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Widest lens possible for panoramics


rupa_sztraka1

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<p>Hello Rupa Sztraka!<br>

Maybe this would be something for you to consider?<br>

The Canon TS-E 17mm f/4L is wide and in factual almost equal to about 10mm.<br>

Using the shift function, you can take a series of three images, that are overlapping by 30% or so, and then merge them in photoshop. You will have an effective sensor size of something like 48mm x 36 mm( depending on the direction of the shift) and with that size sensor you will still have a 17mm lens! You are effectively getting medium format sensor resolution with a 35 mm camera ( Once you merge the images together) These files have an angle of view on a 35 mm camera, that is equal to about a 10 mm lens, with no fisheye effect and little distortion unless you are close to things. This lens will give you images that will amaze you. The perspective (in these merged files) is real but unreal. It is unlike anything else.<br>

-------------------<br>

//Charl</p>

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<p>What Jamie said. I've also seen 360 deg pano shots done with fisheye lenses, which of course would be wider. As I recall, 360 panos could be done with only 3 shots -- perhaps 4 or 5 for a complete sphere. Unfortunately I don't recall whose software does that.</p>
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17F4 goes very wide if you left then right shift. I don't know the exact angle of view this gives you but it appears to be

around 10mm. Everyone who uses and owns this lens loves it - I know that I do and despite the price it makes

remarkable images. My copy gets a lot more use than my 16-35 F2.8 II. Sarah also mentions the fishes - a few months

ago I went from the Sigma 8mm F3.5 and the Canon 15 mm to the new Canon zoom 8-15. Again this is a great lens and

is optically very sharp. Either of these lenses may well work out for you. Personally I only shoot panoramas as wide as

my shifted 17mm lens on full frame (I also shoot them with the same technique on my film Fuji GX680). However, here is

a link on shooting panoramas with the fisheye zoom that may be of interest http://michel.thoby.free.fr/Canon_8-15mm/8-

15mm_review.html

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<p>Rupa: if you are fussy about alignment of near detail in your panoramas, using a very wide angle lens might disappoint you. OTOH a moderate WA (35, 28 or even a 24 mm) might require more shots but can provide more predictible results. Using a shift lens (esp. with a slider rail) is also a good idea but shots with a 17 mm T/S lens might need some serious preprocessing (lens abberation correction) before stitching. All other things (camera leveling, nodal point, etc.) of course must be also attended to regardless of the lens used or your panoramas will be only "sort of OK."</p>

<p>Also, depth-of-field is a function of the object magnification and f/stop used, rather than focal length, but various focal lengths provide different near-far object relations ("wide-angle effect", "telephoto compression") and therefore strongly influence our perception of a photograph.</p>

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<p>I regularly stitch panoramas using my Canon 10-22 set at 10mm and used vertically on my crop camera (60D). This is equivalent to 16mm on a full frame but I would recommend 17mm for full frame.<br>

The first most important need is to keep the camera level and rotate the camera about the mid point of the lens.<br>

The second point is overlap each shot by about 20% and use software that sort out the blending etc. I use Panorama Studio.<br>

The third point is to realise that if you create a panorama that is very wide then straight lines in the foreground will appear curved. Some people do not like this effect.</p><div>00asdV-498303684.jpg.61a012fa0209c6c9739b7c01a1060d04.jpg</div>

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<p>Michael - I don't shoot more than 2 shot panoramas and generally use lenses from 17mm to about 35mm with no change in the tripod position. In general I just use a left and right shifted image from a TS lens or bellows camera set up. In the case of the 17mm TS lens I have found it needs no correction in a two shot arrangement. In this case all you need to be careful of is that the aperture is reasonably small and that you do not go to the extreme shift as this causes slight vignetting on each image - just where you stitch them. I have not had any other real issues when stitching two shots from this lens except when I have gone to extreme shifts. I suspect that one issue with any of the extreme wide angle lenses is flare - the front elements of both the 17 TS and 8-15 zoom make them quite susceptible to flare. I find that my 16-35 II is also vulnerable to flare and has more aberrations than the TS lens. I suspect the OP may be looking for some interesting effects - while technically there are obvious issues I have seen some very good panoramas taken with fisheye lenses and this may be the effect the OP is looking for.</p>
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<p>Be aware that the image scale at the edges of a wideangle rectilinear lens is stretched. That means an object at a given distance will look "normal" in the center but it will be stretched horizontally near the edges.</p>

<p>So....</p>

<p>As long as you have a constant overlap, the stretched object at the left/right edge of the first shot will match the scale of the right/left stretched object in the seconds shot. However the whole panoramic will exhibit periodic stretching. Whether this is visually obvious or not depends on the subject</p>

<p>If you crop by different amounts, say 30% off the side of one image and only 10% of the side of the next one, you'll get a mismatch.</p>

<p>The longer the focal length of the lens you are using, the less likely you are to have distortion and mismatch problems.</p>

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<blockquote>

<p>The longer the focal length of the lens you are using, the less likely you are to have distortion and mismatch problems.</p>

</blockquote>

<p>True. I personally find panoramas done with multiple shots at longer focal lengths usually work better, but even there you have to realize that the closer you get to 360°, the more there will be differences in sky color (angle of reflection of light off the water in the air), etc.<br>

A lovely shift lens <em>will</em> make it easier, but buying one of those for panoramas seems to me like using a sledge hammer to kill a mosquito.</p><div>00ashY-498329584.jpg.af695f5566db6291d708f9cced69f1a4.jpg</div>

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<p>Thanks all for the helpful input.<br>

I have a Tokina AF 17mm f/3.5mm AT-X<br>

But because of the stretching\distortion around the edges of close up objects<br>

i have never even bothered trying to do a pano with it.<br>

Atm i am looking into getting the Canon 24mm f/2.8</p>

<p> </p>

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<p>Yes, you can digitally correct the stretching to some extent, as long as you know the FL of the lens. The effect is called . There are different types of correction some of which may do better with straight lines and others which may do better with off axis areas. You may get the relationship between areas right, but that may result in curvature of straight lines, and why you try to correct that you may introduce other distortions It's inevitable that you lose some of the image when you do the correction (assuming you want a rectangular image). The corrections also inevitably lower image quality even if you can get the distortions the way you want them because you are either throwing pixels away or you are creating pixels by interpolation.</p>

<p>I don't know how well the panoramic stitching programs do at making the best form of correction for panoramas. Probably better to shoot so that minimal correction is required (i.e. longest focal length that's convenient).</p>

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You're mistaking "correction", which is total, not "to some extent", with "projection", which controls how the final image is

presented. The correction process will also compute the focal length for you, more accurately than the number the

manufacture stamps on the lens.

 

Suggest, rather than digging yourself in deeper, you download some relatively current panorama software, such as hugin,

and see what the rest of us have been doing.

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<p>As Bob says 'rectilinear lenses have edge perspective distortion'. I used to manually try to fit panoramas together in Photoshop and not only did it take a long time it was not always very effective due to this edge distortion effect.<br>

I bought Panorama Studio a few years back and now the process is almost magic! First it asks if you want to set the parameters which include setting the horizon (no problem) then it asks if you want to correct for the lens focal length etc. I always say 'yes'. It uses the image meta data to sort out the lens and 'warp' the image accordingly. The whole process sets off and does it's work.<br>

If you are not exactly happy with the result or if the subject matter is too difficult (usually as a result of the initial camera operation) you can correct the stitching etc. Perfect!</p>

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<p>In general, the whole idea of stitching is to combine a lot of smaller images to cover a wide area, with the result potentially being very high resolution. So it is actually a lot more common to use normal or even long lenses for this work.</p>

<p>There is nothing to say that you cannot use ultra-wides, but there are reasons that most people might not want to take that approach except in unusual circumstances. You'll end up with a lower resolution image since it will be comprised of fewer separate captures. You'll deal with the typical lower resolution near the frame edges on ultra-wide lenses, and you'll also likely have to content with vignetting issues, which can be a challenge with stitching. And there are normal "distortion" issues with ultrawides that can be tricky to deal with.</p>

<p>Dan</p>

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