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Author Topic: Stitched Nikon to emulate medium/large format capture?  (Read 25003 times)
sbay
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« Reply #20 on: December 27, 2010, 04:08:57 PM »
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the quality is very good (even without stiching...), i didn't go down the MFDF route so i can't compare but i've made exhibition prints up to 2,66 meters wide using this technique and if properly treated they are really very good.

I've been using the 5dII and various t/s lenses for stitching. With a three frame stitch I get a picture that is roughly the same size as the files from the H4D-40. It seems to me that while the overall quality is good, using digital medium format is still better when the number of pixels are the similar. I think this is because with the stitch you are starting to use pixels on the far edge of the image circle and there seemed to be more degradation than with MF lenses.
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BernardLanguillier
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« Reply #21 on: December 27, 2010, 05:38:35 PM »
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I've been using the 5dII and various t/s lenses for stitching. With a three frame stitch I get a picture that is roughly the same size as the files from the H4D-40. It seems to me that while the overall quality is good, using digital medium format is still better when the number of pixels are the similar. I think this is because with the stitch you are starting to use pixels on the far edge of the image circle and there seemed to be more degradation than with MF lenses.

Indeed, this is one of the major advantage of cylindrical stitching/planar projection compared to T/S stitching. You always use the central portion of the lens and the corners of the resulting pano are just as sharp as the center.

Some very experienced Japanese landscape photographers who had never seen large panos before couldn't believe their eyes when they saw some large prints at a show I did a few months ago at the Nikon salon in Tokyo. They had a hard time dealing with the fact that corners were just as sharp as the center portion. The reproduction of the scene was so real that it had almost lost its photographic dimension to them. It did trigger some interesting discussions though. Smiley

I have tried both extensively and have basically given up on shift pano, it is slower, less scalable and offers lower image quality.

Cheers,
Bernard
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cecelia
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« Reply #22 on: January 02, 2011, 03:31:58 PM »
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Do you walk and snap?  Are there some tricks to keeping the line and the plane of focus?  Overlap?  Are you using the 100/f2 ZF?

Very cool shot of the store front.

Thanks,
Cecelia
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BernardLanguillier
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« Reply #23 on: January 07, 2011, 06:16:07 PM »
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Do you walk and snap?  Are there some tricks to keeping the line and the plane of focus?  Overlap?  Are you using the 100/f2 ZF?

Those were shot from a single location, indeed with the 100 f2 ZF.

Cheers,
Bernard
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rschlierbeck
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« Reply #24 on: January 10, 2011, 08:28:26 PM »
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Elliot,

I'm sorry I found this thread late. I have been shooting this way for several years. I shot 4x5 for about 30 years. Stitching started out as a curiosity and now all my work is stitched mosaics. I could write about it here but my thoughts have already been captured in the pages in the links below.

All the best.

Scott

http://www.scotthendershot.com/ThoughtsOnADigitalWorkflow.html
http://www.scotthendershot.com/Example01.aspx
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MalcolmL
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« Reply #25 on: January 19, 2011, 11:59:17 AM »
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Hello !

I have finally joined Luminous Landscape as I think this site best represents my photographic heartland.

I have just posted the following tutorial on stitching on my FLICKR site.
I have about 2 years experience in developing this technique so what is said below is my from my own personal experience. In terms of software I may not have tried all stitching suites but the Arcsoft package I use seems to work very well. Needless to say once you have made your final mosaic then post process as normal. With in camera dynamic range modulation and PP HDR suites such as HDR Expose, high dynamic range is not an issue.
Just so that there is no misunderstanding I am regularly attaining resolutions of 10,000 x 6,000 pixel size mosaics with the minimum of fuss and processing time.
Hope this helps and of course I welcome feedback::


STITCHING DIGITAL IMAGES. A TUTORIAL

Stitched mosaic composite images have a very high resolution attained by stitching multiple photographs together. Most photgraphers avoid stitching as a way to increase image resolution because it is thought of as too hard, just for panoramas, time consuming or "cheating''. The key is to see stiching - or more accurately digital mosaic, as a cool way of producing super resolution digital photographs.
It seems ludicrous to pay for large format film (equipment, film processing and drum scanning) when near large format quality images can be easily and readily produced by stitching small numbers of full frame digital images together.
The technology of stitching has been explored historically by the likes of Max Lyons (no relation to me) and Roger N. Clark - and the internet references are easy to Google.

However here I take the process a little further - not in terms of resolution but in terms of a practical tool.

Firstly - you can stitch any images from any camera provided the pixel dimesions are the same. The larger the sensor the greater the end resolution.
In my experience the greater the number of images stitched the greater the chances of stitching errors (seams, overlaps and ghosting) and the greater the time involved.

SHOOTING
Use a SMALL number of images.

Holding level is important. If you require perfect stitches then you must use a tripod with a leveling head. An expensive panoramic head is not really required. I have a dual head system for this work. It consists of a Manfrotto 438 ball level head with a Manfrotto 293 long lens support with a quick release plate bolted to just below the lens end (on the long lens support), rather than the camera centre. This is a poor man's version of a panoramic head, which are very costly. It works really well.

So you now have the camera on a level footing - so when the camera rotates in a horizontal arc it does not diverge from the horizontal - good !!

Oh and use a 50mm SHARP lens. Too wide angle a lens and linear distortion will screw up your mosaic, and there is no point using a soft lens when resolution is your main concern !

How many images will you need ? - 3 full frame taken in PORTRAIT orientation is all you need to give super resolution (assuming you are a full frame user). Even with APS-C sized sensors you will achieve very great resolution.

Do a test shot to meter your scene- stopped down for depth of focus. FIX the shutter speed. FIX the white balance, set the dynamic range adjsutment as required and keep it FIXED.
Shoot 3 images in a horizontal line overlapping by 15 to 20 %. That you can estimate by eye.
Thats all at the shooting stage.

POST PROCESSING
I have tried many stitching programmes. Most are heavily flawed. The only one that I recommend is Arcsoft Panrorama Maker Pro version 4. It is easy to use, intuitive, fast and yields consistently good results. It can rotate your images and compensate for exposure and some linear variations. However if you have followed the guidelines above it will not even have to do that. The better aligned your images in camera, the more sensor area you will end up with and the less chance of stiching seams.
Hey presto you will have a PERFECT high resolution image with an aspect ratio of approx 5:3.

I consistently get images now of approx 10,000 x 6000 pixels.
As a rule of thumb the 3 in a row horizontal stitch (portrait orientation) gives 2.6 to 2.75 times the area of your camera sensor.

If you believe (as I do) that a good digital sensor has 4.8 times the resolution of fine grain film (per unit area) then this is then giving about 85% of the resolution of 5"x 4" large format film.

((It is widely believed now that a full frame digital sensor will give the same or slightly better resolution than fine grained 7cm x 6cm film. This is of course an argument that applies to resolution only and not some of the other qualities that film fanatics argue make film so attractive. It could be said though that in the film vs digital debate the technical argument is over, so it now boils down only to personal preference, pre- existing camaras you may own and your skill set))

Experimenting with stitching is much cheaper than trying out large format film. Your outlay is a tripod and two heads and a suite of inexpensive software.
Malcolm Lyons
January 2011
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Steve_Townsend
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« Reply #26 on: January 20, 2011, 01:43:49 AM »
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I have tried many stitching programmes. Most are heavily flawed. The only one that I recommend is Arcsoft Panrorama Maker Pro version 4. It is easy to use, intuitive, fast and yields consistently good results.


Hi Malcolm

I use PTGui. Not sure of your thoughts on that stitcher but interested if you have tested and find it flawed. I find it great and getting better all the time.

I just had a look at the Arcsoft website to find some answers to the questions I would ask, but they were not available, so I thought I would reply here. Yes I could download and try but there is little point as I am very pleased with PTGui. But specifically though, two things that are important for me. In Arcsoft (i) can you correct for perspective, i.e. get the verticals vertical and (ii) can you template a series of images for hdr?

I do a lot of what you describe but find hdr very useful to increase my dynamic range capture when needed. Stitching images first and replicating for each exposure set (template needed) then into hdr. Trying HDR Efex by Nik at the moment which I think I might prefer over my normal Photomatix. But it keeps crashing on me! That said I think the main reason is that my laptop is underpowered for the task really, trying to merge three 20000x4500px tiffs!!!

The other thing to add is correcting for vignetting before all of the above. Really important, but perhaps more so when going to HDR.

Steve

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MalcolmL
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« Reply #27 on: January 20, 2011, 11:37:25 AM »
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Thanks Steve
I do not think I looked at PTGui, but if you have a suite that works well then I would stick to it.
In reference to your questions about Arcsoft ::
The suite will correct barrel and pincushion, will NOT correct perspective will but attempts to match in perspective errors anyway and does a good job. I have never had white balance, vignetting of exposure artefacts with Arcsoft as it auto-corrects all of these. My lenses have insignificant vignetting anyway.
If I have bad perspective distortion I will correct those before I load into the stitching software. It seems to make little difference to the final IQ in terms of the small loss of definition that this will cause along one image edge and helps to get a smoother stitch.
I bought Altostorm Rectlinear Plugin for Photoshop (works with newer PS Elements and Media Chance Photobrush) recently. This will completely correct the common horizontal (and vertical) curvature in mosaics and can be fine tuned. It is BRILLIANT.
In reference to HDR I try and use the appropriate dynamic range settings in camera then stitch those images. They are of course JPEGs.
If I need further HDR afterwards I do it to the final stitched image by creating  a -2EV and + 2 EV version of the stitch and combining in HDR Expose which is my preferred suite. I know know its not true HDR but it works very very well.
Otherwise you are into so many shots and so much post processing time you might as well be shooting film and paying for drum scans (or buying an Epson flat bed film scanner).

In terms of lenses I am now only using an old Pentax SMC 50mm 1.8  M42 lens with an adapter on a Sony A800. The combination works well in terms of IQ. A 50mm lens like this gives to much detail and so little distortion that stitching is then a dream. Because the lens is manual there is no chance of exposure of focus variations.
Cheers Malcolm
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rschlierbeck
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« Reply #28 on: January 20, 2011, 07:43:38 PM »
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I'd like to comment on a couple of things that I've found make a big difference in this process.

First is that I Shoot RAW. RAW offers some significant image quality advantages over jpeg. Not the least of which is the ability to correct for lens distortions prior to stitching. I import all my RAW files into Lightroom and use the automatic lens correction built in. It's painless. I have a preset that applies the appropriate corrections based on the lens identified in the EXIF data. The image is corrected for distortion, CA and vignetting automatically. I find that when distortion is corrected for images made with short focal lengths they stitch better. Images made with longer focal lengths stitch well corrected or not.

I always bracket. Most of the time I shoot -2, -1, 0, +1, +2 even if the histogram on the camera says I'm good. I find that Shadows render much better when they are exposed longer and I very very often blend in highlight detail that would have been lost on a normal exposure.

Next is that I use Autopano Giga from Kolor (www.autopano.net). I have not used PTGui or Arcsoft so I can't comment on how well they work or how easy they are to use but I can tell you that Autopano builds magnificent mosaics whether you are stitching 2 frames or 2000. It can also handle bracketed images seamlessly. With one click Autopano will separate all the bracketed frames into separate stacks and then allow you to output a separate file for each bracket All stitched identically. This is great for combining for HDR or layering in Photoshop. Autopano also has tools for easily correcting distortions such as convergence. It's an easy program to install and learn and I believe worth a small investment in time to try out their trial version.

For HDR processing I haven't found anything that works better than Oloneo PhotoEngine. PhotoEngine can take in 7 100megapixel images and let you process them in real time without skipping a beat. I just did an image that was 5 separate 10,600 x 16,300 pixel files and Oloneo read them in as cleanly as if they were single frames. Try those file sizes with Photomatix or Nik.

I love large format film. I worked with large format for 30 plus years and can say that the view camera experience has always been thing of joy. I won't pretend for a moment that stitching is easier or replaces large format film. But it does have some very real advantages.

I can carry one camera and use it for casual spontaneous photographs or for deliberate calculated stitched mosaics. I don't need to make two trips to the lab and spend $5 for film and processing for each press of the shutter release. When I leave the location I know that I have captured the image and I don't have to worry about film being ruined going through airport security or having someone open the film box not understanding the consequences. For any focal length you can increase the field of view by stitching additional frames without changing the perspective. I no longer need to send my negs off to be drum scanned or mess with oil mounting on my flatbed scanner. I can easily capture wide subject brightness ranges by adding additional exposures. But the most compelling reason I have found is that I am able to produce stunning prints at my favorite sizes (20 x 24 and larger.)

In many ways shooting stitched mosaics exercises the same brain functions as shooting with a view camera. You really have to pay attention to the details of what you are doing. You can't see the final image through the viewfinder so you have to use your mind to visualize what you are shooting. It becomes a slow methodical experience that I truly enjoy.

One issue with using a DLSR for stitching is that many lenses don't stop down to those extreme apertures that you have on large format lenses. Along with that there are perceived diffraction issues with using apertures smaller than say f/16 on my D300. I say perceived because you have take the entire system into account when considering diffraction. That means the print size and viewing distance. When stitching images the magnification of the final print is reduced and thereby reduces the effects of diffraction.

But depth of field is a real issue. Where I could easily stop down to f/45 or smaller on a large format lens I can only stop down to f/16 on my 85mm. That makes the plane of focus critical. I used to make assumptions about actual depth of field and just stop down to cover it. Now I use a DOF application on my iPhone and a laser distance meter to measure everything. It adds more time and complexity but even changes in the plane of focus of 6 inches can sometimes mean success or failure when f/16 is your minimum aperture. A laser distance meter is an excellent tool to add to your bag.

Below is an image that is from 125 stitched frames (5 rows x 5 columns x 5 exposures.) I found that I was not able to capture the field of view I needed using my normal 3x3 matrix because I was already against the wall behind me. Adding a couple of columns and a couple of rows solved my problem. The length of time to capture all 125 frames was 38 minutes. Seems like a long time but I always found I averaged about one image per hour with the view camera.



Sorry for the long winded post but this is a subject that is very dear to me.

All the best.

Scott
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kers
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« Reply #29 on: January 21, 2011, 07:40:58 AM »
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i use a D3X with the 24 45 and 85 PCE lenses, using the shift makes stiching quite easy...
http://adriantyler.net/

I use the same material and must say the quality is very good indeed. The PCE lenses are very good even at 2.8 .
here an example of a panorama made with a shifted 45mm pce with tilt as well... I made a print of about 210 cm wide that looks gorgeous...

« Last Edit: January 21, 2011, 07:44:19 AM by kers » Logged

Pieter Kers
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« Reply #30 on: January 21, 2011, 03:10:15 PM »
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Indeed, this is one of the major advantage of cylindrical stitching/planar projection compared to T/S stitching. You always use the central portion of the lens and the corners of the resulting pano are just as sharp as the center.
Cheers,
Bernard


I don't do stitching (don't own a pano head) but there's another big difference in that cylindrical projection looks really different perspective-wise.  Everyone's (least?) favorite website outlines the difference pretty clearly here:

http://www.kenrockwell.com/tech/fisheye-hemi.htm

If there are a lot of horizontal lines this can be an issue.  Otherwise, it mitigates a lot of the perspective distortion most people find so unpleasant and so you can go much wider than you would otherwise.  Honestly, panoramic stitching offers a pretty insane number of benefits over other methods.  But it's so different ontologically from shooting large format or any single image format that it's not so much emulating it as doing something entirely different (and arguably much better).

((It is widely believed now that a full frame digital sensor will give the same or slightly better resolution than fine grained 7cm x 6cm film.

Believed by whom?  While I agree that the 5DII looks subjectively better than 6x7 film, it's because it has less grain and more micro-contrast, not equal resolution.  Fwiw, 4x5 has equal resolution to high-end 6x7 (more-or-less) but it has less grain and more micro-contrast.  I'm not sure the 5DII has 4x5 beat yet, but it's close.  The huge prints I've seen from film look better from a short distance away, on par with FF digital from a normal viewing distance.  But then I'd argue the difference is in approach to how you shoot more than image quality.
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Dennis Carbo
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« Reply #31 on: January 21, 2011, 03:20:07 PM »
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5DII is maybe close to MF Film - Not even close to 4 X 5 drum scanned chrome done correctly ...the key is DONE CORRECTLY....many many ways to mess up 4 x 5 tranny
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MalcolmL
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« Reply #32 on: January 21, 2011, 11:00:10 PM »
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Having read the comments about stitching suites here I decided to try a trial version of PTGui. The comments on this site are now bourne out - this is a superior suite than the Arcsoft - is capable in so many more ways - dealing with large files where Arcsoft crashes, offering superior perspective and seam control, easily dealing with larger numbers of tiles than Arcsoft is able to handle. It can also do in house exposure bracketing and HDR with the pro version.
Oh well - thats NZD 270 to find. Good jiob its my birthday soon !
Malcolm
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Policar
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« Reply #33 on: January 22, 2011, 12:21:47 AM »
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5DII is maybe close to MF Film - Not even close to 4 X 5 drum scanned chrome done correctly ...the key is DONE CORRECTLY....many many ways to mess up 4 x 5 tranny

I agree, but only up close.  From a distance, the 5DII can look as "sharp" as anything but 8x10, then it falls apart on close inspection.  Whereas 6x7 has much more resolution than the 5DII (rarely in practice because you need perfect technique, a cable release, and slow film) but it's grainy and with poorer micro-contrast.  Only the rare 4x5 negative has much more resolution than 6x7 (lenses and film flatness work against you), but the tonality is much better.  Looks more digital to me, actually.

While I agree 6x7 is easily replaced by full frame digital, the two are still quite different looking and have distinct technical merits.

Is there any way to stitch hand held and make it work, btw?  If I could do that I would be very happy.
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rschlierbeck
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« Reply #34 on: January 22, 2011, 07:48:25 AM »
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Is there any way to stitch hand held and make it work, btw?  If I could do that I would be very happy.

Depending on the amount of light you have and the subject matter you will have various degrees of success stitching hand held. Parallax is the problem. Even small movements will change the relationship of objects in the foreground to objects in the background. If the subject is in a single plane then stitching hand held is pretty easy. Otherwise it requires really good technique and the more your subject is in a single plane the better. It's the foreground to background relationships that mess things up.

I have rotated the camera vertically and been successful stitching 4 frames in a single row when there was a fair amount of image in the foreground but I had to brace myself against a wall and place my index finger under the barrel of the lens and use that as my point of rotation. Some people use a string as guide with one end under their foot and stretch it tight. I haven't tried it but I don't see it being effective for me.

I think it's always worth a try if you don't have a panohead with you. Do everything you can to rotate around the No Parallax Point of the lens. If you can avoid foreground objects then you will have an easier time stitching. Keep in mind that simple and effective panoheads are very easy to build. And if you purpose one for a specific camera and lens they can be really fast to use. I'm currently building a "travel" panohead out of a bamboo cutting board so I don't have to trust my heavy expensive one to the airlines.

Scott
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« Reply #35 on: January 22, 2011, 11:25:07 AM »
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Having read the comments about stitching suites here I decided to try a trial version of PTGui. The comments on this site are now bourne out - this is a superior suite than the Arcsoft - is capable in so many more ways - dealing with large files where Arcsoft crashes, offering superior perspective and seam control, easily dealing with larger numbers of tiles than Arcsoft is able to handle. It can also do in house exposure bracketing and HDR with the pro version.
Oh well - thats NZD 270 to find. Good jiob its my birthday soon !
Malcolm

why spend that much when you can buy APP as noted above. even the standard program gives many features, again as noted above and  iam sure does not cost that much. with out checking it was 90 euros last time around
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Policar
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« Reply #36 on: January 22, 2011, 02:59:13 PM »
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I have rotated the camera vertically and been successful stitching 4 frames in a single row when there was a fair amount of image in the foreground but I had to brace myself against a wall and place my index finger under the barrel of the lens and use that as my point of rotation.

Interesting...is the parallax point usually where the lens meets the body (or half way between sensor and front element or something)?

I don't have any plans to use this technique, but I've been trying to carry my t2i with me everywhere and sometimes I see something that deserves a little more resolution.
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BernardLanguillier
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« Reply #37 on: January 22, 2011, 04:46:41 PM »
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I don't do stitching (don't own a pano head) but there's another big difference in that cylindrical projection looks really different perspective-wise.  Everyone's (least?) favorite website outlines the difference pretty clearly here:

http://www.kenrockwell.com/tech/fisheye-hemi.htm

If there are a lot of horizontal lines this can be an issue.  Otherwise, it mitigates a lot of the perspective distortion most people find so unpleasant and so you can go much wider than you would otherwise.  Honestly, panoramic stitching offers a pretty insane number of benefits over other methods.  But it's so different ontologically from shooting large format or any single image format that it's not so much emulating it as doing something entirely different (and arguably much better).

Are you aware the pano softwares like autopano pro and PTgui offer planar projection which is geometrically impossible to distinguish from a single capture? That is what most of us doing pano have been using for years.

Regards,
Bernard
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« Reply #38 on: January 22, 2011, 04:51:14 PM »
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Didn't know that.  Doesn't it stress the image a bit, so much restructuring?  I actually prefer the look of cylindrical projection most of the time.
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« Reply #39 on: January 22, 2011, 05:25:03 PM »
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Didn't know that.  Doesn't it stress the image a bit, so much restructuring?  I actually prefer the look of cylindrical projection most of the time.

Well, you can of course choose either depending on your needs.

There are of course limits to the field of view that can be handled by planar projection, which are the same limitations impacting wide angle lenses. The good news is that you are "stretching" pixels less and less the closer you get to the edge of the field, since you are using more original frame pictures to represent those near the edge of your resulting image.

The net outcome is perfect corner to corner very wide shots that are way superior to what can be achieved with a single wide lens or a T/S lens.

Anyway, try it for yourself and you will see.  Smiley

Cheers,
Bernard
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