10mm 1:4 Eyepiece for Canon EF/EF-S Lens, Angle View, White Color

I ordered this eyepiece for use with my Canon 100-400 F4.5-5.6 IS L zoom lens. I have an older B&L spotting scope that was top quality in its day, but I wanted to use my Canon zoom instead of lugging the spotting scope around. I must say--I am very pleased with the optical quality and build quality of this Lens2scope unit.With my 100-400 zoom, the image is very sharp. It has good eye relief (I wear glasses). It works very well with my 100-400 zoom. The quality is good at all zoom focal lengths, including 400mm which provides 40X. The image is bright and contrasty with no apparent color fringing. The exit pupil, reportedly 2.5mm, is somewhat small. I have to keep my eye centered on the eyepiece, but this is not really a problem. But overall, the optics on this unit are very good--I expect to use this unit with my 100-400 zoom a lot.The Lens2scope website talks about the eyepiece being optimized for F4. My 100-400 lens ranges from F4.5 to F5.6 depending on zoom position. I don't see any image degradation that I would attribute to F-stop. My lens is always wide open when it is off the camera so I cannot test this specifically.I am able to focus down to 7-8 feet with the eyepiece attached--pretty close focusing.Mechanically, the lens mount works well with my EOS lens. It is a high quality metal mount and it mounts easily.The body of the unit is plastic, but it appears both tough and solid. I am not worried about mechanical durability. It comes with a nylon belt case and caps for both the eyepiece and camera mount. The white color of the eyepiece matches the white color of Canon L telephotos quite well.The eyepiece has a nice rubber eye cup. It fold back easily for eyeglass wearers. The eyepiece itself still has a rubber rim on it to prevent scratching eyeglasses when the eye cup is folded back. With the eyecup folded back, I can still get the eyepiece cap to fit, but it is pretty tight.The tripod mount has metal threads, but the mount itself is plastic. There is no way I would trust my 100-400 or any other large lens to this mount. A smaller lens should be fine. The instructions clearly warn against using the mount for heavier lenses. My 100-400 has its own mount so this is not an issue for me. The Lens2scope tripod mount is easily removed, and I intend to leave it off.I also ordered the "straight" eyepiece Lens2scop adapter in addition to the angled version. I have to say, the angled unit had noticeably higher optical quality with my 100-400 lens. The straight version was softer. It did not have the contrasty "snap" of the angled version. I returned the straight version for a refund. Is it possible that the image inversion prism has more complexity with the straight version, contributing to a softer image overall? In my case, however, I am extremely happy with the angled eyepiece. I am fairly tall, so an angled eyepiece will be more convenient for people of various heights to use the scope without readjusting height. The mount for my 100-400 lens rotates, so I also have the option to turn the eyepiece to the side or down for shorter people or simply for different viewing angles.Overall, I am extremely pleased with the optical and mechanical quality of this unit. Will it outperform a $1500+ scope--probably not. But coupling it with my $1500 lens, will clearly give a very good quality spotting scope. It clearly rivals consumer-level scopes and surpasses my older B&L scope. The convenience of adding this small device to my camera backpack make this a very nice addition to my camera gear.I highly recommend this angled Lens2scope eyepiece unit!

Not seeing many reviews with the product details I have been searching for, here is my somewhat overdetailed review.Summary: As an avid outdoor photographer, I have tested this on my collection of canon lenses and also compared it to 2 spotting scopes I own. Construction is average entirely of plastic (with the exception of the mount ring) though well executed fit and finish. It mounts to all of my lenses well. Optics are average with coatings present only on one side of two (of five) elements. Eyerelief is good, though field of view and exit pupil could use improvement. As advertised, the lens attached to the eyepeice will primarily govern the global quality of the image. The item performs well with brightness being similar or better than my scopes. Contrast is slightly lower as is sharpness, but very close. Most usefull when paired with a light tele-zoom. Not a super value for the sum of its parts, but performs as advertised.Construction: My first observation was how light the lens2scope is. Being familiar with heavy lenses and scopes, this item felt feathery light. It came packaged with a nice fabric belt-loop pouch with a velcro flap top lightly padded with a soft interior. The foot used for mounting on a tripod is plastic (fiber reienforced?) and is beefy enough to support a light lens. It slides into place from the front side of the lens2scope and clicks into place via a plastic tab. There is a very small amount of play as the fit is snug. The foot releases by pulling down on the tab and can be done with lenses in place only when equal or smaller in diameter to the lens2scope. The lens mount is a machined aluminum ring attached by 4 screws to a black plastic cylinder that bears the product name and specs. The machined ring fits my canon lenses well with just the right amount of tighness, though the internal edges are sharp and may prematurely wear any lenses with plastic mounts. No problems with my Canon lenses with metal mounts. I will refer to this assembly as the "lens mount". The lens mount drops on to three "bayonet" style tabs moulded into the next black plastic peice (which supports the tripod mount foot and houses the front group of lens elements) and rotates to lock into place. It is secured by 3 screws, and the design appears to allow quick exchange for lens mounts for different lens standards by the manufacturer. The grey plastic prism housing is screwed on next terminating with the angled plastic eyepeice barrel (glued in) with a rubber eyecup. The eyepeice element group appears to be assembled by drop in elements secured by a screw ring (similar to how lens filters sometimes are). Assembly fit is excellent though there appears to be no rubber weather sealing or purging. I would not get this unit wet. The glass prism is uncoated, as are the internal surfaces of the lens elements. There is coating on the enternal sides of the two visible elements and clean easily. The eyepeice element is approx 21mm in diameter and the front element 15mm. The rubber eyecup is a flip down design and is not removeable. When flipped down, the lower portion makes contact with the angled prism housing as the clearance is smaller on this one side not allowing unrestricted deployment. Its not a big deal, but a minor annoyance. The eyepiece is not interchangeable.Use: I tested the lens2scope mounted on a tripod with my scopes on tripods side-by-side indoors. I mounted it to the following Canon L lenses: 17-40mm f4, 50mm f1.2, 100mm f2.8 macro, 70-200mm f4 IS, 300mm f4 IS, 500mm f4 IS, 1.4x extender II. My two scopes are a Nikon ED50 with fixed 16x standard eyepiece, and Vortex Razor with 20-60x eyepeice both angled. The lens2scope works well. At the lower magnifications, the Nikon ED50 is a bit brighter, sharper, with better contrast. The difference is small but noticable. The lens2scope performs very well with a sharp crisp bright image but the nikon with a fixed eyepiece is very sharp and bright and hard to beat. At low magnification compared to the ED50 I would guess that the limiting factor may be the lens2scope as a moderatley priced ED50 with a fixed eyepiece can outperform it attached to lenses of higher price. The color appears very neutral (as is the case when attached to all the mentioned lenses). The exit pupil is on the lower side but very usable. Compared to the Vortex Razor, the color is better as the razor has a slight red cast. Contrast and sharpness are slightly better with the razor at low magnification (20-40x) and equal at high mag (50-60x) with the 500mm and 500mm+1.4x. Brightness using the lens2scope is slightly better at low magnifications and signficantly better with the lens2scope attached to the 500mm, but this would be expected from a $$$$ large aperature lens compared to the vortex with a zoom eyepeice. I would guess a fixed eyepiece on the vortex may yield similar brightness. The field of view is smaller than either scope at similar magnifications. CA issues were not apparent in any case. The 1.4 extender pairs well with the lens2scope w/o noticible loss in IQ. What this all means to me is that at low magnifications, the dedicated scopes have better sharpness and contrast likely due to the fact it is less challenging to produce good IQ at these levels with decent glass. When you move to high magnifications, the vortex with a zoom can not compete with a 500mm supertele lens in terms of brightness. Still it is impressive the vortex sharpness and contrast are equal as it is pushed to its limits. This is consistent with how the image quality is determined primarily by the lens and not the lens2scope, but it appears with this level of lenses, the limiting factor may be the lens2scope. Resulting image quality is not objectionable, far from it. It is quite good and nothing to balk at, but I believe there is more here to tap into when paired with top quality lenses.When paried with a 500mm f4 in the field, at 50x magnification, shake is hard to combat due to the weight of the lens. Its not an issue paired with normal camera magnifications, image stabilization, and high shutter speeds, but when used for observation at 50x, its apparent the lens foot attached to the 500mm has significant flex and can show significant vibration not as problematic with a smaller dedicated scope. I find that when paired with a 70-200 f4, or a 300mm f4, combined with a 1.4 converter the lens2scope is the most useful as it provides a small light compact scope alternative. Testing with lenses brighter than f4 did not produce a noticably brighter immage (as would be expected if the lens2scope is optimized for use at f4). Will it replace my scopes?, no, but this is exactly the product I have been looking for when traveling with my camera gear when I do not want the extra burden of a scope on occasions where one may come in handy. My only reservation is the price as it is a bit high for the construction/optics quality. My hope was for even better quality here for the price paid (I.E. better value). It may match up well with excellent consumer lenses, but attached to top end glass, it feels a bit cheap.Room for improvement?, yes. Interchangeable eyepieces (compatible with Nikon Fieldscopes maybe?) would make the lens2scope much more flexible/desired. Multicoatings on all glass to air surfaces is desireable. Better rubber eyecup. If it had these features, I would call it a definite winner, highly recommended. As-is, it performs well, but is not the best value. As such it is a very good option for those who have a good quality tele lens but no scope, but weight your options carefully. I would be happy to elaborate on product improvements.