[Michael Piziak]

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I notice these Sigma 600mm mirror lens are an affordable super tele lens - 2 on ebay for around $250:

Sigma 600mm f8 Mirror Lens for Pentax K with hood and filters. Sony a7rIV, a7III | eBay
&
Sigma mirror pentax k 600 mm f 8 macro multi-coated | eBay

I seem to have read that the Pentax version has Donut-shaped rendering/bokey.... Likely the nature of any such type lens....

Just wanted to read any comments on the lens, if anyone has used it.... Also would be interested in any review of any of the Sigma or Pentax mirror lens that I can be linked to to this site...Also, which of the 2 Sigma lens, in the links above, would be a superior lens? (I thought they were the same lens, but the green one says macro - one might think this would be superior in image sharpness-?)

Regards,

Michael

Addendum: https://www.pentaxforums.com/userreviews/sigma-600mm-f8-mirror.html
& https://www.flickr.com/photos/tags/sigma600mmf8/
Also, interesting that a Minolta version is around $100 but Pentax & Nikon are 2.5x to 3x higher in price. Must be because of Minolta's discontinuation (?)

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Last edited by Michael Piziak; 09-29-2021 at 03:49 AM.

[MarkJerling]

Other than the reviews here on PF, I have found this very nice detailed review.

Mirror! Mirror! -a guide to choosing and using Mirror lenses part two – Wayne Grundy's PhotoTech Blog

[RICHARD L.]

I had this exact same Sigma mirror lens in a Minolta MD mount in the 1990's. Worst optic I ever bought. Unusable because of a huge veil covering most of the image as soon as the light direction was sideways or facing the lens. Even the bayonet was too thin and the lens wobbled on any Minolta body. I resold it in no time and got the Minolta MD 500 mm f/8 catadioptric in its place : a world of difference. Sigma : no thanks, never again !

Regards

[Michael Piziak]

I had this exact same Sigma mirror lens in a Minolta MD mount in the 1990's. Worst optic I ever bought. Unusable because of a huge veil covering most of the image as soon as the light direction was sideways or facing the lens. Even the bayonet was too thin and the lens wobbled on any Minolta body. I resold it in no time and got the Minolta MD 500 mm f/8 catadioptric in its place : a world of difference. Sigma : no thanks, never again !

Regards

I guess this should be asked in the beginner section, but tell me more about what a catadioptric lens is as compared to the ones I've referenced. I see one on the site for $150:

Vint Tamron SP Mirror Lens 500mm F/8 Tele Macro Catadioptric BBAR MC55BB #A44 | eBay

[RICHARD L.]

A "mirror lens" is a catadioptric optical instrument, like a Cassegrain telescope to observe stars at night. It uses mirrors to lengthen the optical distance the light has to travel inside the lens to reach the sensor or film. There is a large mirror in the back of the lens with a hole in its center, focusing the light rays on a smaller frontal mirror that finally redirects the light rays towards the sensor (folded path). It is also called a "reflector" instead of a "refractor" (all ordimary lenses creating a single straight light path are refractors). Check these concepts on the WEB to grab their meaning accurately.

Regards

P.S. It's not often that I will denigrate an optical instrument but this Sigma mirror lens was "garbage". I could not produce one decent picture with it. The Minolta 500 mm f/8 OTOH was a magnificent lens, very sharp though difficult to focus, but better be aware that catadioptrics produce "low contrast" images because of the interference between the scattered light rays traveling inside the inner tube of the lens. Coatings on the surface of the mirrors are of a primordial importance.

[mlynch53]

Take a look at the Mirror Lens Club here: The Mirror Lens Club! - PentaxForums.com

Yes, mirror lenses can be challenging to learn and to use; the donut-shaped bokeh, which shows up under many circumstances, turns some people off. The design of a mirror lens results in a very shallow depth of focused area, so good focusing can be a challenge.

The quality of the different lenses varies.

But you will also find that some users have managed to get very nice shots through these lenses, incluing the Sigma 600mm version, which I have. (I have posted several photos in the Mirror Lens Club shot with this lens.)

No, they're not for everyone....but those who have patiently worked with them can get good results!

Mike

[bassek]

I have a Tokina mirror lens, which I assume is one of the better mirror lenses.
The price tag for the Sigmas are a bit much.

Seb

[marcusBMG]

General consensus is that the sigmas are of variable quality (see cooltouch's review, and also here ). I have had a couple - one black one, one grey one - and they've been ok actually. Couple of sample pics: the castle turrret focused using 8x magnification in the evf, 2 secs timer, samsung NX20 on a bean bag = approx best results (first pic resized and sharpened, 2nd a 1:1 pixel peep crop); egret by eye = more typical results (pic cropped a lot, resized a bit)! And in anything other than good light - well quite frankly leave the mirror at home.

I would suggest a target price of $50-70, ebay auction. Swapping the mount is relatively easy diy , there are no aperture connections, just 3 screws, so you can bid on eg a MD mount one that will go cheap. Look out for ones that have silvering deterioration pic below - though in practice I didn't really notice any effect on iq.
Overall, TBH, these are more frustrating and lower quality than the tamron adaptall 500mm mirrors, so the tamrons are what I recommend, not the sigma 600's.

[aslyfox]

. . . Overall, TBH, these are more frustrating and lower quality than the tamron adaptall 500mm mirrors, so the tamrons are what I recommend, not the sigma 600's.

I had a mirror lens once:

a Tamron Adaptall-2 SP 500mm f/8 Mirror (55BB)

Tamron Adaptall-2 SP 500mm f/8 Mirror (55BB) Lens Reviews - Tamron Adaptall Lenses - Pentax Lens Review Database

here is a thread you might like to review:

Mirror, Mirror ( in the lens ) eek ? ! ? - Page 4 - PentaxForums.com

if you find a good one, it can be interesting

ps I no longer have mine

[Thagomizer]

Another recommendation for the Tamron 500mm f8 55BB. Also, as marcusBMG notes, if you don't have good light, forget it. If your subject is still small in the frame, forget it.

Here are some results I've managed with my 55BB.

[wadge22]

Just to note for OP, mirrors aren't the only budget way to supertele.
I waited and watched awhile, and wound up getting a Tamron Adaptall 60b 300mm 2.8 (non-mirror) super-tele for about $350 on ebay. For that same $350 on ebay, you could probably find an A 400 5.6 or a K 500 4.5. That's more than the 250 you mentioned, but not by a ton, and might be worth considering those if you are in it more just for the reach, than partially for the curiosity of the mirror lens.

Two distinct advantages of the mirror lenses are the size, and that they shouldn't have purple fringing problems. My 60b, especially with the 2x converter to make it a 600, is large and unwieldy, and prone to CA unless stopped well down.

[mlag]

Mirror are compact super teles, can be fun, but difficult to use.
For me , my 2 mirror lenses belong to my fun range rather than my daily use lenses. I find it easier to use a 1,4 or 1,7x convertor on a 300 or 400 mm vintage (manual focus) lens to get 600mm like performance.
Mirrorlens disadvantages:
- fixed aperture in f6 to f12 range, hence less light and no control of dof.
- Note that the small aperture in combination with higher shutterspeed requiredto minimise risk on lens shake on long range , requires high iso shooting 6400 or more causes more noise on image.
- bit low on contrast , needs correction in postprocessing.
- manual focus. Due to the supertele also difficult on the view finder. Easier with live view and focus peaking...
- ring bokeh can be busy and prominent but some times nice. It is caused by the "mirror with hole" construction, can't be avoided on certain background distances.

Some recent BOOOkeh on The Mirror Lens Club! - Page 81 - PentaxForums.com, scroll also up & down ...

[Michael Piziak]

Thanks everyone for the replies - I read all of them....

Regards,

Michael