Widest eyepieces (1 Viewer)

Luric · Jun 25, 2004

Hello,

I would like to know which eyepiece(s) has (have) the widest field of view?

I was intended to buy a Kowa TSN-823M 82mm but somebody told me that their eyepieces were too narrow in compare to the Swarovski ones so, with the CP 4500, it doesn't seem to have a very big zoom range without vignetting.

So, what about the Pentax Models? I mean the XL series?

Has someone had a chance to experiment some of them?

Thank you for any explanation you may have!

Regards,
Luric

scampo · Jun 25, 2004

The widest zoom eyepiece by a mile is the Zeiss Vario 20-60x; it goes with the superb 85T* Diascope or the 65T*. Nothing comes close for field of view (almost 50% greater than the Swaro!).

Of fixed magnification eyepieces, all are very similar: Nikon is superb, as is Leica, Swaro, Zeiss, Kowa and the Opticron HDF.

Jay Turberville · Jun 26, 2004

Luric said:
Hello,

I was intended to buy a Kowa TSN-823M 82mm but somebody told me that their eyepieces were too narrow in compare to the Swarovski ones so, with the CP 4500, it doesn't seem to have a very big zoom range without vignetting.

I'm not familiar with the Kowa eyepieces, but the "Basics" section of this page:
http://www.jayandwanda.com/digiscope/vignette/vignetting.html
will explain the issues that are important to getting a wide zoom range while digiscoping.

With the CP4500, you want to find an eyepiece that has very close to 20mm of eye relief. Then with the proper adapter you will be able to use virtually the full FOV that an eyepiece offers.

An eyepiece with 15mm of eye relief but a wide AFOV could easily perform worse than an eyepiece with 20mm of eye relief but a relatively narrow AFOV.

Of course, direct testimony from people using specific gear is probably the most reliable method of predicting results.

Neil · Jun 26, 2004

The long Eye Relief Kowa eyepieces are pretty good.
Neil

stevo · Jun 26, 2004

Hi Luric the best wide angle eyepiece made by Kowa & suitable for digiscoping is the 32xww eyepiece,although some people regard the 20-60x zoom as being just as good

Regards Steve.

scampo · Jun 26, 2004

Hmm... my experience is that the Kowa zoom is not a very wide fov eyepiece, giving quite a tube-like view, I would say. The 32xW is magnificent, though, for sure.
The fov might not matter, though - it depends how much the camera needs zooming in to get rid of the vignetting.

Neil · Jun 26, 2004

I've just looked at the Eageloptics site and the new Kowa 27x LER 82mm has 32 mm of ER. This should give unvignetted views from Wide to Tele on a CP series camera. I'm thinking of digging out my old Kowa and getting one of these , or the 21x.
Neil
http://www.eagleoptics.com/

Jay Turberville · Jun 27, 2004

Neil said:
I've just looked at the Eageloptics site and the new Kowa 27x LER 82mm has 32 mm of ER. This should give unvignetted views from Wide to Tele on a CP series camera. I'm thinking of digging out my old Kowa and getting one of these , or the 21x.
Neil
http://www.eagleoptics.com/

I did some calcs and the 27x LER has an AFOV of about 55 degrees which is just short of the 59 degrees of the CP4500 at its widest. So you'll probably miss the full range by a smidge.

The very long eye relief of the 27x LER would be great for marginal cameras and perhaps for video cams.

The 21x has about a 65 degree AFOV. So this one is a good bet for full zoom range on the CP4500 yielding about 800mm to 3250mm equivalence range. That's a nice range IMO.

iporali · Jun 27, 2004

Although I agree with stevo's individual claims (32x is great, it is suitable for digiscoping as is the zoom) I could not strongly recommend any of Kowa's current eyepieces for digiscoping either because of their poor eye-relief (32x, zoom) or exceptionally narrow FOV (27x LER). This may easily result in images like the one shown below

Unfortunately zooming in (or out!) with the camera does not help here. OTOH the recently introduced new eyepieces may fix this problem once and for all - no idea about their availability and/or image quality though (http://www.kowascope.com/news/tse_21_14_17.htm)
- OK, so they are available now, forget the old ones - thanks Neil !

From the currently available models (if maximal image area is your main concern) Leica 20xWA with its 20mm eye-relief is one of the best options. Pentax XLs are maybe optically even better, but they are BIG (may be more difficult to couple with the camera) and fit directly only with Pentax- or astro-scopes (the astro adapters available with the Swaro and Zeiss may prevent the scope from focusing to the infinity - can be checked easily).

No zoom eyepiece has a very wide usable field of view but many like their versatility also in digiscoping, when they are mainly used at their lowest power (20x). The widest FOV of the Zeiss zoom is not as superior in digiscoping as it is in normal viewing due to its shorter eye-relief (than Swaro & Leica zooms). Sure the Zeiss zoom is fine, but CP4500 camera wastes some of this advantage. Zeiss does not have low-power wide angle eyepieces (yet?).

My suggestion for a shortlist
1) Kowa TSN-823M with the NEW eyepieces (esp. 21x)
2) Leica APO Televid with 20xWA
3) Pentax scope + XL 30mm etc.
4) Swaro ATS + 20xSW
5) Leica, Zeiss, Swaro scopes with the 20-60x zoom

BTW From some eyepieces you may be able to pull out some FOV with a camera other than CP4500 (like Canon A60-80).

Good luck,

Ilkka

Jay Turberville · Jun 27, 2004

iporali said:
Although I agree with stevo's individual claims (32x is great, it is suitable for digiscoping as is the zoom) I could not strongly recommend any of Kowa's current eyepieces for digiscoping either because of their poor eye-relief (32x, zoom) or exceptionally narrow FOV (27x LER). This may easily result in images like the one shown below Unfortunately zooming in (or out!) with the camera does not help here.

The new 27x has a 55 degree AFOV and the old one has a 35 degree AFOV. Eith should be plenty for digiscoping. I'm going to hazard a guess that you have the camera place fairly close to the eyepiece. Since the CP4500 requires about 20mm of eye relief and the 27x has about 32mm (30mm on the old), you should move the camera about 10-12mm back from the eyepiece to get something close to the optimal range. With the old eyepiece, you should still have about half the zoom range of the camera available and nearly the full range with the new eyepiece.

Since few birding eyepieces have eye relief beyond 20mm, very few digiscopers run into the situation where they can get the camera too close to the eyepiece. The 32mm of the 27x LER could easily create some confusion.

iporali · Jun 27, 2004

Jay Turberville said:
The new 27x has a 55 degree AFOV and the old one has a 35 degree AFOV. Eith should be plenty for digiscoping. I'm going to hazard a guess that you have the camera place fairly close to the eyepiece. Since the CP4500 requires about 20mm of eye relief and the 27x has about 32mm (30mm on the old), you should move the camera about 10-12mm back from the eyepiece to get something close to the optimal range.

The image was taken with 32x, but you are probably right that in my trials with the 27xLER I have held the camera too close to the eyepiece. The older Kowa 27x was probably designed mainly for the shooters, who may not need the wide FOV but want to peek into the eyepiece from a longer distance. I still think that having to zoom the camera halfway means that the eyepiece is quite narrow for digiscoping - even some zooms have a wider field at 20x. Anyway, it now looks like the Kowa eyepiece line has changed from one of the worst - in terms of eye-relief (the image has always been great) - to one of the very best (if not THE best). These new eyepieces will surely sell loads of Kowa scopes for digiscoping.

Ilkka

scampo · Jun 27, 2004

It would be nice to see Kowa resuming its once enviable position with birders.

Geoff Brown · Jun 27, 2004

Steve

I think Kowa will soon do that with their new telescope incorporating a digital camera which I believe is shortly going on sale.

scampo · Jun 27, 2004

Hmmm... time will tell. I'm not convinced by it yet.

Jay Turberville · Jun 28, 2004

Geoff Brown said:
I think Kowa will soon do that with their new telescope incorporating a digital camera which I believe is shortly going on sale.

It will be VERY interesting to see how people react to the TD-1.

Its a bold move in so many ways. It should take a LOT of the guesswork out of digiscoping. But as digiscoping goes, its definitely on the low side of magnification. It also doesn't seem like that great of a spotting scope. The FOV is pretty narrow and its a 55mm objective. Nothing to write home about.

OTOH, from a photography standpoint, a 1350mm lens with a dedicated 3Mp camera and an effective f4.0 aperture is actually fairly exotic by camera standards. How nice that the optics can be designed for the purpose rather than torturing the light by sending it through fundamentally unneeded prisms, eyepieces and lens optics.

I can't help but think that if they had a better FOV, larger aperture (80mm), 4-5Mp sensor, IS, and a bit more ISO sensitivity (ISO 400) that this would be a solid winner - even at $3000.

Yep. It will be interesting to see the market reaction.

galt_57 · Jul 2, 2004

Jay Turberville said:
It will be VERY interesting to see how people react to the TD-1. [...]

If it was 4mp with IS it would sell. As it is I doubt it will be taken seriously.

Jay Turberville · Jul 2, 2004

galt_57 said:
If it was 4mp with IS it would sell. As it is I doubt it will be taken seriously.

Sure, those would be good features. But this is a 10-30x scope as well. That pretty much dictates the need for a tripod. And while it may be important from a psychological/marketing standpoint, the difference between 3Mp and 4Mp is slight.

Time, of course, will tell.

Glen Tepke · Jul 2, 2004

Jay Turberville said:
With the old [Kowa 27x] eyepiece, you should still have about half the zoom range of the camera available

That is correct in my experience. Glen

Luric · Jul 4, 2004

Thanks all for your nice answers! It is very kind of you!

Like I said in another thread, I took a bunch of information and in August, I will go to Montreal in a specialized Astronomy/Scopes store and will make some tests.

After all my researches, Kowa 823M + their new eyepieces, Swarovski ATS 80 HD and Zeiss are on target!

Prices will also help me make my final decision.

Thanks again!
Luric
Canada

lima · Jul 8, 2004

Please excuse my ignorance, but what exactly is meant by eye relief and why is long eye relief better?

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