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Thread: Panoramas and correction vs. Tilt-shift lens

  1. #1

    Panoramas and correction vs. Tilt-shift lens

    Posting here, because this post perhaps relates more to panoramas and correction than lenses . . .

    I'm looking at purchasing the Canon TS-E 24mm II for street and travel photography--not an exclusive lens, but one for photographing buildings and interiors. I haven't been too happy with perspective correction in Photoshop.
    Perhaps I'm shooting wide enough that by the time I process the image, it's not close to my visualized result. Perhaps it's because some of the images look corrected to me.
    (I'm using ACR lens correction, lens correction filter, or crop with the perspective option, depending on need.)
    I'm familiar with techniques for minimizing converging verticals: Level, and where possible, shoot from a distance, or from a higher location. I'm also familiar with the benefits of tilting, and the increased workflow for capture using a tilt-shift lens.
    I also understand how a tilt-shift lens can be used for panoramas (not my question today), and know that the 24mm TS-E II would meet my needs, slightly more so than the 17mm.
    QUESTION: Can I achieve the same quality results using a panorama head and a super-wide or fish-eye lens and correcting verticals, INSTEAD of a tilt-shift lens? Obviously I could squeeze in more pixels using a panorama, but should I expect to achieve a realistic correction of converged verticals in a panorama, vs a tilt and shift lens?
    Trying to get opinions from those who have experience with tilt-shift lenses, panoramas, or both.
    I currently have a 5D Mark III and 7D, the 16-35mm II and the 8-15mm Fisheye, panorama head, PT Gui and PS CS5. Wondering if I need to improve my technique, go for the 24mm TS-E, or both!

  2. #2
    Senior Member Andy Stringer's Avatar
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    Welcome to the forum.

    You may already have seen the Canon-TS-E-24mm-f-3.5-L-II-Tilt-Shift-Lens-Review elsewhere on this site, but if not it's worth a read. The second half of the review gives some great examples comparing this lens to super-wide angle and fisheye lenses, but it doesn't discuss your question about using software to correct verticals.

    The answer is that if you are prepared to invest the extra time on location with your tripod and a TS-E lens, you will achive superior results versus post-processing a series of wide angle shots to correct for verticals.

    A correction in software needs to stretch parts of the image, requiring some interpolation of pixels and a consequent loss in quality. Depending on your sensor resolution and the amount of cropping and rotating you need to do, this effect could range from barely noticeable to very noticeable. In addition, you need to leave plenty of space around your subject if you will be correcting verticals later. Anything near the edge of the frame could be lost after you apply the correction.

    I'll share an example, which is probably not the type of construction you intend shooting but there are enough vertical lines to get the idea.
    First, here is the uncorrected scene, shot at 22mm with a 16-35mm zoom.


    Now here are two shots with the verticals corrected. The one on the left is a processed version of the image above and the one on the right is re-shot with a TS-E 24mm and cropped to match the height of the subject.


    You can click through to Flickr and peep at the pixels if you wish. The biggest difference is that the TS-E includes more detail from the sides of the image.
    Last edited by Andy Stringer; 10-01-2012 at 08:57 PM.

  3. #3
    Quote Originally Posted by jrw View Post
    Always thought that the distortion of a fish-eye was its charm?

    Still waiting on Samyang 24 TS lens reviews, recently announced, before plunging into purchasing Canon's. Ability to shift focal plane is reason for me to get one, not panarama via shifting though that is an option.
    Yes, the distortion on super-wides and fisheyes are enough to drive me crazy on some of the 360 panoramas I've done, even those that were correctly calibrated--especially where there is little detail to match seams.

    I was not aware of the Samyang. Very interesting announcement. Still will probably be priced fairly high, but it will give Nikonians the ability to rotate the axis for the first time.

  4. #4
    Thank you for the examples. I did read the review, as well as many others. Although the reviews and tutorials have been invaluable, they didn't address my few remaining questions. Your shots here give me a prime example of what is possible with the 16-35mm, shot wide and corrected, or the 24mm cropped. Which is a fair comparison. I know filling the frame on the 24mm TS-E would result in higher quality, and therefore not fully expose the limits of either technique.

    I can see a slight loss in detail in the areas you'd expect from the 22mm shot. Less loss of detail than I expected for a web image. Although that loss would be more pronounced on a large print, it still could be within acceptable limits--a result I didn't expect. You have done an admirable job in correcting the verticals!

  5. #5
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    Who needs dpreview. We have distortion charts here at TDP. Here's a 16-35 vs. TS-E 24mm comparion.

    Also, I'm really not sure if the Samyang will be expensive. Their 35mm prime is as sharp as the Canon L, but a fraction of the cost. Some of that cost savings comes from not having autofocus, or electronic aperture controls. I think I've read that TS-E lenses are manual focus already, so perhaps the price difference will be less for the the tilt-shift lens, but I'd still expect a healthy discount.

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