Some digiscoping experiments with a dslr (1 Viewer)

[RJM]

IMO, the easiest way to connect a DSLR to a spotting scope is to use the camera side of a T mount and connect it to a threaded eyepiece via a stepping ring.

For example, the Pentax WX eyepieces have a 43mm thread and the bayonet side of a T mount has a 47mm thread (I'm not sure of that - please check). Using a 47-43mm step down ring connects the 2 solidly and cheaply.

Jules, this can work with PENTAX spotting scopes as they accept standard 1.25" astronomical eyepieces. But all other spotting scopes use proprietary eyepiece designs and mounting systems. Kowas use a bayonete mount and have an irregular 41mm thread under the rubber eyecup to fit their DA10 adapter for compact digicams.

There really is no other practical way to connect a DSLR to a Kowa than the PA2. It is really not that expensive either at about $180. Certainly cheaper than a high quality widefield eyepiece and any adapters.

cheers,
Rick

 

[RJM]

I agree that Paul has not invented prime focus digiscoping. However, before his experiments, most considered a DSLR as a poor choice for digiscoping.

Why do you think this? All the major fieldscope makers have sold film SLR camera adapters for their scopes since at least the early 90's. And using an SLR with a telescope has a long history too. Tele Vue has probably made much more money from their smaller APOs as spotters and as an alternative to expensive telephoto lens for more than 10 years now than they do for astronomy.

I think the DSLR though has only recently evolved to the point that its resolution can compare to film and at an entry level price point that now puts them up against formerly cheaper compact digicams that launched the "digiscoping" craze.

Of all the telescope makers, BORG is probably the most forward thinking when it comes to digiscoping, especially with a DSLR. In fact, they see it as their mainline business.

cheers,
Rick

 

[JGobeil]

Why do you think this? All the major fieldscope makers have sold film SLR camera adapters for their scopes since at least the early 90's. And using an SLR with a telescope has a long history too. Tele Vue has probably made much more money from their smaller APOs as spotters and as an alternative to expensive telephoto lens for more than 10 years now than they do for astronomy.

I think the DSLR though has only recently evolved to the point that its resolution can compare to film and at an entry level price point that now puts them up against formerly cheaper compact digicams that launched the "digiscoping" craze.

cheers,
Rick

I think we are both right Rick. Some people have been doing prime focus digiscoping for a while and, as you write, Tele Vue seems to have made it a specialty. However, many digiscopers are under the impression that DSLRs are a poor choice for digiscoping - expensive, heavy and so-so results. Of course, it is not right.

I have been monitoring this forum for the last couple of years and I have read this fallacy over and over unfortunately. Hopefully, some of those people will read this thread and change their mind.

I have been very active in bird photography over the last 6 years around Quebec City. Would you believe that I have seen only one photographer using prime focus digiscoping and that was 2 months ago... Not very popular indeed, at least in my part of the world. By the way, he was using a Tele Vue 85.

 

[maxxxx]

Rick,
You misunderstand what Jules is saying.

He was referring to "most" people who are actually out in the field doing wildlife photography quite apart from what equipment any particular manufacturer may or may not be offering.

I have been shooting prime focus with a scope and a DSLR for years now and have never seen another wildlife photographer out in the field use a DSLR other than with a conventional telephoto lens.

 

[Paul Corfield]

I didn't know much about Powermates and was under the impression that they were Tele Vue's name for barlows... Was I wrong ! Thanks for the info. There is some good info about them on the Tele Vue site and I'll be reading more about them. A 4X Powermate would be an interesting replacement for my stack of 2 TCs (2X and 1.4X) with more magnification.

I've looked into using a Powermate many times but have only ever found one bird photo taken with one on the web. The photo was very poor and because of the cost of the Powermate I have never taken the gamble and got on myself. Astro photographers use them the most, usually couple to a webcam that has had it's lens removed. Webcams have tiny ccd's which provide a huge crop factor.

GSO make a apochromatic 5X barlow that I may try that one day.

Televue Powermates aren't considered barlows because the light path that exits the barlow is different to a barlow plus they are a 4 element design.

Rick - agreed it's not just the FPL-51 or the FPL-53 ED element that should be taken into consideration with regards to CA. The mating element will have a big effect on the resulting image but very rarely do telescope makers say what the mating element is made of so that we can look them up on charts to see what the performance will be.

Paul.

 

[dreamline]

I have been following this thread with great interest. From Paul's and Jules' pictures, it seems that digiscoping is a viable alternative to using a long telephoto (which I cannot afford, let alone justify...) so a big thank you is in order to all the contributors so far.

Firstly some background. I'm a regular user of a Canon 30D so I'm familiar with f/stops, aperture and speed etc. I tend to carry out a lot of bird photography in Autumn/Winter and I find my Sigma 70-300 limiting. It's too short for a lot of the 'sit and wait' subjects. (My haunt is a series of gravel pits with regular anglers - and passing 'angler traffic' means the birds will rarely come within range. |<|) The best shots are often on the far bank. So a longer lens would be pretty useful...

Now, for the thing that's been puzzling me and the point of the post. I had all but decided on a short tube refractor (Vixen or similar with an F/5 focal ratio), when I saw a review for an Orion 127 Mak, praising its quality and construction and crucially, its light-gathering ability and low light performance as a spotting scope. Aha, I thought, here we have a good dual-purpose scope, suitable for digiscoping, which won't need too short a focal-length eyepiece to produce reasonable magnification, and will be suitable for the odd bit of astronomical use to boot. However, I notice it has a focal ratio of around F/12.

How can a scope have good low-light performance with such a small ratio? From a photography perspective, during winter F/12 would be almost unusable for wildlife, even at ISO 1600. I'd estimate shutter speeds slower than 1/30 would be required, especially against the far bank, and that won't be fast enough to freeze any motion.

So, have I missed something here? I would have equated good low-light performance with a faster focal ratio, and I suspect I will eventually go with my original choice. Just thought I'd ask to satisfy my curiosity (and in case I may be able to make the perfect compromise.)||

Bernie

 

[Paul Corfield]

My scope is a 600mm F7.5 but with a 2X converter it goes to F15 and if I treble the power it goes to F22.5 etc. The shutter speed isn't that much of an issue. It's dull and cloudy here today and with a 2x converter (1200mm F15) I'm at 1/100 sec ISO800 in my back garden, probably be higher if I was out in the open. On a bright day the speed would be well up.

Only thing to think about if using a mirror lens like a Mak across water is that any sparkly highlights on the water will look like little rings. The photo below is an example of what I mean.

Post some ideas of scopes you are looking at before you buy.

Paul.

 

[JGobeil]

Bernie,

You are most welcomed to the "Club". Yes indeed, for birding lenses are never long enough unfortunately. I started with 300mm, moved to 400, added a 1.4X teleconverter and that still was too short. I figure my maximum range is about 20 m. Just like you, no budget for the Canon long guns unfortunately.

I then decided to try digiscoping - spotting scope and P&S. A long horror story of bad pictures and frustration. And now it is Prime Focus Digiscoping and my first decent long range pictures - at last.

Taking decent bird pictures at close range is quite easy with any method - camera lens, P&S digiscoping, bridge camera, etc. At long range it is a different story. Of course it depends what your standards are... o

From my research on the Net, it seems that the way to go is with a DSLR coupled to an astro APO ED REFRACTOR scope, APO ED REFRACTOR being the important words. The following manufacturers make decent products with these caracteristics: Tele Vue, Williams Optics, Syntra (it makes cells for Skywatcher, Celestron, Orion and others), Stellarvue and Astro-Tech. You can get a new 600mm f/7 for 500-1500$, or a used one on eBAY if you are patient.

Regards
Jules

 

[Paul Corfield]

Another scope I've read some good things about is an ED Apo Triplet design by someone called Maxvision. From what I read it's the same as Astro Tech and they are made by a company called Kunning Optical in China.

See here, not a bad price for a triplet design. http://www.astronomica.co.uk/EDTriplets.php

Paul.

 

[dreamline]

Thanks for the welcome guys. |:d|

The scopes I have in mind are:

• The Vixen A80SS (see the review here I can pick this up for about £250. I know I'll need eyepieces/barlows to go with it. Cloudy Nights users seem to have a good opinion on this scope, and indeed Vixen as a whole.
  
• The Orion Apex 127. It is reviewed here. This is about £299 but comes with eyepieces and accessories.

Thanks for the example of the highlights Paul. Could be distracting, but I'd hope to be able to crop most of them out, as the whole idea of me using a scope is to get the subject filling as much of the picture as possible. The extra focal length of the Mak could negate the use of a barlow or converter, and give me faster shutter speeds at higher magnifications.

Hmmm this is getting very interesting. A tough decision coming up I feel...

 

[Paul Corfield]

The Vixen is a bit too short at only 400mm focal length. That's not a lot different to your current 300mm lens. My last scope was 480mm and I sold that because the reach I was getting wasn't enough.

With the Orion Apex 127 you could also consider the Skywatcher Skymax 127 or the Celestron Omni XLT 127. All three are made by Synta who own all those brands. The Celestron has the XLT coatings which is the main difference. The Orion one is an ok price for the ex display model though.

Paul.

 

[Derry]

Bernie, welcome to the group,,

I agree with Paul to purchase at least a 600mm scope in the f7 area and would recommend a refractor,, I have a 3.5 Questar (mak family) which is a phenomenal small scope but to hang a DSLR on the back plate I find it not as useful as using my TeleVue TV85,,

your 30D an a f7 scope can be used on some very overcast days,,

Derry

 

[Neil]

The Vixen is a bit too short at only 400mm focal length. That's not a lot different to your current 300mm lens. My last scope was 480mm and I sold that because the reach I was getting wasn't enough.

With the Orion Apex 127 you could also consider the Skywatcher Skymax 127 or the Celestron Omni XLT 127. All three are made by Synta who own all those brands. The Celestron has the XLT coatings which is the main difference. The Orion one is an ok price for the ex display model though.

Paul.

Paul,
I'm following this thread with interest. On the issue of focal length - is there any difference between a long focal length scope and shorter eyepiece or the other way around.
I'm going to experiment with my Nikon 300/4 this weekend using the Televue Radian 12mm and the Olympus E420.
Also I'm liking what I'm seeing out of using prime SLR lenses as eyepieces. Have you done much experimenting with them?
Neil.
Neil

 

[Neil]

Tena,, here is a photo of my Oly E3 on the back of my TeleVue TV85 scope,,

I have the T mount to the camera and then there is one spacer to allow me to focus closer than the scopes focus rack will move,, for father distant objects the spacer/extension tube would be removed and just the T mount would be used,,

Derry

Derry,
How much closer can you get the focus with the spacers?
Neil.

 

[Derry]

Neil, I'll see how close I can focus with the extension tubes in prime focus,, never really measure just engaged the tubes as required,, I have a 50mm and 90mm,, will do the test with 50, 90 and 50+90 and post the results,,

if you want me to also test with some eyepieces, will do,,

have the following TeleVue that I can mount the E3 on,,
55 Plossl
32 Plossl
22 Panoptic
12 Nagler
3-6-8-18 Radians


thanks for the photo of the slide rack holding your camera,, I made a rack for camera support and works great,, did not like the E3 camera weight hanging on the back of the extension tubes unsupported,,

Derry

 

[Paul Corfield]

Paul,
I'm following this thread with interest. On the issue of focal length - is there any difference between a long focal length scope and shorter eyepiece or the other way around.
I'm going to experiment with my Nikon 300/4 this weekend using the Televue Radian 12mm and the Olympus E420.
Also I'm liking what I'm seeing out of using prime SLR lenses as eyepieces. Have you done much experimenting with them?
Neil.
Neil

Probably not a lot of difference as far as eyepieces vs focal length. Of more importance would be the resolving power of the scope. A scope with a higher resolving power will take more magnification before the image deteriorates. For resolving power the diameter of the objective is more important in this respect.

Yeah, prime lenses make great eyepieces. They work ok for digiscoping too but not all that high a power and a bit of a pain to mount to the scope.

With a 60mm spacer on my scope I can focus to around 5.5m with my 17mm Baader eyepiece and an erecting prism.

Paul.

 

[Derry]

Neil, here are the closest focusing distance I can acquire with the TeleVue TV85 scope with an Olympus E3 and various extension tubes,,

Prime mode = 12.8m

50mm extension = 6m

90mm extension = 5.1m

50 & 90mm extension = 3.3m

with the 22mm Panoptic eyepiece and Olympus 35mm macro I needed the 90mm extension to focus 25.6m on the test chart,,

I have posted a crop of the test chart below and can see the 19 line area on the original,,

Derry

 

[Paul Corfield]

with the 22mm Panoptic I needed the 90mm extension to focus to 25.6m, no closer with that eyepiece,,

Derry

With your eyepiece Derry, was that with an erecting prism/mirror as well?

With an eyepiece, a prism and a 60mm extension tube I got down to just under 6m on my scope. If you were going to digiscope through an eyepiece then you would need a prism also.

Paul.

 

[Derry]

no diagonal or erecting prism,, just Oly 35mm macro lens and 22mm Panoptic with teh extension tube,,

was shooting test chart so upsided down did not matter,, will post results as just cropped a portion,,

I have a 45 degree erecting prism an use at times for viewing to keep the scope lower,, have not used for photograpy though,,

Derry

 

[Paul Corfield]

Here's a 100% crop from a photo I took today through the Skywatcher 80ED scope with the 2X GSO 2" ED barlow. Range was 10m. Picked up some nice detail.

Canon 450D - 600mm Skywatcher Pro 80ED scope - 2" GSO 2X ED barlow - ISO800 - 1/125sec

Paul.