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Apo triplet lens cells on ebay (1 Viewer)

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Paul Corfield

Well-known member
This is a seller whose stuff I look in on from time to time on ebay. They never have a great amount of things for sale at any one time but it's one of the few sources of triplet lens cells that I know of. They have a nice 106mm diameter, 700mm focal length, FPL-53 triplet cell for sale at the minute which I bet would make a lovely scope or an upgrade to an existing scope.

http://shop.ebay.com/great-eye/m.html?_nkw=&_armrs=1&_from=&_ipg=&_trksid=p4340

Paul.
 
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I've been looking/hoping for a 600mm F/6 (Triplet or at least FLP-53 doublet) lens for sometime now, that's very close to it, great find... my finances are a bit low at this time but if they keep selling it, I'm gonna give these a serious though in the future, although I'd still prefer a 600mm due to size of the scope.
I'd really love to build my own scope one day, with machined tubing, aperture control, etc.
 
If you look at that sellers feedback you can see some of the stuff they've sold in the past. One of the most common ones they sell is an 80mm f7 triplet (560mm focal length). They average at around $250 per sale which is very reasonable. Might be worth emailing them to see if they can do a particular size, maybe something nearer to 600mm.

Paul.
 
The FPL 53 is Ohara glass, yes ? Is there a signifcant increase in sharpness and IQ compared to the ED glass in the SW 80ED ?
 
The Skywatcher also has FPL-53 but doesn't have the third correcting element. Generally you get one element of FPL-53 in a triplet and a doublet. The other two elements are made of something else and they all come together to form the best colour correction possible. That's the theory anyway, it depends on the manufacturer as to whether they find the best combination of glass. Stray colour aberrations are so small in the SW 80ED that's it isn't something you would ever really try and improve upon. And a bad triplet can have more stray colour than a good doublet. The only upgrade I would really consider would be to get a larger aperture over a similar focal length to the SW. As a standard rule of thumb, a larger aperture should give you better resolution compared to a smaller one.

Paul.
 
In my case, what I'm looking for isn't a resolution increase, I'm more than happy with the ED80 resolution or colour correction.
What I want is more light, 100mm is 1/2 stop increase over the ED80, it's not much but it will help, every bit helps.
Of course bigger would be even better, but a 100mm aperture is as much as I'm going to afford while keeping good color correction and quality, also I don't think I want to carry much larger than a 100mm tube in the real world.
 
I'm sure i have seen somewhere , a 100mm scope that has a short tube assembly

cant think of the name right now

Maybe Astro-Tech, Stellarvue, or TMB
 
Paul Corfield said:
360mm focal length isn't much use to anyone. You would need to be like 10m from the bird, even with a teleconverter it would be a struggle.

Paul.
Click to expand...

With the greatest respect, as a TV-60 owner, I have to disagree with that last statement. None of my wildlife shots are taken over 400mm and I think I do pretty well, considering. The target doesn't always have to fill the frame to make a good shot.
 
markkilner said:
With the greatest respect, as a TV-60 owner, I have to disagree with that last statement. None of my wildlife shots are taken over 400mm and I think I do pretty well, considering. The target doesn't always have to fill the frame to make a good shot.
Click to expand...

Who said anything about having to fill the frame to be a good shot, I certainly didn't. A 360mm scope is ok if you can get on top of the bird or sit in a hide all day and wait for the bird to come to you. Why limit yourself though? At 10m it would barely fill 1/4 of the frame. My 600mm scope at 10m will fill about half the frame with a Robin sized bird at 10m. I like to get out and walk country lanes and am usually shooting across fields, maybe 50m, 100m sometimes as much as 300m. Get what suits your needs but if just starting out there's no need to limit yourself to a little scope, may as well get a lens.

Paul.
 
Fair enough, but the whole point of getting a small scope was so I could move around quickly and comfortably and shoot without a tripod, which I wouldn't be able to do with a bigger, heavier scope. Like you, I'd rather enjoy the countryside than sit in a hide all day.

(I'm not trying to start an argument here; there are pros and cons to every approach, which is why I took issue with your sweeping "360mm focal length isn't much use to anyone" statement.)
 
My first few scopes were all small, I never carried a tripod and just used to lean up against what ever was available and it's a great way to photograph. There's a lot of times though that the photos suffered through lack of reach. I upgraded to a 520mm scope and still found I needed a bit more and the 600mm fits quite nicely. If you already have a TV60 then it's a great lens but if just starting out with no scope I wouldn't recommend a short scope over an equivalent length lens when they are around the same price. When you get up to 600mm then the price difference is so vast that the scope is the obvious choice.

Paul.
 
There was a similar discussion to this on one of the Flickr groups a while back. (I'll post the link if I can find it.)

I agree with you that a 600mm scope is a steal compared to a 600mm (or even a 500mm) prime lens, but I wasn't aware that there were lenses in the 300-400mm range that could be bought for the same price as a scope of equivalent focal length.

Even I wouldn't recommend a brand new TV-60 as a shooting scope unless the prospective buyer also had an interest in astronomy (and a diagonal and some eyepieces to put in it), but scopes like the Skywatcher Equinox-66 (and the William Optics and Astro-Tech 66's) are relatively inexpensive, and I can't imagine they'd be too far behind the TV-60 in terms of image quality.

(Though I wouldn't advise trying to photograph birds with a Ferrari-red scope!)
 
At the 600mm range a scope is far more “profitable” than a lens, no doubt. But even at 400mm I think a scope is very worth it.

I started using scopes with a 400mm F/5 scope I had, and it had more resolution than any lens I ever had. Even my fine Nikkor 300mm F/4 ED IF isn’t as good, and I had a few other teles in that range, pretty much everything I could mount on my Nikon bodies. Of course that scope was quite bad in CA, but it was an achro, with todays prices on shorter APOs, EDs , etc, you can find better than a lens for a much cheaper price.
Like Mark said the Equinox 66 (400mm F/6) or other clones, that cost less 280€ are quite good, and I’m betting capable of better results than any tele bellow 800€ or more, if you’re willing to cope with the manual focus. Also considering it’s a scope, it’s light transmission it’s a bit higher than a lens at the same aperture, so we’re looking at least for a 400mm F/5.6 or faster.
The “problem” with these scopes may be the focuser, at 1.25” it’s doubtful that it would fully illuminate an APS-C sensor…I don’t know this for sure, but I’m almost sure it wont.

Also, if one is willing to buy used, several good MF lenses can be found for more or less the same price, for example a Nikkor 300mm F/4.5 AIS ED (300€), or a 400mm F/5.6 AIS (500€)...or my 300mm F/4 AF witch I'm selling for 500€ |:D| ...also they’re smaller, have aperture control and focus much closer. A 300mm F/4.5 is perfect for dragons and butterflies.

JMHO on the matter, don’t want to argue with anyone ;)
 
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