12-24mm DX now in my lens table

Started Sep 7, 2003 | Discussions
BJN
BJN Veteran Member • Posts: 5,084
csv file has zeros in fields for points

Joseph S. Wisniewski wrote:

For all you panorama shooters, I've added the entrance pupil
measurements for the 12-24mm DX (for 7 different focal lengths) to
my lens measurement table.

http://www.swissarmyfork.com/photo_resources.html

Thanks very much for clearing up the terminology misconceptions I've absorbed from various pano sources. I downloaded your .csv file and it opens with zeros in the data fields for the points that have values in your html table.

I'm using a Really Right Stuff focusing plate to set perspective for my pano shots. I'll translate your measurements for the 12-24mm to my device.

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BJN

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OP Joseph S Wisniewski Forum Pro • Posts: 34,169
Oh Crud...

BJN wrote:

Thanks very much for clearing up the terminology misconceptions
I've absorbed from various pano sources.

You're quite welcome.

I downloaded your .csv
file and it opens with zeros in the data fields for the points that
have values in your html table.

I see what I did wrong. The fields that became zeros are the results of calculations. When I did the save as HTML, I did it from the original spreadsheet, and it automatically used the calculated results. When I pasted the page into a smaller page to save as .csv, I lost the columns that had the numers for the calculations.

I'm using a Really Right Stuff focusing plate to set perspective
for my pano shots. I'll translate your measurements for the 12-24mm
to my device.

Let me know how that goes. If you've got measurements for the RRS plate, I'll set those into the "gadget table" along with the parameters for my Bogen QTVR head.

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OP Joseph S Wisniewski Forum Pro • Posts: 34,169
Re: Coolpix??

brian wrote:

Joseph S. Wisniewski wrote:

.. . . . . the UV Wisniewskinar lens
--

There are times when I could really use a completely unfiltered
camera to get really good UV/IR sensitivity.

One of these days, a scruffy, used D1 or D100 is going to come into my hands at a low enough price for cruel and inhuman experiments, and the UV/IR and AA filters are going away.

What are you planning
to do with your UV lens,

Much like Bjorn, get an "insect's eye" view of flowers.

and are you doing your own CaF2 work?

No Fluorite in this design at all, just quartz. Pair of three element, one glass airspaced achromats. I need a source of better coated lenses.

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brian Senior Member • Posts: 1,206
Re: Coolpix??

Joe:

Improving the IR sensitivity would be easy since it just involves removing the AA filter. Unfortunately, improving the UV sensitivity is very difficult because you need to remove the Bayer filters, which are transparent to IR but not to UV.

You can't make a UV achromat with fused silica alone. In fact, SiO2 is normally used as the high dispersion "flint" element in such designs. CaF2 + SiO2 are required unless you can live with lousy wideband performance and/or a very very small maximum aperture (f/16?). Its important to have correction into the visible in order to focus accurately using the viewfinder, especially for macro subjects like flowers.

Here's a UV/Vis comparison shot I recently took using the new Coastal Optical UV-Micro-Apo lens ( http://www.coastalopt.com/stan_02.asp ):

This would have been a very difficult shot if the lens weren't corrected over the entire UV-Visible spectrum.

Brian

Joseph S. Wisniewski wrote:

brian wrote:

Joseph S. Wisniewski wrote:

.. . . . . the UV Wisniewskinar lens
--

There are times when I could really use a completely unfiltered
camera to get really good UV/IR sensitivity.

One of these days, a scruffy, used D1 or D100 is going to come into
my hands at a low enough price for cruel and inhuman experiments,
and the UV/IR and AA filters are going away.

What are you planning
to do with your UV lens,

Much like Bjorn, get an "insect's eye" view of flowers.

and are you doing your own CaF2 work?

No Fluorite in this design at all, just quartz. Pair of three
element, one glass airspaced achromats. I need a source of better
coated lenses.

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OP Joseph S Wisniewski Forum Pro • Posts: 34,169
UV, good points...

brian wrote:

Joe:
Improving the IR sensitivity would be easy since it just involves
removing the AA filter. Unfortunately, improving the UV
sensitivity is very difficult because you need to remove the Bayer
filters, which are transparent to IR but not to UV.

I wonder if I can "fade" them. Hit the sensor with a decent sized UV source (and cool it). Or strip them chemically.

You can't make a UV achromat with fused silica alone. In fact,
SiO2 is normally used as the high dispersion "flint" element in
such designs. CaF2 + SiO2 are required unless you can live with
lousy wideband performance and/or a very very small maximum
aperture (f/16?).

I was looking at a Silica/Fluorite Dogmar, as a cost effective, practical UV design. The first one I was building also had some thermal shock requirements that made the all SiO2 design very desirable.

Its important to have correction into the
visible in order to focus accurately using the viewfinder,
especially for macro subjects like flowers.

I thought of that. Was going to try putting my crossings in the UV and in the green (focusing with no filter) or in the UV and visible blue (composing and focusing with a Wratten 47).

Here's a UV/Vis comparison shot I recently took using the new
Coastal Optical UV-Micro-Apo lens (

Very sweet. Did you layer the UV image into one of the channels of the visible image, or do you have a camera that works well for UV false color?

This would
have been a very difficult shot if the lens weren't corrected over
the entire UV-Visible spectrum.

Yes, expecially if you're doing false color, or if you need accurate alignment between a visible shot and a UV shot for the channel mixer.

I envy you all those nice Coastal Optics toys you have...

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brian Senior Member • Posts: 1,206
Re: UV, good points...

Joseph S. Wisniewski wrote:

brian wrote:

Joe:
Improving the IR sensitivity would be easy since it just involves
removing the AA filter. Unfortunately, improving the UV
sensitivity is very difficult because you need to remove the Bayer
filters, which are transparent to IR but not to UV.

I wonder if I can "fade" them. Hit the sensor with a decent sized
UV source (and cool it). Or strip them chemically.

It probably makes more sense to find a Kodak 760M (monochrome). I think the AA filter is user-removable in that camera also. The Betterlight large format scanning backs are also available in monochrome versions, which would give good UV-Vis-IR sensitivity. With the large format you could also get away with using a single element SiO2 landscape lens.

You can't make a UV achromat with fused silica alone. In fact,
SiO2 is normally used as the high dispersion "flint" element in
such designs. CaF2 + SiO2 are required unless you can live with
lousy wideband performance and/or a very very small maximum
aperture (f/16?).

I was looking at a Silica/Fluorite Dogmar, as a cost effective,
practical UV design. The first one I was building also had some
thermal shock requirements that made the all SiO2 design very
desirable.

Its important to have correction into the
visible in order to focus accurately using the viewfinder,
especially for macro subjects like flowers.

I thought of that. Was going to try putting my crossings in the UV
and in the green (focusing with no filter) or in the UV and visible
blue (composing and focusing with a Wratten 47).

I'm still confused. With an all-SiO2 design you can only have a single color crossing and lots of primary color. CaF2/SiO2 can give you three crossings, which really helps in a hyperspectral design. An alternative to using CaF2/SiO2 is to use some of the special UV glasses that are transparent down to 350nm or less. Such a design would make sense when paired with ordinary photographic sensors because the camera can't see into the deep UV anyway. With these glasses you could at least get two crossings.

Here's a UV/Vis comparison shot I recently took using the new
Coastal Optical UV-Micro-Apo lens (

Very sweet. Did you layer the UV image into one of the channels of
the visible image, or do you have a camera that works well for UV
false color?

I shot both images with a D1x. UV images come out orange with this camera, with the red channel having the greatest sensitivity, the green channel having about half as much response, and the blue channel having almost no resoponse at all. A bit non-intuitive perhaps, but thats what I get. For the UV image I tweaked the levels on the green channel a bit to bring out more detail in the image. This had the side effect of making the yellow of the flower look almost the same in both the UV and visible images.

This would
have been a very difficult shot if the lens weren't corrected over
the entire UV-Visible spectrum.

Yes, expecially if you're doing false color, or if you need
accurate alignment between a visible shot and a UV shot for the
channel mixer.

I envy you all those nice Coastal Optics toys you have...

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kcb064 Junior Member • Posts: 47
nikon 17-35

Hey i have the Nikon 17-35 2.8 and have been doing pretty good with panos so far using the Bogen QTVR head and rotating to as close as i could get to what i thought was the nodal point. well looking at your chart it says the entrance pupil is at 129mm at 17mm focal length. pardon my ignorance but that is 129mm from what? maybe stitching would go a little easier if i had this truely pinpointed. thanks in advance

here is some of my stuff i have already done

http://members.cox.net/kcb064/home.htm

OP Joseph S Wisniewski Forum Pro • Posts: 34,169
Re: nikon 17-35

kcb064 wrote:

Hey i have the Nikon 17-35 2.8 and have been doing pretty good with
panos so far using the Bogen QTVR head and rotating to as close as
i could get to what i thought was the nodal point. well looking at
your chart it says the entrance pupil is at 129mm at 17mm focal
length. pardon my ignorance but that is 129mm from what?

129mm from the image plane (the sensor itself). There's a little "image plane" mark on the top of your camer that shows you the point.

I also have a table that lists several cameras, and has the distances from the image plane to the tripod screw. It's a little archaic, that column is labled "tripod-film". The only digital cameras in the table are Nikon D100, Fuji S2, and Sigma SD-9. On a D100, the tripod screw is 12mm forward of the sensor, so the entrance pupil of the 17-35 (at 17mm) would be 117mm (129-12) from the tripod screw. Unfortunatly, I have not yet measured the D1X.

Now, all I need is a table that translates this into Bogen QT-VR settings...

maybe
stitching would go a little easier if i had this truely pinpointed.
thanks in advance

here is some of my stuff i have already done

http://members.cox.net/kcb064/home.htm

Very nice. I especially enjoyed the Bellagio Water Show and the Kualoa Beach Park. It's hard to get a panorama shot near sunset to stitch well. The Luxor shots are very cool. How friendly were they to you setting up a panorama setup?

Yes, a good entrance pupil setup would make the stitching go well on several of these, notable Malaga Cove, Hermosa Beach Pier, Maunawili Deomonstraion Trail, and Huntington Beach.

Really careful leveling might have helped on Huntington Beach and Lanikai Beach, and Hermosa Beach Pier. Hermosa Beach shows both a slight curve to the horizon, and the large poles leaning to one side or another, both signs that you were slightly off level. You've really got to nail that with the 3418, just 1/2 a degree off is enough for visible problems. If possible, get up high enough so you can look straight down on the level on the 3418. Redondo Beach Pier also shows leaning lamp posts, but I have the feeling that they really are leaning, not an artifact of the stitching.

It needs a second level on the bottom. I often set up the head, set my exposure, then raise the tripod up to about 9 feet. At that point, I could level it vis the leg extensions.

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