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Soviet Tair-3 300mm f/4.5 lens as Astrograph tests

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#1 Falcon-

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Posted 07 July 2011 - 10:28 PM

With the summer's wealth of large objects to image I have been yearning to once again borrow my friend's excellent Canon EF 300mm f/4 L IS USM lens. Oddly though he had what was (obviously) an unreasonable desire to use his own lens! :p So... given the success I have had with the old manual focus Super Takumar 200 f/4 and Pentacon 135 f/2.8 I decided to see if I could find myself a dirt cheap old manual 300mm+ lens. I had a few options to look at, but several times in researching those other lenses I repeatedly saw comments comparing them to the Soviet erra Tair-3 long lens. Everything I read indicated that:

1) the Tair-3 is optically good
2) the Tair-3 is very large and heavy

Heavy long lenses may be an issue for hand-held daylight photography, but this is astrophotography! Surely the lens would weigh similar to a small APO, and that is no problem at all... right? ;) So I found a Tair-3a m42 mount version on ebay and ordered it! Last night I defied the clear sky chart and spend the dark hours using holes in the passing clouds to do a test sequence on the lens.

Short version? I am happy! :grin:

Lens Details:
- The aperture iris of this lens has quite a lot of blades. Makes for a tight grouping of a large number of spikes off bright stars (I like the effect). It also has a nifty double-setting system for the iris. First ring is an outer-stop position that sets the maximum amount you can stop down - this ring has notches at 1/2 stop intervals. The second ring controls the iris and has no notches at all, allowing free setting of any iris position from wide-open to whatever stop you set on the first ring.
- Focus on my lens requires more force then I would expect with a modern lens, but I have found that no impediment to achieving critical focus.
- This is a "Long Lens" rather then a Telephoto, in a way it has optically more in common with an APO scope then a Telephoto lens! I believe it is a three element design (doublet + third element further back in the tube).
- The Tair-3A is set up as a standard camera lens, while the Tair-3S is set up for a funky riffle-stock type mount for handheld photography. The 3A is may be easier to focus in small increments. This lens is a Tair-3A.

Performance notes:

- Wide open at f/4.5 the lens performs passably, but not perfect. Stars at the edges are slightly distorted and there is an center-directed blue flare off of brighter stars. I should note that the performance when wide open is better then the *best* performance from some cheap modern zooms I have used!
- At f/5.6 things are looking very good, stars are still not *PERFECT* at the corners, but already quite a lot better then many APO+flatteners can produce!
- At f/6.7 stars are round across the whole field and slightly shaper then f/5.6. The blue flare on bright stars is gone. A *very* slight red halo shows up on my moded 350D if the focus is a bit off, so perfect focus is important (but when is perfect focus *NOT* important!)
- At f/8 the stars *might* be just a very slight bit shaper still, but not enough to make up for the loss of light gathering power.
- I found that with my lens if you are not careful with how you tighten the tripod collar you can create a situation where you can not quite reach infinity focus. Once I figured that out though it is very easy to avoid. :)
Edit: Looking closely at the stars in the wide open test and specifically how they are not quite the same in each corner I have a feeling that part of the off-round shape may have a lot to do with the very likely years of rough treatment this lens has endured - it is possible a better condition copy will be even better!

Test image info:

To test the lens I decided to point far south at M8 and M20. The result is a nice image, but I wish I had selected a field with more bright stars in view to really test the optics! To create these test exposures I used the Baader UV/IR modified Canon 350D auto-guided on the CI-700 mount. I used no Darks and no Flats. I used Nebulosity to align&stack and performed identical background neutralization and histogram stretch operations on each image in PixInsight. I shot:

- 4x 60s exposures at f/4.5
- 4x 60s exposures at f/4.8
- 4x 90s exposures at f/5.6
- 14x 120s exposures at f/6.7
- 1x 180s exposure at f/8

Attached is the forum-sized full frame result of the f/6.7 exposure stack. I intend to re-do this image with proper calibration later and will post that in another thread later (including high res full frame image). I boosted the saturation on this image only.

Attached Thumbnails

  • 4680166-tair3_test_f6.7_14x120s_A1.jpg


#2 Falcon-

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Posted 07 July 2011 - 10:29 PM

1:1 Resolution Corners and Center crops at f/4.5 (Wide Open)

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  • 4680168-tair3_test_f4_5_corners.jpg


#3 Falcon-

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Posted 07 July 2011 - 10:31 PM

1:1 Resolution Corners and Center crops at f/4.8

Not much difference between this and wide open.

Attached Thumbnails

  • 4680173-tair3_test_f4_8_corners.jpg


#4 Falcon-

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Posted 07 July 2011 - 10:32 PM

1:1 Resolution Corners and Center crops at f/5.6

Tightening up, but still not quite round stars

Attached Thumbnails

  • 4680178-tair3_test_f5_6_corners.jpg


#5 Falcon-

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Posted 07 July 2011 - 10:33 PM

1:1 Resolution Corners and Center crops at f/6.7

This may be the sweet spot for this lens!

Attached Thumbnails

  • 4680180-tair3_test_f6_7_corners.jpg


#6 Falcon-

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Posted 07 July 2011 - 10:35 PM

1:1 Resolution Corners and Center crops at f/8

Ignore the noise, this was a single frame.

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  • 4680183-tair3_test_f8_corners.jpg


#7 Falcon-

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Posted 07 July 2011 - 10:37 PM

To make up for the lack of a bright star in the corner crops I found a bright star near the lower center of the image. It is not all THAT bright of a star, but you can start to see the hint of the many spiked diffraction spikes this lens produces.

Attached Thumbnails

  • 4680185-Tair3_test_brightstar_crops.jpg


#8 Falcon-

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Posted 07 July 2011 - 11:55 PM

Ok, just in case I have not caused several simultaneous rampages through the globe as dialup users go nuts trying to load this thread.... A few pictures of the lens itself are called for!

First off - I did say this is a Soviet lens....

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  • 4680295-IMG_3199.jpg


#9 Falcon-

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Posted 07 July 2011 - 11:58 PM

I think I also mentioned that this lens is LARGE ;)

From left to right my complete astrophotography lens collection: Tair-3A, Super Takumar 200 f/4, Pentacon 135 f/2.8, Canon 50mm f/1.8. All with lens shades either extended or attached.

Attached Thumbnails

  • 4680296-IMG_3195.jpg


#10 Falcon-

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Posted 08 July 2011 - 12:05 AM

Last a the Tair-3A attached to the 350Da used in these tests.

Since I did not explicitly say earlier....

Conclusion

An excellent economical astrograph lens. It may not be as good wide-open as a Canon 300 f/4 L but at 1/15th the cost it is close enough!! :grin:

Attached Thumbnails

  • 4680301-IMG_3201.jpg


#11 Nils_Lars

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Posted 08 July 2011 - 01:32 AM

Looks like a sniper Rebel :)

A very good performer even wide open , I think this lens was a great choice and thanks for all the in depth testing.

#12 robjohn

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Posted 08 July 2011 - 04:13 AM

Each blade on the iris creates two spikes perpendicular to the edge of the blade. It looks as if the Tair-3 has 16 blades (with an even number of blades, there are an equal number of spikes, assuming opposite blades are parallel; with an odd number of blades, there are twice as many spikes).

The spikes should disappear if the lens is used wide-open, when the blades of the iris are outside the edge of the lens.

#13 Dan Watt

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Posted 08 July 2011 - 11:54 AM

Great post! I've been looking for an older lens around 300mm for some time but everything I've come across was either out of my budget or of inferior quality. I'm going to be picking one of these up asap.

#14 vmsguy

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Posted 08 July 2011 - 12:08 PM

I've tried 4 or 5 times on eBay to get a Tair 3 lens but always got outbid.

I finally got an old Nikkor 300 f/4.5, but I'd still like to try getting a Tair someday.

#15 Falcon-

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Posted 08 July 2011 - 12:48 PM

Each blade on the iris creates two spikes perpendicular to the edge of the blade. It looks as if the Tair-3 has 16 blades (with an even number of blades, there are an equal number of spikes, assuming opposite blades are parallel; with an odd number of blades, there are twice as many spikes).

The spikes should disappear if the lens is used wide-open, when the blades of the iris are outside the edge of the lens.


16 sounds about right, I did not physically count them but there certainly are a lot of blades so this is certainly not a double-count of spikes in the image (in other words an even number).

In any case the spikes certainly do not concern me, I quite like them. :)

#16 Falcon-

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Posted 08 July 2011 - 12:54 PM

I've tried 4 or 5 times on eBay to get a Tair 3 lens but always got outbid.


I got mine via a Buy It Now auction... I do not think I have bothered to bid on anything on ebay for more then 5 years! My particular lens came from the Ukraine - felt like a bit of a gamble to buy something from the Ukraine to be shipped to Canada, but the seller looks reputable and turns out he/she was. :)

In that it shipped from the Ukraine and arrived in Canada JUST as a postal strike began, so it got shipped BACK to the Ukraine, and then it was shipped back FROM the Ukraine to a PO box I have in the US.... where it of course arrived a week *after* the canadian postal strike finished. :foreheadslap:

I finally got an old Nikkor 300 f/4.5, but I'd still like to try getting a Tair someday.


One of those was a prime contender for an alternative... What model of Nikkor 300 f/4.5 did you end up with? How do you find it for astro work?

#17 Mike C

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Posted 08 July 2011 - 01:26 PM

Thanks for that report, Sean. I hadn't heard of the Soviet Tair lens.

Another alternative 300mm f4, if one can be found, is a Pentacon. I bought one secondhand, well-used, in the late 80s and I think it must about 40 years old. It weighs around 5lb, so heavy compared to a modern equivalent.

I'm not sure how it compares optically with the Soviet Tair, and I have to say that colour-fringing is pretty obvious when using magnified Live-View to focus! Furthermore, the iris in my sample broke a few years ago and I can no longer stop it down to improve quality.

I still make use of it though, for large objects such as the Veil. A couple of example images (The Veil and the Cepheus nebula) can be seen in this thread: http://www.cloudynig...5/o/all/fpart/1

Regards.

#18 Falcon-

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Posted 08 July 2011 - 02:02 PM

Furthermore, the iris in my sample broke a few years ago and I can no longer stop it down to improve quality.



I have a similar problem with my Pentacon 135 f/2.8. My plan is to make an external aperture stop-down ring (a plastic donut to sit in front of the lens instead of the iris internal to the lens). Perhaps that would work for your old 300mm?

I have to say that colour-fringing is pretty obvious when using magnified Live-View to focus!


That is something I find very impressive with the Tair-3. While not as good as the Canon 300 f/4 L the lack of colour fringing when compared with my Takumar 200 and Pentacon 135 is amazing! Does the fringing on your Pentacon 300 f/4 disappear when in critical focus?

#19 Mike C

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Posted 08 July 2011 - 02:30 PM

Re. the iris, thanks for the suggestion - I should try that!

Unfortunately where the fringing is least is not quite at the focus point, so it's a compromise. Some fringing remains, but as long as I don't need to crop heavily or print very large I find it acceptable (for web use at least).

I found a pic of the Pentacon 300mm f4 that I posted some years back. (Note that the mount is over-loaded with the C8 and heavy lens in this photo, but I now use a G-11).

Regards.

Attached Thumbnails

  • 4681364-Pentacon 300mm.jpg


#20 Falcon-

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Posted 08 July 2011 - 03:09 PM

Nifty looking lens. Certainly a lot shorter then the Tair-3 (A telephoto rather then a long-lens) but it does appear to be be quite hefty!

#21 Mike C

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Posted 08 July 2011 - 04:14 PM

Hefty it is, certainly - all metal build, very different to today's lenses, and of course a lot of glass!

#22 Nils_Lars

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Posted 08 July 2011 - 06:39 PM

I would think a cheap step down ring would work as well as a plastic circle and it's guarenteed to be in the center and round , also I've seen Hiro use a metal shim/washer to get the same effect.

I'm curious about using these kind of lenses for Narrowband since that would mostly fix the fringing right?

I just picked up a Pentax 135 f/3.5 on auction and I'm hoping it works well for Ha at least.

Also has anyone tried a fring killer filter on one of these , I guess funny stars will still be a problem though.

#23 Falcon-

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Posted 08 July 2011 - 10:38 PM

Narrow band would *certainly* be much less sensitive to chromatic aberration then full RGB imaging is. Fringing occurs because it is hard to focus a wide-band swatch of spectrum in a single point - narrowband is certainly one way to solve that!

#24 avarakin

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Posted 10 July 2011 - 12:42 AM

Sean,

Thanks for publishing this!
Looks like a great lens.
How does it compare to Pentax 200mm?

Alex

#25 Falcon-

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Posted 10 July 2011 - 03:38 AM

How does it compare to Pentax 200mm?


The Super Takumar 200 f/4 shows a lot more chromatic aberration then the Tair-3a does, you *have* to stop the Tak200 down and be very careful with the focus to get best results. The Tair-3 certainly performs a lot better wide open at f/4.5 then the tak200 does! Still, I am glad I have both - the Tak200 does well if you are able to nail focus properly with it. Going to be nice to have the option of both focal lengths! :)


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