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12-03-2008, 02:43 PM   #136
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QuoteOriginally posted by Wheatfield Quote
The camera companies have chosen no to do this, so now we are saddled with finders that are too small.
Yeah I hate that. Although I'm afraid the magnification they'd have to use would make them really dim. But maybe with new materials...
I haven't seen an E-3, but it has an incredible 1.15x magnification, so I wonder how bright it is? If my K100D had that magnification, it would have the same size viewfinder as the A900. Bigger, actually. Here's a shot of the E-3's prism: http://en.wikipedia.org/wiki/Image:Olympus_E-3_cut.jpg

12-03-2008, 03:12 PM   #137
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QuoteOriginally posted by Michael Barkowski Quote
To Tokina: I think we agree there is a normal angle of view.

The point I was trying to make is, there is a concept of normal perspective also, it's just not as well defined, in fact it's really hard to define. There are certain distances at which we normally interact with things. If you want to be artistic, it's great to throw out all ideas of "normal", but there has to be a normal to throw out. And there's also something to be said in art for showing people a situation as it would look to them if they were there.
I agree that there is normal angle of view (approximately) for human eye. You explained it so well earlier:

QuoteQuote:
When you're really close to someone, you can have trouble looking at their whole face at once, but the wide angle lens has no trouble at all. Which means the wide-angle lens at that distance is giving you an unnatural field of view of someone's face.

As for "flattering" and other descriptions, Tokina, these are empirical fact and should not be thrown away just because they are subjective on a person by person basis. It's what's called a rule of thumb, and very useful. After all, people who take photos of people for a living use the facts about an average person's perception all the time to their advantage.
12-03-2008, 04:16 PM   #138
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QuoteOriginally posted by Michael Barkowski Quote
Yeah I hate that. Although I'm afraid the magnification they'd have to use would make them really dim. But maybe with new materials...
I haven't seen an E-3, but it has an incredible 1.15x magnification, so I wonder how bright it is? If my K100D had that magnification, it would have the same size viewfinder as the A900. Bigger, actually. Here's a shot of the E-3's prism: Image:Olympus E-3 cut.jpg - Wikipedia, the free encyclopedia
Think of how dim a 1.2x or so magnification viewfinder would be with the typical f/4-f/6.3 zoom lens that they flog as part of a kit, and imagine how many cameras they'd sell.....
Personally, I'd be happy with a compromise finder with a somewhat higher magnification and they could fill where the pop up flash (the whole concept of which I detest) with viewfinder bits.
12-03-2008, 04:48 PM   #139
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QuoteOriginally posted by audiobomber Quote
Take the same shot from the same position using a normal lens and then your longest telephoto lens. Now print all of them (or display at the same size on your monitor). Measure the size of the foreground ornament and the size of the distant mountain. The ratio of the sizes will change based on focal length.
If you try this test and you take them from the same position you will be surprised to find that whatever fits in the field of the view of the telephoto lens will look identical to a crop of the same field of view from the shorter lenses.

12-03-2008, 04:53 PM   #140
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QuoteOriginally posted by Tokina Quote
I agree that there is normal angle of view (approximately) for human eye. You explained it so well earlier:
"When you're really close to someone, you can have trouble looking at their whole face at once, but the wide angle lens has no trouble at all. Which means the wide-angle lens at that distance is giving you an unnatural field of view of someone's face."

I'm sure it won't surprise either of you that I disagree with that statement. My fov is wider than a 16mm lens on my K20, so I don't see that I would have trouble looking at someone's face if the lens can see it. I don't know what my actual fov is, but it's a lot more than 24mm equivalent. And looking at someone's face close up has naught to do with perspective distortion. My proximity does not distort their features. Nor does poking a 35mm macro lens right up to a bug cause perspective distortion.
12-03-2008, 05:34 PM   #141
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QuoteOriginally posted by Sean Nelson Quote
If you try this test and you take them from the same position you will be surprised to find that whatever fits in the field of the view of the telephoto lens will look identical to a crop of the same field of view from the shorter lenses.
OK, I did the test for you. Sorry for the mundane subject matter: a light stand placed about halfway between the camera and my garage. Three shots, DA12-24 at 12mm, DA35, and FAJ 75-300 at 130mm, all taken from the same position using my K100D Super. Each is a composite, the full frame at the left and a crop that's roughly equivalent to the 130mm field of view at the right (in the last image the left and right are the same since there is no "crop"):

12mm:


35mm:


130mm:


I think you can see there's no change in the relative size of the light versus the garage door at approximately twice the distance. Hence, "perspective", defined for the purposes of this test as the relative size of near versus far objects, is NOT affected by focal length.

Can we all agree on this?
12-03-2008, 05:41 PM   #142
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QuoteOriginally posted by audiobomber Quote
To recap, I say that the relative size of the foreground and background images will change with focal length.
Not according to my test above. Your test will show the same.

If you stop and think about this for a second, it's pretty obvious that the relative size of objects doesn't change when you simply zoom using a lens with a variable focal length. When you zoom, everything in the image gets bigger or smaller by the same amount. So of course changing lenses will have exactly the same effect.
12-03-2008, 06:49 PM   #143
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QuoteOriginally posted by Sean Nelson Quote
Not according to my test above. Your test will show the same.

If you stop and think about this for a second, it's pretty obvious that the relative size of objects doesn't change when you simply zoom using a lens with a variable focal length. When you zoom, everything in the image gets bigger or smaller by the same amount. So of course changing lenses will have exactly the same effect.
All right, I did the test and what I said was wrong. You and the others were right. Focal length does not change perspective. I'm here to take my lumps. Clearly I don't know wtf I'm talking about.

12-03-2008, 07:24 PM   #144
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QuoteOriginally posted by audiobomber Quote
All right, I did the test and what I said was wrong. You and the others were right. Focal length does not change perspective.
As with a lot of concepts, sometimes a picture says it a lot better than a thousand words ;-D

As I suggested regarding your example of portrait photography earlier, there's a quite reasonable association of wide angle lenses with exaggerated depth and telephoto lenses with flattened depth. This comes about because a portrait photographer will often change his/her position so that the subject fills the same proportion of the frame no matter what lens is in use. That way of thinking is perfectly understandable, but it's important to realize that the perspective differences are coming from the changes in distance, not focal length.

If a portrait photographer keeps a constant distance and changes lenses so as to switch from a head-and-shoulders shot to a full body shot, there isn't a change in perspective (in terms of sight lines and sizes of objects at different distances), just a change in field of view.
12-03-2008, 07:34 PM   #145
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QuoteOriginally posted by Wheatfield Quote
Well Mark, you are going up against several generations of optical engineers, photographers and every camera manufacturer from Alpa To Zeiss and telling them all that they were wrong.
I'm not telling them they are wrong - they are not the ones making the claims being made here. I've yet to hear anyone from any camera company try to tell me there is an objective measurement that defines precisely what the angle of view of the human eye is, and that a "normal" lens (50mm? 43mm? take your pick) mimics this precisely.

I have a feeling at this point you are probably thinking I am saying something other than I am intending to say. I'm not saying that the non-peripheral angle of view of the eye isn't anywhere close to that of a 50mm lens (or 43mm lens) on FF. I'm saying that it's sort of true if we ignor peripheral vision, and I'm happy to do so if we are explicit about doing so. But still, only "sort of" true, because it's not like anyone can put a precise number on what makes up the angle of view of the non-peripheral portion of vision. It's a general ballpark, and 43mm and 50mm are both within that ballpark, but so is 35, and 55, maybe arguably up the 60's somewhere. Any of these could be said to sort of resemble the angle of view of the non-peripheral portion of the eye. Because the problem is, there is no hard and fast line separating out the periphery from the rest.

QuoteQuote:
Carry on if you like, but do read up on the subject of peripheral vision to find out why it is meaningless from a photographic point of view.
I am quite familiar with the subject of peripheral vision and have to admit I am somewhat baffled as to why it has no meaning yo you, but it most certainly does to me.

Last edited by Marc Sabatella; 12-03-2008 at 07:51 PM.
12-03-2008, 07:43 PM   #146
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QuoteOriginally posted by Sean Nelson Quote
Audiobomber is coming from the point of view of maintaining a constant subject size in the frame. In that scenario a wide lens requires moving closer to the subject, changing the perspective, and vice versa.
Actually, as we can see more clearly now that the tests have been and the results made clear, this was not the case - he *was* previously thinking that focal length alone would make the difference. I kind of knew this because I remember a recent thread in which references was made to a site that showed a face shot at different focal lengths and distances with the face kept the same size in each image - with the obvious resulting changes in perspective - and the same confusion came up in that thread. Namely, the (incorrect) notion that the distortions in the face as focal lengths got shorter and distance closer were caused more by the former as the latter.

Anyhow, at least now I believe everyone still paying attention to all this is convinced that it really is distance, not focal length, that causes the change in this form of perspective (here, I am am specifically *not* referring to the type of "perspective distortion" that also depends on print size and viewing distance).
12-03-2008, 07:47 PM   #147
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QuoteOriginally posted by Marc Sabatella Quote
I'm not telling them they are wrong - they are not the ones making the claims being made here. I've yet to hear anyone from any camera company try to tell me there is an objective measurement that defines precisely what the angle of view of the human eye is, and that a "normal" lens (50mm? 43mm? take your pick) mimics this precisely.



I am quite familiar with the subject of peripheral vision and have to admit I am somewhat baffled as to why it has no meaning yo you, but it most certainly does to me.
Keep in mind that magnification is going to have a greater effect than FOV on
whether or not a lens seems 'normal'. (normal being used as: 'just like I see it'.)

If you put a lens up to your eye, open the other eye, and everything looks
about the same - that's 'normal', as I understand it.

FOV may be different, but our effective FOV is much narrower than you think -
we can 'see' at probably the equivalent of 8mm, but everything outside of a
50mm (film) FOV cone is degraded to the point of obscurity - our brain tricks us
into thinking we have this expansive FOV, but really, we only detect shapes,
colors and especially movement outside of this cone. It's not as accurate as you
think to describe the human FOV as really wide - it's probably about 40-60mm
equiv.


.
12-03-2008, 08:29 PM   #148
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QuoteOriginally posted by jsherman999 Quote
If you put a lens up to your eye, open the other eye, and everything looks about the same - that's 'normal', as I understand it.
I don't buy this definition of "normal" because whether the view through the viewfinder matches the view through the other eye depends too much on how the viewfinder works. Let me give some examples:

The K100 and the K10 have different viewfinder magnifications. The K10 with it's Pentaprism has a larger apparent viewfinder, and with the same lens on both cameras your eye will see a bigger image with the K10. Does this mean that a "normal" lens for a K10 is different than that for a K100? They both have the same sensor size and therefore the same lens would have the same field of view. Why should "normal" be different for the two cameras?

My K100D usually has the 1.2X magnifying eyepiece on it. When I remove the magnifier, does that change what focal length "normal" should be? I don't see why it should.

What about a full frame camera that allows the use of lenses designed for a cropped sensor camera. What would be considered "normal" for the cropped field of view certainly wouldn't be a lens that gives a "1X" apparent magnification through the viewfinder.

For all these reasons I think that the viewfinder apparent size is not a very valid definition of what a "normal" lens should be.
12-03-2008, 10:49 PM   #149
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It's amazing how many people are providing such cogent arguments to prove their point, while in actuality so many are discussing different things!
12-04-2008, 03:19 PM   #150
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FA35 is the new Fast Fifty.

The FA35 is physically a 50mm lens. Just kidding. Please no lectures. A lot has been said about a 50 is a 50 is a 50. And it's true, a 50mm lens on a DSLR is the same lens when it is on a 35mm film SLR, but only a fool would say it acts the same. It renders a different FOV, and hence a different DOF when trying to keep the subject the same size in the shot (or in another way, a different DOF when making the photographer switch out lenses to obtain a similar FOV). Speaking to the original poster's post, I would like to throw my FA35 hat in the ring for the new fast normal lens. I've stated it in this forum in a few places, but I'll state it again. That lens is the es aitch eye tee. I love, love, love it. In photozone's tests, it fairs better for sharpness than the DA35. Unlike my FA50, it's very usable wide open. And it's sharper at f2 than the FA50 is at f2. Despite having only six aperture blades and an aspherical element, it has excellent bokeh. Despite being plastic, it has an excellent build (better than my DA70--uh oh, here come the flames). It is compact, and comes with a bayonet lens hood (the FA50's hood is another 25 bucks and is a snap on--or you can by a third party screw on lens hood, but I hate screwing that thing on every time). The FA35 slaps the FA50 back into the camera bag. It's possibly Pentax's best return on investment. And I love having a lens that is excellent at f2. Others have pooh-poohed the need for larger apertures since the new DLSRs have made high ISO noise a thing of the past. I have a K20D, and while I'm impressed with its performance, for me, high ISO noise is a thing of the present. ISO 100-200 is great, 400 starts to show its number, 800 shows more of its number, and 1600 and up means you have to decide if you like having all that grain in the image. Notice I said grain. I know it is actually noise, but that is what I do love about DSLRs these days. The noise looks like grain, and I've taken a number of ISO 1600 shots that I'm quite pleased with. Still, I usually like to keep the noise down. But what's most important to me about having a fast lens, is the ability to take shots with a very shallow depth of field. Since the APS-C sensor makes it more difficult to get a shallow depth of field, I feel it's even more important to have a fast lens. Get the FA35 if you want a fast normal that won't break the bank, but will give you superb results.
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