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Old Spiratone Mirror

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#1 vidrazor

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Posted 17 July 2020 - 06:12 PM

I picked up an old Spiratone mirror lens at garage sale, and while physically it looks fantastic, it's makes for the softest images. Is that just how this lens was, or is it in need of some kind of adjustment? It was only $40 so not a great loss, but it would be nice to have something this compact to shoot and view with.

Thanks.

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  • minitel.jpg


#2 markb

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Posted 17 July 2020 - 06:55 PM

My newer (relatively speaking on a 40 year old product), small and lightweight Spiratone was good to very good. My guess is late 80s. My Lentar was a bit better, solid very good, both in daytime use. The Lentar was just gifted to a friend, we'll see how it does at night. Neither would be called soft, nor would they be called amazing.

 

The Lentar still hold some resale value if that is any indication.  The best were some, but not all, of the name brand mirrors, and possibly the Celestron and Meade photo converted maks.

 

You best bet, if no one with the same model posts, is to search for reviews.

 

You may find old Spiratone Minitel reviews on line at camera sites, and Modern Photography back issues are hosted somewhere, maybe archive.org, not sure  if you find a citation. Match your photo as Spiratone relabeled tons of stuff.


Edited by markb, 17 July 2020 - 06:56 PM.


#3 vidrazor

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Posted 17 July 2020 - 10:53 PM

Well, I was just thinking in terms of what I got from this lens, which was quite useless. Was this lens always this bad, or is it in need of some adjustment?



#4 markb

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Posted 18 July 2020 - 07:13 AM

Curious, I poked around photo websites but did not happen on a specific review, but it does appear this was an early Spiratone relabel, with the distinctive foot. Owners tended to be satisfied.

 

I came across no nasty owner posts, so I will assume yours has an unknown issue.

 

I would not expect useless, Spiratone stuff was at least solidly usable, they would have been taken to task for less. Word of mouth was powerful, pre-internet. Some stuff was excellent.

 

Photo lenses are sometimes disassembly capable, but I am not aware of any adjustments other than spacers shifting the focal point to flange and perhaps element spacing.

 

My guess is something is loose or contaminated.

 

Oils from the focuser grease made many diaphrams 'lock up'. Oils could certainly contaminate a mirror with a thin film. On writing this, I think this is what got my first Minolta AF mirror.

 

One thing you can check is serious contamination internally, degraded mirror coatings, scratches, and, particularly, loose elements or retaining rings.

 

I picked up a Minolta AF lens that would not focus, and whole disassembling it to fix diaphragm contamination, the rear elements just fell out. Apparently the retaining ring was very loose and not noticed. On reassembly it was very sharp (and very clean).

 

I have a Minolta mirror that had some kind of contamination on the inner 1/3 of the main mirror, and it showed up as a shadow in the 'bokeh', an out of focus highlight. Gee, sounds similar to Suiter star testing... Point at a bright small light, and look at the out focus donut. It should be smooth and even.

 

So check visible surfaces for issues, check retaining rings are secure (jiggle and wiggle to see if elements shift; if tightening is needed buy a spanner (but toothpicks are safer than tools if you don't want to spend the $$), and don't overtighten!

 

These small old mirrors are fun to keep around.

 

Better ones have multiple elements, but yours may not, in case you attempt disassembly for cleaning. Make pictures of every step and every screw to aid reassembly if you try it. I've never had a mirror photo lense apart.



#5 markb

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Posted 18 July 2020 - 07:29 AM

See http://www.subclub.org/Tomioka.pdf

 

No negatives there, and apparent shared design with a major manufacturer, so it should be at least a good performer.



#6 TxStars

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Posted 18 July 2020 - 03:04 PM

From what I remember of the Spiratone mirror lens, you needed to place tape on the focus ring to keep it from moving if the lens was pointed up at the sky.

It is not a fast system so exposure times are lengthy and they had distortion as you move away from center.

 

For daytime use they are meh... Most prime telephoto lenses are better.


Edited by TxStars, 18 July 2020 - 03:06 PM.


#7 calypsob

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Posted 21 July 2020 - 09:55 AM

What is the bayonet? If its t2 it would make a decent guide scope paired with an imx174. For imaging, there will be donuts coma and no ability to collimate

#8 vidrazor

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Posted 23 July 2020 - 01:07 PM

What is the bayonet? If its t2 it would make a decent guide scope paired with an imx174. For imaging, there will be donuts coma and no ability to collimate

It's universal mount, but rather heavy and narrow for a guide scope I think. I dunno, maybe I'm just too used to working with refractor lenses that what a mirror puts out just doesn't look right to me.



#9 woodrim

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Posted 19 November 2020 - 12:08 PM

I have the later (last) version of that Spiratone but it's much the same image quality. Yours was the first version, made by Tomioka. Tomioka was a quality lens manufacturer that made lenses for Yashica, including their mirror lenses. They also made the Mirotar for Zeiss and to Zeiss specifications. Your results could be from poor focusing technique or any of several issues with the lens itself. Haze or fungus will do that. While the Minitel isn't one of my better mirrors, it is quite satisfactory when focus is nailed. There isn't much room between perfect and total miss. This will take you to some of my Minitel images:     And information about the lenses can be seen here: https://technodocbox.com/Cameras_and_Camcorders/73737322-Tomioka-yashica-spiratone-and-mirotar-sigma-etc-500mm-f8-lens-timeline-history.html?fbclid=IwAR15ZdX2rRj8aqa2Z6UP5FYPzl-daMc1wowR-PRlqT8tKb7nESBSWNgCqSs


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#10 vidrazor

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Posted 23 November 2020 - 11:26 AM

I have the later (last) version of that Spiratone but it's much the same image quality. Yours was the first version, made by Tomioka. Tomioka was a quality lens manufacturer that made lenses for Yashica, including their mirror lenses. They also made the Mirotar for Zeiss and to Zeiss specifications. Your results could be from poor focusing technique or any of several issues with the lens itself. Haze or fungus will do that. While the Minitel isn't one of my better mirrors, it is quite satisfactory when focus is nailed. There isn't much room between perfect and total miss. This will take you to some of my Minitel images:     And information about the lenses can be seen here: https://technodocbox.com/Cameras_and_Camcorders/73737322-Tomioka-yashica-spiratone-and-mirotar-sigma-etc-500mm-f8-lens-timeline-history.html?fbclid=IwAR15ZdX2rRj8aqa2Z6UP5FYPzl-daMc1wowR-PRlqT8tKb7nESBSWNgCqSs

Yeah, no this lens is just really soft, even properly focused. Compare it to a cheap 500mm f/8 refractor from the same era below. The Spiratone mirror lens is on the left. The refractor (a discount manual "preset" lens that was sold via various labels), while it is also relatively soft and with it's owns anomalies, looks significantly better. That's the best I can get out of the mirror.

 

I can't help but think that, seeing such a drastic difference even when compared to another lens from it's own era, that there must be some issue with the Spiratone. I just can't figure it out.

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  • 500mm lenses.jpg

Edited by vidrazor, 23 November 2020 - 11:30 AM.

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#11 TxStars

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Posted 23 November 2020 - 06:48 PM

Now you know why there are so many of them for sale...  lol




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