FerBatista
Offline
• •
Upload & Sell: Off
|
 p.1 #5 · Spotting scope mfrs elbowing in on supertelephoto lenses? | |
JimBuchanan wrote:
I don't think the big lens companies are worried about spotting scopes at all. To start, most spotting scopes already have prisms to right the image for visual. That restricts the image circle size to the camera sensor. Second, any optic that is added to adapt the scope to a camera will degrade the image to the sensor. The comment about the aperture, while true, is not the main culprit. Spotting scopes have never been known for visual image quality, except for possibly Zeiss or Leica or any other APO scope.
The 2 companies mentioned above marketing new "super telephotos" are nothing new as far as telescopes are concerned. The Kowa with "only 7 elements" is not a selling point in my opinion. If I was going to spend $2700 on a telescope, not a spotting scope, I would be looking at companies that offer real APO quality scopes from Televue, TEC, Takahashi, and maybe some of the Russian APO scopes. I'm not including Astro-Physics, because it is hard to readily obtain one of their expensive triplets (only 3 elements).
Having said all of that, my own Takahashi below is a small 60mm/355mm focal length APO that has a simple fluorite doublet. That works out to be a f/6 or so, but compared to a FD 300/2.8 L, it is only about a stop slower than the FD, but the field of view is approximately that of about a 400mm telephoto on full frame. And the image circle does cover full frame. On a 1.5x crop camera, almost 600mm.
Longer telephotos and small telescopes are both tripod solutions, so I agree with the original poster that small APO scopes are possible alternatives to big long heavy telephotos, just not spotting scopes.
I couldn't agree more.
Spotting scopes are the wrong solution for anyone wanting good IQ, a good APO astro scope is a much better choice, at least on a DSLR.
I've been using APO scopes for years, the only downside I can see to them is being MF, apart from that they're outstanding pieces of gear, they're extremely reliable, extremely sharp and contrasty, with great colors and bokeh.
Apparent downsides like no IS/VR or slower apertures, are not really a factor at all. The lack of stabilization can be if you're using canon or nikon (like I did until recently), but other brands have in body stabilization that can be used with the scope.
And the slower aperture is also less of a problem than it seems. My current scope, a 480mm F/6 Triple APO, actually has the same light transmission as my Nikkor 300mm F4 had at F/4,5. By only having three lenses inside, the APO scope delivers a good bit more light to the sensor than a regular objective at the same aperture.
And MF can be helped with the use of focus peaking in sony cameras, or pentax. Or with the use of trapfocus in others.
Here's the scope I use now, a TS TLAPO 804, the same as Orion ED80T except for the carbon OTA:
It currently has a few changes, I redone the camera adapter and it has a new focuser. BTW it also has an IRIS that allows shooting from F/6 to F/16.
And here are several shots I've done with it these last two years:
http://fernandobatista.smugmug.com/Galeria/Diario-Fotogr%C3%A1fico-Photo/3708197_KR2GVt#!i=2271106179&k=9HDTcBz
And for those who are curious about it's quality a 100% crop, using a Kenko 1,4x PRO300, wide open:
|
