nauticalmike

Ok, I have no doubt that at he price point that they are selling thee things for they are of very low quality and may not even be worth the money that they are asking, but then again I may be wrong. Does anyone have any actual hands on experience using any of these lenses, and of those of you that have actually shot photos with one of these lenses what can you tell me about the actual results? Are the shots you took with one of their lenses better or worse than you would get using say a Meade refractor telescope? If you are careful with them and do not drop them will they hold up for a reasonable amount of time, or will they break from just their own weight hanging off of the camera body? anything else that you can tell me would be appreciated. I am assuming that most of you out there can not tell me anything because their low price is too low for most to even take a chance on them.

speters Loc: Grangeville/Idaho

There are many test reports of them online with actually pictures taken with them all over the place!

JimH123 Loc: Morgan Hill, CA

I borrowed one and gave it a try. It was a 800 to 1600mm zoom. The construction was poor and when zoomed out, it flexed in the middle. The images had very poor contrast. Was able to post process and improve the contrast. In using with a full frame body, I actually could focus on something distant and get a reasonable result, even at 1600mm. With an APS-C body, 1600mm seemed like to much and I limited the amount of zoom to something less. Because of the poor construction, there was also alot of shake while focusing. The longer the focal length, the worse it was.

As for comparing it to a real telescope, I have several. The Explore Scientific 102ed I have is 710mm focal length at f7, and is a pleasure to focus with, and images look great. But it is too big to carry around. And requires a very sturdy tripod.

One option that works quite well for a reasonable price is a m42, 400mm, f5.6 lens. I have one made by Pentax, and it takes great pictures, although you do have to watch out for CA which is a characteristic of these older lenses with coatings from an earlier era. In areas of high contrast, you can get those CA edges.

I also have a 500mm Pentax m42 lens, and it is a whole lot larger and heavier thanthe 400mm.

I would forget cheap teleacopes. Many cheaper ones can't be used in prime focus at all. And if you have to use digiscoping, which is not nearly as good.

RWR Loc: La Mesa, CA

This thread may be of interest. Note especially what Searcher was able to do with the simple thumbnail.
http://www.uglyhedgehog.com/t-206902-1.html

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

I wouldn't use one even if one were given to me free of charge. Awful build quality, full manual, too slow a lens to make it practical - total junk

https://www.youtube.com/watch?v=uoBXhlJSk1o

http://www.curiouswriter.com/opteka-650mm-1300mm-lens-review/

The mirror lens is a tiny bit better:

http://makingitasapro.blogspot.com/2012/06/lens-review-opteka-500mm-f8-mirror-lens.html

nauticalmike

Thank you, your link was both informational and inspiring!

nauticalmike

Thank you for the links as well. I am more and more leaning to the possibility of buying one of these incredibly inexpensive lenses for my small collection...

RWR Loc: La Mesa, CA

I didn’t use it, but I have handled the Bower 650-1300mm lens. The push-pull zoom ring was firm and smooth, no creep, but it was new. Cannot comment on any others. I'm sure you know you'll need a lot of light, a good tripod, cable release or some sort of remote, and mirror lock up. And stationary subjects!

Mac Loc: Pittsburgh, Philadelphia now Hernando Co. Fl.

There was a thread on this just recently. Use the "Search" at the top of the page to find it.

jerryc41 Loc: Catskill Mts of NY

Some reviews -
http://www.curiouswriter.com/opteka-650mm-1300mm-lens-review/
https://www.amazon.com/Opteka-650-2600mm-Definition-Telephoto-Digital/product-reviews/B001GKLLRY
https://www.youtube.com/watch?v=k2poJJz70fo
http://www.galttech.com/research/digital-cameras/best-opteka-lenses.php

NJphotodoc Loc: Now in the First State

I bought an Opteka 500mm f6.3 for some outdoor work. I made the mistake of putting price before quality. Even on a heavy duty tripod the balance was poor using the mounting bracket (have it tied to my D7200) and the focus was not sharp at all. Wide open there was noticeable aberration but it did resolve at higher f stops.
OK so it cost only $90 with the Nikon adaptor from 47th St Photo ( I believe they were the US importer at the time I bought it), but if you are serious, I would save up and buy a better lens.

aellman Loc: Boston MA

Per your abbreviation, "CA," I figured it out after a while but I bet a lot of people didn't. Sometimes it's better to spell the words. Not a lot of effort. >Alan

JimH123 Loc: Morgan Hill, CA

OK, Chromatic Aberration. This is a problem where the different colors of the spectrum do not come to focus at the same point creating color banding around areas of high contrast in the image. SW such as Lightroom have a way to reduce the effect, but it is really hard to completely eradicate it.

More expensive lenses use glass made of fluorite, which has a different diffraction coefficient to remove this ugly problem. The lens may be constructed as a doublet or triplet, which refers to how many lenses are grouped together. And this phenomenon has been understood for a long time as even the 36" objective in the Lick Observatory made use of it.