Wednesday, May 13, 2009

Defocusing Test - 13 May 2009

A number of digiscopers have commented that they seem to get better images when the scope is slightly defocused, thus allowing the camera to find the right focal plane. A couple of Birdforum threads have addressed this issue (1), (2). Since I sometimes have issues trying to keep focus in the field, I decided to perform some experiments under controlled conditions to determine the limits of 'my' digiscoping setup in terms of focusing/defocusing. I emphasize 'my' because I suspect that results could be completely different for other scope/camera setups.

Experiment

I set my Zeiss 85T*Fl, 20-60X Zoom Eyepiece, Nikon Coolpix P5100 and homemade adaptor approximately 30 feet from a resolution chart in the back yard. The eyepiece was set to 20X.

The scope was focused on the center of the resolution chart so that the image was as sharp as possible. The P5100 was set to Aperture-priority (f/5.4) and the 3-second self-timer was set prior to each exposure. I then took exposures after rotating the fine-focusing knob counter-clockwise (CCW) on the scope at ~20 degree intervals and allowed the camera to adjust focus. In this direction the scope focuses to the rear of the chart (back focus). I then repeated the experiments while focusing clockwise (CW), which causes the scope to focus in front of the chart. Note - these directions might be reversed on the Swarovski scopes.

The P51oo was first tested using the Macro setting, and then tested using the AF setting. Series of exposures were also taken with the optical zoom set to 1X, ~1.5X, and 2X (on my system I am unable to get a sharp focus above 2X on the Coolpix due to improper camera/eyepiece distance.

I've posted the test images on my Pbase site after performing the following steps in Photoshop:
Images were first cropped, then Auto Levels was applied to each image followed by an UnSharpen mask (which I normally apply to my digiscoped images).

Note that Auto Levels generally results in a higher-contrast image, which results in a slightly sharper image, but this step did not improve out-of-focus images.

Results

The following lists the amount of defocusing required to produce an out-of-focus image:

Macro - CCW defocusing:

1X - At 20 degree steps I was able to acquire focused images in Macro setting to a rotation of 360 degrees! So even though the scope image was blurry, the camera was able to still capture sharp images of the test chart.
1.5X - 180 degrees
2X - 80 degrees

AF - CCW defocussing:

1X - 80 degrees
1.5X - 60 degrees
2X - 40 degrees

Macro - CW defocussing:

1X - 14o degrees
1.5X - 40 degrees
2X - 40 degrees

AF - CW defocussing:

1X - 60 degrees
1.5X - 40 degrees
2X - 40 degrees

Results indicate that setting the Coolpix P51oo to Macro will provide a wider latitude for getting sharp images when the scope image is out of focus. This 'forgiveness' is reduced, however, when the camera optical zoom is increased. Notice also that the camera corrects backfocusing issues better than it does front focusing. The take home message here is that you can still get sharp images if your scope is focused beyond your subject, but chances are reduced dramatically if your scope is focused in front of your target. AF setting works just fine on sharply-focused subjects, but fails quicker once the subject is out of focus in either direction.

So the next time I'm out in the field digiscoping, I'll be using Macro setting, and continue to focus the scope on my birds, but I'll also be purposely defocussing the scope (CCW) to see if I can get sharp(er) images!

Sunday, February 8, 2009

Limitations! - 08 Feb 2009

I decided to put this post together after playing a bit this morning with the digiscoping setup. The Common Redpolls, Pine Siskins and American Goldfinches were going to town on the thistle feeders outside the kitchen window, so I decided to open the window and digiscope from inside the house. I set the tripod in the kitchen sink (I moved the dirty dishes!....) and aimed the Zeiss 85T*Fl w/ 20-60X Zoom eyepiece to the feeders approximately 20 feet away. The Nikon Coolpix P5100 was set to Aperture-priority and I took my normal hand-held shots using my homemade adaptor (see previous posts).

I've found recently that my most reliable photos come from setting the zoom eyepiece to 20X and the camera at its lowest setting (7.5mm). This gives me some vignetting, but also allows me to verify that I have correct camera / eyepiece distance when the vignetting is sharp. The magnification I get w/ the P5100 at 7.5mm is approximately equal to the view I get w/ the Nikon D300 and Sigma 400mm f/5.6 (actually its slightly larger: 1.3X). With the 1.5X crop factor of the D300 the 35mm equivalent for the DSLR setup is 600mm, so the digiscoping setup at 20X / 7.5 mm is ~ 780mm.















Zooming the P5100 to 15 mm (or 2X) removes the vignetting and still gives a sharp image. Compare the image w/ the image taken at 7.5 mm and cropped to give roughly the same image magnification as the 15 mm image. Processing both images using the same workflow (Noiseware / sharpening in Photoshop) results in the cropped image appearing more sharpened with slightly more jpg-artifacts. Still, the image is acceptable even if the uncropped, 15 mm image looks nicer. Take home message here is that cropping to remove vignetting will give a very nice image for web viewing.
















I've found that image quality degrades drastically if I try to zoom the P5100 to the 3.5X setting (or 26 mm). Because the camera is not an internal zoom (its vari-focal) I believe that my adaptor prevents proper lens/eyepiece distance from being achieved (coupled w/ vibration magnification) that results in a soft image. So I've decided to not push the camera past about 2X if I want to maintain a sharp focus.

The beauty of the 15mm setting is that images can be cropped to give a magnification equivalent of 26 mm without the aforementioned vibration issues. I can be happy with these images.

As a side note: with a steady tripod, however, I will use the camera at 3.5X zoom setting in the Video Mode and get sharp videos.

Note, however, that scope-to-subject distance drastically affects image quality. For example, this Cooper's Hawk was roosting in a pine tree behind the house approximately 80 feet away. Even though image quality was good at the 7.5 mm and 15 mm settings, there is significantly more of a grainy quality to the images and an overall softer focus, especially after cropping the 15mm image.

Wednesday, November 5, 2008

Digiscoping Gallery - 5 Nov 2008

I've finally gotten around to sorting some images, and have generated a gallery of digiscoped images acquired in 2008. I'll be adding to the gallery as I go, but in the meantime, if you click on the image in the side bar you'll go to a slideshow of images in Pbase.

Enjoy!

Saturday, September 27, 2008

Noiseware vs. Noise Ninja - 27 Sep 2008

I must confess. Although I love my Nikon Coolpix P5000 and the images that it produces, the small sensor associated with P&S cameras cannot generate the silky smooth images one can get from the larger DSLR's. And, although I’ve been happy with the output from P5000, it produces an extremely noisy image (even at ISO 100) compared to the above. So I typically resort to post-processing my digiscoped images with Photoshop CS to enhance image quality. I’ve been extremely pleased with my results, but have noticed all too often that my images, when pixel-peeped, still retain an annoying amount of chroma (color) noise in the form of red and green pixel splotches in blue sky or in the dark feathers of birds. After doing a bit of research on the net I came to the conclusion that I need a more aggressive noise reduction software package than Photoshop can provide alone.
Initial searching convinced me that Noise Ninja was the package to get, so I downloaded the trial version from their website. It retains almost full functionality, but places a grid over processed images until the license is purchased. I spent a better part of a day playing with it, and was simply amazed at how well it performed at removing chroma noise from feathers and sky. I was able to produce sharp, low-noise detail in my subjects while generating smooth backgrounds with no noise. Very impressive! Suddenly, the old way of Photoshopping my images looked somewhat disappointing by comparison.
Ready to pull the string on a license I decided to search a bit more on NN to find out what other photographers liked about it. One thread polled users to vote between NN and NeatImage. I was surprised to find that most everyone seemed to be familiar with both, but now prefer a package called Noiseware Pro. Intrigued, I downloaded their trial version and decided that I should do a comparison. So, for the next couple of days I compared Adobe PS CS, Noise Ninja, and Noiseware to see which package gave me (personally) the best results. I downloaded the trial version of Neat Image, and found it to produce output very similar to Noiseware Pro. But I haven't played with it enough to figure out the correct settings to compare w/ the previous two. So my opinion of it will have to wait.

I pulled a couple of images from my Coolpix P5000 and a few from my Nikon D300 so that I could evaluate the packages on both P&S and DSLR. I performed a magnetic selection in PS to highlight the foreground, then I copied the selection to a separate layer. I then copied that layer into separate copies of the photos – one for Noise Ninja and one for Noiseware to process. This way I could selectively sharpen the same foreground and smooth out the background. I would then flatten the images to see how well foreground/background images blended.
For Photoshop workflow I used an Unsharpen Mask (Amount=50%, Radius=2.0 pixels, Threshold=0 levels) on the foreground, and a Gaussian Blur (Radius=1.0 pixel) on the background.
For Noise Ninja, I used all default settings and changed only the ‘Luminance’settings (Strength=5, Smoothness=5, Contrast=10, USM Amount=150, and USM Radius=1.0) for the foreground. The background got the following settings: 10, 10, 10, 0, 0.4.
For Noiseware I used the default settings with the following settings on the foreground:
Noise Level (Luminance=0, Color=0)
Noise Reduction (Luminance=0, Color=100%)
Detail Protection (Luminance=0, Color=0)
Detail Enhancement (Sharpening=5, Contrast=0, Edge Smoothing=Normal)
For the background I used the following: Noise Level (0,0), Noise Reduction (100,100), Detail Protection (0,0), and Detail Enhancement (0,0,Normal)
More experienced users may find fault with these settings, but I was merely trying preserve as much detail and reduce noise as possible in the images I processed. I found that Noiseware could easily produce over-contrasty images, while Noise Ninja tended to generate more high-frequency noise (tinier-grained noise). Hopefully this makes sense when you examine the images.

Rough-legged Hawk

I digiscoped this bird last May at Pt. Mouillee a week before (sadly) I found its carcass below the same tower (a very late migrant that must’ve been ill). The Original image from the Coolpix P5000 was processed using Photoshop CS, Noise Ninja, and Noiseware Pro. At 200% image size, side-by-side comparison showed pixelation and chroma noise in the Original. PS added more detail to the bird and reduced background noise, but chroma noise is evident in both bird and sky. NW removed chroma noise from the bird and sky, and improved bird sharpness just a touch. NN removed chroma noise but showed more graininess in the bird detail.



At 100% image size, NW and NN produced very nice results, with NW getting an edge in image cleanliness. At 300% image size, PS (at right) showed significantly more pixelation and chroma noise in feather detail while NW effectively removed both. When comparing NW with NN at 300% both removed chroma noise from the feathers, but NN (right) showed a bit more pixelation that could be removed with a bit more tweaking of the software package. The edge in this comparison goes to Noiseware Pro.

Indigo Bunting

This bird was digiscoped w/ the P5000 in late June. Although it’s a bit on the soft side I wanted to see how the software handled ‘greens’ and ‘blues’. Here are final versions of the Original, Photoshop, Noise Ninja and Noiseware Pro. At 100% image size side-by-side comparison produced the following: The Original (top left) is not bad, but shows a bit of chroma noise in the green background and in the bird. Noise Ninja removed chroma noise, but left an annoying edge artifact in the bird after layers were blended. Noiseware showed no artifacts and produced a nice clean image while PS shows significant chroma noise and grain in the bird. Edge to Noiseware.



















Forster’s Tern

This flight shot was taken with the Nikon D300 and Sigma 400mm f/5.6. The Original and PS versions of the image show significant chroma noise in the sky, which was effectively removed by both NN and NW. Comparing NN and NW at 100% it appears that NW shows a bit more contrast, but otherwise it’s a toss as to which is better.


Black Tern

Finally, I wanted to see how the packages handled contrasty, severely backlit images, or gray-day pics, like this Black Tern flying directly at me. The original has been already Photoshop’d, so I also wanted to see what NN and NW could do to clean up PS. When compared side-by-side at 100% the tern shows a great amount of noise, which is expected on a gray day. The camera has to try to create a gray sky from red, green and blue pixels, and the resultant images therefore show many of these pixels. Both Noiseware and Noise Ninja did great jobs at reducing this noise, with NN producing a slightly cleaner image at the expense of perhaps a bit of detail. Again, it appears to be a toss-up.













Conclusion

I’d be happy with either package. Both Noise Ninja and Noiseware perform wonderfully as Photoshop Plug-ins and improve on anything that I’m able to do with PS alone. Both NN and NW are great at eliminating chroma noise and producing smooth backgrounds that makes Canon and Nikon images so easy to look at. NW tends to produce higher-contrast images so the slider should be used with great care. NN tends to generate a bit of a watercolor effect with excessive noise reduction, and resulting images can look a bit overprocessed. I found that I preferred Noiseware overall as it seemed to handle all of the imaging situations I threw at it w/o problem. I would encourage anyone else considering these packages (and Neat Image) to download the trial versions and compare them for yourself. I would welcome any additional comments anyone has to offer, and will publish them as long they’re in good taste. Thanks for playing!

Wednesday, September 10, 2008

Review: Nikon ED50 FieldScope

Having received a new Nikon ED50 Fieldscope, courtesy of the good folks at Wildbird Magazine and Nikon*, I decided to put it to the test as a digiscoping setup. The scope came with a 13 – 30X eyepiece, but I tested the unit with the 27x DS eyepiece. I used my current digiscoping camera and adaptor (Nikon Coolpix P5000 and homemade adaptor, which consists of a Canon LADC58F and Teflon tape dispenser cap – see my blog post regarding the setup) as it fits very well over the eyepiece and provides proper spacing between camera lens and eyepiece.

The following settings were used for the camera: ISO 100, Exposure Compensation = -0.7 unless otherwise specified, Auto White Balance, Center-weighted Metering, Image Size = 3640x2736, Aperture-Priority, Continuous Shooting Mode, Macro Setting, In-camera sharpening set to Normal.

My first test was an American Goldfinch at the thistle feeder in the window. From 30 feet away I captured several images at magnifications roughly equivalent to 1X, 2X and 3.5X zoom on the camera. This translates to 27X, 54X and 95X. With the 27X eyepiece the view through the camera viewfinder at 7.5 mm (or 1X) is the same as the view through the eyepiece. With proper orientation of the camera there is no vignetting even at the lowest camera setting.









From 60 feet away I then found a willing subject in the form of a female House Sparrow. From this distance I was surprised that chromatic aberration was minimal at best. Only areas with extremely high contrast and/or blown highlights showed slight CA.


To test CA I focused the scope on the sunlit white siding of the house. At 30 – 40’ I could not find significant CA associated with this eyepiece.

With a steady hand it is possible to digiscope w/ the ED50 without the need for a shutter release or the self-timer. However, I can see that digiscoping in anything but direct sunlight will be difficult since fast shutter speeds will be at a premium.

I wasn’t sure whether I wanted to keep this scope since I am so happy w/ my Zeiss Diascope 85T*FL. However, this lightweight compact offers a bright, sharp view with a wide FOV and good eye relief. Although I also liked the 13-30X eyepiece I found eye relief to be less forgiving and felt like I had a bit of tunnel vision while wearing glasses. Thus I’ll stick to the 27x DS eyepiece and keep this sweet little beauty for travel.

Thank you WildBird, and thank you Nikon!

* - First Place in the Digiscoping Category of WildBird Magazine’s 20th Annual Reader Photo Contest (Aug/Sep 2008).

Saturday, April 12, 2008

New digiscoping adaptor for Coolpix P5000 / Zeiss 20-60X Zoom eyepiece - 12 Apr 2008

Inspired by my friend Pat's digiscoping adaptor (PVC reducer pipe that fits Nikon ED50 scope eyepiece to Fuji F50) I decided to upgrade my current adaptor to make a more convenient setup with my Nikon Coolpix P5000.

My current adaptor is a pesto jar lid and nylon hose clamp rig similar to this one for the Fuji F30. It does a wonderful job aligning the camera and makes for a hands-free setup, but suffers from one drawback. The adaptor has to be pressed onto the eyepiece of the scope before the camera can be inserted to take an image. Its a fast operation, but with the adaptor on the scope eye relief is lost, and its almost impossible to see a moving bird in the scope w/o removing the adaptor. My ideal setup is an adaptor that can be attached to the camera so that the unit can be simply placed over the zoom eyepiece for a snug fit and proper alignment. And I think I've found it!


My new adaptor makes use of a simple PTFE Thread Seal tape dispenser cap and a Canon LA-DC58F lens adapter. The LA-DC58F was an ideal digiscoping adaptor for my Powershot A620 because it attached directly to the camera and it fit over the 20-60X Zoom eyepiece. Unfortunately, the camera suffered from some vignetting at all magnifications, and was thus somewhat limiting for digiscoping. The LA-DC58F unfortunately is also a little too large to connect to the Nikon Coolpix P5000, and I'm not about to superglue it to the front of the camera. Here's where the pipe thread cap comes in. It 'snaps' snugly over the threaded lens cover on the front of the camera, and its outside diameter is the same as that of the LA-DC58F. With a bit of force the Canon adaptor can be pressed inside the teflon cap and the unit can then be snapped onto the front of the camera. The unit is snug enough to support the weight of the camera, and can easily be pulled off. Applying a layer of male velcro tape to the inside rim of the LA-DC58F the unit will fit tightly over the Zeiss 20-60X zoom eyepiece.

The beauty of the unit is that the camera can be easily rotated, zoomed and operated hands-free, and can be easily attached and removed w/o the need for clamps or screws.


Warning! Do not carry the scope w/ the camera attached as it WILL fall off. The unit is stable for hands-free digiscoping (timer mode or taking videos), however! Cost? $0.97 for the teflon thread seal tape. I already had the the LA-DC58F, but it may(?) still be available online for about $20.


Attached to the scope vignetting is visible at the lowest zoom setting, but is easily removed with a few clicks of the zoom. There is the slightest amount of CA along the edges of the vignette circle, which tells me that I don't have the ideal eyepiece / camera lens spacing, but it doesn't appear to affect image quality. Here's a pic of my Asia at 20X and no zoom on the P5000. Here's a 100% crop showing the detail that still present in her fur. A House Sparrow in the background made for a quick capture, as did this Crocus.


For those of you w/ Coolpix P5100's the teflon cap snaps on just the same as w/ the P5000.

Wednesday, March 12, 2008

Digiscoping: Introduction

What is Digiscoping?

Spotting Scope + Adapter + Compact Digital Camera = Super telephotography

It is simply using your spotting scope as a telephoto lens. Place your compact digital camera up to the eyepiece and fire away. An adapter allows you to 'connect' the camera for more stability and centering the camera lens with the scope eyepiece.

Originated: 1999 Laurence Poh, Malaysia – Grandfather of Digiscoping

Mr. Poh is credited with developing the technique and presenting the first of many impressive images taken using his new Nikon Coolpix CP990 and Swarovski HD80 Scope. Sadly, Mr. Poh passed away a few years ago, but his memory and images are still the standard by which we are all compared. Please check out his site at: http://www.laurencepoh.com/

Why Digiscope?

- Poor man’s bird photography - $ vs. $$
The appeal of digiscoping is that it is significantly cheaper than traditional SLR/Telephoto Lens photography. A 'good' digiscoping setup can be had for under $1000 US as opposed to the $5 -10,000 you might spend on a Canon/Nikon DSLR and Prime 400 to 600mm lens.

- Chance to study plumage variations not shown in FG’s
Today's field guides are great and wonderful. Unfortunately we tend to see many birds in basic or molting/worn plumage. Shorebirds, especially are difficult to ID. Digiscoping has helped me improve my ID skills by allowing me to look for the details lacking in today's field guides.

- Records of unusual or rare birds
There is nothing better than seeing a rare or unusual bird on an outing and being able to prove it. Documentation of rare species is made easier because more and more digiscopers are able to provide photographic evidence of that 'casual' Curlew Sandpiper at Pt. Mouillee, MI.