Nikon PK-13

Hi Forum,

I'm considering buying a Nikon PK-13 for use with an FE and an F2. I wonder if you could please clear a few things up for me:

1) I understand that the camera won't focus at all when used with lenses 28mm or shorter (I have a 28mm 2.8 Ai and Nikkor-P Auto 24mm 2.8). Is that correct?

2) Can I mount a non-converted pre-Ai Nikkor-S 50mm f1.4 on the PK-13?

3) Can i stop down to use in-camera metering with my two film cameras?

4) I read in one thread someone complaining that a 105mm lens wouldn't focus at all, does that sound right, or specifically, can I use a Nikkor-P Auto 105mm f2.5 (Ai converted) with the PK-13? I'm aiming to photograph near-field things and not at infinity.

5) I also know the PK-13 is really made to be used with micro/macro lenses and eventually I plan to get a 55mm micro, but can I expect "useful perspectives/enlargements" until then with my 50 and 105mm lenses?

All the best!

B&H site LINK for some of your questions.

It's really just a non -CPU extension tube and there are cheaper alternatives on eBay (search NIkon extension tube) and elsewhere, and there is little reason to buy one new as opposed to "pre-owned" for a lot less money, anyhow.

Have a look here, long the encyclopedic go-to for older Nikon gear:

Extension Tubes - Nikon F2 Macro-photography

Also look out for an M2 tube--27.5mm NAI tube made for the Micro Nikkor 55/3.5.

Focus with tubes usually requires both the focus ring and moving the camera on a tripod.

A reversing ring is another, inexpensive option, especially with wide angles.

Nikon tubes do contain a linkage that stops the lens down to the "taking" aperture when the DOF button is pressed.

As JDM says, it's just an extension tube. It provides auto-aperture operation and Ai coupling. The earlier M2 ring provides auto-aperture, but no Ai coupler.

"Can I mount a non-converted pre-Ai Nikkor-S 50mm f1.4 on the PK-13?"

- Doubtful. It may damage the Ai tab on the PK-13, which is non-retractable.

I think reports of 'non-focusing' with a 105mm lens are pure nonsense. The lens should focus from about half a metre to around 370mm.

There may be an issue with 28mm and shorter lenses focussing so closely that the subject is almost touching the front element, but not focussing at all? - unlikely. In theory you can get 1:1 magnification with a 28mm lens and a PK-13, but it would almost definitely work better with a BR-2 reversing ring or clone thereof (fixed focus only though).

PS. The new price of a PK-13 is ridiculous. You can get an entire set of 3rd party extension tubes for the same, or less money.

Thanks a lot JDM, c_watson and rodeo_joe for the links and information. As well as the PK-13, which is available used where I live at a reasonable price (around US$40 for one in mint condition and without the 100% import duties!), I've also found the BR-2 at a cheaper price still. I may decide to buy the BR-2 first and experiment as it seems like it'll offer the most flexibility at the lowest cost (although I'm a little bit apprehensive at exposing the rear element of the lenses when positioning the camera so close to the subjects). The 105mm focusing between half a metre to around 370mm with PK-13 also sounds interesting.

One more question I have (and sorry if this is explained somewhere and I missed it): with all these magnification ratios given in various tables, to what distance between lens and camera do they apply? Or do the ratios apply to an object in focus when adjusted to infinity on the lens?

You need to realise that using a BR-2, or other reversing ring, takes away the ability to change the focus of the lens. In other words it gives one fixed magnification - which may not even be a useful one.

A BR-2 is really only useful if combined with a bellows or extension tube(s), and then only if you intend to exceed 1:1 magnification.

"I think I found the answer, the ratios are for the closest focal point, correct?"

- Errm, not really. The ratio gives the magnification of the subject on film or on the sensor. For example: 1:2 (or half life size) means that a subject 2cm across will appear as 1cm in the camera. 1:1 (life size) means the subject is the same size in the camera as in real-life. 2:1 means the subjects appears twice as big in the camera as it really is.

Magnification ratios can apply at any focus distance, or with any focal length of lens. It's the magnification at the plane of focus only.

Another example: a subject in-focus at 5.1 metres with a 50mm lens will have an approximate magnification ratio of 1:100.

Of course, when the image is printed or viewed, it will usually appear much larger than in the camera. If you make a life size image of a postage stamp, you can print it out at a metre wide if you want.

Thanks a lot JDM, c_watson and rodeo_joe for the links and information. As well as the PK-13, which is available used where I live at a reasonable price (around US$40 for one in mint condition and without the 100% import duties!), I've also found the BR-2 at a cheaper price still. I may decide to buy the BR-2 first and experiment as it seems like it'll offer the most flexibility at the lowest cost (although I'm a little bit apprehensive at exposing the rear element of the lenses when positioning the camera so close to the subjects). The 105mm focusing between half a metre to around 370mm with PK-13 also sounds interesting.

 

One more question I have (and sorry if this is explained somewhere and I missed it): with all these magnification ratios given in various tables, to what distance between lens and camera do they apply? Or do the ratios apply to an object in focus when adjusted to infinity on the lens?

If you're nervous about that rear element on reversed lenses, look into the BR3. Screws into the lens mount and offers a short extension that's threaded for a filter almost like a short lens hood. Face it, no company could pick its customers' pockets faster that Nikon when it came to accessories back in film days!

You need to realise that using a BR-2, or other reversing ring, takes away the ability to change the focus of the lens. In other words it gives one fixed magnification - which may not even be a useful one.A BR-2 is really only useful if combined with a bellows or extension tube(s), and then only if you intend to exceed 1:1 magnification

I see, that makes a big difference. Thanks for the warning.

"I think I found the answer, the ratios are for the closest focal point, correct?"

- Errm, not really.

If you'll bear with me, please: I was under the impression the ratio expressed the relationship of the actual size of the object with its size as recorded on the negative. So a toy soldier 2cm high at a distance, lets say, of the minimum focal length and with a ratio of 1:2, would be recorded as a 1cm image on the negative. When the soldier is moved further away, the ratio would necessarily change. What you're saying makes me think the ratio is related to the change in size with respect to the size that would be viewed by a standard lens. Are either of these interpretations correct?

If you'll bear with me, please: I was under the impression the ratio expressed the relationship of the actual size of the object with its size as recorded on the negative. So a toy soldier 2cm high at a distance, lets say, of the minimum focal length and with a ratio of 1:2, would be recorded as a 1cm image on the negative. When the soldier is moved further away, the ratio would necessarily change.

You are correct, and that's what rodeo_joe said except for the last part. What he missed was the exact content of your question: at what focal distance does the advertised magnification ratio of a lens (or a given lens-extension tube pairing) hold true? And the answer is as you thought: the closest focus distance of the lens.

However, there is a kind of lens that gives the same magnification no matter what the distance to the object is. Such a lens is called object-space telecentric.

Back again. The PK13 was sold and they hadn't removed the advertisement. There's another reasonable deal on a Nikon E2 and on a Nikon M2 (together). I understand how the E2 works, but I 'm a bit unsure on the M2. Can I do stop-down metering with this? If I find another PK13 at a good price, can I use it with the F2 and stop-down metering?

All the best

In the end, I got lucky and picked up a set of tubes with a PK-11A, PK-12 and a PK13. To my surprise, these do not mount on the F2, so I'll be using the FE exclusively for macro. The PK-11A is extremely useful with the 24 and 28mm f/2.8 lenses that I have. All three are very practical to use in various combinations with the 105mm f/2.5. If anyone stumbles on to this thread in the future, the Nikon Auto PK Extension tubes user manual may be found here:

https://www.nikonimgsupport.com/eu/BV_article?articleNo=000005521&configured=1&lang=en_GB

All the best

I don't know how easy they are to find, but Vivitar made an automatic AI compatible set of extension tubes labeled AT3-AI, that are automatic and meter on an AI camera, and an older set called simply AT-3, which are not AI compatible but do have the meter prong and also are automatic. The earlier AT-3 will safely clear the AI lever, but the rear skirt does not move, so there is no convenient way to adapt it to AI metering. The non AI will have to stop down meter on an AI camera, and the AI one on a non-AI camera. Both come as a trio, 12, 20 and 36 mm. I've found they work nicely.

However you can't mount most true AI lenses to the short tube of the pre-AI set, and although you can mount most pre-AI lenses to the AI set, it's a pretty tight fit to clear the follower, which flexes a little to go underneath the rear lens extension. It will vary a bit with different lenses. Pre-AI lenses converted by milling will work equally well on either.

+

I have a set of Kooka brand tubes. They have CPU pass-through contacts, an AI follower and a screwdriver AF shaft. Why Nikon can't fit all that is beyond me.

Build quality of the Kooka tubes isn't brilliant, but they didn't cost a lot and get the job done.

"To my surprise, these do not mount on the F2,...."

- That surprises me too. What flavour of F2 is it? The F2A should take almost anything.

Even if it's an old 'rabbit ears' meter coupling, there should be no issue with AI tab collision.

rodeo_joe, thanks for picking up on that. It's the Photomic DP-1 head and yes, you're right, it does mount. I tested again and it didn't seem to want to turn, but then I realised i needed to push down firmly first. None of the lenses I use need to be pushed down like that, perhaps they're more worn. So I was being too cautious. And stop-down metering does indeed work and is very clear in the DP-1 finder.

All the best!

Oh no, another correction. While pressing the depth of field lever on the F2 does stop-down the aperture of the lens (when using the K extensions), the metering doesn't seem to work, ie. the needle doesn't move as I adjust the aperture and the lever is pressed. Why would that be?

- Only thing I can think of is that the metering has 'bottomed out'. I.e. reached the lower limit of its metering ability. Or maybe the rabbit ear coupler is in the parked position? IIRC the coupler has to be set by doing the 'Nikon shuffle' when a lens is fitted. However it's been many years since I used a DP-1 and I might well be mistaken.

I was never impressed by the quality of most of the single-coated pre-Ai lenses I had, and sold them to upgrade to Ai-s lenses and a DP-11 finder.