Extending magnification range of PN105?

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Lou Jost
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Extending magnification range of PN105?

Post by Lou Jost »

I've been very impressed with my new Printing Nikkor 105mm, which a forum member kindly sold me. It is so good I am wondering how I might adapt it for use at magnifications farther outside its designed range.

I can easily move the m up or down a bit by using a 1.4x teleconverter or a Speedbooster. But to get higher m, I wonder if I could put Raynox close-up lenses on it, or maybe a reversed lens.

I've done some rough experiments with a reversed Oly 50mm f/2 macro lens on the PN and it seems to work, with excellent resolution and no CA but a huge amount of flare/ghosting around bright areas. Are there any theoretical or empirical guidelines about how much space there should be between the front element of the PN and the rear element of the reversed lens or close-up lens?

I realize that coupled lenses should normally both be focused at infinity, but ...maybe it could work?

austrokiwi1
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Post by austrokiwi1 »

I tried to extend the magnification range and failed miserably. The problem is the lens is optimised for 1-1 it functions well from 0.6X through to 1.5X, beyond that its performance deteriorates considerably.
Still learning,
Cameras' Sony A7rII, OLympus OMD-EM10II
Macro lenses: Printing nikkor 105mm, Sony FE 90mm F2.8 Macro G, Schneider Kreuznach Makro Iris 50mm , 2.8, Schnieder Kreuznach APO Componon HM 40mm F2.8 , Mamiya 645 120mm F4 Macro ( used with mirex tilt shift adapter), Olympus 135mm 4.5 bellows lens, Oly 80mm bellows lens, Olympus 60mm F2.8

Lou Jost
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Post by Lou Jost »

It would be good to know what doesn't work. Can you give details of the methods you used to extend its magnification range?

Its performance when used alone deteriorates outside the range you mentioned, but good teleconverters and speedboosters might still work well. I am not sure about close-up lenses but there may be ways to make them work too. Did you try large-diameter reversed or close-up lenses at various distances between the PN and close-up lens?

austrokiwi1
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Post by austrokiwi1 »

LOL Lou... You are going to get one of my biases: in my "book" there is no such thing as a good teleconvertor or speed booster.. so obviously I didn't try those options. From memory I only tried two methods: reversing an SK 40/2.8 and using the PN as a tube lens. I got full FF coverage but massive loss of sharpness. I then tried coupling the lens to a 210 enlarger lens( set to infinity by extension) I didn't expect much from that method and achieved even less than my expectations. Years ago I tried extension just to see the reported drop off in performance and all I did was confirm that beyong 1.5X the lens performed poorly.

EDIT: The PN105mm is a phenomenal optic and I can not imagine any add on optic that would not introduce image aberrations
Still learning,
Cameras' Sony A7rII, OLympus OMD-EM10II
Macro lenses: Printing nikkor 105mm, Sony FE 90mm F2.8 Macro G, Schneider Kreuznach Makro Iris 50mm , 2.8, Schnieder Kreuznach APO Componon HM 40mm F2.8 , Mamiya 645 120mm F4 Macro ( used with mirex tilt shift adapter), Olympus 135mm 4.5 bellows lens, Oly 80mm bellows lens, Olympus 60mm F2.8

Lou Jost
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Post by Lou Jost »

A teleconverter surely does always degrade the image, but I think a good teleconverter on a good lens can produce good images, if the lens by itself has high resolution.

Back in the film days, I often used a TC 300 teleconverter on very good Nikon ED super-telephoto lenses, and it gave excellent results. That was a special converter designed specifically for long lenses. The TC 200 teleconverters, designed specifically for shorter lenses, was also good on the lenses for which it was designed. So my experience is that a properly-designed teleconverter, on the best lenses, can be very good. On the other hand a mediocre teleconverter, or a good teleconverter on a mediocre lens, can deliver a very poor result.

The latest top-of-the-line weak teleconverters like that TC 14E III contain aspheric elements and more glass than a lot of lenses. Tests show that they hardly reduce the MTF of a top-notch lens.

Microscopy will pose harsher challenges to teleconverters, because they always reduce the NA or EA of the prime lens, and our sensors often outresolve our objectives, so reductions in NA have noticeable effects. Maybe that's what your bad experience reflects.

I just bought the TC 14E III (in fact it just now arrived as I am writing this) and will post tests with the PN when I have the chance.

But a Speedbooster or a front attachment won't reduce the NA or EA, so I think they could be good if they are properly designed. And if there is some aberrations in the PN images due to the thickness of the filter stack on my MFT sensor, the Speedbooster could improve the image, even beyond what would be expected from the size reduction it produces.

ray_parkhurst
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Post by ray_parkhurst »

The question will be if simply stopping the lens down is less or more effective than adding the teleconverter. A 1.4x TC has effect like one stop. The PN105 has optimum sharpness at f3.3, so this would take it to f4. Is the lens itself better at f4 with no TC? Worth a test. Not sure about the other end with speedbooster.

nathanm
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Post by nathanm »

I have used add on close up lenses for times when I am shooting in the field and discover that I need a bit more magnification.

The very high quality ones - like the Leica Elpro, or Century Optics can work.

However, this is typically with a macro lens like Canon 100 macro, or SK 120mm macro for PhaseOne.

The best I have found for the SK 120 is the Leica Elpro 1:2 - 1:1 which is a 3 element close up lens intended for the 100mm f/2.8 Apo Macro Elmarit-R

But it works fine with the SK lens.

I suppose you could try one of these close up lenses. The Leica and Century Optics lenses worked better for me in this mode than Raynox, even though the Raynox worked better for as a tube lens then they did.

The PN105 is such an awesome lens that I wonder if this will really do it justice, but one thing I have learned is that it is worth trying things, even if they seem unlikely. Sometimes they work!
nathanm

Lou Jost
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Post by Lou Jost »

Ray, I expect that at m=1.4 the naked PN with extension will be better than the PN (set to m=1) + TC.

For me, the interesting question is whether we can get a bit beyond the PM's limit of m=1.4 or 1.5 by first extending the PN to somewhere around m=1.2 or 1.3, where it is still very good, and adding the TC to that, to reach 1.7 or 1.8.

Nathan, like you I enjoy trying odd things. Thanks for the tip on those close-up lenses. I did not know about them. I'll have to wait for a year or so to buy any more stuff, but some day I will try them. I would think that reversed lenses may also work in this capacity. I have some good ones for this.

ray_parkhurst
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Post by ray_parkhurst »

Lou Jost wrote:Ray, I expect that at m=1.4 the naked PN with extension will be better than the PN (set to m=1) + TC.

For me, the interesting question is whether we can get a bit beyond the PM's limit of m=1.4 or 1.5 by first extending the PN to somewhere around m=1.2 or 1.3, where it is still very good, and adding the TC to that, to reach 1.7 or 1.8.
At f2.8, the 105PN has about 40% degradation in corner sharpness vs center at M=1.4 If you use a "perfect" 1.4x TC, shooting with the 105PN at 1:1, you would see (I think) a 30% reduction in sharpness across whole field. So the question is whether a better sharpness in center with significant corner reduction, or an overall reduction across the field, is better. Of course if the actual (imperfect) TC degrades the image in the corners, then the comparison would be moot.

I would expect if the 105PN was set to M=1.4, and then a 1.4x TC was used, the TC would magnify the center portion of the field, so the bad corners would be reduced. This might work very well if the TC is very good.

Lou Jost
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Post by Lou Jost »

Ray, I am not thinking about using the TC with the lens set for m=1 (where it would give m=1.4) nor with the lens set at the extreme of m=1.4, where the PN starts to degrade. Rather, I want to use the TC in the range of m where the PN is still very good. This could get us to m=1.8, where the PN by itself is not good in the corners.

Another factor to consider is the degree to which the image of the PN out-resolves the sensor. Even if the TC reduces the resolution of the aerial image by 30%, this could have a much smaller effect on the recorded image, if the aerial image is really sharp.

austrokiwi1
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Post by austrokiwi1 »

Another factor to consider is the degree to which the image of the PN out-resolves the sensor.
Rik would give a much more reliable estimate, than my guesstimate which is: your Oly Pen F sensor would max out at Group 6 element 5 (on a 1951 USAF resolution target). That equates to 101 Cycles per mm. I only have the standard resolution target wit the max test frequency of Group 7 element 6(228 Cycles per mm). My A type PN105mm happily resolves out to group 7 element 6 and I recall( perhaps wrongly) that Rik has shown it gets into group 9.

That may bode well for you. However I know from comparing the A7rII to the OMD -EM10II(16MP) that noise and reduced dynamic range will be much more serious limiting factors that the lenses resolution. Edit: I actually find on my MFT camera the SK APO 40/2.8 HM ( Which is designed for small sensors) matches the PN Nikkor and is much more versatile. On the full frame camera nothing beats the PN105mm ( within its optimal range)

Now a check: I thought the A type performed best at F 2.8 not F 3.3
Still learning,
Cameras' Sony A7rII, OLympus OMD-EM10II
Macro lenses: Printing nikkor 105mm, Sony FE 90mm F2.8 Macro G, Schneider Kreuznach Makro Iris 50mm , 2.8, Schnieder Kreuznach APO Componon HM 40mm F2.8 , Mamiya 645 120mm F4 Macro ( used with mirex tilt shift adapter), Olympus 135mm 4.5 bellows lens, Oly 80mm bellows lens, Olympus 60mm F2.8

Lou Jost
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Post by Lou Jost »

Thanks for that comparison with the SK 40mm. My PEN F has a sensor with a higher pixel pitch, and I often use high-res mode with 50Mp, which reduces noise as well. I wonder if the SK would still match the PN at that higher "pixel" pitch. But I am sure it would be more versatile. Maybe next year I will try it out when my bank account recovers from my recent purchases.

Your earlier posts got me thinking about that Sony camera, but I got discouraged when I found out that in electronic-shutter mode, it reverts to a bit depth of 12 bits/pixel, same as the PEN-F, and in this mode, flash can't be used.

austrokiwi1
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Post by austrokiwi1 »

I had a play today with my one and only 2X teleconvertor. I don't normally use it for macro work. It usually gets paired with my Minolta MD 135/2. I found that yes I can get 2x magnification with the PN 105, however the trade off is vignetting with the full frame sensor. I anticipate with a MFT sensor or even APSc the vignetting would not be an issue. The SK 40 in comparison when mounted normally with the convertor will give me the 2X magnification with out vignetting. However I would not normally use it this way. I haven't tested IQ . My suspicion is a good 50/2.8 reversed would probably be a match for the PN105 plus convertor. All I can tell you for sure is on full frame a teleconvertor and the PN 105mm is problematic
Still learning,
Cameras' Sony A7rII, OLympus OMD-EM10II
Macro lenses: Printing nikkor 105mm, Sony FE 90mm F2.8 Macro G, Schneider Kreuznach Makro Iris 50mm , 2.8, Schnieder Kreuznach APO Componon HM 40mm F2.8 , Mamiya 645 120mm F4 Macro ( used with mirex tilt shift adapter), Olympus 135mm 4.5 bellows lens, Oly 80mm bellows lens, Olympus 60mm F2.8

Lou Jost
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Post by Lou Jost »

I'm surprised that the TC vignetted. I've never seen one vignette. I hope Rik will drop in to explain that behavior.

You are probably right about the 2x + PN being out-done by other alternatives. My intention is to use a 1.4x TC, though. I strongly suspect that this will be very good on the PN. Will report my results when I get back home in a few weeks.

austrokiwi1
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Post by austrokiwi1 »

Lou Jost wrote:I'm surprised that the TC vignetted. I've never seen one vignette. I hope Rik will drop in to explain that behavior.

You are probably right about the 2x + PN being out-done by other alternatives. My intention is to use a 1.4x TC, though. I strongly suspect that this will be very good on the PN. Will report my results when I get back home in a few weeks.
On the vignetting: the teleconvertor is designed for full frame. This may not be a surprise to you but, for me it was amusing; when directly mounted to the PN 105mm the teleconvertor turned the PN105mm into a 210mm lens, with the 1X mag becoming 0.5 Mag. I had to attach the teleconvertor to the other end of the bellows to get the 2X that's when the vignetting occurred.

I do agree ta 1.4X tC will probably give the best result.
Still learning,
Cameras' Sony A7rII, OLympus OMD-EM10II
Macro lenses: Printing nikkor 105mm, Sony FE 90mm F2.8 Macro G, Schneider Kreuznach Makro Iris 50mm , 2.8, Schnieder Kreuznach APO Componon HM 40mm F2.8 , Mamiya 645 120mm F4 Macro ( used with mirex tilt shift adapter), Olympus 135mm 4.5 bellows lens, Oly 80mm bellows lens, Olympus 60mm F2.8

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