photographer? Bad excuse. Maybe he should sell the Rebel and buy a K-500.

08-23-2013, 04:11 PM   #17
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QuoteOriginally posted by konraDarnok Quote
I know that, and it's not what I'm talking about. A 50mm lens, thought the viewfinder has the same perspective as what your eye sees. Why?
No it does not. The image in the finder is a projection from the lens, therefore perspective does not change as a function of format because as discussed earlier perspective is independent of format. I can only guess here but what you are really talking about is that the magnification is similar to what the naked eye sees. This is not perspective...
08-23-2013, 08:52 PM   #18
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QuoteOriginally posted by Lowell Goudge Quote
No it does not. The image in the finder is a projection from the lens, therefore perspective does not change as a function of format because as discussed earlier perspective is independent of format. I can only guess here but what you are really talking about is that the magnification is similar to what the naked eye sees. This is not perspective...


Okay, I'm an idiot that doesn't know the difference between magnification and perspective. You've won that debate. Congratulations. I bow down humbly to your superior knowledge on the subject. I fully admit I was too ignorant to ask the question properly.


To get back to my original thesis, why don't we have viewfinders that give a "normal" magnification at near 100% coverage for different focal lengths. Like 30mm?
08-23-2013, 09:55 PM   #19
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QuoteOriginally posted by konraDarnok Quote
To get back to my original thesis, why don't we have viewfinders that give a "normal" magnification at near 100% coverage for different focal lengths. Like 30mm?
Why do you want that?

Pentax use 100% coverage on all DSLR at the moment, and if they would use 1x magnification it would will make the OVF darker, the camera probably at least 2-3x as expensive and much larger. A APS-C DSLR might end up the size of 645D, as you would need something like a pentaprism that projects a 3" image, which is almost 4x as large as on todays OVF.

If you really need something like this, you might want to use LV and get a loupe for your LCD.


Last edited by Fogel70; 08-23-2013 at 10:15 PM.
08-24-2013, 04:18 AM   #20
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In going back to the real question of "normal" and what the OP wants which is specifically the same field of view as the human eye, and the same magnification I think the answer is simple.

There is a part missing in cameras which cannot yet be replicated, which has a huge impact in all of this

It's called a brain

Humans have one, and it is constantly adjusting and distorting what we see. Don't believe me. Just go back to some experiments done in the 8's and 90's where people were given glasses that inverted the image left to right and upside down. Within 6 weeks, they readjusted to consider their view as normal. The brain does a lot with respect to the images we see that cannot be replicated by optics. It's that simple

Now back to the camera and lenses, what you really need to do is train your brain to see how a cams sees, not the other way around
08-24-2013, 04:51 AM   #21
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QuoteOriginally posted by Fogel70 Quote
Why do you want that?

Pentax use 100% coverage on all DSLR at the moment, and if they would use 1x magnification it would will make the OVF darker, the camera probably at least 2-3x as expensive and much larger. A APS-C DSLR might end up the size of 645D, as you would need something like a pentaprism that projects a 3" image, which is almost 4x as large as on todays OVF.

If you really need something like this, you might want to use LV and get a loupe for your LCD.


Curiosity? I just want to know more about why camera viewfinders have 1:1 magnification for the 50mm lens and not some other focal length. As I've never really understood. I'm not looking for advice, I'm looking to understand something. This is why camera forums can be so tiresome; people can't help but get into technical semantic debates while at the same time questioning people's motives and ignoring what they really want to know. Like it were politics or religion. Not you specifically, you've been helpful.
08-24-2013, 08:05 AM   #22
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I'm failing to understand what viewfinders have to do with the OP's question as the viewfinder has no bearing on what gets recorded by the camera or the frame on the film.
08-24-2013, 08:22 AM   #23
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QuoteOriginally posted by Lowell Goudge Quote
perspective is a function of camera to subject distance only. don't believe me, then take a shot of a subject with a 24mm, 50mm, and 100mm lens from exactly the same position, then crop in on the shorter FL lenses to get the same framing as the 100mm lens. look at the background, and the way lines converge etc. The perspective of all three images will be the same.

what gives perspective therefore is not related at all to the viewfinder, and in fact perspective is really only the visual appearance of the magnification ratio of near and far subjects.

If you change focal length and keep the magnification of a near subject the same by moving your position, this changes the magnification of the far subjects and changes the perspective.
The reason "they are the same" is because you are magnifying the output of the crops so that they match and thus replacing the telephoto lens with an "manual" digital zoom. The telephoto (100mm) is being compensated for at the output stage (printing.screen) as it were.

Linear perspective is the mapping of a 3D space onto a 2D surface and the *only* difference between a 24mm and a 100mm telephoto is the crop and magnification factors. How you define "standard" should really depend on you but I'm pretty sure the FOV of human vision has something to do with it.. the way the perspective is in relation to the FOV and all that. (scientific.. not)

08-24-2013, 11:59 AM   #24
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QuoteOriginally posted by maxfield_photo Quote
What causes "normal" perspective is having a lens on your camera that matches the diagonal of the image area, either film or digital sensor.
That is a convention that has nothing to do with perspective per se.

As was noted above, perspective is based on camera position relative to the subject.* Different focal lengths provides different "crops", but the subject proportions and relationship to adjacent objects remains the same regardless of focal length used. Several years ago (), I posted several comparison photos to this site of the same subject at the same tripod position using long, normal, and wide lenses with all cropped to the same composition. All three were identical.


Steve


*For cameras without movements. More precisely, perspective is related to the distance to the lens front element, lens orientation to the subject and also to the capture medium.
08-26-2013, 10:31 AM   #25
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QuoteOriginally posted by IchabodCrane Quote
I'm failing to understand what viewfinders have to do with the OP's question as the viewfinder has no bearing on what gets recorded by the camera or the frame on the film.
I think this is part of the problem, the OP wants to see in his view finder the same magnification and perspective he sees with his eye.
08-26-2013, 10:32 AM   #26
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QuoteOriginally posted by bossa Quote
The reason "they are the same" is because you are magnifying the output of the crops so that they match and thus replacing the telephoto lens with an "manual" digital zoom. The telephoto (100mm) is being compensated for at the output stage (printing.screen) as it were.

Linear perspective is the mapping of a 3D space onto a 2D surface and the *only* difference between a 24mm and a 100mm telephoto is the crop and magnification factors. How you define "standard" should really depend on you but I'm pretty sure the FOV of human vision has something to do with it.. the way the perspective is in relation to the FOV and all that. (scientific.. not)
No, changing the enlargement magnification is a linear scaling applied to all portions of the image, perspective is a change in scaling of near relative to far, this is only achieved on the capture to film, not by changing enlargement
08-26-2013, 01:36 PM   #27
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QuoteOriginally posted by Lowell Goudge Quote
the OP wants to see in his view finder the same magnification and perspective he sees with his eye.
Well then, that is easy!



...or any one of a number of rangefinder cameras that sport a 1:1 viewfinder. I have two on my shelf.


Steve
08-29-2013, 02:35 PM   #28
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QuoteOriginally posted by konraDarnok Quote
"normal perspective?"
Back in the old days it was supposed to be an equivalent field of view, as to what you saw with your naked eyes.

That was before crop factors and the like had even been invented.
08-29-2013, 03:02 PM   #29
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Once we start comparin' things -- "mine's bigger'n yours" -- we naturally seek a universal standard of comparison. Simplifies the arguments anyway.

Back in the late '50's - early '60's the venerable Herb Keppler wrote an op-ed ( I believe it was in the old 'Modern Photography' magazine) that pointed that out and noted that the diagonal of the 35mm format just happened to coincide with not only human visual habits but the fact that excellent 50mm lenses seemed to be relatively easy to design. Therefore, 50mm could stand as a conventional standard for 35mm format focal length as well as anything else. No other format seems to have cared to compartmentalize FL as much as the 35mm.

I've never heard of a better excuse since and it's amusing to watch people attempt to come up with a better explanation. Sometimes it's just that simple.

H2

Last edited by pacerr; 09-03-2013 at 02:13 PM.
09-03-2013, 02:28 AM   #30
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QuoteOriginally posted by stevebrot Quote
That is a convention that has nothing to do with perspective per se.

As was noted above, perspective is based on camera position relative to the subject.* Different focal lengths provides different "crops", but the subject proportions and relationship to adjacent objects remains the same regardless of focal length used. Several years ago (), I posted several comparison photos to this site of the same subject at the same tripod position using long, normal, and wide lenses with all cropped to the same composition. All three were identical.


Steve


*For cameras without movements. More precisely, perspective is related to the distance to the lens front element, lens orientation to the subject and also to the capture medium.
Hi Steve, may i trouble you with reference to such comparisons? (those photos if you could find them again)

Because at times i do get confused and i've come to a conclusion that 50mm is called a "normal" as the resulting image would be similar to what your eye sees in terms of the subject size in relation to the background, with regards to camera position to subject position.

Meaning, shooting a subject with a 20mm with the same framing to obtain the same subject size would render the background wider and more compressed (subject appear larger and more pronounced) as compared to using a 50mm.

Therefore moving to obtain a similar framing would render the scene as to what your eye would see, of coz with the relevant crop size of your sensor.

And that's why the 50mm is considered as a "normal", am i wrong?



Edit: Hmm... I think this effect of 50mm as a "normal" can be re-enact by putting on a 50mm on the camera and then keeping both eyes open and focus. You can then see that you are seeing the scene in front of you as per normal, with a border due to your right eye looking through the viewfinder.

In comparison, if you try to do so with any other focal length, you would most be stressing your brains in trying to focus 2 different images from both eyes.

Per se, viewfinder magnification would play a role in this exercise to a certain degree, correctable with an additional viewfinder magnifier or using a slightly "longer" "normal" lens, e.g. 55mm or 58mm.
On my K30, with the O-ME53 magnifier (x1.2 magnification), ~43mm would give me the most accurate scene size when looking through the viewfinder with both eyes open. (1.2 magnification x 0.92 stock viewfinder = 1.1, therefore ~1:1)

Further edit: Found a useful comparison here:

http://en.wikipedia.org/wiki/File:Focal_length.jpg

Last edited by SyncGuy; 09-03-2013 at 03:08 AM.
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