Questions of a beginner - PTGui and Bibble

[Attila]

Please help an inexperienced amateur photographer who - to make matters worse - is an absolute beginner in the field of panoramic photography, but crazy enough to enter this special arena.

I have decided to use PTGui for panoramic pictures. I would appreciate your initial suggestions.

Facts: I have Nikon D200 and Manfrotto 055CLB tripod. I am waiting for a Nodal Ninja 3 head, and a 50 mm f/1.8 D AF Nikkor lens. (Most probably I will start with a shorter lens and then gradually move toward longer lenses and higher resolutions.) From among the available raw converters I use Bibble Pro.

As far as I know in the case of panoramic pictures the camera should be used with fixed WB, ISO and aperture. Auto-bracketing can be used only for the exposure time to facilitate HDR, but in a consistent way for all pictures. :clap First question: How many and how big exposure steps would you suggest for bracketing? I know this depends on the particular scene. The point is whether to use, in general, a series of 3 shots with 1EV distance, or 5 shots with ½ EV, etc. (D200 allows the user to bracket up to 9 shots, but exploiting this maximum would certainly be a silly idea in terms of shooting and processing time, possible ghosting, disk space, etc.)

I intend to take the pictures in portrait mode. :clap Second question: Is it enough the have an overlay of 1/3 of the width of the pictures? Could I reduce the distortion by applying ½ or even bigger overlay, or this would drive PTGui crazy – even if we forget other drawbacks of taking a hell a lot of pictures for a moment?

I intend to pre-process the bracketed series of pictures with Bibble, then to convert them into 16-bit TIFF as input for PTGui. :clap Third question: What kind of corrections would you suggest in this phase in order to exploit the features of both Bibble and PTGui to the utmost? I have in mind to correct only the following parameters, if necessary: sharpness, noise reduction, lens correction (barrel and pincushion), and perhaps WB. I am afraid that fiddling too much around ‘perfect’ settings in Bibble may lead to harder application of HDR and stitching in PTGui (which has its own brightness, saturation, and contrast control sliders, anyway, but I may prefer to set these in Bibble during post-processing the panorama pictures).

:clap Forth question: Is there a way to keep HDR properly managed in PTGui beyond the contrast control? I would like to produce more or less ‘natural looking’ panorama pictures, without too dark/blue skies and too much lightened objects.

I intend to post-process the resulting TIFF picture in Bibble, and then convert it into JPEG just before printing.

If you deem any other points to be important enough to consider, please give additional comments.

Thanks in advance for your kind assistance.

Attila

[Tanuki]

I know you're excited, but easy on the big font. It's hard to read, and just as bad as typing in all caps.

HDR panoramic photography is a pretty specialized field. Unless there happens to be someone at Dgrin doing HDR panoramas, You'll probably get the best advice from PTGui at the PTGui HDR page (http://www.ptgui.com/hdrtutorial.html). Since PTGui is just a front end for Panotools, you might look to other Panotools front end software for advice, e.g., at Max Lyons PTAssembler Forums (http://www.tawbaware.com/forum2/) or Hugin HDR Worlkflow (http://wiki.panotools.org/HDR_workflow_with_hugin) page.

I hope this helps get you started. Good luck!

Mike

P.S. For your second question, I find that it is best to get just enough overlap to avoid stiching at the outer edges of the emage (where the most lens distortion is present), but not so much that you have too many seams. It's a balancing act, and for my lens (Sigma 10-20mm at 10mm setting on a Nikon D80) I find that 1/3 is sufficient overlap, but 1/2 makes too many seams. Your mileage may vary.

[Attila]

Hi Mike,

Thanks for your suggestions. I will visit the proposed websites. Also thanks for sharing your experiences with me.

Attila

[dbd]

PTGui is my usual stitcher, but it can take a while to learn all the capabilities.

It might be a good idea to start by practicing with pans at one exposure and HDRs at one position to learn one thing at a time instead of both at once. That might make it easier for you to learn the answers to many of your questions, some of which depend on your gear.

I use PTGui without making any adjustments if possible. The one adjustment that is best made before stitching, if necessary, is vignetting correction. Unless your lenses have high distortion, it may not be necessary to make any adjustments beside what PTGui determines is needed. The widest (and cheapest) lenses are the most likely to need geometric corrections. I have found PTGui capable of aligning pictures that are far worse than I would ever want to show.

I prefer to make most other adjustments (in non-HDR) after the stitching using gradient masks that are smooth across the image

25 to 30 % overlap is usually plenty. The requirement can be less if the image has dense detail in the region of overlap to provide well resolved control points.

A good, tough test image for the geometric corrections has a detailed foreground in the lower quarter of the image, clear sky in the rest of the image, except for a phone line near the top, slanting as it crosses a stitching boundary. If the optical distortion has not been corrected in PTGui or before, there will be a gap in the line.

Using moderate to longer focal lengths to exclude foreground can let you get a lot of practice, and good images, before Nodal Ninja arives. (I use NN3 when I want foregrounds.)

Dale B. Dalrymple
mostly pans at http://dbdimages.com