Monthly Archives: August 2006

Getting rid of zenith and nadir ‘holes’

QTVR

The coup de grace of 360 x 180 QTVR panoramas.

Photograph a 360 x 180 panorama with just about any lens, even a fisheye, and you will be left with nasty empty ‘holes’ at the top and bottom, visible when the viewer of the resulting QTVR ‘movie’ scrolls up and down with the mouse to the zenith and nadir. That’s because the lens, even a full frame fisheye, cannot cover enough vertical angle to get everything in, dictating that two more pictures of the zenith and nadir areas be made, with the camera pointed vertically up and down, respectively.

I can think of no fewer than five ways to get rid of the ‘holes’:

1- Avoid the issue by restricting the vertical scroll angle in CubicConverter:

With the Canon 15mm fisheye on the full frame 5D, the vertical angle of view is approximately 136 degrees, meaning that each hole will subtend a 22 degree angle (180 – 136)/2). So if you restrict the Tilt in CubicConverter to +/- 68 degrees (90-22=68) the viewer will be restricted as to Tilt angle and will not be allowed to see the holes, as here:

This is a quick and effective solution where sky or ground details add little to the panorama, as in this 180 x 180 QTVR of a deserted motel:

Click here

I have also restricted the pan settings to 180 degrees as that’s the area in which the most interesting portion of the subject lies.

2 – Use the clone stamp in Photoshop on the top and bottom faces:

If the top and bottom holes are largely devoid of details – say bland sky or grass areas, you can drag and drop the top and bottom cube faces from CubicConverter into Photoshop and simply use the clone stamp to get rid of the black areas, as has been done in this candid panorama:

Click here

3 – Use PTMac to stitch in the zenith and nadir images:

Sometimes this works, sometimes not. I like to select control points to match image overlap manually using PTMac, but on occasion letting the program do this for all eight images works – manual addition of control points for zenith and nadir images is mind bending and very slow, as each image pair requires at least three points, making for 36 in all with a six picture circle. As often as not PTMac goes crazy generating lousy control points for all eight images. In this case I got away with it – I restricted the base tilt in CubicConverter as the image of the wooden bridge is not interesting and detracts from the whole:

Click here

4 – Use Photoshop layers and the transform tool to insert the zenith and nadir images:

If you dislike using layers in Photoshop as much as I do, well, this method is not for you. However, it’s worth the effort, providing the easiest, fastest and best stitch. In addition to Photoshop and CubicConverter, you will also need ‘de-fishing’ software like ImageAlign to get rid of fisheye distortion in the original zenith and nadir images.

I sort of learned this technique from Eric Rougier who shows it in his excellent video here. The issue with that video is that everything is so smooth and fast it’s very hard to follow all the steps as Eric (a great panographer, by the way) does his Photoshop magic at a blinding pace. If you read what follows you will learn exactly how to do this – a process that took me a while to crack, not without a bit of help from a friend who has forgotten more about layers than I ever want to learn!

a) Drop the TIFF file created by PTMac into Cubic Converter thus:

b) Generate the QTVR file and select the zenith (top) cube face as here:

c) Drag and drop the zenith face into Photoshop:

d) Drag and drop the true zenith image you made by pointing the camera up to the sky into Photoshop and de-fish it with ImageAlign – it looks like this after de-fishing:

e) Using the Crop Tool, cut out a central rectangle from this image like so:

f) Switch to the Move tool in Photoshop and drag this cropped image onto the original zenith image – the one with the hole in the middle:

g) Click on the superimposed zenith image – the one without the hole – and hit Apple-T. This enables the Transform tool and allows rotation of the zenith cut-out over the base image with the hole:

h) Place the mouse pointer outside the corner of the superimposed zenith image and it will become two arrows on the ends of a quarter circle. Rotate the image by moving the mouse until something aligns. In this example I have roughly aligned the tree trunks at the lower left:

i) Actuate the Edit->Tranform->Distort tool as shown here. Better still, use Edit->Transform->Warp which gives you finer control. This allows you to drag the corners (+sides if you use ‘Warp’) of the superimposed zenith image to your heart’s content until everything lines up nicely:

k) After a few minutes of clicking and dragging you will be close, like this:

l) Once things are properly aligned, adjust the opacity of the top image using the slider as here:

j) Shift-click both layers to make them mergeable:

k) Now merge the layers like this:

Save the file to the desktop.

l) Go back into CubicConverter, make sure the top cube face is selected, and import the file you just saved to the desktop:

You are done with the zenith image. A like approach can be adopted for the nadir image; in this case, the nadir is a tangle of undergrowth so to speed matters I simply used the clone tool to patch up the hole in the nadir image. Simply drag and drop the nadir image from CubicConverter into Photoshop, do the Clone work, save the file to the desktop and reimport it into CubicConverter to replace the existing nadir image. Now in CubicConverter regenerate the QTVR picture with the new zenith and nadir faces and you are done.

Here is the resulting 180 x 360 panorama:

Click here

You will note that the stitching at the top is not perfect as I jogged the camera resulting in some image blurring – the ‘2 stops under’ image (I am using three HDR pictures for each of the eight constituent images in the panorama) called for a slow shutter speed in the dark confines of the forest. Since then I have been hosed down $45 by Canon for one of their electrical cable releases so this should not recur. (You can buy cheaper afermarket clones on eBay if you want to run the usual eBay risk of fraud and theft). Oh! for the days of old fashioned $5 mechanical Bowden cable releases. I suggest you use a cable release wherever slow shutter speeds are involved as a heavy camera on a KingPano head and a tripod is not the acme of stability.

5 – Tilt the camera up 30 degrees when taking the ‘circle’ panorama images:

This approach will get rid of the zenith hole but will increase the size of the nadir hole, so it may have limited use.

One last thought on taking the nadir shot. This is best done freehand with the camera removed from the tripod. The layer technique illustrated above will fix any alignment problems and you will avoid getting the panorama head and tripod in the picture.

* * * * *

Phew! That’s it. Time to put all this into practice. I hope the above provides some useful options for those photographers seeking to excise those nasty zenith and nadir holes.

[tags]QTVR photography[/tags]

Quality VR photography

QTVR

Some fine examples of Virtual Reality photography.

As an enthusiastic, albeit novice, panographer – got to watch for typos with that one – here are some example of fine Virtual Reality pictures.

Magnificent European churches are a treat to look at with this technology. If I was marketing religion I would certainly be pushing work like this shot of St. Peter’s Basilica or of Sacre Coeur.

There’s an amazing shot by Gilles Vidal of a rugby scrum (how did he do that?) and some, like this ski scene come with a sound track!

That great panographer Eric Rougier contributes something out of the ordinary in this cartoonish scene while Andre Ilyin makes a fine night time picture of Moscow’s Red Square. Back home you can welcome the New Year in with 10,000 sloppy, sentimental drunks.

These and dozens of great VR panoramas are on the Panoramas DK site which I recommend you take a look at.

[tags]QTVR photography[/tags]

Candid Virtual Reality

QTVR

A bit of fun.

When you are fiddling about with that panorama head and tripod it seems you become invisible. I was maybe a couple of feet away from the fat woman with the green blouse in this case. I told her what I was doing after I completed the eight shot routine and her reaction was “You mean we were in the picture?”. Then she returned to her super-sized hamburger.

Click here

The ghostly arm near her results from a child coming/going in between overlapping pictures. I could have taken it out in Photoshop but left it in to illustrate one of the problems with candid QTVR photography and moving subjects.

Payola and conflicts of interest

Photography

Pulling punches in the photography ‘review’ world

When I was a lad I enjoyed reading car magazines if for no other reason that I dreamed of actually owning one. So it never hurt to read about Stuttgart’s or Modena’s latest. What beauty! What performance!

Then reality, cynicism if you prefer, set in. Many years ago the Wall Street Journal ran a page one article about the shameful conflicts of interest in the car magazine world. As they simply explained it, the quid pro quo for a good ‘review’ of the latest car was a free one year loan of the vehicle to the crook passing as a reviewer. (A rule that did not apply to Ferraris because the factory could not spare a car, having sold next year’s production already). This cannot be, I reasoned, so I wrote to Road & Track, to which I had a subscription, asking for a copy of their Conflicts of Interest policy. Well, guess what I received by return mail? A refund check for the balance of my subscription and not so much as a world of explanation. I suppose they guessed that when they admitted they had no such policy that a refund would be due anyway.

Except for one or two quirky specialist magazines which take no advertising, I have not subscribed to a car magazine since depositing that R&T check in 1983. I now read this garbage, well I don’t read it, I look at the pictures, at the local barber’s once a month. Much the same approach I adopted with regard to Playboy back in the days when the barber could actually display such a thing in his store without risking a five year to life sentence. When I read a car magazine, I want the bad as well as the good. When I read a girlie magazine I sure as hell do not need an interview with Jimmy Carrter.

What prompts this tirade is the lack of disclosures of conflicts among the broad population of camera equipment ‘reviewers’ whether in magazine or web formats. The bottom line is that unless I see a clear statement that the writer gets no remuneration – cash or in kind – from the manufacturer or his agents, then I’m not going to believe a word of what I read. What I am reading, I realize, is nothing more than a paid version of the press release. Whether paid directly, through advertising, tickets to the Superbowl or by equipment loan, it’s paid. Write something bad, Mr. Reviewer, and we will pull the advertising from your magazine or web site. And you can forget next year’s all expenses paid trip to Wimbledon.

Indeed, what I would really like to see is a statement that all equipment reviewed was paid for by the reviewer, but given the price of some of the better gear out there today, I realize that’s impossible. So it’s a really tough situation. Were I a manufacturer I would not lend you my gear unless I knew you would write well about it. And you cannot afford it if you want to tell the truth.

That leaves the web with its feedback from users on some of the better equipment sites. Now it can rightly be argued that feedback fora are like hospitals. The only visitors are ill and in need of repairs. So that would tend to make the comments overwhelmingly negative. On the other hand, cheats posing as independent reviewers could also be posting laudatory comments where none are warranted. So it’s tough to come up with a system with a guaranteed standard of integrity. That’s why magazines like Consumer Reports, where all tests are of equipment they bought with subscribers’ money, are so valuable. The car guys will tell you that these people really don’t know how to drive, to which I reply “Well, then, Mr. Car Guy, what are you doing writing/flacking when you could be driving at Indianapolis?”. The Consumer Report model seems pretty valid to me.

What prompts this column is that I finally received my last copy of a monthly photography magazine after disregarding the fifteen or so renewal reminders. Boy, those advertising dollars must really be something. After all, does not magazine advertising cost vary directly in proportion to paid circulation? I had decided to drop my subscription after some twenty years realizing that I could get press releases every bit as easily on the web, free at that, and knowing that pearls of honest insight were not to be found in its pages. My eye chanced on the mention of an exotic new DSLR lens on the cover so before turning cynically to the review, I made a mental list of what I could expect from the writer, a flack of quite exceptional …. flackery. Here’s what I guesed:

1 – The photographs illustrating the article would be truly horrible.
2 – None would be taken at the lens’s very large full aperture, the only reason to buy this lens unless you have a Napoleon complex.
3 – The writer would gush about the ‘….superior quality of the manufacturer’s glass’.
4 – The lens would be tested on a small sensor camera, so the reader would get no idea of its covering power on full frame camera.

Well, guess what? I was four for four, though I was being kind on #1. The photographs were not horrible. They were nothing short of execrable.

But even this super-flack managed to surprise. It’s so nice to drop a subscription with that warm feeling of confirmation. Among the things he points out in his press-release-passing-for-a-review is that:

1 – The lens elements are coated to cut reflection. Fancy that. Just like every camera lens made since about 1942.
2 – It pays to keep a filter on the lens to protect the front element. Aw, go on.
3 – Oh! and there was almost a critical note thrown in, to salve this sap’s twinge of guilt that even he must feel when he deposits his check. The lens is heavy. Imagine that. A monster aperture medium telephoto that is heavy. Shame, really.

Now in case you think there’s rancor born from rejection in the above, forget it. I have never submitted work for publication to this magazine, having long ago concluded there are simply some things that are beyond redemption.

Googling (now officially a verb!) on ‘Camera Review Ethics’ your first hit will be to a site named Digitalcamerainfo.com, with its clearly set forth ethics policy here. Pretty straight if you ask me.

Another with a clearly stated ethics policy and a larger review database is DP Review. It has user feedback discussions, too.

Both sites seem worth a visit if you are looking for objective opinions about gear – a whole lot more than that magazine.

Lens aficionados – mostly Canon and Nikon – can do far worse than to check the reviews at Fred Miranda. All are written by users so get enough of these and it becomes statistically meaningful. Check the Canon section and you will learn that the very costly 14mm ‘L’ is only so-so optically whereas the Fisheye is a knockout. I know as I contributed one of the reviews of the latter and can testify to the veracity of opinions on the former!

[tags]Press fraud[/tags]

Arno Rafael Minkkinen

Photographers

A site with over thirty years of self portraiture.

I wrote about photographers’ propensity for self-portraiture a while back.

Check out the work of Arno Rafael Minkkinen who seems to have made a career of the genre. That is not meant in any sense to be derogatory as his photography is simply outstandingly original.

The site design is sheer agony to get through, with big pictures constantly reverting to small originals, but it’s worth the effort.

To wet your appetite, here is an extract from the site’s brief Preface:

I consider myself to be a documentary photographer. If you see my arms coming up from under the snow, I am under the snow.

I treat the medium the same way a street shooter does. What happens in front of my camera happens in reality. There are no double exposures, no digital manipulations.

But I also look at the world through the mind. “What happens inside your mind can happen inside a camera.” It is the line I wrote as a copywriter for a camera campaign before becoming a photographer.