A Question To You All On The Topic Of Shift Lenses

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A Question To You All On The Topic Of Shift Lenses

Postby Wiener » Sun Nov 25, 2012 8:56 pm

Does anyone here have experience with 'shift' lenses? In days of analogue they were intended to correct convergence of verticals and the like. In the digital world, can exactly the same correction be achieved during post processing, or is their still some merit in correcting the image at source? All comments welcome/appreciated.

Andy
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Re: A Question To You All On The Topic Of Shift Lenses

Postby Tom Caldwell » Mon Nov 26, 2012 5:02 am

Andy

I have used a Canon 24mm f3.5 tilt/shift on a Canon dslr. Hard to use on a dslr as the extreme shifts mess with the camera's metering. You can get around this and a bit of trial and error helps. They should be a dead-set easier deal on any EVIL-type camera or on newer live-view bodies. WYSIWYG helps adjust it correctly. Unfortunately Canon adjust the aperture electronically on their EF lenses, so you shoot wide open on anything other than a Canon body. Something that hasn't actually motivated me to rush out and use it a lot.

Post processing will delete pixels and fill in others to get the alignment right - therefore I suppose you will have less pixels in critical areas and made up ones in other critical areas. Does not seem to wreck the PP images though. With a tilt/shift lens the theory must be that as the lens is adjusted to compensate the light rays then the pixels captured must be evenly spread.

No matter what system is used it cannot correct for what cannot be seen from the eye perspective. In other words you can straighten things such as "battlements" but cannot made them look exactly as they might reveal detail if they were captured at eye level.

There are other tilt/shift lenses about other than Canon but they all seem to be fairly expensive for their limited purpose. The Canon 24mm T/S is in fact a very good if bulky and heavy lens if used "straight". Good fun though and the tilt function can get wider expanses of angled scenery in focus at wide apertures. Mmmm maybe the fixed wide open situation might be ok - must get it out and try it again.

In the end they might be a bit extravagent unless you do a lot of architectural or angled scenery work.

Tom
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Re: A Question To You All On The Topic Of Shift Lenses

Postby Blow-in » Mon Nov 26, 2012 11:09 am

Andy,

You may want to take a look at this thread....it gets quite interesting as you read down:

http://www.ricohforum.com/viewtopic.php?f=18&t=9381

Regards,

Richard
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Re: A Question To You All On The Topic Of Shift Lenses

Postby riccadonna » Mon Nov 26, 2012 12:53 pm

Well everybody that`s a topic that interested me a lot in my architectural past. There`s a quite a difference between film and digital. In film days one had to maximize the quality hence shift lenses. Otherwise an alternative to, say 28mm shift would be between 15mm and 18mm non shift and the crop, which of course would have to be enlarged to match 28mm properly shifted. With a loss of resolution and gain of grain. In digital one can adjust in post of course provided one starts with enough resolution for interpolation. For sure serious digital architecture photographers use shift for exact composition and max quality. For us APS-C users, it would be really cool if somebody produced m-mount shift adapter for FF lenses. More precisely at least 18mm FF lens which would give a 28mm effect.
There`s Nikon 24mm tilt/shift with aperture ring but it`s big and expensive. Olympus had the smallest 24mm tilt/shift.
Personally I`m more interested in tilt mechanism allowing the use of scheimpflug effect (extended DOF at moderate apertures). Unfortunately Lensbaby doesn`t and won`t make m-mount barrels for mirrorless APS-C. Have to DIY :( . Stanislaw
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Re: A Question To You All On The Topic Of Shift Lenses

Postby Wiener » Mon Nov 26, 2012 10:26 pm

Tom Caldwell wrote:Andy

I have used a Canon 24mm f3.5 tilt/shift on a Canon dslr. Hard to use on a dslr as the extreme shifts mess with the camera's metering. You can get around this and a bit of trial and error helps. They should be a dead-set easier deal on any EVIL-type camera or on newer live-view bodies. WYSIWYG helps adjust it correctly. Unfortunately Canon adjust the aperture electronically on their EF lenses, so you shoot wide open on anything other than a Canon body. Something that hasn't actually motivated me to rush out and use it a lot.

Post processing will delete pixels and fill in others to get the alignment right - therefore I suppose you will have less pixels in critical areas and made up ones in other critical areas. Does not seem to wreck the PP images though. With a tilt/shift lens the theory must be that as the lens is adjusted to compensate the light rays then the pixels captured must be evenly spread.

No matter what system is used it cannot correct for what cannot be seen from the eye perspective. In other words you can straighten things such as "battlements" but cannot made them look exactly as they might reveal detail if they were captured at eye level.

There are other tilt/shift lenses about other than Canon but they all seem to be fairly expensive for their limited purpose. The Canon 24mm T/S is in fact a very good if bulky and heavy lens if used "straight". Good fun though and the tilt function can get wider expanses of angled scenery in focus at wide apertures. Mmmm maybe the fixed wide open situation might be ok - must get it out and try it again.

In the end they might be a bit extravagent unless you do a lot of architectural or angled scenery work.

Tom

Hi Tom,
the extravagent comment hits home with my current thinking. However, I do do quite a lot of architectural detail work and am never quite tall enough to get the 'eye level' view, so...tricky one! Perhaps I just need to get one at the 'right' price.
Thanks for your help!
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Re: A Question To You All On The Topic Of Shift Lenses

Postby Wiener » Mon Nov 26, 2012 10:28 pm

Blow-in wrote:Andy,

You may want to take a look at this thread....it gets quite interesting as you read down:

http://www.ricohforum.com/viewtopic.php?f=18&t=9381

Regards,

Richard

Hi Richard,
I had forgotten that there was so much relevant information on this thread.
Thanks for thereminder and the link!
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Re: A Question To You All On The Topic Of Shift Lenses

Postby Wiener » Mon Nov 26, 2012 10:39 pm

riccadonna wrote:Well everybody that`s a topic that interested me a lot in my architectural past. There`s a quite a difference between film and digital. In film days one had to maximize the quality hence shift lenses. Otherwise an alternative to, say 28mm shift would be between 15mm and 18mm non shift and the crop, which of course would have to be enlarged to match 28mm properly shifted. With a loss of resolution and gain of grain. In digital one can adjust in post of course provided one starts with enough resolution for interpolation. For sure serious digital architecture photographers use shift for exact composition and max quality. For us APS-C users, it would be really cool if somebody produced m-mount shift adapter for FF lenses. More precisely at least 18mm FF lens which would give a 28mm effect.
There`s Nikon 24mm tilt/shift with aperture ring but it`s big and expensive. Olympus had the smallest 24mm tilt/shift.
Personally I`m more interested in tilt mechanism allowing the use of scheimpflug effect (extended DOF at moderate apertures). Unfortunately Lensbaby doesn`t and won`t make m-mount barrels for mirrorless APS-C. Have to DIY :( . Stanislaw

Hi riccadonna, thanks for your thought-provoking in put. Having enough resolution to allow some of the captured resolution to be lost in PP seems to be the key to this. Also that one has to have enough spare pixels outside the frame of interest to allow the subject to remain intact after squeezing/stretching/cropping. One thing a shift lens would allow one to do is to see how the image would look before you leave the 'field' so to speak. I sometimes find that after straightening converging lines in photoshop that too much of the subject has to be cropped off when squaring up the image. The crop factor is another problem if one wished to use the m-mount with a 35mm lens. Most of these wide tilts would then end up as standard tilts, and a lot of money spent on going wide is then lost. Guess I should wait for Ricoh to produce a full frame mount for the GXR? Dream on... :mrgreen:
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Re: A Question To You All On The Topic Of Shift Lenses

Postby Tom Caldwell » Mon Nov 26, 2012 11:28 pm

Blow-in wrote:Andy,

You may want to take a look at this thread....it gets quite interesting as you read down:

http://www.ricohforum.com/viewtopic.php?f=18&t=9381

Regards,

Richard


You can also see my point with the balcony railing here on top of the church. It might have it's convergence corrected but the angle of view leaves it still looking a bit odd. Neither PP nor perspective control lenses will fix this. What cannot be seen fom the camera viewpoint cannot be fixed.

A great image of the kirsche, glad I have a T/S lens. Where I live there are no "old stone" buildings and they are relatively limited even in Australian capital cities and early regional provincial centres.

Tom
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Re: A Question To You All On The Topic Of Shift Lenses

Postby Wiener » Tue Nov 27, 2012 10:56 am


You can also see my point with the balcony railing here on top of the church. It might have it's convergence corrected but the angle of view leaves it still looking a bit odd. Neither PP nor perspective control lenses will fix this. What cannot be seen fom the camera viewpoint cannot be fixed.

A great image of the kirsche, glad I have a T/S lens. Where I live there are no "old stone" buildings and they are relatively limited even in Australian capital cities and early regional provincial centres.

Tom

I do see exactly what you mean. It is impossible to correct details in the image 'unseen' by the camera. Clearly the best way to avoid such 'errors' is to use them as sparingly as possible. Sounds like a good argument to buy a tall, light weight step ladder! ;)
hm...
Thanks Tom,
Andy
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Re: A Question To You All On The Topic Of Shift Lenses

Postby Blow-in » Tue Nov 27, 2012 1:21 pm

Wiener wrote:

You can also see my point with the balcony railing here on top of the church. It might have it's convergence corrected but the angle of view leaves it still looking a bit odd. Neither PP nor perspective control lenses will fix this. What cannot be seen fom the camera viewpoint cannot be fixed.

A great image of the kirsche, glad I have a T/S lens. Where I live there are no "old stone" buildings and they are relatively limited even in Australian capital cities and early regional provincial centres.

Tom

I do see exactly what you mean. It is impossible to correct details in the image 'unseen' by the camera. Clearly the best way to avoid such 'errors' is to use them as sparingly as possible. Sounds like a good argument to buy a tall, light weight step ladder! ;)
hm...
Thanks Tom,
Andy


If only there was a remote view finder capability you would be able to hoist the camera on a very long pole (monopod gone mad) and trigger the camera with your wireless remote - also not available as standard. Of course you could always use the long pole with the camera set to interval and see what you got.

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