I'll be honest, when I got this package from Amazon I opened the box and I was intimidated. I saw this humongous lens and thought, "There is no way I am going to be able to manage this beast." So I kept the packing box and headed up to Snoqualmie Pass, WA to see how it would do capturing the ski lodge at the top of the hill. The first photo is made with a simple EF 75-300mm telephoto lens from the parking lot. The second shot is a picture of the lodge at the top of the hill. It was the second photo I took and it was done freehand with no tripod. This lens is extremely easy to use and I know that the pictures are just going to get better from here as I learn to use it.

Let's just say I just put the shipping box in the recycle bin. It won't be needed anymore.

Up to now, I'm generally please with the Opteka Lens, but I'm not an expert and I didn't have the chance to use it as often as I expect to do. I bought that lens simply to develop a hobby as an wildlife amateur photograph. It seems to work very well. But I didn't have the chance to compare with other lens. An expert who used other lens might be able to judge this one differently. I learned to use this one quite easily. However you need to have a good quality digital camera to get good results. First I used this lens with an older camera and the results were very disapointing. But with a more recent and higher quality digital camera, I was able to take some good shots. I still need to learn how to adjust the camera to get better light exposure. For now, I could say that it's a good ratio quality/price. Not sure that it can be used other than for amateur photography.

Considering the price which makes this an amateur and NOT a professional lens the optical quality is OK - Good. It is definitely NOT a professional lens, but if you want such quality you will have to pay at least 8-10x the money. I like to summarize some important notes and remarks which some other customers in several feedbacks have given as well to help you to get the most possible out of these lenses:
(1) The sharpness limited by the lenses chromatic aberration is good at 650 - ca. 900mm and from 1150-1300mm. For some strange reason in the middle zoom range it gets worse and very noticeable! So try avoiding the middle zoom range. You will either way have to set the zoom before you shoot as there is no autofocus nor any smooth zoom setting via turning a ring. One has to first unlock, then slide out or in your changing the focal length and finally lock again. If you looking for a tele with fast zoom and auto focus, then these are not the ones!
(2) Place the telephoto lenses with set zoom/focal length and attached camera on a REALLY ROCK-STABILE tripod! This is VERY ESSENTIAL!!! I bought a semi-pro Tripod from Davis+Sanford (Provista 18 with FM18 Head) which came about the same price like the lenses, but it is really essential and that made all the difference in the world!! Believe me, you will NEVER get sharp and well focused shots WITHOUT a real GOOD and STABLE tripod!! Another important fact to consider concerning tripod: Get one with a good smooth Fluid Drag Head for at least 10-15lbs weight! and NOT with a FRICTION Head. If you want to find a photo target (wildlife etc) with a zoom lens at 1300mm and your tripod head has NO smooth gliding and fine adjustable head, it will get a pain in the a... to ever find your desired object.
(3) To accurately focus the lens on your object is EXTREMELY important but tricky too. A camera (like Canon EOS 70D I use) with a digital zoom option helps here a lot: Focus first without zoom, then put your digital zoom (mostly only available on your display screen and not your viewfinder) to x5 or even x10 magnification and fine adjust your focus. That way set up you will get everything out of these lenses they are capable of, which is pretty good. I did several test shots using test charts (4' x 8') in distances of 100 - over 1000ft. The final image quality is pretty well when all the former mentioned recommendations are met see sample photo taken at 1300mm, 800ft distance, 1-125sec, ISO1600 at aperture 16 (picture 2+3).
(4) A final word to the 2x tele converter and optional filters (UV, CPL etc.): The offered 2x tele converter is like the lenses amateur and NOT professional quality. The focus and sharpness will drop a little, but noticeably (picture 1 taken at 2600mm, 800ft distance, 1-100sec, ISO2500, aperture 32) and trying to shoot at 2x1300mm = 2600mm is only at extreme bright environmental circumstances possible as your aperture is 32 only!!! That means either very long shutter times or extreme high ISO settings, both not very suitable for crystal sharp pictures at long distances and especially not for moving objects! So the tele converter can be used, but reveals immediate quality loss. Filters I can NOT recommend at all, as they all reduce the already spare ambient light and have a significant blurring effect.
If you are not looking for Professional quality (at prices $1'000 - $15'000) but for a good Have-Fun or Introduction-To Telephoto lens with a really long focus length and immediately plan on purchasing a very stable tripod (if you not already have one) with it, then this is one for you to go for.

With the 2x at 2200mm there was a weird cromic abrasion in middle of sun, but at 650-100mm it captures the sun nicely a solar filter was used. You never want to look or shoot the sun without one. You can see one sm sunspot on bottom right. Is was cloudy also when pics were taken. The Orion Nebula was shot at 1100mm my tripod was not stable enough for 2200mm single shots using live view on Canon 6d. It is a manual focus lens with no image stabilization so don't expect it! Overall for what I bought this for it is great! You get what you pay for!

Updated!
Couldn't be happier! I saw only the partial eclipse, but the lens performed beautifully! It was a very still day, which likely helped a lot to minimize camera shake. See for yourself.

I bought this lens to photograph the upcoming solar eclipse. I have been practicing for a few days, and LOVE this lens. Let me preface by saying I am not expecting crystal sharp photos, nor the ability to point and shoot within seconds. I'm not expecting to shoot moving objects hundreds of meters away. This lens requires some patience, and is limited in how it can be used, but for what I am planning to use it for it's perfectly fine. Focusing can be a little tedious, and with no image stabilization it's pointless to try to use it without a tripod AND remote shutter release. I had it a couple of days without a shutter release, and even with a 10 second exposure delay, I was still getting some image blurriness. I invested in the remote shutter release, and immediately noticed the difference. I'm using it with a black polymer solar filter rated at ND5 for photos of the sun, and pretty easily seeing sun spots. It's a heavy lens, which makes me feel confident it can survive a bump or two, but which also means it needs a sturdy tripod to support it. I haven't used the 2x converter and probably have no reason to for my interests, so can't comment on the image quality or usefulness with the converter. Overall, a great lens for my interests and budget!