TILT/SHIFT in use.

[Sheetshooter]

TILT/SHIFT lenses are an attempt by camera manufacturers to provide some of the image flexibility of the view camera (a fully adjustable monorail or flat bed camera - usually Large Format or Medium Format) to the user of the SLR camera.

Nikon and Canon produce TILT/SHIFT lenses (Canon 24mm, 45mm & 90mm - Nikon 85mm Micro) and there are also simpler devices which only have SHIFT made by those and several other makers.

SHIFT

The use of a shift lens is primarily to avert (or exagerate) diminishing perspective in vertical subjects such as buildings or product packets. By setting the camera level (using a spirit level in the flash shoe for instance) the lens is either raised or lowered by a worm-screw and dovetail mechanism to raise or lower the field of view. If the film plane remains parallel to the subject plane there will be no distortion (tapering) of the subject.

Shift can also be applied in a lateral orientation by rotating the lens on the camera and intermediate notches are provided to allow other settings.

There is a technique possible with SHIFTING on a DSLR (or on film for subsequent scanning) whereby the lens can be shifted all the way in one direction for a shot and then all the way in the opposite direction for another snap and the two stitched together for a distortion minimised panorama. ( Additional exposures in between might prove beneficial for smoothing the optical transition - and in critical work a macro stage used sideways will prevent any distortion at all by maintaining a constant position for the lens and an effective shifting of the camera (sensor).

Problems with SHIFT on DSLRs arise due to chromatic aberration because the angle of incidence of image forming light on the pixel array increases and faults may increase.

TILT

TILT has a different application entirely and it is used to alter the plane of sharp focus in the scene in accordance with the Scheimpflug Principle. In normal orientation with the optical axis precisely perpendicular to the image plane the plane of sharp focus is parallel to the image plane and depth of field is extended by stpping the lens down. Now, it is important to remember that DEPTH OF FIELD refers to an area of acceptable focus for an image of a given size and a given viewing distance. In other words there is still only one parallel plane of sharp focus but there is a greater or lesser range of stuff that is near as damn it to sharp.

If the optical axis is moved away from the perpendicular then the palne of sharp focus is no longer parallel to the image plane. Briefly, the plane of sharp focus follows a line that intersects with the junction of the new optical plane and the image plane.

In Paul's image of Mount Connor it may have been possible to leave the camera set as it was and to simply TILT the lens down to such an extent that the plane of sharp focus would extend from the scrub in the foreground, all the way to the mountain itself - EVEN WITH THE LENS WIDE OPEN at its maximum aperture. Obviously there would be issues wide open with the lens's resolving and vignetting characteristics but by stopping down to f/5.6 to f/8 an ideal optical performance could be achieved with perfectly sharp content from front to back (or near/far in photo parlance). The negates needing to stop right down to f/16 or f/22 where the optical performance of any lens will be adversely affected by DIFFRACTION - or a softening of the image by the ratio of the aperture opening becoming to close in value to the thickness of the aperture blades.

*********

Of course there is more to it than this and the movements of the TILT/SHIFT lens ca be used in concert with each other within the mechanical limitations of the device. But that should do for now.

Cheers,

[kipper]

Thanks Sheetshooter for spending the time explaining. I did have a brief read into a Canon tiltshift today and a bit about the scheimpflug (sp?) theorem. Even though I have started to read other articles on tilt-shift I never really got to thinking about the film plane and the relevance it has to when shooting a photo of a building. After reading what you said about making sure that the camera's film plane is in the same plane as that as the main face of the building it all makes sense.

[MattC]

Thanks for that. There are one or two things that I am a little fuzzy on, but will have a think and try to find some stuff online that is a little more indepth.

Cheers

[big pix]

This can now be achieved by using the crop tool and perspective in Photoshop.......also PSCS2 has lens correction for greater control.......

[Sheetshooter]

With all due respect Big Pix PhotoShop can effect some of the simpler aspects of shift lens control but not all and not without losing something somewhere. In most discussion circles in the architectural sphere the concensus seems to be that it is preferrable to see the balance of the image with the corrections applied in camera.

As for the placement of the plane of sharp focus in PhotoShop - I don't think so - not in a simple single exposure way, at least.

PhotoShop is very capable but so too are specialist optics. I would agree that the Chromatic Aberration isues with SHIFT lenses (and possibly TILT) on digital sensors could be a reason to forego the use of adjustable lenses.

From a personal viewpoint I am still not convinced that I would be any better off shooting my architecture on digital as opposed to film. It is the quest for ultra-wide-angle excellence that swallows up all the money in my calculations. If I continue with film and gear that I already own and which does a masterful job with adjustments on ALL lenses I have to be in front.

[big pix]

Shift len's on 35mm and medium format DO NOT MATCH a 5x4 view camera in any way, and shooting architecture on film using a view camera would give you better control.

But with a digital back on a 5 x 4 view camera, would this not give you the best of both, total control using the movements of a view camera and the convenience of digital.......

[gstark]

Sheetshooter,

Excellent explanation, many thanx for taing the time anmd effort to put this all together.

This can now be achieved by using the crop tool and perspective in Photoshop.......also PSCS2 has lens correction for greater control.......

With all due respect, no. PS can certainly try to emulate this, but there is no sustitue for simply getting all of the available details that are visible into the image in the first place, which, of course, is at the time of shooting.

[big pix]

Sheetshooter,

Excellent explanation, many thanx for taing the time anmd effort to put this all together.

This can now be achieved by using the crop tool and perspective in Photoshop.......also PSCS2 has lens correction for greater control.......

With all due respect, no. PS can certainly try to emulate this, but there is no substitue for simply getting all of the available details that are visible into the image in the first place, which, of course, is at the time of shooting.

.....but in comparrision to using a shift len's on 35mm, medium format or digital it only gives some control, in most cases not a lot, so if you require straight verticals the job has to be finished with photoshop. Then again it comes down to the job at hand and using the correct tools to do the job.........

[lejazzcat]

Incompatible Accessories and Non-CPU lenses that can NOT be used with the D70.
I figured ide add this info(mir.com) for those that are now thinking to buy a PC lens after reading this.
Im not sure about the accuracy of this list, nor why they cant be used ...

*TC-16A AF Teleconverter
* Non-Ai lenses
* Lenses that require the AU-1 focusing unit (400mm f/4.5, 600mm f/5.6, 800mm f/8, 1200mm f/11)
* Fisheye (6mm f/5.6, 8mm f/8, OP 10mm f/5.6)
* 2.1 cm f/4 Nikkor-O (old type)
* K2 rings
* ED 180-600mm f/8 (serial numbers 174041-174180)
? ED 360-1200mm f/11 (serial numbers 174031-174127)
* 200-600 mm f/9.5 (serial numbers 280001-300490)
* Lenses for the F3AF (80mm f/2.8 AF, 200mm f/3.5 AF, TC-16 Teleconverter)
* PC 28mm f/4 (serial number 180900 or earlier)
* PC 35mm f/2.8 (serial numbers 851001- 906200)
* PC 35mm f/3.5 (old type)
* 1000mm f/6.3 Reflex (old type) May be the 500mm f/5 as well.
* 1000mm f/11 Reflex (serial numbers 142361 -143000)
* 2000mm f/11 Reflex (serial numbers 200111-200310)

[Sheetshooter]

BP you are right,

A TILT/SHIFT lens on 35mm or a Medium Format Reflex is the photographic equivalent of being just a little bit pregnant.

The new generation of view cameras are in the size range of the earlier 6x9 cm models or smaller. Sinar has released the P3 and now the F3 which are much smaller than the 4x5 siblings. Reason being that sensor technology prevents larger chips and so the common size seems to be about 6x4.5. There are full 4x5 devices but these are scan backs and require very lengthy exposures with all the inherent problems that presents. And, of course, the smaller capture backs require shorter lenses (Schneider are making Digitars in 35mm and 24mm focal lengths) so conventional cameras do not permit the use of such short focal lengths. I used to have an Apo-Grandagon 35mm lens for shooting 6x12 and it was a real bitch to handle. Sinar have a work around where the lens is actually inside the bellows rather than in front of it.

Until photo receptor technology changes dramatically the status quo is likely to continue. Besides, it is really very convenient to shoot some film, drop it at the lab and then deliver it to the client without having to sit in front of a 'puta half the night. Horses for courses - situation normal!!

Cheers,

[gstark]

Incompatible Accessories and Non-CPU lenses that can NOT be used with the D70.

Ladeeeees and gentlmen!

Step right up, folks, and place your bets ....

I figured ide add this info(mir.com) for those that are now thinking to buy a PC lens after reading this.
Im not sure about the accuracy of this list, nor why they cant be used ...

*TC-16A AF Teleconverter
* Non-Ai lenses

Just like my Nikkor 55 Micro, from around 1968, I'd guess.

No metering.

No AF

But it fits and works.

Many of the rest might work too, but you'd to satisfy yourself as to practicalitis and risks before buying and trying.

If you have the lenses in hand, examine them carefully for points that may contact one another, but failing that circumstance, playtime is your's.

[lejazzcat]

Incompatible Accessories and Non-CPU lenses that can NOT be used with the D70.

Ladeeeees and gentlmen!

Step right up, folks, and place your bets ....

I figured ide add this info(mir.com) for those that are now thinking to buy a PC lens after reading this.
Im not sure about the accuracy of this list, nor why they cant be used ...

*TC-16A AF Teleconverter
* Non-Ai lenses

Just like my Nikkor 55 Micro, from around 1968, I'd guess.

No metering.

No AF

But it fits and works.

Many of the rest might work too, but you'd to satisfy yourself as to practicalitis and risks before buying and trying.

If you have the lenses in hand, examine them carefully for points that may contact one another, but failing that circumstance, playtime is your's.

To quote from the site(http://www.mir.com.my/rb/photography/co ... lSLRs/D70/)

Compatible Non-CPU Lenses:
Non-CPU lenses not included in the list above can be used, but only in mode M. Aperture must be adjusted manually using the lens aperture ring and the camera exposure meter, depth-of-field preview, and i-TTL fl ash control can not be used. If another mode is selected when a non-CPU lens is attached, the shutter-release will be disabled.

[gstark]

Compatible Non-CPU Lenses:
Non-CPU lenses not included in the list above can be used,

But my point is that my lens, a non-CPU lens, WAS included in their list. It's a non-Ai lens, and they list them, all, with no exceptions. It's still the second item on that list!

So, the bets are still on.