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Digiscoping


I'm fortunate in having the view of a virtual bird sanctuary outside
my window


(Vignetting) (Email Xtract) (Vignetting Examples)  (Minimize Vignetting)  (Adapter) (Tripod) (LCD Sunshade) (Choosing a Camera)  (Choosing an Eyepiece) (Settings)

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My interests in Digiscoping stemmed from a desire to be able to take photographs of subjects that I would not normally be able to take with my camera even with its 4 x zoom lens, or, without going to extremes and buying very expensive telephoto lenses. Even then I would be hard pushed to achieve getting as close up a photograph as one can get with the combination of the magnification of the Fieldscope or Telescope coupled with the 4 x magnification of the Nikon 4500 or any other zoom digital camera.
I am aware of the fact that the majority of Digiscopers are bird watchers
I am sure, like myself, you will be aware that Digiscoping can be used for taking photographs of other subject other than birds. It is my intention to try and show the power of the combined zoom digital camera and the fieldscope.
Since I started taking an interest in digiscoping I have looked at so many bird web sites and have found many beautiful photographs of birds (See my Digiscoping and Photography Links pages) to see some of these birds.
You may also find my Gallery worth a visit.

Digiscoping
To simplify what the word digiscoping means. Digiscoping is the practice of shooting digital photos through a Field/Spotting scope. The scope magnifies the subject image for the camera, just as it would magnify the subject image for your eye through the scope. To achieve the same results using this method with a conventional SLR camera and telephoto lenses would cost hundreds of pounds more


Attaching a Camera to a Scope
Attaching a camera to a fieldscope/telescope is one of the biggest problems with setting up for digiscoping, you need to be able to hold it both central to the eyepiece and steady at the same time. A lot of different ways have been suggested and designed, some even handheld, most of which work in their own way. I will try to point you in the direction of a Few Different Types as well as the adapters I devised for my own use for the Opticron and the Leica.
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Vignetting

Photographers use the term Vignetting to describe an image that is missing its edges. It can just be the corners of the square frame missing, to a more severe tiny round image in the center of the frame. Vignetting is caused by the cone of light entering the camera not fully illuminating the CCD chip. At some stage vignetting is to be expected with most digital cameras with this type of photography. I have found vignetting to be a real problem and everything possible should be done to try to minimize it. All aspects of the proposed camera, eyepiece, and attachment system should be considered to minimize the problem. By choosing a camera, attachment system, and eyepiece that will reduce vignetting you will make your life much easier in several ways. With a smaller camera lens you have more freedom in choosing eyepieces (for example the tiny lens of the Nikon 4500 can shoot through an eyepiece with a much smaller exit pupil . At the other end of the scale is the likes of the Minolta Dimage S304 (Not knowing any better at the time and it being my first camera I used for Digiscoping) where the zoom mechanism works entirely opposite to the Nikon 4500. See an extract from an email I received from Robert Augustine when trying to find out why I was getting more vignetting when zooming in on a subject with the Minolta S304. Also the less vignetting your setup has the more freedom you have to zoom out to a lower power (wider field) . You will also have an easier time locating and centering the object to be photographed if you have more usable area. There are ways to keep vignetting to a minimum and you must take this part seriously or you will probably be disappointed with your usable image size.

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Extract from email from
Bob Augustine
Problem with Vignetting with Minolta Dimage S304
From your description, I do have a theory. As you may know it is a good idea to provide a camera lens with a shade to screen out bright light from outside the picture area that can nevertheless enter the lens. But this causes certain complications in a zoom lens. As the focal length changes, the shade must change too. If it doesn't, it will vignette at the short end or let in too much light at the long end. Ideally, you want a shade that zooms too. This change in shape/length is difficult to engineer. But many designers are so convinced of the value of a shade in preventing flare that they build one into the lens mount. Let me say this another way. A longer focal length (telephoto) lens requires a longer shade. If such a lens is then rolled back to wide angle, that shade will cut off (vignette) the image. On the other hand, if you make the shade wide enough to accommodate the angle of the wide-angle lens, it won't shade the telephoto very well. The design engineers came up with a zooming shade. This is actually better described as a "variable recess". Instead of the shade extending when the lens is put to telephoto, the lens actually retracts deeper into the lens mount with the same effect. This works fine in normal usage. But not in digiscoping. Many people try to get rid of the vignetting they find at shorter focal lengths by zooming out. With some cameras (that don't have a "zooming shade" or "variable recess") this works just fine. But when someone else tries it with a variable recess type camera, zooming out actually increases the vignetting by moving the lens farther from the eyepiece. I suspect this may be what you are seeing. Just look at the front of your camera lens as it zooms. Please let me know. We may have to investigate further if this is not the correct explanation.
Bob Augustine
raugustine@tms-hq.com
Rockville, MD

My Reply

Hi Robert Thanks for the info.
You are correct, looking at the front of the camera (Minolta S304) as it zooms out the lens
recesses back into the camera. When it is first switched on the hood/shade pops out the camera body first then the lens follows to the wide angle position ie.7.15mm focal length. From there the lens recesses back into the camera when zoomed to focal length of 26.5mm So I would say you hit the nail on the head.
Thanks again Stan

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Examples of Vignetting
Have a look HERE at examples of Vignetting

Ways to Minimize Vignetting

1. Choose a camera with a physically small lens.

2. Choose an eyepiece that has the following attributes .
See(a) to (c)

(a) A flush mounted lens design, the glass lens should be at the very top of the eyepiece.

(b) Get the correct sized eyepiece lens. Don't be afraid to take your camera to the shop where you are buying the eyepiece and trying it out with the fieldscope, you will get a good idea of how it will perform by just hand-holding and shooting a reasonably distant object through there shop window, if you are allowed to take the scope into the street and shoot off a couple of frames, all the better. That's how I decided on my own lens. I must thank Stewart Gillies of Charles Franks shop in Rose Street Edinburgh (suppliers of optical equipment to the RSPB) for his help. Stewart does all the demonstrations of optical equipment for Charles Frank. He also helps me out when I have difficulty in identifying a bird.
Remember to click the shutter release button a few times so that you have a record for when you get home. I only decided once I had seen the results. (eyepieces are an expensive item)

(c) Decent eye relief.
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Adapter

3. A coupling device that ensures a secure close contact between camera and scope as near as glass to glass as possible. Have a look at the adapters that I devised for coupling the Nikon 4500 to the Opticron Classic IF-2 and Leica APO Televid 77 fieldscopes. Click on the photo links below.

  
                                  Opticron          Leica
4.You will find you will have to Zoom in to minimize vignetting. On small lensed cameras such as the Nikon 4500 you may only have to zoom in just a little bit to totally eliminate vignetting.

5. Try the different modes on your camera. Some cameras prefer to be in macro mode to minimize vignetting, some prefer to be fixed at infinity. There are so many different cameras out there that there is no one hard and fast rule, except to experiment.

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A good sturdy Tripod is a must

I have found out the expensive way that a decent sturdy tripod makes all the difference to taking an as near to shake free image. I had a pretty lightweight one to start with and the least bit of wind made it near impossible to get a decent shot. I have now bought the 42604 Opticron Bird watchers Tripod with moveable center column which weighs in a lot heavier than the Jessops one which I still have. (I would suggest a tripod as heavy and robust as you are prepared to lug around)

An LCD sunshade

A shade to eliminate bright sunshine reflecting on the LCD viewer is another item that will make life a lot easier when trying to focus on your subject with the sun looking over your shoulder.
There are a few shades on the market. The one I purchased an Extend a View Pro, I adapted to suit, so that it would fit the Nikon Coolpix 4500. See Photo

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Choosing a Suitable Digital Camera

My preferences for a digital camera would be as listed below.

1. An LCD view screen, this is really a necessity otherwise you can't see what you are shooting. Luckily this is standard on virtually all mid to high range digital cameras.

2. A filter thread on the lens or on the body.

3. A physically small lens, smaller lenses vignette less and allow the use of a wider variety of eyepieces. Less vignetting means you can also zoom out farther since the primary means of reducing vignetting is by zooming in.

4. A lens which zooms internally rather than moving outside of the camera body. This allows for closer coupling, and from my experiences with the Minolta S304 I know the pitfalls of not checking the workings of the zoom mechanism

5. A swivel body, a highly recommended feature, but not entirely a necessity. You will appreciate it when in bright sunlight and can angle the LCD to get a better image. I would highly recommend the use of a LCD shade in bright conditions.

6. A remote shutter release. I suppose standard with some cameras but optional with Nikon. This can be a big help in reducing the shakes when shooting at high power. The one I use is a cable release and bracket supplied by Jessops which I find very good. You can also use your built-in timer which eliminates most of the shake but sometimes not quick enough to catch that elusive subject.

Another type of remote control shutter release is the DigiSnap 2000

The DigiSnap 2000 line is a four button remote digital camera controller. It lets you operate your digital camera from a distance, allowing you to take pictures, adjust the lens zoom, as well as perform time-lapse photography. The DigiSnap 2000 line is compatible with a wide range of digital cameras. If your camera has a serial port it may very well be controllable by the DigiSnap 2000.

Some popular models known to work with the DigiSnap:

Nikon Coolpix 950/990/995/880/885//5000/5700/4500/4300
Nikon Coolpix 700/800//900
Epson 750Z
Olympus C-3030 Zoom
Olympus C-2020 Zoom
Sanyo VPC-SX500


7. A camera that stores all the information about an exposure so you can see what worked well, and in my experimental stages and in a lot of cases"what didn't". I think you have to be pretty critical with what you keep as decent photos and the ones you toss out.

Having the Nikon Coolpix 4500, I have found that this camera provides all of the above features and more.
Have a look at the specification of the Nikon 4500
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Choosing a Suitable Eyepiece
See the paragraph above on minimizing vignetting. Assuming you already have a suitable camera and adapter the eyepiece can make the difference between a reasonably full image or a very small image not worth keeping

One of the questions that is often asked is, what settings to use for the camera when digiscoping. I do not think there is any hard and fast rules for settings. I would say, to experiment like I did myself. What you are trying to achieve is to get as much light into the camera via the scope (aperture), to freeze any movement of the subject (shutter speed), to get as sharp and crisp a photograph as possible (focus). Below are the settings that I have use myself. I'm still experimenting.

My Settings

The settings that I used for the majority of the bird photographs taken with the Nikon Coolpix 4500 are pretty simple and straight forward. I set the camera to Apeture Priority the "A" setting so that I have control over the aperture setting to allow as much light into the camera as possible, plus Spot metering , the focus mode button to macro, with the flash switched off. If I have the opportunity, before attaching the camera I focused the scope to an area where the bird(s) are settling rather than a particular bird, because the bird would most likely have moved by the time I had attached the camera. I then attach the camera and then zoomed in on the bird I had now picked out to maximum zoom even digital zoom. I then fine focused the scope on the bird, its eye if possible and then zoomed out until the macro icon (the little tulip) turned yellow and then 'snapped' via the cable and bracket release.
Use the same settings as above but change the focus mode button to 'infinity' if you have waving grass or leaves in the way of the bird, as the camera is liable to try and focus on these rather than the bird

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