24mm TS panorama (paralax) question

[alexander_strbac]

Hello everyone!

 

I have a dilemma which seems insolvable. I am about to get a fullframe Canon

camera and need wideangle lens. I have my heart set to 24mm 1.4L since I like

lowlight photography, bars, nudes (in rooms, "Fetish motel" style) etc, but I

also like landscapes. Now, I understand the way 24mm TS works, and I have seen

it is possible to make panoramas by stitching two images together ("far lest

image" and "far right image").

 

BUT, what about paralax error? If there is a flower in front of me, meadow in

the background, and a mountain in the distance (sound familiar? :-), is it

possigle to use this technique end not have any issues with this flower in the

near plan?

 

The way I see it, sensor is in the same place so I should be fine right?! If

this is not true, what would happen if somehow I managed to keep the lens in the

same position, and move the camera left/right instead?

 

Thanx all

Alex

[ken munn]

Eh?

 

The 24mm TS is f3.5, not f1.4. So not ideal for motel nudes.

 

Are you're proposing buying the 24mm TS just for panoramas? For the same sort of money

you could buy a used Hasselbald Xpan, the best pocketable panoramic camera in captivity.

Or for no extra money at all you could stitch together a panorama using conventional

panoramic techniques, any lens you own, and free software.

[mikemilton]

Keeping the lens still moves the sensor across the image circle (useful for pano's), keeping

the camera still is useful for stereo images

 

HTH, m

[zml]

EF 24.1.4 L does NOT have Tilt/Shift: you are confusing it with the EF TS-E 24/3.5 L. Should you really mean the T/S lens, one way to do panoramas with a T/S lens and avoiding the parallax errors is taking 3 pictures: <br>

1. Shift the center axis of the camera by 24 mm to the left, shift the lens 24 mm to the right. <br>

2. Set both the camera and lens shift to neutral (zero.)<br>

3. Shift the center axis of the camera by 24 mm to the right, shift the lens 24 mm to the left. <br>You'll have an overlap w/o parallax.

[mark u]

Here's the technique:

 

http://www.outbackphoto.com/workflow/wf_58/essay.html

[zml]

Mark: Thanx! 11 mm of course, not 24 mm.

[alexander_strbac]

ehm, sorry English is not my first language so I may have not made myself clear -

 

I am contemplating buying wither of the TWO lenses

 

24mm 1.4 (because I can do my "normal" shooting style, lowlight etc.

OR

24mm TS (loosing f-stops and autofocus but gaining TS and architecture/interior shooting)

 

Now, as far as this pano-stitching, I dont quite get it. If I shift the lens 11mm to the left (that is as far as it will go as I know?), how can I shift the camera to the right? Why dont I make some sort of a ring (?) that would hold the lens still to the tripod and simply shift the camera body? So to say.

 

That should keep things in perspective, no?

 

cheers!

A.

[zml]

Alexander: There are many ways to skin the stiched panorama cat so to speak but in order to stich w/o parallax and artifacts, one needs to move the lens/camera combo around its nodal point (yes, there are many panorama heads...) Read up on panoramas (there are several threads here - on photonet - as well as lots of resources in the wilderness of cyberspace.

[w_t1]

"Now, as far as this pano-stitching, I dont quite get it."

 

You're thinking too hard - I use my 24ts to do stitched panoramas. The camera stays on the tripod and does not move, only the lens moves left and right (or up and down). Tom

[w_t1]

yeah or you can spend an extra grand on RRS ewuipment from the link and shift both.

[rodeo_joe1]

Keeping the lens still and shifting the camera body is the technically "correct" way to do this. Think about it - a shift lens has a much wider than normal image circle, and all you need to do is shift the sensor area across the image circle to get a seamless pano. If you shift the lens, you shift the viewpoint, and that's exactly the same as if look alternately through your right and left eye - you'll get a parallax shift.

 

Nodal swivelling doesn't give you a seamless pano either, it just reduces the effect of keystone distortion as the camera is panned left or right. The natural shift of perspective you get when rotating the viewpoint remains, and has to be "fudged" in the stitching by using more shots with plenty of overlap between them. Whereas, theoretically, you could stitch two shift-lens frames together with almost no overlap at all.

 

You don't need to spend megabucks on overpriced special gizmos either. All that's needed is some way of holding the front of the shift lens still while letting the camera body do the shifting. In fact I'm surprised that Canon haven't just fitted a tripod socket to the appropriate part of their TS lenses. Anyhow, a cheap lash-up could easily be rigged by screwing or clamping a lens hood to a tripod collar and then fitting the TS lens to it.

[david_lau3]

I use my 24/f3.5 TS-E a lot in taking pano. A few points:

 

1. The max shift of this lens is 11mm but this will give you dark corners and a lot of CA. Practical shifting is about 8-9mm only. If you take 3 photos (centre, left, right), it gives you an expansion of about 20% each way, 40% in total. This is not much when compared with Nodal swivelling, but the out of the box alignment of photos is usually much better.

 

2. Technically if you shift your lens 8mm to the right, you should shift your camera 8mm to the left for absolutely no parallax. But in practice if you are shooting distant objects (>5m away), this parallax error is very small and can be ignored. If you really want to do the camera shifting, you can buy a macro focusing rail which has markings and can let you precisely move your camera left or right.

 

3. Technically you need only the 2 left and right pictures to do the pano, but in practice it is better to take also the centre one. Reason being the centre one has no shoft and will be of the best quality. In this way you are using the best 100% centre and the less than best 20% on each side.

[andrew robertson]

I hemmed and hawed about this one too, and ended up buying the 24 f/3.5 TS-E and also

the Sigma 20 f/1.8.

 

Hah!