• Ultraviolet Photography
  •  

Kuri 35mm vs. Noflexar 35mm

Lens
68 replies to this topic

#1 Andy Perrin

    Member

  • Members+G
  • 4,098 posts
  • Location: United States

Posted 03 May 2021 - 22:12

This was a not-especially-scientific quick and dirty test of the Kuribayashi K.C. Petri Orikkor 35mm/3.5, Kuri for short, and the Novoflex Noflexar 35mm/3.5. The results surprised me, in fact.

The filters were 1.75mm S8612 + 2mm UG11 (from Cadmium, with ongoing thanks), and the settings were 1.3" ISO1600 F/11 in both cases. Camera was the Sony A7S (converted by LifePixel) which is full frame and 12MPix. The white balance was whatever I had on my camera from the last time I used it (heh) but I made sure both shots used the same white balance in PhotoNinja by copying it from one to the other.

Exposure was adjusted in PN on the Noflexar image and then copy and pasted to the Kuri photo also. The PN processing settings are exact duplicates, in other words, so any differences are due to the lenses.

Vignetting on the Noflexar pic is caused by the 49-52mm step ring, since my filters are 52mm.

Full image (reduced to 1000px width)

Kuri
Attached Image: _DSC8598 Kuri S8612 1.75mm UG11 2mm F11 1.3%22 iso1600 UVP.jpg

Noflexar
Attached Image: _DSC8596 Noflexar S8612 1.75mm UG11 2mm F11 1.3%22 iso1600 UVP.jpg

Center crop (1000px, 1:1)

Kuri
Attached Image: _DSC8598 Kuri S8612 1.75mm UG11 2mm F11 1.3%22 iso1600 center crop.jpg

Noflexar
Attached Image: _DSC8596 Noflexar S8612 1.75mm UG11 2mm F11 1.3%22 iso1600 center crop.jpg

Side crop (1000px, 1:1)

Kuri
Attached Image: _DSC8598 Kuri S8612 1.75mm UG11 2mm F11 1.3%22 iso1600 side crop.jpg

Noflexar
Attached Image: _DSC8596 Noflexar S8612 1.75mm UG11 2mm F11 1.3%22 iso1600 side crop.jpg

Conclusion that I drew is that the Kuri has a much larger bandpass than the Noflexar (as expected) — even ignoring the colors, it was significantly brighter — but actually the Noflexar is the sharper lens! At least for these particular Kuri and Noflexar copies.

Edited by Andy Perrin, 03 May 2021 - 22:17.


#2 Stefano

    Member

  • Members(+)
  • 1,813 posts
  • Location: Italy

Posted 03 May 2021 - 23:18

Seeing yellow is always a good sign for reach, but as you said it isn’t everything, you noticed a brightness difference too. Anyway, the colors are going to look better with the Kuribayashi because there will be more separation.

To really test the sharpness you could try it wide open, that will affect the edges for sure. I wonder if my Soligor can be comparable to the Kuribayashi in that, maybe the difference is not as much as I think.

#3 dabateman

    Da Bateman

  • Members+G
  • 2,779 posts
  • Location: Maryland

Posted 04 May 2021 - 04:19

Well you don't know what you have until you have something to compare it to.

Reminds me when I first compared my UAT f4.5 lens, which I will not say what I paid for, to my $20 Nikkor 80mm EL f5.6 lens outside in sunlight with 370bp filters. I thought what!

Edited by dabateman, 04 May 2021 - 04:21.


#4 colinbm

    Member

  • Members+G
  • 2,423 posts
  • Location: Australia

Posted 04 May 2021 - 04:28

Looking good Andy

You could think about a sparticle test ?

#5 UlfW

    Ulf W

  • Members+G
  • 1,614 posts
  • Location: Sweden, Malmö

Posted 04 May 2021 - 06:45

View PostStefano, on 03 May 2021 - 23:18, said:

Seeing yellow is always a good sign for reach, but as you said it isn’t everything, you noticed a brightness difference too. Anyway, the colors are going to look better with the Kuribayashi because there will be more separation.

To really test the sharpness you could try it wide open, that will affect the edges for sure. I wonder if my Soligor can be comparable to the Kuribayashi in that, maybe the difference is not as much as I think.
The yellow is just an indication of a better reach than for the lens used for all WB.
To me it looks like the WB was done by the Noflexar that is known to have less UV-reach than the Kuri and it's clones.

I would bet that the UV-reach of the Soligor (KA) made by Kuribayashi Acall is very close to the lens Andy bought.
https://www.ultravio...m-f35-noflexar/
https://www.ultravio...or-35mm-f35-ka/
When I want to quickly compare two lenses graphs I open them in two separate tabs and scroll to the graphs in both tabs.
Then it is easy to flip between the graphs.

The UG11 is likely chosen here to show the difference in UV-reach, as the filter combination peaks at around 355nm.
Attached Image: Screenshot 2021-05-04 at 08.30.51.png
I expect that if a U-360 had been used instead, the visual difference in colours would have been a bit smaller.

If the images were individually WB it would be very difficult to tell the difference form the colours as the UV-reach of the Noflexar is quite good enough for outdoor UV-photography.

Edited by UlfW, 04 May 2021 - 06:47.

Ulf Wilhelmson
Curious and trying to see the invisible.

#6 Bernard Foot

    Bernard Foot

  • Members+G
  • 718 posts
  • Location: UK

Posted 04 May 2021 - 06:58

Andy - do you have an IgorOriginl to test against? I'd love to see the enswer to that nd the question about whether to IgorOriginal really id a Kuri clone.
Bernard Foot

#7 nfoto

    Former Fierce Bear of the North

  • Owner-Administrator
  • 3,184 posts
  • Location: Sørumsand, Norway

Posted 04 May 2021 - 07:52

One should always keep in mind these lenses are old and depending on build quality and actual wear and tear, might not be performing at their best after so many years. That being said, I'm not surprised by Andy's original observations. I have 4-5 "Kuri" of different designations and some of them show really bad corners. The others are not that bad, but not particularly outstanding either. My 3 Noflexars are much more even across the frame. I did not notice the questionable performance towards corners initially as I mainly used the lenses on smaller format cameras (Panasonic GH-2, Nikon D40x).

#8 dabateman

    Da Bateman

  • Members+G
  • 2,779 posts
  • Location: Maryland

Posted 04 May 2021 - 12:12

View PostBernard Foot, on 04 May 2021 - 06:58, said:

Andy - do you have an IgorOriginl to test against? I'd love to see the enswer to that nd the question about whether to IgorOriginal really id a Kuri clone.

Do you mean a clone like the stormtroopers are a clone of Jango Fett and can't hit a target 6 feet in front of them?

Bernard you know the answer to that question is impossible. It depends on what your base lens is and how the elements were flipped out with others during cleaning. My outer barrel looks like Ulfs recent Soligor. I need to double check.

Yes my igoriginal 35mm f3.5 looks exactly like the photo Ulf posted for the Soligor KA 35mm f3.5 lens in the normal section.

Edited by dabateman, 04 May 2021 - 14:03.


#9 Stefano

    Member

  • Members(+)
  • 1,813 posts
  • Location: Italy

Posted 04 May 2021 - 12:34

View PostUlfW, on 04 May 2021 - 06:45, said:

The yellow is just an indication of a better reach than for the lens used for all WB.
To me it looks like the WB was done by the Noflexar that is known to have less UV-reach than the Kuri and it's clones.

I would bet that the UV-reach of the Soligor (KA) made by Kuribayashi Acall is very close to the lens Andy bought.
https://www.ultravio...m-f35-noflexar/
https://www.ultravio...or-35mm-f35-ka/
When I want to quickly compare two lenses graphs I open them in two separate tabs and scroll to the graphs in both tabs.
Then it is easy to flip between the graphs.

The UG11 is likely chosen here to show the difference in UV-reach, as the filter combination peaks at around 355nm.
Attachment Screenshot 2021-05-04 at 08.30.51.png
I expect that if a U-360 had been used instead, the visual difference in colours would have been a bit smaller.

If the images were individually WB it would be very difficult to tell the difference form the colours as the UV-reach of the Noflexar is quite good enough for outdoor UV-photography.
Yes, this is what I meant. Andy said he white balanced both images the same way with whatever the camera already had and copy-and-pasted the settings on the Kuribayashi. The Noflexar is known to reach less deeply than the Kuribayashi.

#10 Bernard Foot

    Bernard Foot

  • Members+G
  • 718 posts
  • Location: UK

Posted 04 May 2021 - 14:47

View Postdabateman, on 04 May 2021 - 12:12, said:


Bernard you know the answer to that question is impossible.


Sorry, David - I don't understand the point you're making.

The lenses that Igor classes as "Kuri clones" are simply re-badged (Soligor, Prinz, Hanimex, et al.) versions of what Igor believes are lenses made by Kuri. He just refurbishes them, does something with the T-mount adapter, and fits a 52mm filter mount. He doesn't change the optics. (He does have some other homegrown lenses that he builds from components, but these are not the Kuri clones.)

So my question is quite simple - do these "Kuri Clones" perform like a real one?
Bernard Foot

#11 Andy Perrin

    Member

  • Members+G
  • 4,098 posts
  • Location: United States

Posted 04 May 2021 - 15:02

I don’t own an IgOriginal (although it makes me laugh that a guy named Igor is building Frankenlenses. I always figured the lab assistant was the real brains of that pair and Dr. Frankenstein was hogging all the credit.)

I do think I would use this lens on the NEX-7 which is APS-C since that will give better performance under adequate light.

So far my sharpest lens with the best bandpass remains the EL-Nikkor 80mm.

Edited by Andy Perrin, 04 May 2021 - 22:13.


#12 dabateman

    Da Bateman

  • Members+G
  • 2,779 posts
  • Location: Maryland

Posted 04 May 2021 - 21:19

Bernard,
When I ordered mine back in 2017 Igor said that he takes them apart, cleans them adds seals and removes elements. He has swapped out some elements from others to get good working ones. So they will not be equal to the original lens and may not be equal to each other. The Igoriginal is a 35mm all to its self. Mine is nice and sharp at least. Only little improvement in the center with a SvBony 0.5x focal reducer. That turns it into a 23mm lens.

Andy thank you these tests. Its eye opening the difference on even the low resolution (12 Mpixel) 7S.

#13 colinbm

    Member

  • Members+G
  • 2,423 posts
  • Location: Australia

Posted 05 May 2021 - 02:29

Dave, have you done a tutorial on this adaptation to the Igoriginal 35mm lens with the SvBony 0.5x focal reducer please ?

#14 Andy Perrin

    Member

  • Members+G
  • 4,098 posts
  • Location: United States

Posted 06 May 2021 - 17:59

Well this is getting stranger and stranger. I put the Kuri on my NEX-7 (APS-C sensor with 24 Mpix) and I couldn't reach infinity focus! That camera has always been just fine and it works with other lenses. So it must be the Kuri. The FFD for the Kuri seems to be off perhaps? But it sheds some light on the previous results also — probably it was not reaching infinity before either but I put it down to the lens being a bad copy. At 1.5x crop factor and 24 Mpix, the issue is now obvious.

Edited by Andy Perrin, 06 May 2021 - 18:00.


#15 Stefano

    Member

  • Members(+)
  • 1,813 posts
  • Location: Italy

Posted 06 May 2021 - 18:08

Strange. With my camera + lens I reach infinity at the maximum setting possible, I always thought having some extra distance (beyond infinity) could be helpful in cases such as this but as long as everything works I am fine with that.

Has the lens been taken apart and re-assembled? I think this is done quite often to clean them. Probably it is a matter of a fraction of a millimeter.

#16 Andy Perrin

    Member

  • Members+G
  • 4,098 posts
  • Location: United States

Posted 06 May 2021 - 18:19

Quote

Strange. With my camera + lens I reach infinity at the maximum setting possible, I always thought having some extra distance (beyond infinity) could be helpful in cases such as this but as long as everything works I am fine with that.
Yeah, this is the opposite. With some lenses I do reach beyond infinity sometimes but this one is not getting to infinity. I bet it has been "repaired" or something.

I tried again using a helicoid and got infinity to focus by that method. I noticed that I'm also getting some depth of field effects even at F/11. The trees and even the most distant buildings are at different distances and if I put the trees in focus, the buildings are not, etc.

#17 Stefano

    Member

  • Members(+)
  • 1,813 posts
  • Location: Italy

Posted 06 May 2021 - 18:34

So your helicoid is shorter than the adapter (I guess you used). The closer the lens is to the sensor, the farther the focus point is. At f/11 it is odd to see depth of field effects. It is odd in general for distant objects. If you have the Moon in focus (~380,000 km) you will have the Sun in focus too (~150,000,000 km), even if there is a massive difference in distance.

#18 Andy Perrin

    Member

  • Members+G
  • 4,098 posts
  • Location: United States

Posted 06 May 2021 - 18:54

It really depends on how distant and what resolution and crop factor you have. The moon and sun are much much much further away than these trees and buildings.

Edited by Andy Perrin, 06 May 2021 - 18:55.


#19 Andrea B.

    Desert Dancer

  • Owner-Administrator
  • 8,787 posts
  • Location: UVP Western Division, Santa Fe, New Mexico

Posted 07 May 2021 - 05:28

So my question is quite simple - do these "Kuri Clones" perform like a real one?

Well, no. And they are not Kuri "clones". They are not even original anythings.
Andrea G. Blum
Often found hanging out with flowers & bees.

#20 Andrea B.

    Desert Dancer

  • Owner-Administrator
  • 8,787 posts
  • Location: UVP Western Division, Santa Fe, New Mexico

Posted 07 May 2021 - 05:35

Andy, did you check for focus shift as a cause for the unsharpness?
Like, if you focus wide open, then stop down and shoot - it can happen that the original focus goes off a bit. I'm pretty sure that I have not seen that happen with the Noflexar. But I don't know the Kuri well enough to know if it is prone to focus shift in any way.

I have jostled the Noflexar out of focus when rotating the stop-down dial, but that is not focus shift. That is just klutziness. :lol: :rolleyes:
Andrea G. Blum
Often found hanging out with flowers & bees.