Luminous Landscape Forum

Equipment & Techniques => Cameras, Lenses and Shooting gear => Topic started by: allegretto on November 04, 2013, 05:34:55 pm

Title: so would a shift lens help or hurt in a panorama
Post by: allegretto on November 04, 2013, 05:34:55 pm: Think it would help flatten things, but does it shift the nodal point?

thanks
Title: Re: so would a shift lens help or hurt in a panorama
Post by: robdickinson on November 04, 2013, 05:42:44 pm: Quote from: allegretto on November 04, 2013, 05:34:55 pm
Think it would help flatten things, but does it shift the nodal point?

thanks

You can shift the lens for panoramic stitching. For 'nodal point' if you move the camera when you shift rather than the lens you have a perfect match. In practice it normally doesnt matter.

As for framing for example a canon 24tse with 12mm shift can give you an effective 60x24 or 48x36 mm sensor giving fov roughly 24mm , 17mm or 14mm. You can get away with just 2 frames for 60x24 but need 3 for 48x36.

I alternate between nodal rotation and shift stitching depending on situation.
Title: Re: so would a shift lens help or hurt in a panorama
Post by: Glenn NK on November 04, 2013, 05:49:05 pm: Quote from: allegretto on November 04, 2013, 05:34:55 pm
Think it would help flatten things, but does it shift the nodal point?

thanks

I have the Canon 24TSEii - it will shift up to 12 mm left/right or up/down. In order to avoid parallax shift (I think the point of rotating about the nodal point is also to avoid parallax shift), by using my ball head, I can shift the camera in the opposite direction to which I shift the lens.

So essentially what this does is keep the lens in the same position - thus avoiding any parallax shift errors. However there could be some distortion with shift depending on the amount of shift.

Glenn
Title: Re: so would a shift lens help or hurt in a panorama
Post by: langier on November 04, 2013, 09:16:46 pm: Thought the right way is to keep the nodal point stationary, with what I've shot using both my legacy shift lenses and newer auto shift lenses, the stitching goes together easily. My feeling is for landscapes, the nodal point is less critical than in would be for a macro subject where moving the lens will drastically change the perspective/p.o.v. of the image.

I've seen the rigs for keeping the nodal point in place (home made, of course), and they are just too unruly looking to be practical in the field.

With a real view camera, it's simply a matter of shifting or rising/falling the back to do the job. But with the full-frame and dx cameras, that's a P.I.A. I'd say go out and shoot and see how shifting works for you in the situations you'll use it for. I'll bet that if you are doing landscapes, you'll be pretty happy to simply shoot a left and right frame or top and bottom, let Photoshop to the pieces together.

If it's easy and fast, you are likely to use it on a regular bases. If it takes a lot of work to do, that will impede your shooting in the field and gets in the way of image making, IMO.
Title: Re: so would a shift lens help or hurt in a panorama
Post by: Glenn NK on November 05, 2013, 12:14:32 am: Quote from: langier on November 04, 2013, 09:16:46 pm
Thought the right way is to keep the nodal point stationary, with what I've shot using both my legacy shift lenses and newer auto shift lenses, the stitching goes together easily. My feeling is for landscapes, the nodal point is less critical than in would be for a macro subject where moving the lens will drastically change the perspective/p.o.v. of the image.

Agreed. By shifting and moving the body in the opposite direction, this keeps the lens and hence the nodal point stationery does it not?

For first shot, shift lens N mm to the left, and slide the camera N mm to the right; now the lens is back where it started.

For next shot, centre the shift, and centre the camera/lens; lens is still in same position wrt the world.

For third shot, shift lens N mm to the right, and slide the camara N mm to the left; lens is still in same position wrt the world.
Title: Re: so would a shift lens help or hurt in a panorama
Post by: Chockstone on November 05, 2013, 09:48:00 pm: I'd be interested to hear peoples experiences with keeping the tripod and camera completely level in all directions, then shifting down to eliminate unwanted sky and proceeding to do a normal 7 or 8 shot panorama by panning both the camera and lens left to right, while centred around the lens' nodal point.

Specifically I'd like to know if the use of shift in this way helps to keep straight lines straight? Could you use Photoshop’s "reposition" (which doesn't lose quality) stitching mode rather than "cylindrical"?
Title: Re: so would a shift lens help or hurt in a panorama
Post by: Ellis Vener on November 06, 2013, 12:18:42 am: It would depend on the subject material. I tried this once when shooting a cityscape but with the lens shifted down instead of up. I was very careful with nodal point alignment. There were lots of parallax problems with the architecture.
Title: Re: so would a shift lens help or hurt in a panorama
Post by: allegretto on November 06, 2013, 06:10:15 am: Quote from: Glenn NK on November 05, 2013, 12:14:32 am
Agreed. By shifting and moving the body in the opposite direction, this keeps the lens and hence the nodal point stationery does it not?

For first shot, shift lens N mm to the left, and slide the camera N mm to the right; now the lens is back where it started.

For next shot, centre the shift, and centre the camera/lens; lens is still in same position wrt the world.

For third shot, shift lens N mm to the right, and slide the camara N mm to the left; lens is still in same position wrt the world.

sounds like a great deal of work or approximation

I guess you can still use the shift to affect your in-focus zone, but at some cost in ease of use and accuracy
Title: Re: so would a shift lens help or hurt in a panorama
Post by: Bart_van_der_Wolf on November 06, 2013, 08:06:36 am: Quote from: allegretto on November 06, 2013, 06:10:15 am
sounds like a great deal of work or approximation

Not really. With the right tools it's simple, accurate, and quick:

(http://bvdwolf.home.xs4all.nl/temp/OPF/RRS_OrthographicStitch.jpg)

The assembly above is shifted to the right, the lens would be shifted to the left. Then shifting the assembly to the left and the lens to the right, will cover the other side of the pano. Depending on frame orientation (portrait or landscape) and amount of overlap (depends on shift amount), one may want to add a center shot as well. The stop-bars are prepositioned to compensate the exact same distance as required for the opposite shift distance. I use a small spacer that I made for that purpose to set the distance between the dual-clamp and stop-bar, it takes a few seconds to set up).

Cheers,
Bart
Title: Re: so would a shift lens help or hurt in a panorama
Post by: Bart_van_der_Wolf on November 06, 2013, 08:14:45 am: Quote from: Chockstone on November 05, 2013, 09:48:00 pm
I'd be interested to hear peoples experiences with keeping the tripod and camera completely level in all directions, then shifting down to eliminate unwanted sky and proceeding to do a normal 7 or 8 shot panorama by panning both the camera and lens left to right, while centred around the lens' nodal point.

It will only work flawlessly every time when you compensate for the vertical shift of the entrance pupil. Unless you also include tilt in the setup, it would be faster to do a rotational stitching. That would assume you have a multi-row pano setup.

Quote
Specifically I'd like to know if the use of shift in this way helps to keep straight lines straight? Could you use Photoshop’s "reposition" (which doesn't lose quality) stitching mode rather than "cylindrical"?

When only vertical shift is used, then the horizontal alignment is no problem (can even be done by manual dragging and nudging), but there may (depending on type of foreground detail) be vertical parallax errors if the entrance pupil was shifted and not compensated for.

Cheers,
Bart