Coverage and resolution of fast wide angle lenses, especially the 65mm Nikkor SW

[Jan-H]

I'm tinkering with the idea of building my own "kind-of-large" format camera (i.e. 6x12) and a lens that has caught my eye is the 65mm f/4 Nikkor SW. As per this spec sheet its image circle at maximum aperture is 110mm, i.e. 20mm shy of actually covering a 56x118mm frame. Stopping down, it obviously covers with plenty of room to spare.

I don't have any first-hand experience with large format lenses, but it is my understanding that:

a) the indicated image circle is often more of a guideline beyond which vignetting and resolution may be considered unacceptable for critical work (the notable exception being Rodenstock lenses)
b) the larger apertures of these lenses are intended to be used for focusing them on the ground glass and not for taking pictures with

Can you confirm the above? If so, how is the resolution and drawing character within the image circle wide open?

For context, the camera I am planning to construct will be a rangefinder with one lens fixed to it. I plan to use it both for handheld portrait and travel photography - where I will often use a wider aperture - as well as locked down on a tripod for landscapes using the optimal aperture for the lens.

I called out the 65mm Nikkor since it fits my ideas the best, but I am also wondering how Schneider's and Rodenstock's lenses are doing wide open. Specifically, I am considering the 58mm Super Angulon XL, the 55mm Apo Grandagon and 65mm Grandagon N. I have found samples online for most of these, but all of them are using the lenses "properly", i.e. stopped down.

Thanks a lot in advance for chiming in with your opinions and experience!

 

[Duff photographer]

Howdo Jan-H,

Oooh, another Franken-camera. Good stuff.

In answer to your query...

a. Correct. It also varies between manufacturers. For example, Schneider are a little more conservative than say Rodenstock. Can't comment on Nikon.
b. Yes and no. Most 'modern' LF lenses at f4 will be 'soft'. This may or may not be an attribute of the lens, and will depend on your style of photography. Suffice to say that it is not ugly.

I did possess a Nikkor SW 65mm, but can't remember if I used it at f4. I have used it at f6.3 (I think) and the image was fine with regard to resolution (however, see below regarding image circle). The drawing character is, as always, in the eye of the beholder. I would say bokeh, compared with a Schneider or Rodenstock, has a hint of 'skittishness' or 'harshness', but that is only in comparison (and it's a subjective observation on my part). Suffice to say, it's not ugly.

One problem you will get is issues with the very narrow image circle at f4 (110mm for the Nikkor 65mm). The image circle needed, just to cover 6x12, will be 126mm, so you will get softer edges and vignetting wide open, which might work to your advantage depending on the type of image you are looking for.

All the lenses you mention as alternatives will be good (I have the Schneider 58mm). At f5.6, including the Nikkor SW 65mm, these will be 'sharp' enough with good bokeh, nothing special about the latter on any of them though, and they will cover 6x12 at that aperture. However, at such apertures, you will need a centre filter if you want even light coverage (as and aside, Nikon never made centre filters for their lenses, and it's argued that the wide angles needed them).

If you don't mind the increase in focal length, one lens that you may wish to consider, which is in the realm of the 65mm in price, weight and size (albeit slightly more in all cases), is the Nikkor SW 75mm f4.5. I never used it, but many consider it to be better than the 65mm and will give you much more room for manoeuvre. It's apparently sharp at f4.5, and will cover 6x12 (with no movements) at that aperture.

The cop-out comment here is to try the lens for yourself (if you can) and sacrifice a roll of 120 film. The good thing about second-hand LF lenses is that the price is unlikely to get lower, so you can buy, try, and if not satisfied with the results, resell it with little financial loss, and if you're shrewd, you may make a profit.

Hope some of this waffle helped.

Cheers,
Duff.

 

[Jan-H]

Thanks a lot for your insights, Duff, they were indeed helpful.

I'm reassured by your observations about the behaviour of the 65 SW on the edges - a bit of softness and vignetting wide open is fine for me as long as it doesn't go completely black or smeared. I'll try to get my hands on one.

I was originally planning to stay on the wider side of things, but you might have instilled some temptation to venture into the 70-something territory and with that the idea of making a 6x17 companion for the 6x12 . That 72 SA sure looks attractive (let's not talk about the price)... Daydreams aside, I think I'm also going to sketch out a few concepts for a longer-lensed camera to see if I can't come up with something pleasing. Thanks for tickling that nerve .

 

[Duff photographer]

Good luck Jan.

We'll await the photo's in due course

...and yes, the 72mm SA is a very good lens, and the second-hand price (arguably over-priced despite its quality) reflects that!

All the best,
Duff

 

[gasmag]

Thanks a lot for your insights, Duff, they were indeed helpful.

I'm reassured by your observations about the behaviour of the 65 SW on the edges - a bit of softness and vignetting wide open is fine for me as long as it doesn't go completely black or smeared. I'll try to get my hands on one.

I was originally planning to stay on the wider side of things, but you might have instilled some temptation to venture into the 70-something territory and with that the idea of making a 6x17 companion for the 6x12 . That 72 SA sure looks attractive (let's not talk about the price)... Daydreams aside, I think I'm also going to sketch out a few concepts for a longer-lensed camera to see if I can't come up with something pleasing. Thanks for tickling that nerve .

The 65mm works wonderful in 4x5, at f 16 the circle goes to 170 and then a bit more as you close more.
There are cameras made by 3D printers (I have one) that cost below $200 and work perfectly, I advise you to go that way unless you love tinkering and making things yourself.
I use that camra with the 65 permanently attached all the time and am very happy with it. It weighs nothing!
Good luck and happy shooting.
Gaston

 

[Jan-H]

I'll certainly come back with photos once I've laid down enough filament and milled off enough chips to make any .

---

Hehe, I am definitely the tinkering kind . Those 3D printed ones are certainly part of the inspiration for this project, but I also want to try and up the game a little bit by bringing together ideas from different 3D printed camera projects (semi-panoramic format + rangefinder + some rise/fall if I can manage it). I also want to learn new things, so it is definitely worth it to me to probably pay a premium and also have to do all the work.

 

[Shashin]

I had a 6x12 camera with a Rodenstock APO-Grandagon 55mm. With view camera lenses, they are designed to be shot at f/11 or smaller. The maximum aperture is not a shooting aperture, but for focusing. The Grandagon has pretty bad vignetting wide open. Even at f/11, a center filter is needed to minimize natural vignetting. Now, you can shot at f/11 without a center filter and the vignetting is pleasing. Wide open you lose exposure and resolution toward the edges. That being said, I did shot this camera wide open and simply learnt to live with the results. With color film, you will also see yellow to blue color shifts.

I imagine the Nikkor is going to be very much the same, but the slightly longer focal length will help. A 75mm lens will also be better. As the angle of incidence decreases, the amount of natural vignetting will also decrease (Cosine 4th law). But there again, things will be worse wide open than stopped down.

 

[anyone]

I had a 6x12 camera with a Rodenstock APO-Grandagon 55mm.

If that camera happened to be the SW612 I'm seriously envious. It's on my list since years.

 

[Shashin]

If that camera happened to be the SW612 I'm seriously envious. It's on my list since years.

It was. A great camera.

 

[Jan-H]

Thanks a lot for sharing your experience! In the end I went with a 75mm Grandagon N but resolved to make the format a little wider - ~56x150mm. I figure I should be able to squeeze five frames onto a roll like that and for the first prototypes I can go off the 645 frame numbers on the backing paper for winding.

Haven't got a body to mount that lens onto yet, but I'll see if I can't 3D-print a quick-and-dirty (and hopefully light-tight) box-with-rollers in the next few weeks to see how I like that angle.

BTW, that image is one of the pieces of inspiration that kicked off my desire for a wide format travel camera .

 

[stevev]

Hi Jan,

I have the Nikkor 65mm SW F/4 (and the Rodenstock 55mm F/4.5 APO-Sironar digital). Last night I was shooting with the Nikkor 65mm, but at my normal shooting aperture of F/11.



I am happy to reshoot the scene in the next few days using the lens wide open, if you would find the results interesting. Bear in mind that I am using a Cambo Actus with a Nikon Z7 as my "digital back", so I understand that you may not be interested in this particular use case for the 65/4. For interest, the final (cropped) scene is 18,000 by 6,000 pixels i.e. 108 MP. I shifted 20mm left and right and 5 mm up and 5mm down to give me sufficient coverage to make my 3:1 crop.

I can report that at F/11 the lens is wonderful to use, in addition of course to being small and lightweight. Below are 100% crops from near centre and from the edge of the scene. I believe that with a higher resolution sensor on the back of the Cambo the lens would be capable of resolving a little more detail, at least in the central area.

Let me know if you want me to reshoot at F/4.

*** Edit: just saw that you bought the 75 Grandagon. And you said that you are interested in the 110mm image circle coverage wide open whereas I can only demonstrate 76mm of that with my setup (36+20+20)…..Oh well. Still happy to reshoot at F/4 if you, or anyone else, is interested

Cheers,
Steve.



Above is a crop from near centre and below a crop from the left edge.

 

[Jan-H]

Hi Steve! Thanks a lot for sharing your experience with the lens and with such a beautiful image on top! Even though I didn't go for this one in the end, I'd still be interested in what it can do wide open to help build a general feel for that issue. Please don't rush out to shoot a test for me of course - whenever the fancy strikes you is good for me.

In case some of you lovely folks are wondering, the camera design is moving ahead, at least in CAD: I am currently trying to figure out how to fit both the focusing dial and the film winding mechanism in the same space (Plaubel Makina-style).

 

[stevev]

Hi Jan.

Here are some test shots with my Nikkor SW 65mm F4 shifted 20mm, using a 36mm x 24mm sensor, on a Cambo Actus G. One was shot at F4 and one was at F11. Each was focused on the extreme shifted edge. All settings in Lightroom were the same except white balance.

When I focus only once in the centre of an unshifted frame, and then shift without refocusing, the edges are, as you might expect, less sharp in each case than what you see here.

So this is approaching 38mm (about 1.5 inches) off axis on the left hand side of the image circle. The F4 images were quite hazy as you can see.

Hope this helps.

Cheers,
Steve.

 

[Jan-H]

Hi Steve, thanks for the update! This is really not the difference I was expecting to see. But then again I'm "learning large format gear" all from scratch, so I'll call this the beginning of a new frame of reference '.

In other news, I created a Twitter account to serve as a kind of "journal" for the DIY camera project (which as already devolved into two projects) and others that might follow: https://twitter.com/BzEngineering

 

[stevev]

You’re welcome!