PT Gui stopped recognizing my bracketed exposures

[Rachel]

Hello,

I shot photos for Street View spheres using Aperture priority mode. I read in your article (http://www.ptgui.com/support.html#6_3) that we can't use any automatic exposure shots for the HDR, however, as needed for the HDR panos, only the shutter speed changed. The ISO was the same and the aperture was at f/8. 

The first set of 12 photos (four angles, 3 shots per angle) shot in aperture priority mode, worked fine two days ago. Today with the new set, shot exactly the same way, it says I have 12 different exposures.

I'm not sure why it recognized the bracketing the first time and not the second time. I triple checked the files, and there are no errors. All have a set aperture, set ISO, and varying shutter speed. Bracketing at +/- 2.

Thank you!

Rachel

[John Houghton]

Rachel, You need to check the exposure settings on the Image Parameters tab after loading in the images.  You need to see exactly the same repeating pattern for all four bracketed sets for HDR sets to be recognised.  As an alternative, merge the images for each set separately and then stitch the resulting images normally.

John

[Erik Krause]

Am 31.01.2016 um 03:10 schrieb Rachel:
> The first set of 12 photos (four angles, 3 shots per angle) shot in
> aperture priority mode, worked fine two days ago. Today with the new set,
> shot exactly the same way, it says I have 12 different exposures.

Could well be you had the same shutter speed by chance in the first set.
However, don't use aperture priority, use full manual instead, also for
white balance. See http://www.ptgui.com/support.html#6_6

Meanwhile you can try to fake the exposure settings on Image Parameters
tab. Enter a repeating pattern for shutter speed. Simply 1 for images 1,
4, 7 etc, 2 for images 2, 5, 8 etc and 3 for images 3, 6, 9 etc. would
do. You can change several values at once by Ctrl-Click, then enter the
value. At last you click "Link HDR..." (bottom left). However, this will
give you less than perfect results.

--
Erik Krause
http://www.erik-krause.de

[Rachel Dawn Lincoln]

Hello,

Thank you for the reply.

1.Google trusted program says to use aperture priority mode. Why would they recommend that AND your software it their techniques aren't compatible?

2. The thing is, the places I'm shooting have massively different lighting as you turn the camera, which is why the shutter speeds vary so much. For example, the shooting in the doorway of dimly lit restaurant. The outdoors at noon will be extremely bright, but the inside photos (as I'm turning the camera) will all be underexposed if I use the same shutter speeds as for outside, especially at f/8. This is how I understand your instructions.

Are you saying that it's ok to have some photos that aren't anywhere near properly exposed? How do I get bright parts of the photo then for the final hdr pano?

Thank you!

Rachel

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[Erik Krause]

Am 31.01.2016 um 17:45 schrieb Rachel Dawn Lincoln:

> 1.Google trusted program says to use aperture priority mode. Why would they
> recommend that AND your software it their techniques aren't compatible?

I don't know how they come to recommend this. It's plainly wrong. I can
only guess that they don't trust their photographers to learn how to
expose correctly in full manual and think better they bring a bad
panorama than none at all.

> 2. The thing is, the places I'm shooting have massively different lighting
> as you turn the camera, which is why the shutter speeds vary so much. For
> example, the shooting in the doorway of dimly lit restaurant. The outdoors
> at noon will be extremely bright, but the inside photos (as I'm turning the
> camera) will all be underexposed if I use the same shutter speeds as for
> outside, especially at f/8. This is how I understand your instructions.

Correct. It is even possible that you have the brightest and darkest
parts in one image. The darkest corner of a room is usually the one near
the window. Here's where HDR comes into play.

> Are you saying that it's ok to have some photos that aren't anywhere near
> properly exposed?

That's quite normal for HDR panos. The beauty of HDR is, you capture all
there is, bright and dark. No need to have all images properly exposed.

> How do I get bright parts of the photo then for the final
> hdr pano?

You shoot -2, 0 +2 EV. You chose your -2 EV exposure such, that the
brightest parts of your panorama are not completely blown and the +2 EV
exposure such that the darkest parts are not totally black.

Think of it like this: For HDR you take three images at different
exposures, but the exposure throughout one image must be the same as is
for a single shot. The only difference for panoramas is: You don't take
one image at a given exposure with one shot. You have several shots.

All images shot at -2 EV must give a seamless panorama, same for all
images at 0 EV and +2 EV. Only if you get three perfect panoramas you
can merge them to a perfect HDR panorama. Anything else is botch.

More read: https://www.ptgui.com/hdrtutorial.html

[Rachel Dawn Lincoln]

Hi Ian,

How do I get the repeating sequences for shutter speed? I know how to use manual mode, I'm just not understanding your instructions and requirements for the photos.

If each set of 3 photos has to be taken with the same three shutter speeds so that ptgui recognizes the repeating sequence, if I shoot half of the image outside of the restaurant and its broad daylight, then rotate my camera and use the same shutter speed sequence for the inside portion of the pano, the shutter speeds that were appropriate for outside might be all way too fast for the dark inside. I will then have three inside shots that are bracketed but all of them completely black and out or extremely dark. Is that okay?

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[Erik Krause]

Am 31.01.2016 um 19:21 schrieb Rachel Dawn Lincoln:
> If each set of 3 photos has to be taken with the same three shutter speeds
> so that ptgui recognizes the repeating sequence, if I shoot half of the
> image outside of the restaurant and its broad daylight, then rotate my
> camera and use the same shutter speed sequence for the inside portion of
> the pano, the shutter speeds that were appropriate for outside might be all
> way too fast for the dark inside. I will then have three inside shots that
> are bracketed but all of them completely black and out or extremely dark.

As said before: There is a chance you have this problem in a single
frame. What then?

If the inside is really that much darker than the outside that even the
+2 EV image will be too dark you would need to do more brackets (f.e. -4
-2 0 +2 +4). But given your camera captures 10 to 12 EV in one shot (raw
of course), you cover 14 to 16 EV with -2 0 +2. This is enough in most
cases. If you really need more see:
http://wiki.panotools.org/Extended_bracketing_control

[Rachel Dawn Lincoln]

Thank you so much for your responses.

If I do more brackets, doesn't that come back to the same issue of the shutter speed being different from the repeating sequence needed for the program to recognize the series?

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[Erik Krause]

Am 31.01.2016 um 21:25 schrieb Rachel Dawn Lincoln:
> If I do more brackets, doesn't that come back to the same issue of the
> shutter speed being different from the repeating sequence needed for the
> program to recognize the series?

No, of course not. PTGui is not limited to 3 exposures per series. Any
number will do, but any set has to have the same values.

[Rachel Dawn Lincoln]

Hi Eric,

I guess you meant to do more brackets for every photo, not just the ones that need it, correct?

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[Rachel Dawn Lincoln]

...more brackets for every *angle, not every photo. Sorry for the typo!

[Erik Krause]

Am 31.01.2016 um 22:35 schrieb Rachel Dawn Lincoln:

> I guess you meant to do more brackets for every photo, not just the ones
> that need it, correct?

Yes.

Some more background: PTGui first stitches all images of a given
exposure, then merges the resulting seamless panoramas into an HDR image
which can be output as such or tonemapped / exposure fused. As for any
panorama all it's images need to have the same exposure to create a
seamless image. This is the best way to do it which gives the most
perfect results.

The second possibility is what John suggested: merge the images from one
set into an HDR image and stitch those. That can be tonemapped /
exposure fused versions or true HDR format images (.EXR, .HDR or
floating point TIFF). With some luck the brightness differences in those
images might not be that large and PTGui will be able to blend them into
a seamless panorama. However, this needs more work (an external
program), more skill and probably gives the worse quality.

I also recommend to read the complete HDR section 6 starting at
http://www.ptgui.com/support.html#6_1

[iulianaio...@gmail.com]

https://support.google.com/maps/answer/6281095?hl=en
See Step 3.

[Erik Krause]

Am 02.02.2016 um 15:15 schrieb iulianaio...@gmail.com:
> https://support.google.com/maps/answer/6281095?hl=en
> See Step 3.

That's exactly the point where google is wrong...