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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

SMC-XW 20mm eyepiece (1 Viewer)

I tried this eyepiece out in my 80mm scope. Comparing it to my 40mm XL and a Meade 14mm UWA, The 20mm had more chromatic aberration. So much so, that it was distracting for identifying birds at long range. For such an expensive eyepiece, it was disappointing. Has anyone else here used the 20mm XW?
Thanks,
Doug
 
I have the XW20mm and love it. I have used it for digiscoping too and never had to do any correction of CA. As for birding I have used in several settings (overcast, sunny tropical south america, rainforest, etc.) and if something happens to it most likely I will get another one. Sorry to hear about yours. Jose.
 
mmdnje said:
I have the XW20mm and love it. I have used it for digiscoping too and never had to do any correction of CA. As for birding I have used in several settings (overcast, sunny tropical south america, rainforest, etc.) and if something happens to it most likely I will get another one. Sorry to hear about yours. Jose.

mmdnje,

I am thinking about buying a fixed-power eyepiece as well as I understand they can provide some excellent viewing with the Pentax PF-80ED. The only eyepiece I have any experience with is the Pentax 20-60X zoom that came with the scope, which I understand is considered to be a good eyepiece in itself. Would the XW20 effectively eliminate the need to carry the zoom with me while birding? Or does the zoom have any advantages over the XW20 that I would miss if I made the switch?

Thanks!
Pat
 
Xw20

HI Pat:
personally, i now much prefer the fixed EP (I use the XW20mm and Orion status 13mm). The FOV is much wider. As a matter of fact i do not carry the zoom with me at all anymore, just the other 2 eyepieces, and do not miss the zoom eyepiece.
take alook at this post http://www.birdforum.net/showthread.php?t=56693
Jose
 
Last edited:
mmdnje said:
HI Pat:
personally, i now much prefer the fixed EP (I use the XW20mm and Orion status 13mm). The FOV is much wider. As a matter of fact i do not carry the zoom with me at all anymore, just the other 2 eyepieces, and do not miss the zoom eyepiece.
take alook at this post http://www.birdforum.net/showthread.php?t=56693
Jose

mmdnje,

Thanks for your advice. There seems to be no question that the fixed eyepieces provide a nicer view. Sorry to be nitpicky, but do you find that you are frequently switching from the XW20 to the Orion so you can get a closer look? The only advantage to a zoom eyepiece that I can see would be not having to swap eyepieces in this fashion -- but again, my perspective is limited because I have never used fixed eyepieces.

Thanks again...

Pat
 
Pat,

I'll give a contrary view. For birding I use zoom eyepieces almost exclusively (Zeiss, Swarovski and Nikon) because I don't want to keep up with extra eyepieces or take time to change them. The great advantage of zoom eyepieces is that they allow instant choice of the most useful magnification for the conditions. If the air is unsteady that may be 30x or less, but when the air is calm I've successfully used magnifications above 100X. To see all the detail available from a high quality 80mm scope requires at least 60X (really more like 70-80X), provided the air is steady enough. The best current zoom eyepieces have no optical disadvantages at high magnification compared to fixed eyepieces. They are just as bright and sharp. All the dimness and loss of detail come from the limitations of the telescope objective lens, not the eyepiece. The low magnification views through wide field eyepieces can be very impressive (I sometimes bring along my favorite such eyepiece, the 30X swarovski), but I would never want to be without the ability to take advantage of the scope's full resolution when the air is steady enough to allow it.

Henry
 
Henry,

I always enjoy reading your posts on eyepieces as I known there is hardly anyone participating in any of the relevant forums who has more knowledge and first-hand experience with top eyepieces. Also, because I know what scopes you use them on, I can trust that your assessment of what is caused by an eyepiece and what is caused by the scope is more accurate than any of us, including myself, could provide. Which brings to mind, did you ever come about to doing a full-fledged comparo-report on the three zooms you mentioned in this post?

On zooms and birding, I would add that unlike stars, birds are not virtually stationary, and there is always a real risk the uncooperative avian will no longer strike an opportune pose by the time the hapless scope user has switched the low-mag/widefield eyepiece for a higher-magnification one.

Kimmo
 
henry link said:
Pat,

I'll give a contrary view. For birding I use zoom eyepieces almost exclusively (Zeiss, Swarovski and Nikon) because I don't want to keep up with extra eyepieces or take time to change them. The great advantage of zoom eyepieces is that they allow instant choice of the most useful magnification for the conditions. If the air is unsteady that may be 30x or less, but when the air is calm I've successfully used magnifications above 100X. To see all the detail available from a high quality 80mm scope requires at least 60X (really more like 70-80X), provided the air is steady enough. The best current zoom eyepieces have no optical disadvantages at high magnification compared to fixed eyepieces. They are just as bright and sharp. All the dimness and loss of detail come from the limitations of the telescope objective lens, not the eyepiece. The low magnification views through wide field eyepieces can be very impressive (I sometimes bring along my favorite such eyepiece, the 30X swarovski), but I would never want to be without the ability to take advantage of the scope's full resolution when the air is steady enough to allow it.

Henry

Very interesting, Henry.

What if we throw digiscoping into the discussion? Let's say a birder carries a scope around for the primary purpose of viewing birds, but also carries a digiscoping camera and adaptor with him in case a good photo opportunity arises. Would the quality of the pictures taken with a zoom eyepiece be comparable to those taken with a fixed-power eyepiece?

Also, since I am currently considering the purchase of either the Radian Universal Digiscoping Adaptor or the SRB-Griturn swing-away adaptor, does anyone know if there would be any problems with using a zoom eyepiece with either one? (My scope is an angled Pentax PF-80ED and the camera I am purchasing is the FujiFilm F30. The F30 does not have threads for a lens adaptor and cannot be thread-mounted to an eyepiece).

Thanks!
Pat
 
Kimmo,

Sorry to say I dropped the ball with the zoom comparison. Other than the things that are already well known about them such as eye relief and field width I can add that the Swarovski (7.7mm-22.1mm) and Nikon (7mm-21mm) are brighter and higher contrast than the Zeiss (8.4mm-25.1mm). In fact only the very highest transmission simple eyepieces are visibly a little brighter. My rough estimate would be around 95% for the Swaro and Nikon, closer to 90% for the Zeiss. Color transmission in mine looks slightly yellow in the Zeiss, nearly neutral in the Swaro (perhaps very slightly yellow, not blue) and neutral (with the usual slight red) in the Nikon. All of them are as sharp as any eyepiece at high magnification. The Swaro and Zeiss make excellent wide field eyepieces at the highest magnifications, easily comparable to Pentax XW and TeleVue Panoptic. At low magnification (exit pupils above 2mm where eyepiece sharpness might be the limiting factor) the Zeiss appears slightly sharper than the other two, but not enough to show any extra detail. Now that you've reminded me maybe I can do a more detailed test of off-axis behavior; astigmatism, field curvature and distortion.

Pat,

I'm afraid I don't know anything about digiscoping. Maybe Ikka or one of the other digiscopers can answer your question.

Henry
 
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