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#1 |
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He's pining for the Fjords !
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Anyone digiscoping with DSLR at prime focus?
I bought my Nikon D70 digital SLR a while ago (mid 2004) and used it successfully with big scopes for astronomy at prime focus. Now I'm quite happily using it with my new much smaller 500mm FL f6 scope (effectively a 500mm f6 manual lens, instead of the Tamron 28-300mm).
Just wondering if anyone else here uses the prime focus technique, rather than the much more commonly used afocal projection (with eyepiece and adaptor to camera) ? |
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#2 |
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Registered User
Join Date: Jul 2003
Location: Jerusalem - Israel
Posts: 505
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Hi David,
I use it now and then with the Celestron C5 scope. Focal length is about 1200 mm, and even though the scope is quite big, it's not heavy enough to balance well with my D2X or D200 cameras. With very long exposures and very short exposures it's fine and outputs nice results. There's some vignetting though at the edges. I've added recently the reducer and vignetting is gone. Focal length is shorter (700~800mm) and the results are very nice. However, the bulkiness of the scope prevents me from walking around with it. On top of that, I fell in love lately with the Leica SLR adapter mounted on my Apo 77 - providing the same focal length with stellar results (I've uploaded some samples in this site). That said, I usually prefer the safe way - the 200-400 AFS VR F/4 + TCs and a P&S camera with scopes for the ultra long range... |
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#3 | |
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Registered User
Join Date: Jun 2004
Location: Portugal
Posts: 303
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Quote:
Here's a page with shots from it, most have a kenko 1.4x converter on, and some even a stacked Sigma 1.4x too: http://www.smugmug.com/gallery/1489917 |
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#4 |
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He's pining for the Fjords !
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Nice work Fernando !
What ISO settings do you use if you are running the scope and converter (at what must be f10 or so ?) |
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#5 |
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Registered User
Join Date: Jun 2004
Location: Portugal
Posts: 303
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Thank you for the compliment.
Yup, F/10.5 with one converter. Mostly between ISO 400 and 800, depending on the situation. Flight shots I allways do at ISO800 to keep the shutter speed high. With the scope alone I'm allways at ISO400 unless the light is very very poor. |
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#6 | |
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Registered User
Join Date: Feb 2005
Location: Near Metz, Lorraine, France
Posts: 54
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Quote:
Your setup is not common and very interesting. Did you compare it with "standard" disgiscoping or "standard" telephoto ? The main problems with long AF lenses are the price and the weight. And they are not "that" long... With digiscoping, the focal is much higher and it is very difficult to get a precise focus, especially on far subjects. Is the focus very precise on this scope ? Do you use a tripod or monopod or can it be used without it ? |
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#7 | |||||
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Registered User
Join Date: Jun 2004
Location: Portugal
Posts: 303
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Quote:
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Second, practice, my keepers rate as been improving more and more through the time I've been using the scope, an year and a half now. Right now in ten flight shots maybe two or three are out of focus but not by much. Quote:
http://www.smugmug.com/photos/65421586-O.jpg You can see moiré in the pic, that shows that even with stacked converters the lens is reaching the camera's full resolution. About comparing it with other systems, not really, only with my own telephotos, Sigma 400 APO Macro, Tokina ATX400, Sigma 100-300. But the scope is much better than any of these in any level. I wish I could get the opurtunity of comparing it to other systems or big lenses but so far I hadn't. Quote:
About the reach of the scopes VS telephotos, in this case the reach is the same as a 600mm lens, as this is a 600mm scope at prime focus, alltough the 600mm lens is much brighter. Off course you can add converters to strech the reach but you also can do that with a 600mm lens. Quote:
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#8 |
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Registered User
Join Date: Feb 2005
Location: Near Metz, Lorraine, France
Posts: 54
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Hi Fernando ,
Thanks for all these answers ! Your pictures (and others from a French photographer) are so convincing that a friend of mine is about to order the scope ! I have a last question : I've read that the minimum focus distance was pretty high (15m ?) . Even if the purpose of such a setup is not to make macrophoto, this can be a problem. Do you use an extension tube to reduce it ? |
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#9 | |
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Registered User
Join Date: Jun 2004
Location: Portugal
Posts: 303
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Quote:
In my scope the 7.5cm focusing travel is enought to focus from infinity to +-6m witch is more than enought with this focal lenght. Make sure you set the adapter in a way that the scope is focused at infinity when the focus barrel is retracted. I'm using a homemade adapter made from an unused Nikon lens, I took out every piece of glass from inside it and also the mechanical parts, I only left the electronic gear, this way I get to keep the metering on the lens. I stuck a 2" focus extender (for telescopes not photography) inside it and it's done. Here's a pic from the gear: http://www.smugmug.com/photos/53578989-L.jpg This is not the color of the scope, I repainted it as I hated the original color. BTW witch scope is your friend gonna buy? |
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#10 |
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He's pining for the Fjords !
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Hey Fernando, that is a great idea using an old Nikon lens to use the metering!!!
You should try selling them, I'd buy one for sure ! Guessing the exposure timing is OK but you only need the sun to go in or come out, and your guesswork is way off. I reckon I get only 20% of my scoped shots coming out with OK exposures. |
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#11 | |
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Registered User
Join Date: Feb 2005
Location: Near Metz, Lorraine, France
Posts: 54
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#12 | |
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Registered User
Join Date: Jun 2004
Location: Portugal
Posts: 303
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For example the adapter I have works from infinity to about 6m on the ED80 but on a Vixen 80SS I had it would only work from infinity to about 15m or so, for the Vixen the adapter needed at least 5cm more lenght. But if you really want one made, find a lens you don't want/need and we'll discuss the price for the mod ![]() |
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#13 | |
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He's pining for the Fjords !
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Quote:
![]() Thanks for the concept at the very least ! |
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#14 | |
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Registered User
Join Date: Jun 2004
Location: Portugal
Posts: 303
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Quote:
Tell her to show some photos when she gets it. |
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#15 | |
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Registered User
Join Date: Jun 2004
Location: Portugal
Posts: 303
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Why would you need to know the pin connection? Just make sure you don't damage the electronics while disassembling the lens. There's no need of messing with pins. |
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#16 | ||
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Registered User
Join Date: Feb 2005
Location: Near Metz, Lorraine, France
Posts: 54
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Her English is even worse than mine, so she prefers me to ask the questions... If you speak a little French, you can write to her directly ! |
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#17 |
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Registered User
Join Date: May 2006
Location: suffolk
Posts: 4
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David
Sorry to drag you back to the start of this thread, but I am a beginner and trying hard to catch up. In my earlier thread I asked for advise on using a D70, Nikon FSA-L1 and a suitable Nikon 'scope. As the FSA plugs directly into the 'scope (i.e. no eyepeice) and bayonets directly into the body of the D70, is this not prime lens working? I agreed the adapter is not cheap, there is a commitment to use a Nikon ED 'scope and a support for the camera is probably required, but would it match Fernando results? |
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#18 |
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Registered User
Join Date: Jun 2004
Location: Portugal
Posts: 303
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Go preparing your wallet then, you'll sure like it.
![]() I took a look at her gallery, the deer shots are great. And no, unfortunately I can't speak French at all. |
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#19 | |
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He's pining for the Fjords !
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Quote:
The biggie here with say a Nikon spotting scope is the focal length and focal ratio of the scope, as it is taking the place of the lens. My scope is a 500mm f6.2 with an 80mm objective lens. If the Nikon is an 82mm, check its overall length - that may give you an idea of the focal ratio. I think the smaller spotting scopes must have a much shorter focal length, therefore, not *that* much better at prime focus than say my 28-300mm zoom lens. example of the sums : diameter x focal ratio = focal length 80mm x f6.2 = 496mm focal length Fernando does take some damn fine images but he has a lot of experience and has the advantage of metering with his special modded lens adaptor, so he does NOT have to guess his exposure times as I do. However, if you can gain that experience with a bigger scope, then there is no reason why you too could not achive similar results.To summarise (sorry, Ive just been thinking out loud here) - How much can you afford ? (my scope and T2 mount adaptor was about £250) What level of convenience do you want ? (my setup is fully manual only) What weight are you prepared to lug about ? (mine weighs in with camera and scope & tripod at over 10KGs, NOT really portable if out walking !) Feel free to contact me by PM or email and we can arrange a chat on the phone if you like, I'm always happy to try and help. Bear in mind my background is astronomical photography, so my knowledge of scopes is slightly different to most in here (not meaning to sound big headed guys !) Still confused ?? Hope not ![]() =========== Fernando, thanks for the last message. I assumed that the AF system would need to be disabled. |
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#20 | ||
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Registered User
Join Date: Jun 2004
Location: Portugal
Posts: 303
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Quote:
images, but I still prefer the system I'm using for many reasons: - Price, a Nikon 82ED cost +-1000€ +350€ for the FSA adapter. The ED80 costs 400€ and the homemade adapter costs around 30€ to 50€ at best. You can add two kenkos converters for more 350€ to have the same focal lenght more or less. Anyway it's around 800€ for the SKywacher system VS 1350€ of the Nikon system. - Optical quality, the spotscopes are nice and resolution wise they can probably outresolve the D70 anyway so in this department they're both very good, but the bokeh I've seen from this systems is really harsh nothing at all like what I'm getting from the skywatcher even with converters, witch is very smooth. - Focal lenght options, with the skywatcher I have 600mm F/7.5, 840 F/10.5 or 1200 F/15 depending on the converter used, so I can pretty much adapt to every situation. With the Nikon system you're stuck with 1000mm at F/13, in some situations this is too much focal lenght and more important too dark. - If I want to change my camera brand I can still use my scope just have to redo the adapter, with the Nikon you're stuck. For DSLRs the only advantage I find on the Nikon system or any similar system is the size, the scopes are very compact and easy to put on a backpak, the Skywatcher on the other hand is huge. For compact cameras spotscopes are the best choice though. Quote:
Of course the gears of the lens should come off. |
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#21 |
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Registered User
Join Date: Jul 2005
Location: Singapore
Posts: 168
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Hi Fernando,
I can honestly say that I am blown away! Your images are splendid! I just purchased a William Optics Zenithstar II ED (80mm) and have the intention to use it for prime focus bird photography. I would be interested to know more about Nikon lens modification you made and the actual connection between the Nikon lens, the 2" extension and your teleconvertors. Have you ever tried a barlow/powermate instead of the teleconvertors? After seeing your images, I think I will forego digiscoping and focus on getting my scope set up to work with my D50 Thanks again for sharing. |
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#22 | ||
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Registered User
Join Date: Jun 2004
Location: Portugal
Posts: 303
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Quote:
I've been considering changing my ED80 for your WO, so I'm very interested in seeing the results that your scope can do. I want the WO because of it's size and also it's mechanical quality. SO when you finish your setup please show me a few shots (from and with the scope) and also how long is it with the adapter instaled and with the hood retracted, OK? Here is a few shots of the first lens I used for this setup, I build this when I was using a Vixen 80SS, a Quantaray 35-70mm: http://www.smugmug.com/photos/75971734-O.jpg The adapter finished and ready to use http://www.smugmug.com/photos/75971733-O.jpg Inside the focus ring rubber there's four screws holding the extension tube in place. http://www.smugmug.com/photos/75971730-O.jpg A pic of the extension tube and the lens allready without the glass and ready for the tube. This extention tube was done with a 1.25" barrel. On the other one (the 28-80 lens) I used the 2" barrel. While doing this you'll have to measure the point where your camera is focused on infinity, you'll have to consider this distance when building the adapter, I suspect for that WO the adapter is going to be quite long. If you don't do this and built a short adapter the setup will focus way past infinity and will never reach the closest focus possible, in my scope I have a range from about 6m to infinity, without extra parts. Here is how everything looks today with the 28-80 lens and the D70. http://www.smugmug.com/photos/75971727-O.jpg Obviously this isn't the original skywatcher color. The converters (after the adapter is made) are connected the same way their connected to any regular lens. I didn't use barlows but I did try a Powermate 2" 2x on the Vixen not the ED80, so I cannot comment about how well it would work on the ED80. With the Vixen I considered the powermate unusable, it was soft on the center and very soft on the corners, but keep in mind that the Vixen is a 400mm F/5 achromat and converters/barlows/powermates results are only as good as the glass they're atached so I can't draw conclusion from it, but I did expected better. What I also didn't like is that it's a very heavy part, much heavier than the Kenko 2x. Frankly considering the weight and price of the powermate alone I think you'll be better of with a Kenko 2" converter, plus it will fit allmost every other lens you'll attach it to. I hope this helps, anything more please ask. |
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#23 |
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Registered User
Join Date: Jul 2005
Location: Singapore
Posts: 168
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Thanks Fernando.....
I can see myself asking more detailed questions when I actually have everything in hand and find myself ready to put it all together. I am very happy to assist as much as I can. You must understand though....I am a complete novice. I just received this scope last Wednesday and I am a bit overwhelmed. Still, I will share my experiences for what they are worth. I have a 1.4x teleconvertor. This should be good to start with. However, I am looking at a device from Siebert Optics called a Power Mag Wheel. It is a Barlow type device that allows the user to dial between 2x, 2.5x & 3x (there are about 4 different power combinations available) I will be traveling next week. I hope to be able to get busy with my scope the week after. I will let you know how I get on. Actually, I have already started a thread under scope section where I plan to let folks know how I get on with digiscoping with the WO scope when I get a chance. Last edited by birdeast : Saturday 17th June 2006 at 14:42. |
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#24 | |
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Registered User
Join Date: Jun 2004
Location: Portugal
Posts: 303
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Quote:
About the Power Mag, I know nothing about it but I really doubt you're gonna use much of the 2.5 and 3x settings, remember that your scope with a 2x converter is at 1090mm F/13.6 witch is still useable a lot of times and with a 3X it will be at 1635mm F/20.4, I really doubt you'll find many times where you can use such a setting for bird photography, that's too long and way too slow, you'd also need a monster tripod to keep a setup like this steady enough for photography. So you'll probably find out that it's cheaper, lighter and better optically to stick with a 2x converter. This is just my opinion of course. |
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