Astroscope + DSLR = Gallery! (1 Viewer)

[DanC.Licks]

As I understand it a barlow is a TN, though usually geared to eye pieces rather than projection. Paul has tried them also, me thinks.

I agree with Paul on the TC vs TN thing for scopes. Olympus TCs are excellent (EC14 and EC20) but they don't match my €9 TN ripped out of an old Canon zoom when coupled with my SW. Bought them both used for a total of about €600. Now lets see....600 divided by 9 equals....

 

[Paul Corfield]

Hi Cango,

Thank you for the helpful clarification.
The initial focus was indeed on astroscopes, but as usual on BF, the thread 'evolved' somewhat, so comparisons with spotting scopes took over the discussion.
That said, it seems intuitive that a lens designed to provide an optimal image across a 35mm sensor would be much more challenging to build than something that serves the human eye. So presumably the crux is the sensor the scope or lens is designed for. Or is that another misunderstanding?

I think with the majority of camera lenses there's just too much glass to beat a simple two/three element telescope. Spotting scopes are a different matter because the prism/eyepiece are usually the limiting factors.

Paul.

 

[Paul Corfield]

As I understand it a barlow is a TN, though usually geared to eye pieces rather than projection. Paul has tried them also, me thinks.

Triplet element barlows are quite similar in design to triplet telenegatives from zoom lenses. Two elements are usually cemented and one isnt, it's just air spaced. The main difference I've seen is just that the two cemented elements in the barlow are different to the two that are cemented in the zoom lens teleneg. The main thing in common is they both use a double concave negative element. I've used the ones from zoom lenses on eyeypieces and they make a lovely cheap barlow alternative.

Paul.

 

[punta]

Sorry to be a pain, but can some one point me to the thread about how to mount these telenegatives. I have a old Pentax zoom that i have removed the TN from and would like to try it with my astroscope, but not sure how to do this.

Cheers

 

[Paul Corfield]

Sorry to be a pain, but can some one point me to the thread about how to mount these telenegatives. I have a old Pentax zoom that i have removed the TN from and would like to try it with my astroscope, but not sure how to do this.

Cheers

The thread is here (link below) for telenegatives and there's some examples for mounting. The easiest method is to get hold of a cheap second hand teleconverter off ebay, then strip it down and just glue in the telenegative. I keep my best one permantly glued into a housing like this and I've lined it all with black flocking paper. I have a few other other empty teleconverter tubes that I use as macro extgension tubes. I've got one telenegative which is a snug fit in the back of my 2" scope adapter and I've got another two which fit perfectly in the rear recess of an old teleconverter tube. There's lots of ways to do it, just depends on the shape of the telenegative to begin with as they vary in size/shape quite a bit.

http://www.birdforum.net/showthread.php?t=182146

Paul.

 

[punta]

The thread is here (link below) for telenegatives and there's some examples for mounting. The easiest method is to get hold of a cheap second hand teleconverter off ebay, then strip it down and just glue in the telenegative. I keep my best one permantly glued into a housing like this and I've lined it all with black flocking paper. I have a few other other empty teleconverter tubes that I use as macro extgension tubes. I've got one telenegative which is a snug fit in the back of my 2" scope adapter and I've got another two which fit perfectly in the rear recess of an old teleconverter tube. There's lots of ways to do it, just depends on the shape of the telenegative to begin with as they vary in size/shape quite a bit.

http://www.birdforum.net/showthread.php?t=182146

Paul.

Brilliant, thanks Paul

 

[Tord]

Perched Herons

A tiny river near home quite often attracts Herons wintertime.

I think the contrast shows signs of improvement after having flocked the extension tube (which was not too difficult).

SW80, E-620 @200 ISO

/Tord

 

[Tord]

Kingfisher

Same tiny river as I visited the other day. Light conditions we not that great in between showers. I wish the KF would have posed closer to get more details but still the picture is OK I think. Half crop of frame.

SW80, E-620 @ISO 800, 1/80s

/Tord

 

[DanC.Licks]

Very nice, Tord, but then, I have a soft spot for Kingfishers.

Super color!

 

[cango]

Nice catch Tord. Glad to see you still have Kingfishers down there

 

[JGobeil]

Nice photo Tord. This KingFisher is much different from the ones we have in Canada. Do you paint directly on the bird or is is done in post-processing ?

Seriously, this is a very nice picture. In fact, I'm a bit jealous - I don't even have a decent picture of our Belted Kingfisher we have locally.

Good work !

 

[Tord]

Nice photo Tord. This KingFisher is much different from the ones we have in Canada. Do you paint directly on the bird or is is done in post-processing ?

Seriously, this is a very nice picture. In fact, I'm a bit jealous - I don't even have a decent picture of our Belted Kingfisher we have locally.

Good work !

Jules,
Thanks for feedback.

This species of Kingfisher is Alcedo atthis. It is also known as Eurasian Kingfisher or River Kingfisher. We have them in southern part of Sweden, with conservation status vulnerable. Where I live the KF population is resident. This tiny river has, though it is flowing through a semi-urbanized are, quite clear water and is relatively unpolluted. Furthermore we are close to the coast meaning a higher chance of finding open water wintertime (i.e. free from ice). This tiny river is regarded as one of few places offering a decent chance to spot a KF wintertime.

I had just deployed the setup when he/she landed and posed a few seconds, long enough for me to take five frames.

Light was not that great (800 ISO and 1/80s) and the sheer distance (25-30 meters) meant I had to crop so details are missing. I have not enhanced the colors or contrast, just applied a slight unsharp mask.

I plan to go back later this winter when light is more favorable (higher sun or snow) and try to take pictures from a better location (read: closer). Stay tuned...

/Tord

 

[JGobeil]

Hello Tord,

Thanks for the info on your Kingfisher Alcedo atthis. Ours is the Belted Kingfisher (Ceryle alcyon). Although it is not rare, it is quite fierce and very difficult to photograph. I've never been able to get a good photo.

Happy New Year
J

 

[Tord]

Kestrel

Not the prettiest of settings and shot in not so great light conditions from the car window but I am quite pleased with this one.

SW80ED + 1.4 EC, E620 @ISO 400.

 

[DanC.Licks]

Nice, Tord. You are a lucky guy to see one that close!
Could be a tad lighter though. Looks pretty dark here.

 

[JGobeil]

My first serious test with the Astro-Tech 80ED

My friend the Great Grey Owl was a cooperative model for this first test since it stayed motionless for hours... What a threat ! 25-30 m. distance. However, Owls are not ideal for these tests since their feathers are very fluffy and often look like out of focus.

P1 - OM-D with 100-300mm telephoto lens at 300mm (600mm FF eq.)

P2 - OM-D with A-T 80ED and 50mm spacer only (1100mm FF eq.)

P3 - OM-D with A-T 80ED, 2X Barlow and 50mm spacer (2200mm FF eq.)

P4 - P2 cropped about 100% to compare with P3 (2200mm FF eq.)

All pics: no crop except P4. Usual post-processing in LR and PS. ISO 800, 12 s. shutter delay except P1.

I'm quite pleased with the results. The cropped 1100mm photo (P4) looks as sharp as the one taken with the Barlow (P3); this seems to indicate that the Barlow is not that good a performer. A 1.4-1.5X TC or TN would have been nice.

What do you think ?

 

[DanC.Licks]

For me, P3 wins. Even though there is a little IQ degradation due to the added glass the increased resolution more than makes up for it. Which Barlow did you use? TNs are better than TCs on the scope. Lucky guy to have such a cooperative model!

 

[Paul Corfield]

Would love to have a subject like that Jules, I'd probably fill up a few memory cards just trying stuff out lol.

If you look at the barlow photo, especially down the right hand side of the bird (as we look at it), you can see a lot of very fine feathers sticking out. In the cropped photo you can hardly see any of these so I'd say the barlow has a slight edge here.

Paul.

 

[cango]

Lovely model and series!

IS on or off?

 

[JGobeil]

Lovely model and series!

IS on or off?

Thanks. IS on with the 100-300mm lens, off with the scope where I used a 12 s. shutter delay.