[cooltouch]

Well, if you go out on the 'net and google "samyang 800mm" and then click on 'images' you'll come across a variety of images taken with it. For example, here's a photo of a half-moon on flickr that rivals my very sharp 650mm refractor in sharpness:

All sizes | Moon next phase | Flickr - Photo Sharing!

I'm not familiar with the Chinese copies of the Russian MTOs. I know the Russian MTOs are great mirrors, though. But there are a couple other 1000mm optics worth considering: the Celestron C90 and the Meade 1000mm. Both of these are outstanding, diffraction-limited 1000mm f/11 optics, which would come configured as telescopes, spotting scopes, or lenses. There's a camera store local to me that has an older C90 sitting in a display case that's in nice shape. Has the camera adapter already on it. They aren't asking much for it either -- less than $100 -- and I feel it calling out to me, although I don't really need it. But you know how that goes.

[Horus28]

Hi this is the first time on this forum. I have a 500mm pentax mount mirror lens which I used with difficulty on my *istd Pentax DSLR. I upgraded to a Pentax Kx-r and found it was not usable
at all. I was thinking of buying an ODS Mirror Lens and asked the dealer for assurance that the adaptor for your 500mm Mirror lens the exposure problem. That is the Kx-r will know it is a F/8
aperture and set the exposure properly. The dealer came back and said it is entirely manual so everything must be set manually. So can anyone here advise me on this please?

[Stone G.]

Hi this is the first time on this forum. I have a 500mm pentax mount mirror lens which I used with difficulty on my *istd Pentax DSLR. I upgraded to a Pentax Kx-r and found it was not usable
at all. I was thinking of buying an ODS Mirror Lens and asked the dealer for assurance that the adaptor for your 500mm Mirror lens the exposure problem. That is the Kx-r will know it is a F/8
aperture and set the exposure properly. The dealer came back and said it is entirely manual so everything must be set manually. So can anyone here advise me on this please?

HI and welcome,

First, you should note that the ODS requires a T2 adapter for Pentax K. This is a purely mechanical coupling. Further, the lens - as most mirror lenses - is a fixed aperture lens without any aperture coupler and thus, the only information your camera body receives from such a lens is the brightness of the image and with a Pentax DSLR also - in principle at least - whether your subject is in focus or not. (I don't know the quality of that lens).

So your dealer is right: You will have to work in M-mode and find the correct exposure time by means of the green button or, you could possibly also use it in Av-mode and let the camera determine the exposure time. Working in Av mode works fine for me with my Tamron Model 06B on my *ist DL and K200D bodies. Consult your manual and this thread:

https://www.pentaxforums.com/forums/pentax-beginners-corner-q/110658-using-ma...x-dslrs-f.html

Try both modes with the lens that you already have - and do tell us what brand that lens is. It certainly should work in M-mode with as well your *ist D and your K-x (K-r??). So, perhaps you don't really need another lens?

[xjjohnno]

AV mode works fine with mirror lenses, as with M mode but no need to press the green button.
Mike, I don't take moon pics but would love some workable options for stretching focal length for bird pics. The drawbacks the spotting scopes seem to have are portability and that angled view finder. It looks like I'll have to do a bit of product research at the local star gazer and spotting scope shops.

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Last edited by xjjohnno; 08-24-2011 at 05:15 AM.

[Stone G.]

AV mode works fine with mirror lenses, as with M mode but no need to press the green button.
Mike, I don't take moon pics but would love some workable options for stretching focal length for bird pics. The drawbacks the spotting scopes seem to have are portability and that angled view finder. It looks like I'll have to do a bit of product research at the local star gazer and spotting scope shops.

Hmmm....stretching the focal lenght is easy enough, you can use a teleconverter and you can even stack two of them - or you may use eyepiece projection:



This could in its extreme result in focal lengths streched by a factor of 8 or something like that producing images like this:



This is the Tamron SP 350 mm mirror lens (Model 06AB) stretched to 2800 mm FL and with an 810% crop of a 350 mm image inserted for comparison. Quite a "normal" stargazer's trick.

HOWEVER that won't work for birding because exposure times increase dramatically and you will need stacking to overcome the effects of turbulence in the air. No problem for a planetary photographer - but birds have the habit of moving!!!

So, looking at star gazers and streching FL one way or the other is one thing - having a properly fast lens suitable for birds is a very different story.

[Horus28]

Thanks all particularly Stone G.

Yes I have managed to get my existing lens to work with the Kx-r. I found an article about manual focusing on the forum. Critical was the custom setting for the apeture control. Once I did that AV mode worked fine. The lens is a Tokina 500mm f8. I have used mirror lenses for a while. I bought a russian lens (probably mid sixties) 500mm F8 and used it with a Start russian camera. I still have the camera but the lens was a victim of a divorce. I bought the Tokina as a replacement second hand about 1992 but have not used it much. Getting working means I will be using it a lot more particularly since spring approachs and there is a lot of bird life here in Canberra. A particular point of interest is a bird we call a King Parrot.

I might have a go at a teleconverter as well.

[cooltouch]

AV mode works fine with mirror lenses, as with M mode but no need to press the green button.
Mike, I don't take moon pics but would love some workable options for stretching focal length for bird pics. The drawbacks the spotting scopes seem to have are portability and that angled view finder. It looks like I'll have to do a bit of product research at the local star gazer and spotting scope shops.

Most decent spotting scopes I'm aware of have removable angle viewfinders. A camera adapter for these types of scopes is usually a fairly short, straight tube that attaches to the lens at one end and takes a T-mount on the other. The Celestron and Meade mirrors I mentioned above were available in a variety of configurations -- telescopes, spotting scopes, lenses. I've even seen kits that included all three configurations. Being modular like that makes them useful for more than one purpose, obviously.

Stone shows a rather involved setup. Me, about the most I do to stretch focal length of an existing lens is to add a teleconverter, sometimes two. I went nuts one time and attached three to a Tamron 300mm f/2.8 one time -- two 2x's and one 1.4x. Wide open, it was a 1680mm f/16 and it took better photos than I expected it to. That was with a 35mm camera, though. If I were to attach it to my 1.6x crop body EOS, it would be the equivalent to almost a 2700mm lens. Sheesh.

Sometimes the answer for bird pics is to be able to get the birds closer. Here's a link to a blog written by a fellow named Alan Murphy who has some really good ideas:

myBlog

And here's a thread at another forum I hang out at, where the author shows some stuff he's done and the sort of results he gets.

Backyard Birding Studio - Bird Portraits 1 - Updated with photos

The second link especially shows how one person is able to bring the birds to him so that he doesn't have to deal with extra long lenses and all the problems they can introduce into the process.

[xjjohnno]

So far not many tele adapters have impressed me at all due to IQ degradation, but then that's probably because they were cheap Ebay buys. The only ones I've tried to date and liked are the Tamron ones for the adaptall 2 lenses, of which I have both the 2x and the x1.4. Currently the 2x has taken up permanent residency on my SP300 f2.8.
The extra reach is for certain little birds that prefer tree canopies and usually come out as not much better then dots. I'm also very familiar with how they do no follow my plot, deciding to bugger off just as I'm about to hit the shutter button. Thankfully a degree of ISO boost usually helps me get workable shutter speeds to compensate for some of their less exagerated movements.
Feeders aren't an option for me either as I don't have a backyard, I live in a flat (apartment) in inner city Melbourne. Feeders here also attract the feral exotic birds here like sparrows and common mynas. Flowering native plants would attract an array of native honey eaters and much more interesting birds for taking pictures of.

[cooltouch]

Well, since you live in an urban area, one option for you might be to seek out arboretums or similar. We have one here in Houston that's just a few minutes from downtown and it will often have a decent variety of birds hanging out there.

I did a fairly extensive amount of testing with two of my teleconverters recently -- my Tamron 2x and my Vivitar 7-element macro 2x. I was a bit surprised, but I found that in most instances the TCs actually improved the level of detail that was recorded. I also found the Vivitar and Tamron to be approximately equivalent in capabilities. So yeah, a good 2x is worthwhile having.

[xjjohnno]

We have a very decent park at the end of the street with quite the bird population which does the job for close to home birding. We also get out of town quite a bit. That's where the little canopy dwellers hang out.

[GibbyTheMole]

Here's a couple from my Russian 3M-5CA 500mm f:8 lens:



Straight out of the camera, no processing. (K100D body)



Moon shot. Probably with the K-x. Can't remember.



This little dude was in a very shaded area in the park having a bit of lunch. ISO6400 at 1/400 sec. (handheld) K-x body. A little grain reduction in Lightroom, but not much. Had to shrink this one a bit as the original was too large for Imageshack.

I was about to give up on mirror lenses until I found this one. I'm nuts about this lens.

[xjjohnno]

I've got the same lens Gibby, in some conditions you'll get a bit of loss of contrast unless you use a hood with it. The good news is there is a Chinese Ebay sell who sells rubber hoods at just the right size for dirt cheap, postage included.
Got to love the weight of that lens too.
Neat pics btw.

[GibbyTheMole]

xjjohnno:

Thanks much.... Good advice on the hood. I always use one. I have a nice metal hood from a cheap 500mm mirror lens that works great. I've debated on someday getting a 170-500 Sigma, but I dunno... I have a feeling I would still wind up using the 3M mirror more.

[xjjohnno]

The Bigma might be the better option with those Sigmas being the 50-500. You might also want to check out the 3M-6A being the f6.3 version and slightly earlier model. I've posted pics from that lens in this thread quite recently. I has an inbuilt hood, trickier to nail the focus due to the shallower DOF but when you get it right, yummo.

[GibbyTheMole]

xjjohnno

Yeah, I'd love to have a bigma... Unfortunately, they're a bit spendy, so I set might sights on the cheaper variant. One thing I've been thinking of checking into is a small telescope with a camera mount. Something like a Celestron C90, used on a tripod of course. I've never used one, so I don't know what the image quality is like, tho.

Cheers,
Bobbo :-)