"Digiscoping" defined. (1 Viewer)

Sout,

Your reply to my last post on this thread is very interesting.

I'm not sure I fully agree with you opinion that the DSLR big lenses are always used with a wide open aperture. At least, I don't and my 100-400 is only 5.6 at 400mm. One of the interesting features of IS is that it allows using smaller apertures at the expense of slower speeds. Doing so, I have more control over the background and it allows a wider depth of field to keep the entire subject within accurate focus if I want to.

Your argument that the P&S camera will take care of light control to properly expose the image makes sense. Shutter speed control is inside the camera on both systems. However, the diaphragm is not not located at the same place and I don't know how big a difference it makes.

Depth of field - You are obviously right about the long distance shots, let's say over 20-30 meters. However, digiscoping is also used at much closer distance, in DSLR country, where DOF control is an asset for a DSLR.

AF - Here we disagree. I use AF a lot with my DSLR and I think the majority do. AF is now very fast and accurate and works very well in a lot of situations. Of course there are often situations where MF is a necessity.

We also disagree on IS. Wether it is useful when the DSLR is on a good stable tripod is open for discussion but, when handheld I find it a necessity. On my lens, it is easy to switch off the IS control by accident and I have put masking tape over the control, so it is always on. IMO, IS is a major reason for the extraordinary quality of modern bird photography. Also, I have read that in-body IS is not as effective as in-lens IS, but I don't know for sure. Lets not forget that working handheld if one of the major differences between DSLRing and digiscoping.

Regards
Jules

iporali said:

I would call it digiscoping if the system had a spotting/micro/tele/whatever-scope and a digital imager. Thus DSLR + a tele lens would not be digiscoping, but a DSLR + a *scope (regardless of coupling) would.

Ilkka

Click to expand...

In another thread (Exposure Impact - Digiscoping) you state:

"IMHO the beauty of digiscoping is the fact that a spotting scope with a
20x eyepiece & an 80mm objective gives an exit pupil of 4 mm. When
coupled with typical digiscoping cameras having focal lengths of 5 to
20mm and max apertures of 1:2.8 to 1:5.6 this means that the scope
delivers all the light that the camera can possibly gather regardless of
its focal length (= the camera lens has the smallest true aperture in
the light path) - meaning that the above digiscope would be something
like 700-2800mm with effective F-numbers of 2.8-5.6."

I think this is spot on and exactly defines the difference and the one
clear advantage, at least optically, of digiscoping over traditional DSLR+telephoto
photography - the ability to have both high magnifications AND high
light transmission to the sensor of the camera.

However this advantage requires the use of a camera with a relatively
small sensor such as those found in a typical point and shot camera. The
small sensor allows you to design camera objective lens' with small real physical apertures
AND high light transmission. This comparative advantage would be lost if
one tried to couple a DSLR to ANY lens whither a telephoto or a scope
would it not?

So it seems to me what really defines what "digiscoping" is, by your own
words, is not the type of lens attached to the camera's objectives nor
it's method of attachment but rather if that lens is connected to a
camera with a small sensor (a PS camera) or a, relatively, large sensor
(a DSLR camera).

In other words, the advantage of digiscoping REQUIRES the use of a small
sensor point and shot camera.

So your two statements would seem to contradict each other - which one
do you stand by?

Sparrow

Tannin said:

1: You are using a pair of lenses, neither of them designed for the task you are attempting

SF:
Yes.

2: You are using a strictly tripod-only system. You may use a tripod with a non-digiscope setup, but you can quite sensibly hand-hold any SLR lens on the market today (except perhaps the Sigma 300-800) if you wish. You can't do that with a digiscoping rig.

SF:
Speak for yourself on this one. I much prefer the use of a tripod both for comfort and the quality of the images. I can't imagine beating through the woods with a 13 pound 600mm $7000 Canon hanging off my neck. And that 13 pound monster with 150mm objectives is still only going to give me a relatively modest 18x. Speaking only for myself any lens that is practical to hand carry in the field is, generally, not useful for wildlife photography.

3: You are accepting a massive difference in reaction time: no digital SLR is anything like as slow as a P&S, never mind the requirement to manually focus the scope as well as wait for the camera to auto-focus.

SF: Yes. It's one of the primary reasons I use a DSLR - speed. I have watched digiscopers try to catch passerines and it's not a pretty sight. It must be frustrating to use such an unresponsive system.

4: You are working at around 2000mm in 35mm equivalent terms. With an SLR you rarely work at more than about half this magnification

SF: which is a big limitation of conventional telephotos - they often simply don't have the reach needed for wildlife photography.

5: You are using a tiny little sensor which is dwarfed by even the midget Olympus "four-thirds" sensors, never mind the industry standard 1.6 and 1.5 size from Canon, Nikon, Pentax et al, or the even bigger professional-size sensors Canon make. That has very significant implications for your noise levels and your image quality.

SF:Yes but I wonder if it's just size and not also pixel density (resolution). I wonder if a small PS sensor of 6mp would not do about as good as the 6mp sensor on my DSLR? An open question I really don't know.

Obviously, I do not count attaching a DSLR directly to a scope as digiscoping. That is, quite clearly, using the scope as a manual-focus, fixed-aperture telephoto lens, i.e., a form of "normal" photography. Of the five differences I listed above, only #2 applies to this method. Notice also that it produces high-quality images much more akin to those produced by an SLR than to digiscoped images.

SF: Yes. This is exactly why I do things the way I do - get the reach of digiscoping, which is essential for my kind of shooting, while maintaining good quality.

Click to expand...

xxxxx

narawood said:

JCWINGS, I would like to attach a Canon 350D to a Nikon ED82A (minus eyepiece) but have yet to find a suitable adapter, your comment on using a DSLR on a scope with eyepiece fitted is new and interesting to me, what sort of setup achieves this, and what kind of results can be expected.

John

Click to expand...

Hi John,

I have no idea if this set up is available for the Canon to Nikon connection. I just know that as time goes by the option for connecting DSLR to scope and eyepiece is becoming reality. Here is a link demonstrating this feature:

http://www.birddigiscoping.com/2007/02/pentax-k100d.html

Sout Fork said:

So your two statements would seem to contradict each other - which one
do you stand by?

Click to expand...

Sout/Sparrow,

Well spotted :t:. I usually stand by almost everything I have ever said.

For me the easiest, most accurate and by no means serious "linguistic" definition is:
digiscoping = taking pictures using digital imaging apparatus (be it P&S, DSLR, cooled CCD imager...) together with any optical device that ends with the letters s-c-o-p-e. (I often use microscopes and sometimes telescopes).

In the other thread the question was about compact cameras and I was talking about probably the most common "digiscoping subtype" (according to "my" definition). You are completely right that the advantage of having both high powers and large apertures is limited to the compact cameras with small sensors, but I would still not use the sensor size as a separating factor (when is a small sensor small enough?). This "1000mm f/2.8" -idea is also why I personally like P&S-digiscoping.

You have convincingly shown that a large spotting scope can serve as an excellent tele lens when used with a DSLR. You may lose several aperture stops, but you get a much more sensitive and less noisy sensor that may give you back 2-4 ISO steps. Technically these setups look very different, but I would still call a spotting scope + a DSLR a digiscope. For me a spotting scope objective is still "a scope" even if it was used as a prime focus objective - even more so if the setup has some optical adapters. But if others prefer not to call it digiscoping - that is more than fine with me.

Best regards,

Ilkka :t:


Disclaimer: I reserve the right to ignore my own definitions whenever I like, whenever I forget making them, or for any other reasons. This is what I stand by.

How about we call it scopography instead?

Jaff said:

How about we call it scopography instead?

Click to expand...

Actually it's not a bad idea.

Jaff said:

How about we call it scopography instead?

Click to expand...

Thats a great idea. Ernie

NoSpringChicken said:

I would define 'digiscoping' as the art of waiting for a stationary bird to move out of frame just as you press the shutter.

Ron

Click to expand...

Hi All,

Ron,
That is the most accurate description I have ever heard.
Absolutely spot on.

Regards.John

These images portray the difference between telephotography and digiscoping. they were shot from the same distance. The first image is a telephotograph at 140mm fl. of a plumbing vent in the center of the image. The second image is a digiscoped image of the top of the vent.

Here's a photo I took a few years back. I mounted my Olympus C-5050 to a 20mm telescope eyepiece and mounted all that to a Vivitar 80-200mm slr lens and this was the result.

Paul.

The original digiscoping vs. DSLR post from Sout Fork on this thread got the issue right.

A spotting scope mounted directly on a DSLR using Sout Fork’s illustrated setup is a known, conventional variation on telephoto photography. For a good definition see Birding.com, http://www.birding.com/scopetelephotography.asp. This is not a new idea, but many confuse spotting scope telephotography with digiscoping.

The important point to emphasize is that when this setup is used, it very different from digiscoping. It is telephoto photography using the spotting scope body, without eyepiece, with adapters in place that make it function like a conventional SLR telephoto lens. In digiscoping, as other posts in this thread mention, the scope eyepiece is left in place and a small digital camera looks through the eyepiece. By contrast, with the scope used as a DSLR telephoto, the eyepiece is removed and the “SLR adapter” is put in its place, where it directly transfers the image to the DSLR sensors. This kind of “adapter,” as Sout Fork points out, is not a passive transitional piece of metal. Rather, it is an optical device that does the same job that the eyepiece does when you’re looking directly through the scope. Kowa uses the equally confusing term “Photo Attachment” to describe this optical device.

In the case of Kowa (discussed below), the top “Photo Attachment” is a 680-1000mm zoom element. Screw this onto your scope, screw a camera mount that will fit your camera body--then attach the whole shebang to your DSLR and you have a telephoto lens of potentially huge reach. Using a Nikon D200 1.5 crop factor, the maximum reach of this combo is 1500mm or about 30x. When looking through the scope with your eye using the Kowa zoom eyepiece, the Kowa’s 884’s achieves 20-60x zoom in its top scope, but the lower 30x with the Nikon is still huge compared to conventional SLR lenses. For example, my Canon D20 setup with 100/400 + 1.4 extender produces the 35mm equivalent of 896mm, or about 18x.

In the Houston area one of our birding photographers, Joseph Kennedy, is producing outstanding photographs using a Kowa spotting scope setup mounted on his Nikon D200. Although his setup is heavier (I figure 4.5 lbs, without camera) than my Canon 20D with 100/400 + 1.4 extender (3.5 lbs without camera), he is able to do without his tripod, instead using a BushHawk shoulder mount with a remote “trigger” release (when not shooting pictures from his car).

One of his pictures is below, but it is worthwhile examining the photographs on his site, http://www.pbase.com/joseph_kennedy_36/i. I’m no expert, but these look very sharp to me. They include quite a few birds on the wing or otherwise in motion.

Because I found Kennedy’s setup to be quite interesting, I spent a little time digging up model numbers, etc, it in some detail after he first described it in our Texbirds site, http://moonmountaingroup.com/texbirds. The Kowa site is not well organized and the equipment is confusingly described, so I thought I would simply outline here what I found using that site and my favorite online seller’s site. Kennedy is using a Kowa TSN-884 Prominar Fluorite Crystal Straight Type scope plus the TSN-PZ zoom “Photo Attachment” and the Nikon TSN-CM2 (TSPKN) “T-Mount Adapter.” (I’m only familiar with Canon lenses, but here are the T-Mounts Kowa offers: Pentax K-Mount, Pentax screw mount, Nikon F-mount, Minolta MD System, Canon EOS, Canon FD, Contax & Yashica, Olympus, and one to fit the Konica Minolta Maxxum (Dynax) system/and the Sony A mount and Minolta A-type cameras).

There are big tradeoffs, of course, when using a spotting scope as a DSLR telephoto lens. Certainly it means means that any autofocus and image stabilization features are unavailable (although I also lose autofocus but not IS when I attach my 1.4x extender to my Canon setup). Also, using the optical “Photo Attachment” the combination is not bright at f/7.4 to 11.4. Nor would anyone suggest this combination as being competitive with such world-class optics as Canon L series prime 400mm f/2 or 600mm f/4 lenses. But these professional quality, autofocus and image stabilized lenses are immensely more expensive at $6500 and $7200 and, at almost 12 lbs each, they impose a heavy weight penalty. The Kowa 884 is not cheap at $2100, plus $500 for Photo Attachment and T-Mount, but the overall price strikes me as worth it, all things considered.

I assume other scope manufacturers offer similar setups, but I haven't looked. I do think that getting the finest glass the maker offers would be essential to successful using the scope as a DSLR telephoto lens.

I got interested enough in this alternative to run down all a lot of technical information. But until I learn a lot more about nature photography, I’m sticking to my Canon setup.

Not wishing to resurrect this thread but I have been thinking about this
issue since it was first posted.

Instead of trying to define and label the different photo systems I've
come up a list of these different systems based on what I believe are
significant functional optical differences. Essentially this list is
based on the light path through the optical system.

1. Conventional Telephoto lens (Zoom or Prime)+DSLR sensor (large)

2. Conventional Telephoto lens (Zoom or Prime)+Tele Extender+DSLR sensor (large)

3. Spotting scope+(built in internal prism)+"camera adapter"(a complex
multi-element optically active device and not just a mechanical
adapter)+bare DSLR sensor (large) with no camera lens in place. (A-focal?)

4. Spotting scope+(built in internal prism)+eyepiece (Zoom or
fixed)+bare DSLR sensor (large) with no camera lens in place. (A-focal)

Note: although this optically seems to be superficially similar to #3
there is important optical advantages to #3 over #4. Because the camera
adapter is designed from the ground up to match a SLR camera's focal
plane to the light cone coming from the spotters prism one gets better
color correction, better collimation, flatter field, no chance of
vignetting, no focus issues, better contrast and resolution, better
mechanical match etc compared to an eyepiece between the prism and the
camera's sensor. An eyepiece, after all, is designed to match the light
cone to the human eye not to a camera's focal plane. Because of these
cumulative optical advantages I have put them under different headings.

So although they may optically be both a-focal in operation one is a much
better match for a camera focal plane than the other.

5. Spotting scope+(built in internal prism)+bare DSLR sensor (large)
with no camera lens in place. (Prime focus but with the addition of the
built in internal prism )

5. Spotting scope+(built in internal prism)+eyepiece (Zoom or
fixed)+optically passive mechanical adapter+PS camera Zoom lens+PS
sensor (small). This setup, in my opinion, optically defines
"digiscoping".

6. ASTRO SCOPE: Front objective group only (no prism present)+bare DSLR sensor (large) with no
camera lens in place. (True prime focus setup)

7. ASTRO SCOPE: (Barlowed): Front objective group only (no prism present)+Barlow (optically
rather like TE on a conventional Telephoto lens but much simpler)+bare
DSLR sensor (large) with no camera lens in place.

I think that pretty much covers it. There may be other important
variations that I have missed but this pretty much covers the main types
so far as I know.

Which one is "best"? That's for you to decide.
SF