Luminous Landscape Forum

Raw & Post Processing, Printing => Adobe Lightroom Q&A => Topic started by: Ellis Vener on April 18, 2013, 02:44:54 pm

Title: Canon and Nikon tilt shift lenses: why no lens profiles?
Post by: Ellis Vener on April 18, 2013, 02:44:54 pm
I understand that  employing the shift and/or tilt movement changes the optical characteristics, but why not a profile with those movements zeroed?
Title: Re: Canon and Nikon tilt shift lenses: why no lens profiles?
Post by: RikkFlohr on April 18, 2013, 03:04:21 pm
Because there would be no way to know from the photo whether the tilt/shift adjustments had been used and whether the profile would be accurate or garbage in that instance?
Title: Re: Canon and Nikon tilt shift lenses: why no lens profiles?
Post by: Schewe on April 18, 2013, 03:15:21 pm
I understand that  employing the shift and/or tilt movement changes the optical characteristics, but why not a profile with those movements zeroed?

Why would you use those lenses with movements zeroed?
Title: Re: Canon and Nikon tilt shift lenses: why no lens profiles?
Post by: hjulenissen on April 18, 2013, 04:25:42 pm
Because there would be no way to know from the photo whether the tilt/shift adjustments had been used and whether the profile would be accurate or garbage in that instance?
Perhaps the user could input those two parameters manually?

-h
Title: Re: Canon and Nikon tilt shift lenses: why no lens profiles?
Post by: davidgp on April 18, 2013, 05:14:19 pm
Why would you use those lenses with movements zeroed?

Well, the 24mm TS mark II is the best that I have, if the picture does not require any movement, I will still use it (my other option for that focal range will be de 17-40f4... this lens is much more sharper).

My only problem it will be remember if I used the lens zeroed or not, not sure if that values are included in the EXIF of the RAW file.
Title: Re: Canon and Nikon tilt shift lenses: why no lens profiles?
Post by: hjulenissen on April 19, 2013, 03:08:37 am
...not sure if that values are included in the EXIF of the RAW file.
That would be a possibility, perhaps one only Canon knows?. But you would (?) need a 2-d continous range of lense corrections to cover those two settings?

-h
Title: Re: Canon and Nikon tilt shift lenses: why no lens profiles?
Post by: davidgp on April 19, 2013, 06:09:13 am
I suppose you will need a profile for each combination of tilt-shift, in the hypothetical case the exif included those values
Title: Re: Canon and Nikon tilt shift lenses: why no lens profiles?
Post by: Petrus on April 19, 2013, 07:30:44 am
The T/S lenses would have to have tilt and shift sensors with tilt angle and direction, shift amount and direction embedded in the EXIF in addition to the normal info about lens corrections. The correction calculations would be massively more complicated than for normal lenses. When the T/S lenses were designed nobody thought about this. Maybe new models will have it in the future.
Title: Re: Canon and Nikon tilt shift lenses: why no lens profiles?
Post by: hjulenissen on April 19, 2013, 08:05:26 am
What is the use-case for lense profiles? My guess would be primarily shifted to the horizontal extremes for pano? In that case, you only need two profiles.

-h
Title: Re: Canon and Nikon tilt shift lenses: why no lens profiles?
Post by: Aphoto on April 19, 2013, 09:05:00 am
Actually, to determine the shift-amount after the picture is taken is (often) pretty easy:

Canon TS-E 17mm and 35mm full-frame-camera:

(http://www.adrianschulz.de/forum/shift.jpg)
Shift amount = 5,5mm
Title: Re: Canon and Nikon tilt shift lenses: why no lens profiles?
Post by: Chris_Brown on April 19, 2013, 09:18:15 am
I understand that  employing the shift and/or tilt movement changes the optical characteristics, but why not a profile with those movements zeroed?

Why not brew your own lens profiles?
Title: Re: Canon and Nikon tilt shift lenses: why no lens profiles?
Post by: Glenn NK on April 19, 2013, 12:34:24 pm
The T/S lenses would have to have tilt and shift sensors with tilt angle and direction, shift amount and direction embedded in the EXIF in addition to the normal info about lens corrections. The correction calculations would be massively more complicated than for normal lenses. When the T/S lenses were designed nobody thought about this. Maybe new models will have it in the future.

Yes - precisely.

The present TS lenses are not weatherproof by any stretch of the imagination (think of the sliding joints).

If sensors were added, they'd have to be protected would they not?

This would seem to very much complicate matters and increase the cost of the lens significantly.  How many other great TS lenses can you count on one finger?  ;)

Glenn