Canon 10-22mm lens VTs

Hi Douglas,

I have not been using a rotator in my tests, just turning the camera on a tripod, but with some tweaking of settings in PTGui I am now getting a reasonable result.

Can you recommend a rotator? also the least number of shots possible would be my aim.

( from the research I am doing it looks like a 8mm fisheye lens may be required?)

Regards

Tim

Tim
The reason you're having trouble getting the images to line up is you're not rotating the camera/lens around the nodal point of the lens.

With the nodal point forward of the pivot point of the tripod, the overlapping part of the images have a slightly different view of the same objects. Its called parallax. Its like how your left and right eye have a slightly different view of the same object.

Of your Canon 10-22mm lens id the one I'm looking at buying it has about a 90° FOV. With the overlap you probably need a row of 8 to ten shots around horizontal, another row tilted up 30° and another tilted down 30°, .

With a Sigma 8mm you could do a good job with 4 shots around horizontal, plus a Zenith (top) and a Nadir (bottom) shot.

I just got a Nodal Ninja 3 as my first piece for a new setup to be completes with a Canon XTi and the Sigma 8mm. The NN3 is about $235 delivered.

Take a look at their website, www.NodalNinja.com to see how it works. Other manufacturers of virtual imaging rotators are www.Kaidan.com, www.360Precision.com and Manfrotto.

Douglas Aurand
Albuquerque, NM

Hi Doug -

I'm curious what you think about the Sigma 8mm - sharpness, etc. I have the 10-22mm and am thinking of buying the Sigma to reduce the overall number of shots.

Some reviews I've read haven't been too positive, but I'm thinking they are expecting way too much.

Any thoughts?

Thanks,
Matt Terry

Matt
Take a close look at the comments you're reading about the Sigma 8mm. Most of the less than flattering ones are about the older Sigma 8mm f/4 not the new Sigma 8mm f/3.5

There is a side by side photo comparison on Jook Leung's website of the rare Nikkor 8mm with the old Sigma 8mm and there is a visible difference http://360vr.com/fisheye41/fisheye.html

But in the text below the photos says the later Sigma has more even illumination.

You can look in the IVRPA Member Gallery and use the Tags for Sigma 8mm to see actual stitched results.

I don't see enoungh difference in the stitched images shot with lenses like the Nikkor 10.5mm and like you want the reduced number of shots so I'm saving up for a Sigma 8mm f/3.5 myself.

The technique I'm really interested in, is tilting the camera & lens up 10-15°, eliminating the need for a Zenith Shot, so I'll only need 4 shots around with a tripod cap

And with a little luck, the marketing department at Sigma may loan me one of their new 4.5mm fisheyes so I can include sample photos in the eBook I'm working on; Introduction to Virtual Photography . Theoretically, I could produce a full spherical image from just 3 shots if I do the same camera/lens tilt up with the new Sigma 4.5mm and use a tripod cap

Douglas Aurand
Albuquerque, NM

Doug,
for the first time I am reading this part of the forum and I do appreciate your active involvement on this topic/category. Especially coming from a VRartist an REA as yourself. Some good insights from a RE marketing point of view, I must say. Just came off Youtube watching a guy consulting REAs to cancel their VRtours! What a fraud he seems to become just to sell his consultings....

Anyway, the Sigma 8/f4 is not such a bad lens at all, as long as you know its sweet spot and hyper focal distance. It's obsolete now and only available used for some good deals. The new Sigma is improved with coatings for flare and vignetting. The old one looses a full stop to the edge, so raw format is imperative when using high fov. The sigma 8 is also very capable to shoot 3 shots a node on a crop sized sensor. You just have to roll the cam about 30 degrees to shoot on the diagonal. Agnos.com has plenty of demo files from Luca Vascon on its site to download and try if you are interested. This technique will give you more resolution than with the new Sigma 4.5 on the same sensor, unless you want the full circular image and for the sake of your ebook.

Shooting the lens pitched and increased Beta 60 (120 fov) will require a new npp calibration since you shift the optical axis up and shift the entrance pupil away from optimal npp at horizon.

VRcheers,

Milko

Milko
I don't think the f/4 version of the Sigma 8mm was a bad lens, but the general consensus is that he Nikkor 10.5mm is brighter & sharper. And as you mention and can see in the samples in the link, there is a visible brightness drop off to the edges.

Reviews in a few of the photo magazines of the Sigma f/3.5 describe it as an "almost all new lens." And that it corrected some/most of the shortcomings of its predecessor

As far as being able to get a full spherical image from just 3 photos by diagonally positioning a camera with a Sigma 8mm f/4, I beleive Agnos makes a rotator designed specifially to do that.

But my understanding is it only works with the f/4 not the newer f/3.5. So to get down to just 3 shots with a Sigam 8mm, a photographer has to give up the quality gains made with the new lens. I don't think a lot of photographers would make that sacrifice. I won't, so I'm saving up for a f/3.5 and will be doing 4 shots

You're right that 4 shots tilting up 10-15° with the f/3.5 will capture more more pixels than doing the same thing with 3 shots using the new Sigma 4.5mm. But the 4.5mm is a brighter lens (f/2.8) and there are definite advantages to fewer shots when you don't have total control of a scene. I've shot hotel lobbies and its never practical to close the lobby for my shoot. Using the legs on my tripod I can visualize where the seams will be and make sure nothing is moving across the seams.

And I'm not sure the loss of resolution by using the 4.5mm vs the 8mm is a significant factor when the goal is to display the image on a 1024x768 computer monitor over the Internet. If I did my geometry calculations right, a circle with a diameter of 2000 pixels (my Canon is 3888 x 2592) would be 3.1 megapixel circles for each of the 3 shots. That might make a difference if I was printing a wall-sized panoranic poster, but not on a typical computer screen

There's always a balancing act between fewer shots and resolution, but the larger and larger sensors are making up the difference fast. My first digital camera was $800 for .8 megapixels. The Canon I bought this summer was $800 for 10.0 megapixels

As far as re-calibrating the Nodal point, I shouldn't need to since I'll actually be "vertically rotating" up 10-15° on my Nodal Ninja, not "tilting" as I would with a standard panhead. Even if re-calibrating the Nodal point were necessary, the reduced workflow of not taking multiple exposures of the Zenith for HDR compositing and dealing with shifting sunlight from the time of the first shot to the last (in the winter, the low sun moves fast) would be worth the effort and once calibrated, just keep using the new nodal point setting.

Right now, my plan is to go with the Sigma 8mm f/3.5, but not to rule out a 4.5mm in the future.

An after I buy the Sigma 4.5mm, I want to save up for a Coastal Optics 4.88mm and be able to do 2 shot capture with a dSLR camera, like I do now with my Cooplix and the FC-E9

Take care

Douglas Aurand
Albuquerque, NM