More magnification with Micro Nikkor 105mm VR - Raynox?

rjlittlefield · Post by **rjlittlefield** » Thu Oct 04, 2012 10:36 am

WebbCMH wrote:
rjlittlefield wrote:
WebbCMH wrote:1) Assuming the camera and lens were to remain still and using helicon remote to step the focus what kind of focus range would a 105mm micro nikkor VR with the 4x Nikon Objective achieve.
With my Canon 100mm f/2.8L IS USM lens, focus range is about 3 mm with the lens from infinity to 1 meter, and another 3 mm from 1 meter to 0.5 meter. You can probably push that farther and still retain good image quality.
So can I infer from the above that if focus stacking I would have around 6-8mm of attainable depth of field in focus?

Yes, BUT that's only with the 4X objective that you asked about.

When you scale up to the 10X objective, the depth of field achievable by internal focusing gets a lot smaller.

I tested just now with my Nikon MRL00102 objective on the Canon 100. Focus range from infinity focus to 1 meter is only 0.53 mm. I can get another 0.86 meter by refocusing from 1 meter to 0.5 meter, but the corners go astigmatic. At 1:1 focus on the tube lens, the total range from infinity is over 3 mm, but by then even the center is trash.

I recommend not using internal focusing with a 10X objective for subject depth beyond about 0.5 mm.

That's not enough for butterfly wings that have the most interesting colors and textures.

You need to get yourself a StackShot or some other high precision linear focusing device.

--Rik

rjlittlefield · Post by **rjlittlefield** » Thu Oct 04, 2012 11:04 am

Craig Gerard wrote:It requires retouching.....but may serve as a reference as is.
...

WebbCMH, since you're not familiar with this domain let me touch on some of what Craig means by "requires retouching".

One problem with high magnification focus stacking is what's called the "transparent foreground" effect. What happens is that when the lens is focused on background, its wide aperture effectively "looks around" foreground objects. If the background is high contrast, then the stacking process ends up showing background in preference to foreground, with the result that the foreground structure disappears or looks transparent. Outright disappearance is not so bad, but bogus transparency is disturbing.

In the current example, you can see that many of the long hairs sitting in the foreground do not appear continuous as they would if the rendering were done ideally. Compare the stacked result against the single image shown earlier.

Given the current state of stacking software, the only cure for transparent foreground is manual retouching -- using human judgement to decide what should be shown and what should be hidden.

If this issue is important to you, then I'll retract my approval of Helicon Focus for this problem and recommend instead that you make friends with Zerene Stacker. In Helicon, you'll be forced to go clear back to original source images. You'll have many tens or potentially hundreds of those to deal with, so retouching even a single hair can be tedious. In Zerene Stacker, there's a technique using "Stack Selected" that may reduce the retouching effort by an order of magnitude. See the tutorial, "Using Stack Selected to Retouch Transparent Foreground".

There's also a related technique called "slabbing" that can improve the image quality beyond what the basic PMax and DMap methods can give. We can talk about that separately if you're interested.

--Rik

WebbCMH · Post by **WebbCMH** » Thu Oct 04, 2012 1:17 pm

Many thanks Craig & Rik for the time and effort you are both applying to this and the images Craig posted are a great help. Much has been clarified by you both in the past 3 or 4 posts over the last 12 hours or so. The learning curve has been steep but here is where I am at:-

I plunged in earlier today and ordered the MRN 70040 CFI BE Plan Achromat 4x N.A. 0.1, W.D. 25mm from Nikon UK. I need to prove to myself I can achieve good well lit sharp results with a good £41 (includes VAT & postage) 4x objective before splashing out on great £220 (includes VAT and postage) 10x objective. I am at the stage where theory needs to translate to practice.

I comprehend that the 4x Nikon objective will only give me 2.1x magnification using my 105mm Micro Nikkor and I have already established that I probably need 4x or 5x magnification to get the image I am seeking.

The images produced by Craig which I saw 12 hours ago did make me instantly realise that if I was to use the 10x lens (producing 5.25 magnification with the 105mm Macro lens) then any remote camera software to control the lens focus would be a waste of time. Thanks Rik for confirmation of this and I agree that if I am to reach 4x or 5x magnifications then the reality is that quality shots will come with using an accurate rail based system.

So my options are to get great shots at 2.1 magnification and still use remote camera/lens focus control software or replace the lens with a good manual or motorised macro rail and perhaps 200mm of bellows. This I then believe will get me to 4x magnification I seek with the objective I've just ordered and so I probably won't need the 10x lens anyway.

So after all it looks like my 105mm macro could be the stumbling block in the equation. Nikon UK blamed this forum for a three to four week delay in delivery of the 4x objective :) which gives me ample time to investigate bellows, macro rail systems including the budget sapping Stack shot

I will use the D5100 body with 105mm macro with Nikon 4x objective in order to fine tune my set up. Lighting, subject (which butterfly/moth), composition methods (move camera or move subject) all require being looked into with practical experiments along with delving into the virtues of Zerene stacker. Thanks Rik for the great description of the differing methodology between the stacking software. Once good images are achieved with this 1st basic set up then I will look to get more magnification with bellows, perhaps even a 10x objective and if possible a budget sapping Stack Shot.

Interestingly Rik mentions stitching images together to achieve high resolution images and as it happens at the other end of this same art project I am investigating gigpan motorised platforms along with stitching software (again experimenting with trial versions of PTgui and Autopano). If you haven't guessed already the underlying theme of the project is 'Scale' in all it's connotations and uses. (Musical, Weighing Scales, Measuring, Size, Proportion, Mapping , Fish scales, etc....)

Many thanks for all the valuable input and I hope to post some results once the lens has arrived by November.

rjlittlefield · Post by **rjlittlefield** » Thu Oct 04, 2012 1:36 pm

WebbCMH wrote:replace the lens with a good manual or motorised macro rail and perhaps 200mm of bellows
...
So after all it looks like my 105mm macro could be the stumbling block in the equation.

Just to make sure this is clear...

The objective you ordered is designed for use in combination with a tube lens. If you stick it on empty bellows it will still work but it will be soft compared to use with a tube lens.

Either way, using the 4X will be notably less sharp than what you'd get by pushing a 10X down to say 5X. That's just because of aperture. Pushing the 4X NA 0.1 up to 5X will get you roughly f/25 effective, while pushing the 10X NA 0.25 down to 5X will get you f/10. See again the sample images HERE.

Nikon UK blamed this forum for a three to four week delay in delivery of the 4x objective

I suspected that might happen... <giggle>

--Rik

WebbCMH · Post by **WebbCMH** » Thu Oct 04, 2012 2:06 pm

Either way, using the 4X will be notably less sharp than what you'd get by pushing a 10X down to say 5X. That's just because of aperture. Pushing the 4X NA 0.1 up to 5X will get you roughly f/25 effective, while pushing the 10X NA 0.25 down to 5X will get you f/10. See again the sample images HERE.

Thanks for that - saves me looking for bellows and the money can go towards that 10x plus a Stack Shot..... I would like to try & emulate some of the quite wonderful shots I have seen which were taken with the 10x objective they are very inspirational.

Nikon UK blamed this forum for a three to four week delay in delivery of the 4x objective :)
I suspected that might happen... <giggle>

You should ask for a sales commission....

WebbCMH · Post by **WebbCMH** » Wed Oct 10, 2012 4:04 am

Quick update and of course more questions

The adapter rings for the Nikon objective to 62mm (105mm 2.8 Micro) thread have arrived & the 4x Objective is due to arrive within 3 weeks. I will start to organise an studio area for the shot next week. I am hoping to achieve a vibration free zone and I have plans to pass by a Lepidoptera centre here in the UK to look at specimen catching solutions.

Question 1) I understand that with the 4x objective and 105mm micro lens I will achieve 2.1:1 and should be able to achieve accurate focus stacking using Helicon Remote or ControlMy Nikon remote control software and achieve around 6mm or so of focus range. If I do go ahead and order the 10x Nikon objective in the future the 105mm lens combination will have such a small dof that remote software will need to be substituted with a method of physically moving either the camera and lens or the object itself in order to focus stack. As far as I am aware the best solution for this is Stackshot - but are there any other forms of more reasonably priced manual alternatives which can achieve good results?

Question 2) Instead of purchasing the 10x objective to get to 5.25x magnification could quality be better or at least as good (in theory) replacing the 105mm micro with a high quality fixed focal length 180mm f2.8 nikkor (non micro though) whilst retaining the 4x objective?. This would get me to 3.9:1 or so which I am sure will be close enough for my particular shot of the scales on a butterfly/moth wing. (This lens will not autofocus on my D5100 & I assume the Dof will be tiny anyway and question 1 still applies)

Question 3) Any suggestions for a good solid X/Y axis micro adjustable platform in order to manipulate the sample are welcome.

johan · Post by **johan** » Wed Oct 10, 2012 4:19 am

Fwiw, in terms of "specimen catching solutions" in the UK, your best bet would be a Robinson trap from ALS. Don't bother with actinic, get MV. Skinners are ok too although Robinsons tend to do better, I believe Watkins and Doncaster do them as well

rjlittlefield · Post by **rjlittlefield** » Wed Oct 10, 2012 10:09 pm

WebbCMH wrote:1) I understand that with the 4x objective and 105mm micro lens I will achieve 2.1:1 and should be able to achieve accurate focus stacking using Helicon Remote or ControlMy Nikon remote control software and achieve around 6mm or so of focus range. If I do go ahead and order the 10x Nikon objective in the future the 105mm lens combination will have such a small dof that remote software will need to be substituted with a method of physically moving either the camera and lens or the object itself in order to focus stack. As far as I am aware the best solution for this is Stackshot - but are there any other forms of more reasonably priced manual alternatives which can achieve good results?

Sure, a linear stage with micrometer feed will work fine for this application, or you can repurpose the stage of many microscopes, for example by adding an extension to the stage so that you don't have to take the scope apart, or a Proxxon KT-70 milling table. Study the FAQ on focusing for details of these schemes and others.

Question 2) Instead of purchasing the 10x objective to get to 5.25x magnification could quality be better or at least as good (in theory) replacing the 105mm micro with a high quality fixed focal length 180mm f2.8 nikkor (non micro though) whilst retaining the 4x objective?. This would get me to 3.9:1 or so which I am sure will be close enough for my particular shot of the scales on a butterfly/moth wing. (This lens will not autofocus on my D5100 & I assume the Dof will be tiny anyway and question 1 still applies)

Resolution will definitely be better with the 10X. That's because at the same magnification, the 10X has an aperture that's 2.5 times wider (NA 0.25 versus 0.10). With the 4X at rated magnification, you'll be running at effective f/20, which is definitely in diffraction territory with an APS-sized sensor. Push the 10X down to 5X, and it runs at f/10.

Question 3) Any suggestions for a good solid X/Y axis micro adjustable platform in order to manipulate the sample are welcome.

Many microscopes come with an X/Y positioner mounted on the focusing stage. It's not very challenging to build an extension for such a scope that will provide both X/Y and focusing movements for a specimen that is sitting fully exposed either above or beside the microscope body.

--Rik

WebbCMH · Post by **WebbCMH** » Wed Oct 10, 2012 11:43 pm

johan wrote:Fwiw, in terms of "specimen catching solutions" in the UK, your best bet would be a Robinson trap from ALS. Don't bother with actinic, get MV. Skinners are ok too although Robinsons tend to do better, I believe Watkins and Doncaster do them as well

ALS is where I will be going to have a look - I have business I need to attend to in Fakenham later this month and ALS is not far from there. Thanks Johan for the recommendation about the Robinson Trap.

WebbCMH · Post by **WebbCMH** » Wed Oct 10, 2012 11:55 pm

Sure, a linear stage with micrometer feed will work fine for this application, or you can repurpose the stage of many microscopes, for example by adding an extension to the stage so that you don't have to take the scope apart, or a Proxxon KT-70 milling table. Study the FAQ on focusing for details of these schemes and others.

Thanks - I have been scouring the internet for days/weeks it seems and the Proxxon never turned up in any of my searches. Best I got to was the Manfrotto 454 but it never seemed to be a g8 solution. I will read the focusing FAQ too.

Resolution will definitely be better with the 10X. That's because at the same magnification, the 10X has an aperture that's 2.5 times wider (NA 0.25 versus 0.10). With the 4X at rated magnification, you'll be running at effective f/20, which is definitely in diffraction territory with an APS-sized sensor. Push the 10X down to 5X, and it runs at f/10.

Thanks - you had implied this was the case in an earlier part of this thread but I wanted to check whether increasing the size of the tube lens would have gained better resolution with the 4X but I accept that it will not. I can justify the purchase of the 180mm f2.8 Nikkor quite easily as I have a number of other applications for it. Hey ho!

Many microscopes come with an X/Y positioner mounted on the focusing stage.

Thanks again for all the tips and advice and back to more research while I wait for the objective to arrive.

Planapo · Post by **Planapo** » Thu Oct 11, 2012 1:42 am

Thanks - I have been scouring the internet for days/weeks it seems and the Proxxon never turned up in any of my searches. Best I got to was the Manfrotto 454 but it never seemed to be a g8 solution.

There is a seller in England who sells them new via eBay:
http://www.ebay.co.uk/itm/Proxxon-KT-70 ... 45f8859cc4

New ones sell for lower prices on ebay.de though, and "used ones" show up quite regularly over here. One could ask personally and directly via eBay pm, if those sellers are willing to ship to the UK and what that would cost.
http://www.ebay.de/dsc/i.html?LH_TitleD ... &_osacat=0

--Betty

Craig Gerard · Post by **Craig Gerard** » Thu Oct 11, 2012 4:29 am

Thanks - I have been scouring the internet for days/weeks it seems and the Proxxon never turned up in any of my searches. Best I got to was the Manfrotto 454 but it never seemed to be a g8 solution.

I'd agree with this inclination and also apply the same conclusion when considering the Proxxon. To put it succinctly, the Proxxon lacks sufficient precision. I was completely underwhelmed by its performance and I 've played with many such gizmos.

Craig

Planapo · Post by **Planapo** » Sun Oct 14, 2012 3:03 pm

Though a demanding gizmo connoisseur, spoilt for choice and hard to please, may not get overly excited by this small milling table

, from my experience and that of others, the Proxxon KT70 is capable of doing the job with adequate accuracy, at least up to a magnification of around 8x I've tried.

Hmm,... perhaps you dealt with a damaged or misaligned specimen, Craig?

However, come think of it, for those £81.60 one should be able to bag something more posh and sophisticated on the used market, with some luck and patience.

--Betty

Craig Gerard · Post by **Craig Gerard** » Mon Oct 15, 2012 3:09 pm

Hmm,... perhaps you dealt with a damaged or misaligned specimen, Craig?

I would like to think that were the case, Betty; although, the machinist that took the unit of my hands was so impressed with the quality, for the price, he asked if I had any more.

Craig