Some digiscoping experiments with a dslr (1 Viewer)

Paul Corfield · Jan 18, 2009

Jules, I finally got out and about today to try some long range shots with the 2X DOI HQ7 teleconverter. Had this thing a few months now and not tried it out in the field yet so visited my local lake today. It was blowing a gale and freezing cold so not ideal conditions. Plus what I find is that the water temperature is generally a fair few degrees higher than the air temp in the winter and you get a bit of heat haze just above the water so long range shots don't come out all that well due to imperfections in the air.

First image is from 150m approx. I have a map of my local lake with loads of distances marked off using google satellite maps so I can be fairly accurate with distances to birds on the lake. The lake is just over 400m across and the buildings in the 2nd image were on the far side, around 420m. The mechanical digger was a bit further so I'd guess around 430m to that. You can read all the writing on the digger which is pretty good for the range I think.

Paul.

JGobeil · Jan 18, 2009

Hey, this is much better than what I was able to do with the Tamron Pro TC. I guess I'll have to get one on eBay. Thanks for remembering - that's very nice of you.

Very cold here also - we got -35C. this week - not very good for digiscoping...

Regards
Jules

Paul Corfield · Jan 20, 2009

Picked up an Apogee 24mm Super Abbe Ortho eyepiece last week with a view to using it for eyepiece projection. It works well enough for that but even better was its performance when using a camera lens through it.

Took these two today with the Canon 450D and a 55mm Pentax SMC Takumar for the Blackbird (ISO800 1/60sec) and a Tokina 28mm RMC for the Blue Tit (ISO800 1/200sec). They give 1470mm and 750mm respectively through the scope plus if you add on the 1.6X crop factor then its 2352mm and 1200mm.

No vignetting with either lens through this eyepiece.

Paul.

Paul Corfield · Jan 29, 2009

Dug out my Celestron Ultima 2X barlow yesterday which I've had for quite a few months now and never used it after trying out when I first purchased it. Initially I was quite disappointed by the performance because of a lot of stray light issues which were washing out the photos and making the contrast very poor.

Anyway I've applied what I've learnt regarding baffling the light coming into the barlow and it's made a big improvement to the contrast and the initial results are encouraging.

Had to photograph these in the rain yesterday and the first 2 are from near on 100m and last one is 35m. Raining again today but should hopefully improve later so that I can try it out in better light.

Paul.

bluedubius · Jan 29, 2009

Tried one of Paul's stacking experiments. This Northern Cardinal was taken with the Celestron C80ED scope (600mm fl) and stacked GSO 2x barlow with a 2x Kiron teleconverter for a total 2400mm fl (3600mm with the 1.5x crop factor of the Nikon D2h). Just a quick shot (sorry about all the crap in front of the bird), but I think there's potential there if you really need some extra reach. Distance was about 100 feet.

bluedubius · Feb 4, 2009

Schools closed so home today. Decided to play around with the eyepiece projection method. This is a comparison between the Celestron C80ED at prime focus (600mm) and then a photo using a Scopetronix Maxview 40 digiscoping eyepiece coupled to a Fuji S2 Pro. Sorry, no birds in sight. The Maxview 40 yields 15X on the 600mm Celestron scope. Shot out the back door through a storm window in cloudy, snowy weather. The first shot was at 1/500th sec and the second at 1/60th, both at 400 iso. No processing other than to resize for posting (and flipping the image taken through the eyepiece). Had to use a lot of extension tubes to get the camera to focus when using eyepiece projection. Looks like roughly a 300% increase in size between the two.

Rick

Paul Corfield · Feb 4, 2009

Been shooting about 8 gigs a day this week trying out various bits. My favourite so far is the 2X Celestron Ultima Apo barlow combined with the Kenko Pro 300 1.4X teleconverter. I haven't checked exactly yet but at a rough guess I get around 3000mm equivalent with this combination. The Kenko works well combined with barlows and I get very similar results combining it with the GSO ED barlow. The Celestron is slightly sharper if you pixel peep and it also gives a bit more magnification.

Here's 5 images taken today using this combination, all photos have the ranges marked on them. First one impressed me the most at 100m but had to shoot into the sun an this is uncropped. On the Easy Jet I can even read the make of the tyres on the original photo at 100%. Easyjet is uncropped as is the Woodpigeon. Last two photos have been cropped a little but not by much. Had a lot of snow this week but if things are ok at the weekend then I'll try it out in the field.

Paul.

JGobeil · Feb 5, 2009

Last summer, I also tried some stacking. The Canon 1.4X TC and the GSO 2X ED Barlow were performing quite well. Stacking the Canon 2X and 1.4X TCs was not as good - not even close.

Paul, could you please describe the order of the components please - spacers and all. I'm really impressed by those pics.

Thanks
Jules

Paul Corfield · Feb 5, 2009

The order is Camera - Kenko 1.4X TC - 10mm macro tube - T-ring with 2" scope adapter and the barlow is held inside the 2" scope adapter.

I unscrewed the 1.25" chrome barrel containing the barlow lens from the main barlow body. Then I made a collar to go over the chrome barrel so that when I push it into the 2" scope adapter it is a tight fit. It sticks out the back of the t-ring a little which is why I need the 10mm macro tube between the TC and T-mount. On the front of the 2" scope adapter I have a small section of tube painted matte black internally and in the tube are a couple of baffles. Without this the internal reflections are really bad and the whole photo is washed out and lacks contrast. With the baffles it's as you see in the posted images, nice and contrasty. I do the same thing with the 2" GSO barlow and the section of tube with the baffles can be used on either one.

It's my birthday at the end of March so I might get a 2X Televue barlow and give that a try. Would be nice to see how it compares.

Paul.

JGobeil · Feb 5, 2009

Ah Ah ! Now I understand why I had difficulty understanding how you used the barlow. Yours is is different from mine.

Mine came as 3 pieces: the 2" barlow itself, an 8.5 cm long 2" spacer with brass compression rings and a 1.25" adapter also with brass compression rings. The barlow screws at the end of the spacer. There are no labels on the barlow nor the adapter and "Smart Astronomy ED 2x BARLOW Fully Multi Coated" is printed in white on the spacer. See here:
http://cgi.ebay.ca/GSO-2-2x-ED-Barlow-Lens-for-Telescope_W0QQitemZ120362435747QQcmdZViewItemQQptZEye_Pieces_Accessories?hash=item120362435747&_trksid=p3286.c0.m14&_trkparms=72%3A1215|66%3A2|65%3A12|39%3A1|240%3A1318

I can screw the barlow directly at the end of the CNC Supply EOS Adapter. I have not observed any internal reflections or flaring with my setup.

How close can you focus with the setup you described ? And where would you put additional spacers to focus closer ?

Paul Corfield · Feb 5, 2009

My 2" GSO is the same as yours but my Celestron Ultima is different which is the one I mount inside the t-mount. The GSO one I screw onto the front of the t-mount the same as you do. My t-mount isn't blackened inside which is probably why I get the hassle with reflections. Even so, the baffles make my teleconverters slightly more contrasty so they do provide some benefit so I'll probably keep using them once I get around to blackening the inside of my T-mount.

Been comparing the two again this morning and there's very little between them and I think any differences are just coming down to nailing the focus. The GSO being 2" also allows for a slightly higher shutter speed.

For close focus the spacers need to go between the scope and the barlow or teleconverter depending on whats used but it's always between the scope and the optics. I can get down to around 4m but you need about 100mm between the scope and the barlow for that. With a teleconverter I can get a lot closer because they don't increase the back focus needed in the same way barlows do.

Paul.

JGobeil · Feb 5, 2009

Thanks for your valuable info Paul. My CNC 2" EOS adapter is blackened and baffled - good stuff, very well made.

Paul Corfield · Feb 7, 2009

Been playing some more with the Celestron Ultima barlow today. Trying various of ways of mounting it and getting it dead square which isn't all that easy. Had some success though and as these images show it's capable of some impressive detail. Ran out of light in the end so will try some more tomorrow.

Paul.

JGobeil · Feb 8, 2009

Quite sharp isn't ! Some can't even achieve that with regular lenses...

bluedubius · Feb 9, 2009

Super. This is the type of high iso work I'm talking about. An image from my D2H at this iso would be unusable. Need a newer camera.

Rick

Paul Corfield · Feb 15, 2009

Celestron Ultima barlow with a 50mm macro tube between camera and barlow. This combination gives just over 2000mm or 3200mm with the Canon 1.6X crop factor.

1st image is 30m and pretty much faultless. The last two are 95m. Thought the Blue Tit in last photo was ok at this range for a bird that is only 11cm from tip of bill to end of tail.

Paul.

Neil · Feb 15, 2009

Paul Corfield said:
Celestron Ultima barlow with a 50mm macro tube between camera and barlow. This combination gives just over 2000mm or 3200mm with the Canon 1.6X crop factor.

1st image is 30m and pretty much faultless. The last two are 95m. Thought the Blue Tit in last photo was ok at this range for a bird that is only 11cm from tip of bill to end of tail.

Paul.

I'm still impressed with the images you are getting. I'm wondering how the new Panasonic G1 with 2x crop factor would go your type of setup. I can use my Nikon 300/2.8.
Neil

JGobeil · Feb 15, 2009

Wow ! Super photo !!!!

Paul Corfield · Feb 16, 2009

Cheers guys.

Neil, I see no reason why the G1 wont work as there's already people using it on astro scopes. The cost of the adapters have put me off getting one for now though.

There's this link that was posted in another thread a while ago where the G! is being used on a Borg astro scope.

http://www.tomytec.co.jp/borg/world/sakurei08_bird/0811/081104a.html

Paul.

Some digiscoping experiments with a dslr (1 Viewer)

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