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THE TAL SUPER PLÖSSL

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#1 Charlie Hein

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Posted 27 October 2013 - 07:02 AM

THE TAL SUPER PLÖSSL

By William Paolini

#2 etudiant

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Posted 27 October 2013 - 01:02 PM

Thanks to William Paolini for a couple of excellent reviews.
They really are models of what a review should be, factual and informative. One senses a serious observer at work.

My only question is whether the tests were entirely independent. It is so rare that a manufacturers specs are conservative that any example raises concerns that the test samples are selected.
Presumably Mr Paolini ordered these lenses from the TAL site. Were they aware that he would be writing these excellent evaluations?

#3 BillP

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Posted 27 October 2013 - 04:23 PM

Eyepieces were on loan to me from supplier to evaluate. So yes, things like this can be cherry picked as you mention as a possibility. However, this would be unusual relative to the Afov as it would mean that different field stops would have to be in these. So that would be quite a big manufacturing error...especially since all were like this. I feel it is more likely that the marketing dept listed the wrong specs since no Plossl line is marketed with a 45 deg afov that I know of.

#4 etudiant

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Posted 31 October 2013 - 07:29 AM

Thank you, Bill, for a great review and a quick and helpful follow up.

Your explanation makes very good sense.
Marketing has always been a bit of a stepchild in Russian industry, so a glitch there would not surprise.
Nothing wrong with their optics know how though.

#5 Andy Howie

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Posted 31 October 2013 - 10:36 AM

Yep, enjoyable reading, as always.

I have a few Tal Plossls and used to have close to the full range. Always thought they had good glass inside a basic, but solid body. Typical of many Russian optical products, in that they may not be the greatest to look at, but they are very nice to look through.
As for the specs. Some years back, I read on a Russian forun, why the AFOV were under stated. Sadly, at the time, my online translator didn't do a great job, so it's still a mystery. I'll need to hunt out where I found that quote. I'm sure it was from one of the designers. I've noticed the translators have improved over the years, so it would be nice to try again.

Thanks for taking the time to do these reviews.

Andy.

#6 TG

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Posted 01 November 2013 - 07:24 PM

@BillP: A nice read, well done!

Astigmatism is a bugaboo of both orthos and Plossls. As I understand, the design used by Tele Vue, and now copied in the Sterlings, reduced astigmatism at the cost of introducing distortion. How did you find this aspect? You do mention performance to the edge in general terms but given that this eyepiece appears to be orthoscopic in nature, I wonder if astigmatism is still present as in a vanilla Plossl.

Tanveer.

#7 BillP

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Posted 02 November 2013 - 10:53 AM

Unfortunately I did not take critical observations of the far off-axis. When dealing with Plossls I generally don't since they all seem to perform about the same, excepting the oncave surfaced variety which are a little better. Only notes I have on the TAL SP far off-axis is related to the 25mm which was sharp across the FOV except for the very edge...maybe the last 5% was not so sharp when observing the Moon, so probably astigmatism. That was in the f/8 TSA.


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