Nikon C 28/2 Non-Ai - covers GFX sensor and has no IR hotspots :)

[lukaszgryglicki]

I *think* I've finally found a lens that is good for IR on GFX (most native GFX lenses are too optimized for visible light an dthay usually have hotspots, being only usable wide open or stopped 1 or 2 stops - depending on the lens).

I also like landscapes, so I've nbeen hunting for wide lens for GFX.

And here it is :)

- Nikon N (C) 28/2 serial 2957xx - looks like this is a single coated verion, according to http://www.photosynthesis.co.nz/nikon/lenses.html multicoat starts from about 312xxx. this is a non-AI lens which is not an issue - I use K&F Nikon-F->GFX converter.

Now - then lens has NO vignetting even at f=22 when no filter is used. If I add ANY, even the slimmest 52mm filyter - there is a mechanical vignetting (black rounded corners) on f=22 and everywhere else (best visible at f=22).

But when I add 52->82mm step up ring (slim and very wide) and then use even two 82mm filters on it - there is no vignette.

Additionally (possibly because of single coat) I see no hotspots even at f=22.

 

It also seems to be OK with UV - YEAH!

 

This si the lens: https://www.destoutz.ch/lens_28mm_f2_320040.html and I've found there that it SHOULD not vignette on GFX: https://docs.google.com/spreadsheets/u/0/d/1uxvvpxJ9QVFFyh0pW2rs9KBmUW9vlh-d-VnbcLDCTn8/htmlview

 

[Lou Jost]

Interesting. But what about image quality? Especially in the corners?

[lukaszgryglicki]

Here are some samples - but handheld, a bit late and raining, so not the best possible (resized to 25% x and 25% y and quality 70% JPG) - developed from RAFs using 2 programs - Imagemagics and AccuRaw an dthen 100% crops from center, side and a bit up (I don't have corner one because I was shooting this before I saw that post, I will do a corner shot tomorrow, today is already almost dark and reins). Crops are 100% size from screenshots (PNG, so hopefully unchanged). JPGs straight from the camera are too red - but this is max what in-camera WB can do.

 

BTW: then les is about $270 - almost the same as most UV-pass filters.

 

 

 

[Lou Jost]

Thanks for the quick response. What aperture is used?

 

An important test would be to take an unfiltered full-spectrum image, so that we could see if the IR and vis images are focused in the same plane. Judging from the position of the red dot on the focusing ring, this might be sharp  from f/5.6-8. That would be very nice!

[lukaszgryglicki]

Apertures were mostly around 4. As I said, I saw your comment after I was already back from shopping, I will include more photos when I have some time, including:

every aperture from 2 to 22 on both IR and visible (with Kolari hot mirror) and Full spectrum ones. I can also do UV with Kolari UV-Pass 77mm (it is thicker, there might be a very slight mechanical vignetting - because I would have to use 52->82mm step-up then 82->77 step down and then puyt that filter on).

 

EDIT:

if the IR and vis images are focused in the same plane

They will not focus in the same plane - this is not UV-Nikkor that has no chroma aberrations from deep UV until 900nm. The lens has IR focusing dot and it is in offset, so you will either focus in vis or in IR - but on smaller apertures this is not visible judging from my full spectrum snaps that I already did from my window.

 

At f=2 the lens is dreamy as almost ALL wide nikkors from 70s.

 

[Lou Jost]

That  would be really interesting!

[lukaszgryglicki]

Of course IQ is not as high as native GFX glass, but it is still good IMHO, especially for 50+ years old lens.

 

[lukaszgryglicki]

Ok this will be a bit long and I will split this into separate posts.

 

I'm now posting full images resized to 25% of size and saved with 65% JPG quality, they are sorted by the apertur first - 8 images in group (f: 2, 2.8, 4, 5.6, 8, 11, 16, 22), and then first BB (broad band - no filter, on 50R converted to BB but with CFA intact), then IR (same camera, white balance done on full image area), then UV (using another Fuji 50R converted to full specturum but with CFA/bayer RGGB matrix also removed - monochrome), finally VI (again with the 1st camera, white balance set to full image).

 

 

[lukaszgryglicki]

Now edge crop from the same - same order of images (right edge):

 

[lukaszgryglicki]

Corners - note that they are corners of 44mmx33mm sensor (for a 50+ years old lens designed for 36mmx24mm sensor) using non-visible EM radiation (lens is just for visible, while here you have IR, UV, BB).

[lukaszgryglicki]

And I forgot - center crops! - almost center - I've moved a bit to cars so there are more details.

 

[Lou Jost]

A very nice test, very informative, thank you! It's very good stopped down, even in the corners, compared to most wide older FF lenses.

 

One thing that surprised me though is the relatively low amount of IR light in the pictures in the first group (full spectrum). There is a little bit of pink in the spherical tree in the center of the picture, but everything else looks green. When I do full spectrum shots of vegetation with a converted A7R using older lenses (which usually have better IR transmission than modern lenses), the vegetation is generally brighter and more pinkish. Do you have a sense of how good its IR transmission is, relative to other old lenses?

 

My old medium format lenses are particularly good for transmitting IR. You may want to consider the Mamiya medium format lenses as additional options for your camera. Generally very cheap.

 

 

[lukaszgryglicki]

Overall I would say:

For the center:

- IR: good from 4 to 11, best: 5.6 - 8.

- Vis: good from 2.8 to 16, best: 4-11.

- UV: good from 4 to 22, best: 5.6 - 16.

- BB: good from 8 to 16, best: 11.

For the edge:

- IR: ~good from 5.6 to 11, best: 8 - 11.

- Vis: ~good from 5.6 to 22, best: 11 - 16.

- UV: ~good from 11 to 22, best: 16.

- BB: ~good from 5.6 to 16, best: 11.

For the corners:

- IR: good? from 11 to 22, best: 11 - 16.

- Vis: good? from 11 to 22, best: 16.

- UV: good? from 16 to 22, best: 22.

- BB: good? from 11 to 22, best: 16.

 

So to sum up in my opinion:

- For BB - best use f=11 to 16, ideally 11.

- For IR - best use f=8 to 16, ideally mid-click between 9-10.

- For UV - best use f=16 to 22, ideally 16.

- For Vis - best use f=11 to 16, ideally mid-click between 13-14.

 

Overall best aperture seems to be around between 9-10 and 16 (including both), best overall seems to be f=11.

 

[lukaszgryglicki]

Quote

 

One thing that surprised me though is the relatively low amount of IR light in the pictures in the first group (full spectrum). There is a little bit of pink in the spherical tree in the center of the picture, but everything else looks green
 

 

 

I did white balance in-camera, not pointing t into anything white or gray, but into that exact scene. Also adjusted WB (manual dialog with adjusting colors using rectangle - I've removed a lot of red because it was so dominating - note those are JPG SooC - not converted RAWs).

 

 

You may want to consider the Mamiya medium format lenses as additional options for your camera. Generally very cheap.

 

I was considering them, but as a MF lenses they tend to have a long focal length and are slow, while I was looking for the widest IR capable lens for GF, native GF lenses are rather bad in IR - too modern.

 

[lukaszgryglicki]

So regarding the white balance, here are a few shots with white balance set to "auto" in Fuji 50R:

You can see *a lot of* pink (SooC) :)

 

[lukaszgryglicki]

They were in IR, I just figured out you want BB, here you go - auto white balance SooC:

 

[Lou Jost]

Thanks, yes, that looks more familiar.

 

MF lenses are not great for your objectives. They still might be worth considering for longer focal lengths though. The Mamiya 6x7 lenses seem to be especially good in IR for some reason.

[lukaszgryglicki]

I have a bunch of Pentax 67 lenses, they are OK, but obviously longer.

The shortest is 45/4, while I at the same time I have IRIX 45/1.4 for GFX (but has some hot spots) also 20-35/4 GF is a bit usable, but must be wide open at f=4 or max f=5.6.

The best from GF so far is 45/2.8.

 

[Lou Jost]

The Pentax 67 300mm M* is very good in IR.

[lukaszgryglicki]

Yeah, but long, I have UV-Nikkor for 100 mm - it is also very good in IR, I don't need anything else for tele end.

 

[photoni]

off topic
my Nikkor-N 24 mm f2.8

serial number 297729 LINK

with Hoya R72 has no hot spot at f16 (the best aperture)

 

[lukaszgryglicki]

Yes, but according to https://docs.google.com/spreadsheets/u/0/d/1uxvvpxJ9QVFFyh0pW2rs9KBmUW9vlh-d-VnbcLDCTn8/htmlview it will vignette heavy (red) on GFX (mechanical vignette).

I even have the AI version 24/2.8 and it vignettes just like all wide angle Nikkors I have (excluding this 28/2 from this thread), they are 20/3.5, 24/2.8, 35/1.4, 16/2.8 fisheye... even 55/1.2

 

[photoni]

@lukaszgryglicki If you buy the new GFX100 II, and sell me yours 100s at a good price I could try it :)

(and I will sell the Z7 and Z5)

.
In this photo the 24 mm N series, with the diaphragm completely closed, f16

does not have a drop in light at the edges, so I think it covers 33x44 larger format.

.

.

[lukaszgryglicki]

@photoni, unfortunatelly, as I said, Nikkor-N "Nippon Kogaku Japan" 24/2.8 has mechanical vignetting on the GFX sensor, see:

 

[photoni]

Thanks @lukaszgryglicki for the test, in your photos I don't see the serial number, but your 24 mm -M looks the same as mine.

.

If one day I have the GFX I will use it with the 45 and 85 PC-E

and the Micro 60 f2,8 G (in micro/macro mode will cover the whole format).

The thing I don't like about the Leica format is the 2X3.

The 3X4 format seems to me to be the best compromise today

between the square format of Instagram and a Uni A4 advertising page format