Something to ponder!
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Posted 25/11/2013 - 23:08
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These two shots have the Stuka wingtips in very similar places (using the AF markings in the finder for reference). Both taken with my K-5 & FA20-35/4, the first at 20mm, the second at 35mm, changing the camera to Stuka distance accordingly. They are both straight out of the camera and re-sized to 800px wide (apologies for the rough and ready test shots):
1) 20mm:
Perspective Test 20mm by John Halliwell, on Flickr
2) 35mm:
Perspective Test 35mm by John Halliwell, on Flickr
EDIT: An attempt to shoot at 20mm from the same distance as 35mm and then crop. Note the angle of view is slightly higher.
3) 20mm cropped:
Perspective Test 20mm cropped by John Halliwell, on Flickr
John.
1) 20mm:
Perspective Test 20mm by John Halliwell, on Flickr
2) 35mm:
Perspective Test 35mm by John Halliwell, on Flickr
EDIT: An attempt to shoot at 20mm from the same distance as 35mm and then crop. Note the angle of view is slightly higher.
3) 20mm cropped:
Perspective Test 20mm cropped by John Halliwell, on Flickr
John.
Posted 25/11/2013 - 23:09
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TonyM wrote:
Enough! If anyone else posts I'll make them watch Strictly Come Dancing!!!
I already watch Strictly. It's just great telly. And with Tess, Claudia, Abby, Sophie and the female pros to ogle, it doesn't get any better...Enough! If anyone else posts I'll make them watch Strictly Come Dancing!!!
And, just to annoy everyone, I used to be a competitive ballroom dancer, so I know when the judges are talking shite as well.
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Posted 25/11/2013 - 23:10
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TonyM wrote:
John/Smeggy - Strictly or X-factor, which is it?
Strictly, every time!!John/Smeggy - Strictly or X-factor, which is it?
How's Vincent getting on, on Celebrity? I can't bring myself to watch it.
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
.
Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Posted 26/11/2013 - 08:20
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There seems little point in taking this topic any further. It's
beyond the scope of this forum.
I've just looked again at the Photozone article and it just about
covers everything and is spot on. They (Photozone) are a Team of at
least 3 professional people who are friendly with quite a lot of top
names in photography such as Falk and I'm sure any errors would have
been discussed and rectified.
An important statement I missed at first is "The longer the focal length
the more jumps the church (background object) towards the lamp -
the perspective gets COMPRESSED."
Tele compression is accepted everywhere (except here) and because
the 3rd dimension has been compressed relative to the focal length
it can't be derived from or converted to another focal length.
Going back to this WA photo link
It's obvious due to the extreme WA distortion you can't crop it
and get a Tele view. If you crop off just a hand, the fingers are
bigger than the thumb. You could also use a smaller cropped format
and capture just say the hand and it would show the same distortion
which confirms that it is the lens that causes the perspective.
I won't be posting anything further in this thread because it's
fully covered by Photozone and my original post was just to confirm
that they were right. The sketch I did would have
been better with street lights the same as they have.
The Mods need to be a bit more careful about what is said
on here about Photozone. It seems libellous to me.
--
beyond the scope of this forum.
I've just looked again at the Photozone article and it just about
covers everything and is spot on. They (Photozone) are a Team of at
least 3 professional people who are friendly with quite a lot of top
names in photography such as Falk and I'm sure any errors would have
been discussed and rectified.
An important statement I missed at first is "The longer the focal length
the more jumps the church (background object) towards the lamp -
the perspective gets COMPRESSED."
Tele compression is accepted everywhere (except here) and because
the 3rd dimension has been compressed relative to the focal length
it can't be derived from or converted to another focal length.
Going back to this WA photo link
It's obvious due to the extreme WA distortion you can't crop it
and get a Tele view. If you crop off just a hand, the fingers are
bigger than the thumb. You could also use a smaller cropped format
and capture just say the hand and it would show the same distortion
which confirms that it is the lens that causes the perspective.
I won't be posting anything further in this thread because it's
fully covered by Photozone and my original post was just to confirm
that they were right. The sketch I did would have
been better with street lights the same as they have.
The Mods need to be a bit more careful about what is said
on here about Photozone. It seems libellous to me.
--
Half Man... Half Pentax ... Half Cucumber
Pentax K-1 + K-5 and some other stuff
Algi
Pentax K-1 + K-5 and some other stuff
Algi
Posted 26/11/2013 - 08:26
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Right, this is my last attempt.
Over and out.
Algernon wrote:
Going back to this WA photo link
It's obvious due to the extreme WA distortion you can't crop it
and get a Tele view. If you crop off just a hand, the fingers are
bigger than the thumb. You could also use a smaller cropped format
and capture just say the hand and it would show the same distortion
which confirms that it is the lens that causes the perspective.
--
What everyone is saying is that if you took a telephoto shot FROM THE SAME POSITION then it would show the same perspective, albeit with a tiny amount of the picture, assuming you could focus that close.Going back to this WA photo link
It's obvious due to the extreme WA distortion you can't crop it
and get a Tele view. If you crop off just a hand, the fingers are
bigger than the thumb. You could also use a smaller cropped format
and capture just say the hand and it would show the same distortion
which confirms that it is the lens that causes the perspective.
--
Over and out.
Posted 26/11/2013 - 08:33
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If you cropped the WA shot of the man to just his head and
shoulders... his head would be too big for his shoulders.
If you also took a Tele shot from the same distance his head
and shoulders would look OK. There would be some distortion, but
it would be acceptable.
You need to understand that tele-shots are magnified and the
distance compressed. If you look at your finger through a 2X
magnifying glass... It not only looks bigger... it also looks
closer.
--
shoulders... his head would be too big for his shoulders.
If you also took a Tele shot from the same distance his head
and shoulders would look OK. There would be some distortion, but
it would be acceptable.
You need to understand that tele-shots are magnified and the
distance compressed. If you look at your finger through a 2X
magnifying glass... It not only looks bigger... it also looks
closer.
--
Half Man... Half Pentax ... Half Cucumber
Pentax K-1 + K-5 and some other stuff
Algi
Pentax K-1 + K-5 and some other stuff
Algi
Posted 26/11/2013 - 08:38
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Algi, I'm afraid you're incorrect. Sorry to be blunt, but I'd advise you to start again and read a book about lenses.
Telephoto lenses don't have any effect on perspective at all. It's the fact that to shoot a given subject we need to move further away that changes things.
Enough wibbly wobbly perspectivey stuff I think. We could be here in 50 years with this.
Telephoto lenses don't have any effect on perspective at all. It's the fact that to shoot a given subject we need to move further away that changes things.
Enough wibbly wobbly perspectivey stuff I think. We could be here in 50 years with this.
Best regards, John
Posted 26/11/2013 - 11:20
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johnriley wrote:
Algi, I'm afraid you're incorrect. Sorry to be blunt, but I'd advise you to start again and read a book about lenses.
Telephoto lenses don't have any effect on perspective at all. It's the fact that to shoot a given subject we need to move further away that changes things.
Enough wibbly wobbly perspectivey stuff I think. We could be here in 50 years with this.
John is correct. This is a very easy mistake to make, though, the eye sometimes confuses us.
Algi, I'm afraid you're incorrect. Sorry to be blunt, but I'd advise you to start again and read a book about lenses.
Telephoto lenses don't have any effect on perspective at all. It's the fact that to shoot a given subject we need to move further away that changes things.
Enough wibbly wobbly perspectivey stuff I think. We could be here in 50 years with this.
... just another middle-aged guy with a hobby. I have an extreme macro learning site at extreme-macro.co.uk - Pentax-centric, your feedback and comments would be appreciated!
Posted 26/11/2013 - 12:19
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It's very simple.
The change in relative sizes of objects is due PURELY to their relative distances. Try holding your hand close to your face then at arms reach & you'll see it's size relative to the background looks different.
The problem arrises because diferent focal lengths encourage a change in view point, which changes the relative distances of the objects.
The relative sizes of wide angle & telephoto images with the same relative distances (same spot) are identical. You can check this as recompended earlier up thread, or by stitching together telephoto images to civer the same angle of view, or even just by measuring relative sizes with a ruler.
Things differ if you use distorting lenses (fish-eye lenses) or at very short distances where it's difficult to keep the relative distances the same - which part of the lens/camera combination you measure to becomes significant.
The change in relative sizes of objects is due PURELY to their relative distances. Try holding your hand close to your face then at arms reach & you'll see it's size relative to the background looks different.
The problem arrises because diferent focal lengths encourage a change in view point, which changes the relative distances of the objects.
The relative sizes of wide angle & telephoto images with the same relative distances (same spot) are identical. You can check this as recompended earlier up thread, or by stitching together telephoto images to civer the same angle of view, or even just by measuring relative sizes with a ruler.
Things differ if you use distorting lenses (fish-eye lenses) or at very short distances where it's difficult to keep the relative distances the same - which part of the lens/camera combination you measure to becomes significant.
Mike
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Pentax:K5ii, K7, K100D, DA18-55, DA10-17, DA55-300, DA50-200, F100-300, F50, DA35 AL, 4* M50, 2* M135, Helicoid extension, Tak 300 f4 (& 6 film bodies)
3rd Party: Bigmos (Sigma 150-500mm OS HSM),2* 28mm, 100mm macro, 28-200 zoom, 35-80 zoom, 80-200 zoom, 80-210 zoom, 300mm M42, 600 mirror, 1000-4000 scope, 50mm M42, enlarger lenses, Sony & micro 4/3 cameras with various PK mounts, Zenit E...
Far to many tele-converters, adapters, project parts & extension tubes etc.
.[size=11:].Flickr• WPF• Panoramio
.
Pentax:K5ii, K7, K100D, DA18-55, DA10-17, DA55-300, DA50-200, F100-300, F50, DA35 AL, 4* M50, 2* M135, Helicoid extension, Tak 300 f4 (& 6 film bodies)
3rd Party: Bigmos (Sigma 150-500mm OS HSM),2* 28mm, 100mm macro, 28-200 zoom, 35-80 zoom, 80-200 zoom, 80-210 zoom, 300mm M42, 600 mirror, 1000-4000 scope, 50mm M42, enlarger lenses, Sony & micro 4/3 cameras with various PK mounts, Zenit E...
Far to many tele-converters, adapters, project parts & extension tubes etc.
.[size=11:].Flickr• WPF• Panoramio
Posted 26/11/2013 - 17:01
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Algernon wrote:
Perhaps a quick rough sketch will demonstrate that the Photozone
article is correct..... at least for the brighter Pentax Users
The sketch shows a WA shot and a Tele shot looking down a road.
Note the kerbline angles stay the same all the way to the vanishing
point (which isn't shown here). Therefore each lens produces it's
own individual perspective view and you can't obtain one picture
from the other by cropping. The format (FF or APS-C)
wouldn't change the kerb angles either.
The WA lens kerblines always converge faster than the
Tele kerblines which become closer to parallel with
longer Teles.
Moving the camera providing you stay on the centerline
won't make any difference.
If you can't see it from the sketch.... try it yourself with a
camera and two lenses (or a zoom).
--
Algi, there is a big flaw in your sketch. The point of view is different, hence a different perspective.
Perhaps a quick rough sketch will demonstrate that the Photozone
article is correct..... at least for the brighter Pentax Users
The sketch shows a WA shot and a Tele shot looking down a road.
Note the kerbline angles stay the same all the way to the vanishing
point (which isn't shown here). Therefore each lens produces it's
own individual perspective view and you can't obtain one picture
from the other by cropping. The format (FF or APS-C)
wouldn't change the kerb angles either.
The WA lens kerblines always converge faster than the
Tele kerblines which become closer to parallel with
longer Teles.
Moving the camera providing you stay on the centerline
won't make any difference.
If you can't see it from the sketch.... try it yourself with a
camera and two lenses (or a zoom).
--
Yves (another one of those crazy Canucks)
Posted 28/11/2013 - 12:35
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Algi wrote.
Regards, Horst
Quote:
It's certainly not an optical illusion. I don't know why photographers
can't see it. but the average Joe or Beryl can. If I give them a camera
with a 300mm lens to have a look through they immediately say
"It brings everything closer" which it does and it does it by
magnifying the image..... Like all magnification it does that
by making the distance look smaller than it actually is.
With a 10X magnification every step forward of 1M will look
like 0.1M through the viewfinder or binoculars. It can't
be achieved from magnifying a WA view because the distance
information isn't correct.
Horse racing on TV shows this up well. The stuff on Youtube
isn't as good, but this one shows the horses moving very
little approaching the camera and by much more as they
pass it.
Algi is spot on. No question!!It's certainly not an optical illusion. I don't know why photographers
can't see it. but the average Joe or Beryl can. If I give them a camera
with a 300mm lens to have a look through they immediately say
"It brings everything closer" which it does and it does it by
magnifying the image..... Like all magnification it does that
by making the distance look smaller than it actually is.
With a 10X magnification every step forward of 1M will look
like 0.1M through the viewfinder or binoculars. It can't
be achieved from magnifying a WA view because the distance
information isn't correct.
Horse racing on TV shows this up well. The stuff on Youtube
isn't as good, but this one shows the horses moving very
little approaching the camera and by much more as they
pass it.
Regards, Horst
Posted 28/11/2013 - 12:46
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Horst - you didn't heed my warning not to reply to this thread. As you live "down under" your punishment is to join the "I'm a Celebrity..." crowd and eat some nasty bugs. Now!
And to put this to rest I decree that the effect on perspective is down to who is doing the looking; a bit like quantum physics, but without the physics
And to put this to rest I decree that the effect on perspective is down to who is doing the looking; a bit like quantum physics, but without the physics
Posted 28/11/2013 - 12:48
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Clearly there is still some misunderstanding over this, so I'll let Pentax themselves demonstrate it.
The picture on the right is shot using a 200mm lens. The picture on the left, marked A, is shot from the same position using a 28mm lens. The centre of the 28mm image has been enlarged to show the same field of view as the 200mm. The perspective in both images is exactly the same.
The picture on the right is shot using a 200mm lens. The picture on the left, marked A, is shot from the same position using a 28mm lens. The centre of the 28mm image has been enlarged to show the same field of view as the 200mm. The perspective in both images is exactly the same.
Best regards, John
Posted 28/11/2013 - 12:54
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John - I posted a similar comparison further up the thread, taken for this purpose, but that didn't seem to convince Algi. I hope you have better luck! (I'm watching X-Factor (yuck!) as my punishment for posting; I'll let you choose yours )
835 posts
18 years
Surrey
...and as I type this the wife is watching I'm a Celebrity! I need to take some photos!