Nikon D90 + Vixen ED81S ? (1 Viewer)

pinkster2008 · May 2, 2012

Hi

I'm new to bird photo currently own a sigma 50-500 OS but I wish to have more reach. I'm currently in the market for a telescope, my local store have two ED in stock

Astronomy Technologies Astro-Tech AT72ED 72mm f/6 ED doublet refractor $500

or

Vixen Optics ED81S Telescope

http://www.bhphotovideo.com/c/product/657219-USA/Vixen_Optics_5864_ED81S_Telescope.html

including

Vixen Optics f/5.2 Focal Reducer for the ED81S
http://www.bhphotovideo.com/c/product/530638-REG/Vixen_Optics_3666_f_5_2_Focal_Reducer_for.html

for $960

been taking macro pictures therefore I already have two sets of extension tube by Kenko Auto Extension Tube DG.

I will be getting T adapter for Nikon for $25

___________________

I'm looking for advice to what I needed to know when buying these telescope ? how do I test the image quality of these telescope (camera setting ISO, speed etc..)

Thank you very much for your time.

Paul Corfield · May 2, 2012

The astro tech is only 430mm focal length which is shorter than your Sigma lens. Probably FPL-51 galss which isn't as good as FPL-53 like we have in the Skywatcher 80ED.

If I had to pick between just these two I'd go for the Vixen which I think is FPL-53 glass. It's about the same weight as the Skywatcher 80ED and the Vixen comes with a carry handle as standard which helps when you are out and about.

Camera needs to be on full manual mode, ISO400 or 800 is about right. Use spot metering or centre weighted metering as a guide to shutter speed, generally though you might need to under expose a little to get the photo just right.

Paul.

pinkster2008 · May 2, 2012

Hi Paul

Thank you very much for your advice,

Another question.

Since I already have Manfrotto 486RC2 Compact Ball Head with RC2 Rapid Connect System and a monopod. Will I be able to use these or at least the ball head ? I don't have any triop at the moment any suggest for a tripod within $200 ?

Thanks

Paul Corfield said:
The astro tech is only 430mm focal length which is shorter than your Sigma lens. Probably FPL-51 galss which isn't as good as FPL-53 like we have in the Skywatcher 80ED.

If I had to pick between just these two I'd go for the Vixen which I think is FPL-53 glass. It's about the same weight as the Skywatcher 80ED and the Vixen comes with a carry handle as standard which helps when you are out and about.

Camera needs to be on full manual mode, ISO400 or 800 is about right. Use spot metering or centre weighted metering as a guide to shutter speed, generally though you might need to under expose a little to get the photo just right.

Paul.

Paul Corfield · May 2, 2012

A lot of nature photographers use and prefer big lenses with monopods so I don't see any reason why you couldn't use the telescope on one. There's some technique to it from what I gather but it's probably worth a try. Some of the big camera lenses can weigh a few pounds more than the telescope too. Never tried a monopod myself though.

As far as tripods go I'm not really well conversed in them. I got an unbranded copy of a Manfrotto tripod on ebay which was about half the price. I'm living in the UK and wouldn't know what to recommend for you though in the USA. I'm still using the ball head that came with my tripod. It's not as nice as a pan and tilt head in that I have to be careful that the scope doesn't topple to the side if I loosen the head too much. Apart from that I get by fine with it.

Paul.

pinkster2008 · May 2, 2012

Hi Paul

Thank you for your fast reply, what is the total weight of your set up ? if you don't mind please let me know what you're using beside skywatcher 80ED ? (camera body, extension, mount, flash ??)

Thanks

Paul Corfield said:
A lot of nature photographers use and prefer big lenses with monopods so I don't see any reason why you couldn't use the telescope on one. There's some technique to it from what I gather but it's probably worth a try. Some of the big camera lenses can weigh a few pounds more than the telescope too. Never tried a monopod myself though.

As far as tripods go I'm not really well conversed in them. I got an unbranded copy of a Manfrotto tripod on ebay which was about half the price. I'm living in the UK and wouldn't know what to recommend for you though in the USA. I'm still using the ball head that came with my tripod. It's not as nice as a pan and tilt head in that I have to be careful that the scope doesn't topple to the side if I loosen the head too much. Apart from that I get by fine with it.

Paul.

Paul Corfield · May 2, 2012

Total weight of scope + tripod + camera and fittings is 13.75 lbs.

Canon 450D body + T-ring/2" scope adapter + 75mm extension tube.

The total weight isn't too bad compared to an equivalent 600mm camera lens which can weigh around 12lbs on its own.

Paul.

pinkster2008 · May 2, 2012

Thanks again for your fast reply.

Do you have any experience with TC 1.4 or 1.7 or 2 ? how is the image quality ?

I have try sigma TC 1.4 on my sigma lens 50-500 OS and the image is a little soft at 500mm.

Thanks

Paul Corfield said:
Total weight of scope + tripod + camera and fittings is 13.75 lbs.

Canon 450D body + T-ring/2" scope adapter + 75mm extension tube.

The total weight isn't too bad compared to an equivalent 600mm camera lens which can weigh around 12lbs on its own.

Paul.

Tord · May 2, 2012

pinkster2008 said:
Thanks again for your fast reply.

Do you have any experience with TC 1.4 or 1.7 or 2 ? how is the image quality ?

I have try sigma TC 1.4 on my sigma lens 50-500 OS and the image is a little soft at 500mm.

Thanks

I am new in the "astrophotography" myself. Got my setup up this week and tried it yesterday, with and without 1.4 TC

The 1.4 TC worked fine. Viewfinder was darker, as expected and it somewhat more difficult to focus but the IQ was fine on the pictures where I got focus right.

As you write the Bigma with 1.4 TC produces somewhat soft images at 500mm, I share this experience.

/Tord

pinkster2008 · May 2, 2012

Hi Tord

Thank you for your replied.

Is your new set up on tripod or monopod ?

Is shutter release cable is a must ?

Thanks

Tord said:
I am new in the "astrophotography" myself. Got my setup up this week and tried it yesterday, with and without 1.4 TC

The 1.4 TC worked fine. Viewfinder was darker, as expected and it somewhat more difficult to focus but the IQ was fine on the pictures where I got focus right.

As you write the Bigma with 1.4 TC produces somewhat soft images at 500mm, I share this experience.

/Tord

Paul Corfield · May 2, 2012

I have a Kenko Pro 1.4X and that works very well, no detectable loss in image quality. I also make my own 1.5X teleconverters using the telenegative lens group from old zoom lenses. They work as good as my Kenko Pro 1.4X, so much so that I haven't used my Kenko in a couple of years. Here's a link to a photo I took with the lens group from an old Sunagor 100-200mm lens. With old zooms if you remove the front objective there is another lens group which moves up and down when you operate the zoom. This small lens group usually just unscrews and retains its own housing. I just mount mine in an old teleconverter case or inside the T-ring. http://www.birdforum.net/attachment.php?attachmentid=310956&d=1299074522 The old 100-200mm lenses work the best and can usually be found cheap on ebay under the brands Prinzflex, Minolta, Miranda, Sunagor etc. Other ranges like 80-200mm or 80-300mm etc tend to have a slight edge softness but they work ok to a point.

I briefly had a Kenko Pro 3X and that wasn't very good at all. The scope can handle 3X easily but the Kenko just wasn't up to it. Never tried the Kenko Pro 2X so can't comment. I tend to just stack a couple of my home made ones if I need to. Generally 1.4X is usually enough though.

As far as a release cable is concerned, they are useful to have if you need to go to a slow shutter speed. I tend to always like to pan around a lot so I don't use a cable very often. For high mag, like 2x and above they are also useful.

Paul.

pinkster2008 · May 2, 2012

WOW, beautiful picture, how far are you away from it ? (% crop ?)

With my DX body (nikon D90) without TC 1.4. I still have 625mm from ED81S should be enought the get some decent bird body not head shot like yours yet.

Thanks

Paul Corfield said:
I have a Kenko Pro 1.4X and that works very well, no detectable loss in image quality. I also make my own 1.5X teleconverters using the telenegative lens group from old zoom lenses. They work as good as my Kenko Pro 1.4X, so much so that I haven't used my Kenko in a couple of years. Here's a link to a photo I took with the lens group from an old Sunagor 100-200mm lens. With old zooms if you remove the front objective there is another lens group which moves up and down when you operate the zoom. This small lens group usually just unscrews and retains its own housing. I just mount mine in an old teleconverter case or inside the T-ring. http://www.birdforum.net/attachment.php?attachmentid=310956&d=1299074522 The old 100-200mm lenses work the best and can usually be found cheap on ebay under the brands Prinzflex, Minolta, Miranda, Sunagor etc. Other ranges like 80-200mm or 80-300mm etc tend to have a slight edge softness but they work ok to a point.

I briefly had a Kenko Pro 3X and that wasn't very good at all. The scope can handle 3X easily but the Kenko just wasn't up to it. Never tried the Kenko Pro 2X so can't comment. I tend to just stack a couple of my home made ones if I need to. Generally 1.4X is usually enough though.

As far as a release cable is concerned, they are useful to have if you need to go to a slow shutter speed. I tend to always like to pan around a lot so I don't use a cable very often. For high mag, like 2x and above they are also useful.

Paul.

Paul Corfield · May 3, 2012

Photo was from 10m (33 feet), here's a link to the original. Can't remember the size of the crop but you get an idea what the original showed. Detail from that home made 1.5X teleconverter is slightly better than the Kenko Pro 1.4X.

http://www.birdforum.net/attachment.php?attachmentid=310955&d=1299074510

Paul.

pinkster2008 · May 4, 2012

The Vixen ED81S didn't working out.

I saw this one for sell use locally. Please let me your opion regarding to this.

Thanks

WO Megrez 90 Doublet APO for $800

http://www.williamoptics.com/telescopes/megrez90_spec.php

Paul Corfield said:
Photo was from 10m (33 feet), here's a link to the original. Can't remember the size of the crop but you get an idea what the original showed. Detail from that home made 1.5X teleconverter is slightly better than the Kenko Pro 1.4X.

http://www.birdforum.net/attachment.php?attachmentid=310955&d=1299074510

Paul.

pinkster2008 · May 5, 2012

Hi Paul

I saw able to locate two lens

Sigma 100-200mm F/4.5 Telephoto Zoom lens, this is a bayonet mount Telephoto zoom lens used on a Konica for $30

and

Canon 100-200mm FD $40

How are they compare to Sunagor 100-200 ?

Thanks

Paul Corfield said:
I have a Kenko Pro 1.4X and that works very well, no detectable loss in image quality. I also make my own 1.5X teleconverters using the telenegative lens group from old zoom lenses. They work as good as my Kenko Pro 1.4X, so much so that I haven't used my Kenko in a couple of years. Here's a link to a photo I took with the lens group from an old Sunagor 100-200mm lens. With old zooms if you remove the front objective there is another lens group which moves up and down when you operate the zoom. This small lens group usually just unscrews and retains its own housing. I just mount mine in an old teleconverter case or inside the T-ring. http://www.birdforum.net/attachment.php?attachmentid=310956&d=1299074522 The old 100-200mm lenses work the best and can usually be found cheap on ebay under the brands Prinzflex, Minolta, Miranda, Sunagor etc. Other ranges like 80-200mm or 80-300mm etc tend to have a slight edge softness but they work ok to a point.

I briefly had a Kenko Pro 3X and that wasn't very good at all. The scope can handle 3X easily but the Kenko just wasn't up to it. Never tried the Kenko Pro 2X so can't comment. I tend to just stack a couple of my home made ones if I need to. Generally 1.4X is usually enough though.

As far as a release cable is concerned, they are useful to have if you need to go to a slow shutter speed. I tend to always like to pan around a lot so I don't use a cable very often. For high mag, like 2x and above they are also useful.

Paul.

Paul Corfield · May 5, 2012

I've had both of those and while they were ok they weren't ones I'd use in place of my Sunagor or the Prinzflex.

I'd say the Sunagor is my favourite and Sunagor made their own lenses in house so this doesn't turn up under any other branding. Next is the Prinzflex 100-200mm which is very close to the Sunagor. The Prinzflex is a generic lens which turns up under all sorts of names, Mirage 100-200mm is a common variation of it. I just had a look on ebay and saw a Promura 100-200mm which was the exact same lens. I'd probably wait for a Prinzflex, on our ebay in the UK there were 8 listed for sale just now, plus one Mirage and one Promura.

I tend to look for lenses faulty, in need of repair or ones that have fungus in and these can be had really cheap. The fungus comes off easily with a cleaning cloth.

Paul.

pinkster2008 · May 18, 2012

Alright, here is the pictures of my first test with my Skywatcher black diamond 80mm ED, FL 600mm. I don't have any TC yet, so just the my extension tubes; 36mm+20mm+12mm+27.5MM. What I found, there is a limit range of focus, within 6 meter to 30 meter anything closer or further is out of focus.

Thank you Paul for the great advices.

untouch

crop 100%

Paul Corfield · May 18, 2012

I'd check then that you are getting full focus travel. Sometimes when they are new the grease on the focuser can prevent full travel or the grub screws on the focuser may need some adjustment to get the tension just right. This problem has cropped up before and you will be able to get it to focus to infinity with a little bit of adjustment.

Photo looks great btw.

Paul.

pinkster2008 · May 18, 2012

Test again today, and found when I took away 27.5mm extension tube my range to up to almost infinity. So 95.5mm extension not a good idea. Also test with Kenko 1.4x the picture looked very good.

Thanks again for all you help Paul

Paul Corfield said:
I'd check then that you are getting full focus travel. Sometimes when they are new the grease on the focuser can prevent full travel or the grub screws on the focuser may need some adjustment to get the tension just right. This problem has cropped up before and you will be able to get it to focus to infinity with a little bit of adjustment.

Photo looks great btw.

Paul.

pinkster2008 · May 25, 2012

Please help, I just took apart an old vivitar 75-205mm and here is the part that I think is a telenegative. I'm not sure how I could remove the housing.

Thanks

Paul Corfield · May 25, 2012

I've had a few like that and I'm pretty sure that's as far as it can go with regards to stripping down. You can either try and mount it as it is or hacksaw off the bottoms of the three legs and then sand or file them down nice and flat. This style can be mounted but they aren't always as easy as the simple round housings. Sometimes bits of the old lens can be used to make mounting them easier.

Paul.

Nikon D90 + Vixen ED81S ? (1 Viewer)

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